Hell just froze over.....

[JustAnotherNut]

Sahara Desert hit by its biggest snowfall in living memory | Daily Mail Online

Freak heavy snowfall hits the Sahara desert; up to one metre deep | Galactic Connection

....The Sahara Desert covers most of Northern Africa and it has gone through shifts in temperature and moisture over the past few hundred thousand years.

Although the Sahara is very dry today, it is expected to become green again in about 15000 years.....

....global what??? I keep trying to tell ya it's not man-made 'global warming' but natural temperature cycles.

 

[Old Rocks]

And your scientific degree is in what discipline?

 

[Pogo]

And your scientific degree is in what discipline?

Evidently a BS in Being Oblivious to the Difference Between "Climate" and a "Daily Weather Forecast"...

 

[JustAnotherNut]

and it's obvious neither of you read either of the links provided.

1. It also had snowed there just last December 21, 2016, a mere month ago?

2. This snow reported is nearly 3 feet and the area also had freezing or below freezing temps

3. The last time it snowed there was in 1979, a mere 35 years ago.

4. I even copied, with bold & italics for emphasis......

The Sahara Desert covers most of Northern Africa and it has gone through shifts in temperature and moisture over the past few hundred thousand years.

Although the Sahara is very dry today, it is expected to become green again in about 15000 years.....

maybe you two need to learn to read

 

[Billy_Bob]

And your scientific degree is in what discipline?

Yours is obviously in bull shit... but we knew that...

Natural variation wins again....

 

[Billy_Bob]

And your scientific degree is in what discipline?

Evidently a BS in Being Oblivious to the Difference Between "Climate" and a "Daily Weather Forecast"...

LOL...You and Old Fraud must have gone to the same classes and didn't get past crayon renderings.....
Reading is fundamental to knowledge... and understanding...

 

[JustAnotherNut]

Not to mention....another rain storm for southern California. Maybe Cali will finally be out of the drought....

Strongest storm in 7 years could hit L.A. tonight; flooding, mudslides, 'crippling' snow feared

 

[Billy_Bob]

Not to mention....another rain storm for southern California. Maybe Cali will finally be out of the drought....

Strongest storm in 7 years could hit L.A. tonight; flooding, mudslides, 'crippling' snow feared

The reservoirs that were bone dry, just 6 months ago, are now over flowing in Cali and the spring melt hasn't even started yet.. You think its a mess now just wait until all that 300% of normal snow fall starts melting...

 

[Pogo]

and it's obvious neither of you read either of the links provided.

1. It also had snowed there just last December 21, 2016, a mere month ago?

2. This snow reported is nearly 3 feet and the area also had freezing or below freezing temps

3. The last time it snowed there was in 1979, a mere 35 years ago.

4. I even copied, with bold & italics for emphasis......

The Sahara Desert covers most of Northern Africa and it has gone through shifts in temperature and moisture over the past few hundred thousand years.

Although the Sahara is very dry today, it is expected to become green again in about 15000 years.....

maybe you two need to learn to read

Maybe --- no, make that definitely --- you need to read this: Biased Sample Fallacy

Oh look, the sun's shining, no rain. Therefore rain does not exist.

 

[westwall]

and it's obvious neither of you read either of the links provided.

1. It also had snowed there just last December 21, 2016, a mere month ago?

2. This snow reported is nearly 3 feet and the area also had freezing or below freezing temps

3. The last time it snowed there was in 1979, a mere 35 years ago.

4. I even copied, with bold & italics for emphasis......

The Sahara Desert covers most of Northern Africa and it has gone through shifts in temperature and moisture over the past few hundred thousand years.

Although the Sahara is very dry today, it is expected to become green again in about 15000 years.....

maybe you two need to learn to read

Maybe --- no, make that definitely --- you need to read this: Biased Sample Fallacy

Oh look, the sun's shining, no rain. Therefore rain does not exist.

I suggest you read it too. Every time it's warm out you trot out AGW "theory"

See how that works silly boy...

 

[Pogo]

and it's obvious neither of you read either of the links provided.

1. It also had snowed there just last December 21, 2016, a mere month ago?

2. This snow reported is nearly 3 feet and the area also had freezing or below freezing temps

3. The last time it snowed there was in 1979, a mere 35 years ago.

4. I even copied, with bold & italics for emphasis......

The Sahara Desert covers most of Northern Africa and it has gone through shifts in temperature and moisture over the past few hundred thousand years.

Although the Sahara is very dry today, it is expected to become green again in about 15000 years.....

maybe you two need to learn to read

Maybe --- no, make that definitely --- you need to read this: Biased Sample Fallacy

Oh look, the sun's shining, no rain. Therefore rain does not exist.

I suggest you read it too. Every time it's warm out you trot out AGW "theory"

See how that works silly boy...

Oh do I now.

----------------- Link?

You just never learn, do ya.

 

[JustAnotherNut]

Here's some more reading for ya.....

The history of ice on Earth

The history of ice on Earth


By Michael Marshall

Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age.

But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years.

In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the poles and there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over.

Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain.



Snowball Earth
2.4 to 2.1 billion years ago

The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms.

The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect.

Deep freeze
850 to 630 million years ago

During the 200 million years of the Cryogenian period, the Earth was plunged into some of the deepest cold it has ever experienced – and the emergence of complex life may have caused it.

One theory is that the glaciation was triggered by the evolution of large cells, and possibly also multicellular organisms, that sank to the seabed after dying. This would have sucked CO2 out of the atmosphere, weakening the greenhouse effect and thus lowering global temperatures.

There seem to have been two distinct Cryogenian ice ages: the so-called Sturtian glaciation between 750 and 700 million years ago, followed by the Varanger (or Marinoan) glaciation, 660 to 635 million years ago. There’s some evidence that Earth became a snowball at times during the big freezes, but researchers are still trying to work out exactly what happened.

Mass extinction
460 to 430 million years ago

Straddling the late Ordovician period and the early Silurian period, the Andean-Saharan ice age was marked by a mass extinction, the second most severe in Earth’s history.

The die-off was surpassed only by the gargantuan Permian extinction 250 million years ago. But as the ecosystem recovered after the freeze, it expanded, with land plants becoming common over the course of the Silurian period. And those plants may have caused the next great ice age.

Plants invade the land
360 to 260 million years ago

Like the Cryogenian glaciation, the Karoo ice age featured two peaks in ice cover that may well have been distinct ice ages. They took place in the Mississipian period, 359 to 318 million years ago, and again in the Pennsylvanian 318 to 299 million years ago.

These ice ages may have been the result of the expansion of land plants that followed the Cryogenian. As plants spread over the planet, they absorbed CO2 from the atmosphere and released oxygen (PDF). As a result CO2 levels fell and the greenhouse effect weakened, triggering an ice age.

There is some evidence that the ice came and went in regular cycles, driven by changes in Earth’s orbit. If true, this would mean that the Karoo ice age operated in much the same way as the current one.

Antarctica freezes over
14 million years ago

Antarctica wasn’t always a frozen wasteland. It wasn’t until around 34 million years ago that the first small glaciers formed on the tops of Antarctica’s mountains. And it was 20 million years later, when world-wide temperatures dropped by 8 °C, that the glaciers’ ice froze onto the rock, and the southern ice sheet was born.

This temperature drop was triggered by the rise of the Himalayas. As they grew higher they were exposed to increased weathering, which sucked CO2 out of the atmosphere and reduced the greenhouse effect.

The northern hemisphere remained relatively ice-free for longer, with Greenland and the Arctic becoming heavily glaciated only around 3.2 million years ago.

Latest advance of the ice
2.58 million years ago

The Quaternary glaciation started just a few million years ago – and is still going on. So its history is relatively recent, in geological terms, and can be studied in far more detail than the others’. It’s evident that the ice sheets have gone through multiple stages of growth and retreat over the course of the Quaternary.

During “glacial” stages, the temperature was low and ice extended far away from the poles. During “interglacials”, the temperature was somewhat warmer and the ice retreated. Brief, inconclusive periods of advancing ice – typically lasting less than 10,000 years – are called “stadials”; conversely, periods when the ice retreated, but only briefly, are called “interstadials”.

The main trigger for the Quaternary glaciation was the continuing fall in the level of CO2 in the atmosphere due to the weathering of the Himalayas. However, the timing of the glacials and interglacials was driven by periodic changes in Earth’s orbit that change the amount of sunshine reaching various parts of the planet. The effect of these small orbital changes was amplified by positive feedbacks, such as changes in greenhouse gas levels.

During the first two-thirds of the Quaternary, the ice advanced and retreated roughly every 41,000 years – the same tempo as the changes in the tilt of Earth’s axis. About a million years ago, the ice switched to a 100,000-year cycle for reasons that were until recently a mystery. Now more detailed information about the timing of the ice’s movements may have helped glaciologists find an answer.

To make matters more complicated still, the ice didn’t advance and retreat simultaneously all around the world. Often it would begin advancing on one continent, with the others only being covered thousands of years later, and then linger on a few continents several millennia after it had disappeared from the others.

So there were actually many overlapping glaciations within the Quaternary, each separately named: the Bavelian and Cromerian complexes of glacials and interglacials; the Elsterian glacial; the Holsteinian interglacial and the Saalian glaciation, among others.

Between 130,000 and 114,000 years ago, the ice retreated during the Eemian interglacial – and then advanced again to create the glacial that most people know as “the ice age”.

Our ice age
110,000 to 12,000 years ago

The cool temperatures of the Quaternary may have allowed our brains to become much larger than those of our of hominid ancestors. While that’s still open to debate, it’s plausible that the most recent glacial period left its mark on our species.

Neanderthals, with whom we shared the planet until just before the last glacial maximum, 20,000 years ago, may have struggled to survive as the rising and falling ice ate away at their habitat – although many other explanations for their extinction have been suggested. What is beyond doubt is that Homo sapiens survived and turned to farming soon after the ice retreated, setting the stage for the rise of modern civilisation.

As the glacial period drew to a close and temperatures began to rise, there were two final cold snaps. First, the chilly “Older Dryas” of 14,700 to 13,400 years ago transformed most of Europe from forest to tundra, like modern-day Siberia. After a brief respite, the Younger Dryas, between 12,800 to 11,500 years ago, froze Europe solid within a matter of months – probably as a result of meltwater from retreating glaciers shutting down the Atlantic Ocean’s “conveyor-belt” current, although a cometary impact has also been blamed.

Twelve thousand years ago, the great ice sheets retreated at the beginning of the latest interglacial – the Flandrian – allowing humans to return to northern latitudes. This period has been relatively warm, and the climate relatively stable, although it has been slightly colder than the last interglacial, the Eemian, and sea levels are currently at least 3 metres lower – differences that are being closely scrutinised by researchers keen to understand how our climate will develop.

But this respite from the ice is likely to prove short-lived, at least in geological terms. Human effects on the climate notwithstanding, the cycle will continue to turn, the hothouse period will some day come to an end – and the ice sheets will descend again.





And here is another lil tidbit...


Sahara Desert Was Once Lush and Populated

At the end of the last Ice Age, the Sahara Desert was just as dry and uninviting as it is today. But sandwiched between two periods of extreme dryness were a few millennia of plentiful rainfall and lush vegetation.

During these few thousand years, prehistoric humans left the congested Nile Valley and established settlements around rain pools, green valleys, and rivers.

The ancient climate shift and its effects are detailed in the July 21 issue of the journal Science.

When the rains came

Some 12,000 years ago, the only place to live along the eastern Sahara Desert was the Nile Valley. Being so crowded, prime real estate in the Nile Valley was difficult to come by. Disputes over land were often settled with the fist, as evidenced by the cemetery of Jebel Sahaba where many of the buried individuals had died a violent death.


But around 10,500 years ago, a sudden burst of monsoon rains over the vast desert transformed the region into habitable land.

This opened the door for humans to move into the area, as evidenced by the researcher's 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites.

"The climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany.

Frolicking in pools

In the Egyptian Sahara, semi-arid conditions allowed for grasses and shrubs to grow, with some trees sprouting in valleys and near groundwater sources. The vegetation and small, episodic rain pools enticed animals well adapted to dry conditions, such as giraffes, to enter the area as well.

Humans also frolicked in the rain pools, as depicted in rock art from Southwest Egypt.

In the more southern Sudanese Sahara, lush vegetation, hearty trees, and permanent freshwater lakes persisted over millennia. There were even large rivers, such as the Wadi Howar, once the largest tributary to the Nile from the Sahara.

"Wildlife included very demanding species such as elephants, rhinos, hippos, crocodiles, and more than 30 species of fish up to 2 meters (6 feet) big," Kroepelin told LiveScience.

A timeline of Sahara occupation [See Map]:

• 22,000 to 10,500 years ago: The Sahara was devoid of any human occupation outside the Nile Valley and extended 250 miles further south than it does today.

• 10,500 to 9,000 years ago: Monsoon rains begin sweeping into the Sahara, transforming the region into a habitable area swiftly settled by Nile Valley dwellers.

• 9,000 to 7,300 years ago: Continued rains, vegetation growth, and animal migrations lead to well established human settlements, including the introduction of domesticated livestock such as sheep and goats.

• 7,300 to 5,500 years ago: Retreating monsoonal rains initiate desiccation in the Egyptian Sahara, prompting humans to move to remaining habitable niches in Sudanese Sahara. The end of the rains and return of desert conditions throughout the Sahara after 5,500 coincides with population return to the Nile Valley and the beginning of pharaonic society.

Both articles address the fact of the changing climate as a natural occurrence. There is nothing man has done to bring it about, nor is there anything man can do to stop it.

 

[Pogo]

Here's some more reading for ya.....

The history of ice on Earth

The history of ice on Earth


By Michael Marshall

Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age.

But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years.

In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the poles and there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over.

Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain.



Snowball Earth
2.4 to 2.1 billion years ago

The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms.

The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect.

Deep freeze
850 to 630 million years ago

During the 200 million years of the Cryogenian period, the Earth was plunged into some of the deepest cold it has ever experienced – and the emergence of complex life may have caused it.

One theory is that the glaciation was triggered by the evolution of large cells, and possibly also multicellular organisms, that sank to the seabed after dying. This would have sucked CO2 out of the atmosphere, weakening the greenhouse effect and thus lowering global temperatures.

There seem to have been two distinct Cryogenian ice ages: the so-called Sturtian glaciation between 750 and 700 million years ago, followed by the Varanger (or Marinoan) glaciation, 660 to 635 million years ago. There’s some evidence that Earth became a snowball at times during the big freezes, but researchers are still trying to work out exactly what happened.

Mass extinction
460 to 430 million years ago

Straddling the late Ordovician period and the early Silurian period, the Andean-Saharan ice age was marked by a mass extinction, the second most severe in Earth’s history.

The die-off was surpassed only by the gargantuan Permian extinction 250 million years ago. But as the ecosystem recovered after the freeze, it expanded, with land plants becoming common over the course of the Silurian period. And those plants may have caused the next great ice age.

Plants invade the land
360 to 260 million years ago

Like the Cryogenian glaciation, the Karoo ice age featured two peaks in ice cover that may well have been distinct ice ages. They took place in the Mississipian period, 359 to 318 million years ago, and again in the Pennsylvanian 318 to 299 million years ago.

These ice ages may have been the result of the expansion of land plants that followed the Cryogenian. As plants spread over the planet, they absorbed CO2 from the atmosphere and released oxygen (PDF). As a result CO2 levels fell and the greenhouse effect weakened, triggering an ice age.

There is some evidence that the ice came and went in regular cycles, driven by changes in Earth’s orbit. If true, this would mean that the Karoo ice age operated in much the same way as the current one.

Antarctica freezes over
14 million years ago

Antarctica wasn’t always a frozen wasteland. It wasn’t until around 34 million years ago that the first small glaciers formed on the tops of Antarctica’s mountains. And it was 20 million years later, when world-wide temperatures dropped by 8 °C, that the glaciers’ ice froze onto the rock, and the southern ice sheet was born.

This temperature drop was triggered by the rise of the Himalayas. As they grew higher they were exposed to increased weathering, which sucked CO2 out of the atmosphere and reduced the greenhouse effect.

The northern hemisphere remained relatively ice-free for longer, with Greenland and the Arctic becoming heavily glaciated only around 3.2 million years ago.

Latest advance of the ice
2.58 million years ago

The Quaternary glaciation started just a few million years ago – and is still going on. So its history is relatively recent, in geological terms, and can be studied in far more detail than the others’. It’s evident that the ice sheets have gone through multiple stages of growth and retreat over the course of the Quaternary.

During “glacial” stages, the temperature was low and ice extended far away from the poles. During “interglacials”, the temperature was somewhat warmer and the ice retreated. Brief, inconclusive periods of advancing ice – typically lasting less than 10,000 years – are called “stadials”; conversely, periods when the ice retreated, but only briefly, are called “interstadials”.

The main trigger for the Quaternary glaciation was the continuing fall in the level of CO2 in the atmosphere due to the weathering of the Himalayas. However, the timing of the glacials and interglacials was driven by periodic changes in Earth’s orbit that change the amount of sunshine reaching various parts of the planet. The effect of these small orbital changes was amplified by positive feedbacks, such as changes in greenhouse gas levels.

During the first two-thirds of the Quaternary, the ice advanced and retreated roughly every 41,000 years – the same tempo as the changes in the tilt of Earth’s axis. About a million years ago, the ice switched to a 100,000-year cycle for reasons that were until recently a mystery. Now more detailed information about the timing of the ice’s movements may have helped glaciologists find an answer.

To make matters more complicated still, the ice didn’t advance and retreat simultaneously all around the world. Often it would begin advancing on one continent, with the others only being covered thousands of years later, and then linger on a few continents several millennia after it had disappeared from the others.

So there were actually many overlapping glaciations within the Quaternary, each separately named: the Bavelian and Cromerian complexes of glacials and interglacials; the Elsterian glacial; the Holsteinian interglacial and the Saalian glaciation, among others.

Between 130,000 and 114,000 years ago, the ice retreated during the Eemian interglacial – and then advanced again to create the glacial that most people know as “the ice age”.

Our ice age
110,000 to 12,000 years ago

The cool temperatures of the Quaternary may have allowed our brains to become much larger than those of our of hominid ancestors. While that’s still open to debate, it’s plausible that the most recent glacial period left its mark on our species.

Neanderthals, with whom we shared the planet until just before the last glacial maximum, 20,000 years ago, may have struggled to survive as the rising and falling ice ate away at their habitat – although many other explanations for their extinction have been suggested. What is beyond doubt is that Homo sapiens survived and turned to farming soon after the ice retreated, setting the stage for the rise of modern civilisation.

As the glacial period drew to a close and temperatures began to rise, there were two final cold snaps. First, the chilly “Older Dryas” of 14,700 to 13,400 years ago transformed most of Europe from forest to tundra, like modern-day Siberia. After a brief respite, the Younger Dryas, between 12,800 to 11,500 years ago, froze Europe solid within a matter of months – probably as a result of meltwater from retreating glaciers shutting down the Atlantic Ocean’s “conveyor-belt” current, although a cometary impact has also been blamed.

Twelve thousand years ago, the great ice sheets retreated at the beginning of the latest interglacial – the Flandrian – allowing humans to return to northern latitudes. This period has been relatively warm, and the climate relatively stable, although it has been slightly colder than the last interglacial, the Eemian, and sea levels are currently at least 3 metres lower – differences that are being closely scrutinised by researchers keen to understand how our climate will develop.

But this respite from the ice is likely to prove short-lived, at least in geological terms. Human effects on the climate notwithstanding, the cycle will continue to turn, the hothouse period will some day come to an end – and the ice sheets will descend again.





And here is another lil tidbit...


Sahara Desert Was Once Lush and Populated

At the end of the last Ice Age, the Sahara Desert was just as dry and uninviting as it is today. But sandwiched between two periods of extreme dryness were a few millennia of plentiful rainfall and lush vegetation.

During these few thousand years, prehistoric humans left the congested Nile Valley and established settlements around rain pools, green valleys, and rivers.

The ancient climate shift and its effects are detailed in the July 21 issue of the journal Science.

When the rains came

Some 12,000 years ago, the only place to live along the eastern Sahara Desert was the Nile Valley. Being so crowded, prime real estate in the Nile Valley was difficult to come by. Disputes over land were often settled with the fist, as evidenced by the cemetery of Jebel Sahaba where many of the buried individuals had died a violent death.


But around 10,500 years ago, a sudden burst of monsoon rains over the vast desert transformed the region into habitable land.

This opened the door for humans to move into the area, as evidenced by the researcher's 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites.

"The climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany.

Frolicking in pools

In the Egyptian Sahara, semi-arid conditions allowed for grasses and shrubs to grow, with some trees sprouting in valleys and near groundwater sources. The vegetation and small, episodic rain pools enticed animals well adapted to dry conditions, such as giraffes, to enter the area as well.

Humans also frolicked in the rain pools, as depicted in rock art from Southwest Egypt.

In the more southern Sudanese Sahara, lush vegetation, hearty trees, and permanent freshwater lakes persisted over millennia. There were even large rivers, such as the Wadi Howar, once the largest tributary to the Nile from the Sahara.

"Wildlife included very demanding species such as elephants, rhinos, hippos, crocodiles, and more than 30 species of fish up to 2 meters (6 feet) big," Kroepelin told LiveScience.

A timeline of Sahara occupation [See Map]:

• 22,000 to 10,500 years ago: The Sahara was devoid of any human occupation outside the Nile Valley and extended 250 miles further south than it does today.

• 10,500 to 9,000 years ago: Monsoon rains begin sweeping into the Sahara, transforming the region into a habitable area swiftly settled by Nile Valley dwellers.

• 9,000 to 7,300 years ago: Continued rains, vegetation growth, and animal migrations lead to well established human settlements, including the introduction of domesticated livestock such as sheep and goats.

• 7,300 to 5,500 years ago: Retreating monsoonal rains initiate desiccation in the Egyptian Sahara, prompting humans to move to remaining habitable niches in Sudanese Sahara. The end of the rains and return of desert conditions throughout the Sahara after 5,500 coincides with population return to the Nile Valley and the beginning of pharaonic society.

Both articles address the fact of the changing climate as a natural occurrence. There is nothing man has done to bring it about, nor is there anything man can do to stop it.

Perhaps there's some troglodyte living in a cave somewhere that actually doesn't know about ice ages and warming and cooling trends. This isn't news.

Just as obviously humans before the Industrial Revolution had no influence on that. But you can't sit in your easy chair an flatly declare we don't in the present day, simply because it's what you would like to be true. The fact is you have nowhere near the perspective to make such an assessment. At all. That's just delusions-of-omniscience arrogance.

As is the deliberate conflation of "weather" with "climate".

 

[westwall]

Here's some more reading for ya.....

The history of ice on Earth

The history of ice on Earth


By Michael Marshall

Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age.

But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years.

In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the poles and there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over.

Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain.



Snowball Earth
2.4 to 2.1 billion years ago

The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms.

The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect.

Deep freeze
850 to 630 million years ago

During the 200 million years of the Cryogenian period, the Earth was plunged into some of the deepest cold it has ever experienced – and the emergence of complex life may have caused it.

One theory is that the glaciation was triggered by the evolution of large cells, and possibly also multicellular organisms, that sank to the seabed after dying. This would have sucked CO2 out of the atmosphere, weakening the greenhouse effect and thus lowering global temperatures.

There seem to have been two distinct Cryogenian ice ages: the so-called Sturtian glaciation between 750 and 700 million years ago, followed by the Varanger (or Marinoan) glaciation, 660 to 635 million years ago. There’s some evidence that Earth became a snowball at times during the big freezes, but researchers are still trying to work out exactly what happened.

Mass extinction
460 to 430 million years ago

Straddling the late Ordovician period and the early Silurian period, the Andean-Saharan ice age was marked by a mass extinction, the second most severe in Earth’s history.

The die-off was surpassed only by the gargantuan Permian extinction 250 million years ago. But as the ecosystem recovered after the freeze, it expanded, with land plants becoming common over the course of the Silurian period. And those plants may have caused the next great ice age.

Plants invade the land
360 to 260 million years ago

Like the Cryogenian glaciation, the Karoo ice age featured two peaks in ice cover that may well have been distinct ice ages. They took place in the Mississipian period, 359 to 318 million years ago, and again in the Pennsylvanian 318 to 299 million years ago.

These ice ages may have been the result of the expansion of land plants that followed the Cryogenian. As plants spread over the planet, they absorbed CO2 from the atmosphere and released oxygen (PDF). As a result CO2 levels fell and the greenhouse effect weakened, triggering an ice age.

There is some evidence that the ice came and went in regular cycles, driven by changes in Earth’s orbit. If true, this would mean that the Karoo ice age operated in much the same way as the current one.

Antarctica freezes over
14 million years ago

Antarctica wasn’t always a frozen wasteland. It wasn’t until around 34 million years ago that the first small glaciers formed on the tops of Antarctica’s mountains. And it was 20 million years later, when world-wide temperatures dropped by 8 °C, that the glaciers’ ice froze onto the rock, and the southern ice sheet was born.

This temperature drop was triggered by the rise of the Himalayas. As they grew higher they were exposed to increased weathering, which sucked CO2 out of the atmosphere and reduced the greenhouse effect.

The northern hemisphere remained relatively ice-free for longer, with Greenland and the Arctic becoming heavily glaciated only around 3.2 million years ago.

Latest advance of the ice
2.58 million years ago

The Quaternary glaciation started just a few million years ago – and is still going on. So its history is relatively recent, in geological terms, and can be studied in far more detail than the others’. It’s evident that the ice sheets have gone through multiple stages of growth and retreat over the course of the Quaternary.

During “glacial” stages, the temperature was low and ice extended far away from the poles. During “interglacials”, the temperature was somewhat warmer and the ice retreated. Brief, inconclusive periods of advancing ice – typically lasting less than 10,000 years – are called “stadials”; conversely, periods when the ice retreated, but only briefly, are called “interstadials”.

The main trigger for the Quaternary glaciation was the continuing fall in the level of CO2 in the atmosphere due to the weathering of the Himalayas. However, the timing of the glacials and interglacials was driven by periodic changes in Earth’s orbit that change the amount of sunshine reaching various parts of the planet. The effect of these small orbital changes was amplified by positive feedbacks, such as changes in greenhouse gas levels.

During the first two-thirds of the Quaternary, the ice advanced and retreated roughly every 41,000 years – the same tempo as the changes in the tilt of Earth’s axis. About a million years ago, the ice switched to a 100,000-year cycle for reasons that were until recently a mystery. Now more detailed information about the timing of the ice’s movements may have helped glaciologists find an answer.

To make matters more complicated still, the ice didn’t advance and retreat simultaneously all around the world. Often it would begin advancing on one continent, with the others only being covered thousands of years later, and then linger on a few continents several millennia after it had disappeared from the others.

So there were actually many overlapping glaciations within the Quaternary, each separately named: the Bavelian and Cromerian complexes of glacials and interglacials; the Elsterian glacial; the Holsteinian interglacial and the Saalian glaciation, among others.

Between 130,000 and 114,000 years ago, the ice retreated during the Eemian interglacial – and then advanced again to create the glacial that most people know as “the ice age”.

Our ice age
110,000 to 12,000 years ago

The cool temperatures of the Quaternary may have allowed our brains to become much larger than those of our of hominid ancestors. While that’s still open to debate, it’s plausible that the most recent glacial period left its mark on our species.

Neanderthals, with whom we shared the planet until just before the last glacial maximum, 20,000 years ago, may have struggled to survive as the rising and falling ice ate away at their habitat – although many other explanations for their extinction have been suggested. What is beyond doubt is that Homo sapiens survived and turned to farming soon after the ice retreated, setting the stage for the rise of modern civilisation.

As the glacial period drew to a close and temperatures began to rise, there were two final cold snaps. First, the chilly “Older Dryas” of 14,700 to 13,400 years ago transformed most of Europe from forest to tundra, like modern-day Siberia. After a brief respite, the Younger Dryas, between 12,800 to 11,500 years ago, froze Europe solid within a matter of months – probably as a result of meltwater from retreating glaciers shutting down the Atlantic Ocean’s “conveyor-belt” current, although a cometary impact has also been blamed.

Twelve thousand years ago, the great ice sheets retreated at the beginning of the latest interglacial – the Flandrian – allowing humans to return to northern latitudes. This period has been relatively warm, and the climate relatively stable, although it has been slightly colder than the last interglacial, the Eemian, and sea levels are currently at least 3 metres lower – differences that are being closely scrutinised by researchers keen to understand how our climate will develop.

But this respite from the ice is likely to prove short-lived, at least in geological terms. Human effects on the climate notwithstanding, the cycle will continue to turn, the hothouse period will some day come to an end – and the ice sheets will descend again.





And here is another lil tidbit...


Sahara Desert Was Once Lush and Populated

At the end of the last Ice Age, the Sahara Desert was just as dry and uninviting as it is today. But sandwiched between two periods of extreme dryness were a few millennia of plentiful rainfall and lush vegetation.

During these few thousand years, prehistoric humans left the congested Nile Valley and established settlements around rain pools, green valleys, and rivers.

The ancient climate shift and its effects are detailed in the July 21 issue of the journal Science.

When the rains came

Some 12,000 years ago, the only place to live along the eastern Sahara Desert was the Nile Valley. Being so crowded, prime real estate in the Nile Valley was difficult to come by. Disputes over land were often settled with the fist, as evidenced by the cemetery of Jebel Sahaba where many of the buried individuals had died a violent death.


But around 10,500 years ago, a sudden burst of monsoon rains over the vast desert transformed the region into habitable land.

This opened the door for humans to move into the area, as evidenced by the researcher's 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites.

"The climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany.

Frolicking in pools

In the Egyptian Sahara, semi-arid conditions allowed for grasses and shrubs to grow, with some trees sprouting in valleys and near groundwater sources. The vegetation and small, episodic rain pools enticed animals well adapted to dry conditions, such as giraffes, to enter the area as well.

Humans also frolicked in the rain pools, as depicted in rock art from Southwest Egypt.

In the more southern Sudanese Sahara, lush vegetation, hearty trees, and permanent freshwater lakes persisted over millennia. There were even large rivers, such as the Wadi Howar, once the largest tributary to the Nile from the Sahara.

"Wildlife included very demanding species such as elephants, rhinos, hippos, crocodiles, and more than 30 species of fish up to 2 meters (6 feet) big," Kroepelin told LiveScience.

A timeline of Sahara occupation [See Map]:

• 22,000 to 10,500 years ago: The Sahara was devoid of any human occupation outside the Nile Valley and extended 250 miles further south than it does today.

• 10,500 to 9,000 years ago: Monsoon rains begin sweeping into the Sahara, transforming the region into a habitable area swiftly settled by Nile Valley dwellers.

• 9,000 to 7,300 years ago: Continued rains, vegetation growth, and animal migrations lead to well established human settlements, including the introduction of domesticated livestock such as sheep and goats.

• 7,300 to 5,500 years ago: Retreating monsoonal rains initiate desiccation in the Egyptian Sahara, prompting humans to move to remaining habitable niches in Sudanese Sahara. The end of the rains and return of desert conditions throughout the Sahara after 5,500 coincides with population return to the Nile Valley and the beginning of pharaonic society.

Both articles address the fact of the changing climate as a natural occurrence. There is nothing man has done to bring it about, nor is there anything man can do to stop it.

Perhaps there's some troglodyte living in a cave somewhere that actually doesn't know about ice ages and warming and cooling trends. This isn't news.

Just as obviously humans before the Industrial Revolution had no influence on that. But you can't sit in your easy chair an flatly declare we don't in the present day, simply because it's what you would like to be true. The fact is you have nowhere near the perspective to make such an assessment. At all. That's just delusions-of-omniscience arrogance.

As is the deliberate conflation of "weather" with "climate".

Actually we can. There is zero empirical evidence that we have any effect on global temperature. None. On the other hand locally there is a very well documented, but ignored by the climatologists, urban heat island effect.

 

[Pogo]

Here's some more reading for ya.....

The history of ice on Earth

The history of ice on Earth


By Michael Marshall

Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age.

But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years.

In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the poles and there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over.

Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain.



Snowball Earth
2.4 to 2.1 billion years ago

The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms.

The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect.

Deep freeze
850 to 630 million years ago

During the 200 million years of the Cryogenian period, the Earth was plunged into some of the deepest cold it has ever experienced – and the emergence of complex life may have caused it.

One theory is that the glaciation was triggered by the evolution of large cells, and possibly also multicellular organisms, that sank to the seabed after dying. This would have sucked CO2 out of the atmosphere, weakening the greenhouse effect and thus lowering global temperatures.

There seem to have been two distinct Cryogenian ice ages: the so-called Sturtian glaciation between 750 and 700 million years ago, followed by the Varanger (or Marinoan) glaciation, 660 to 635 million years ago. There’s some evidence that Earth became a snowball at times during the big freezes, but researchers are still trying to work out exactly what happened.

Mass extinction
460 to 430 million years ago

Straddling the late Ordovician period and the early Silurian period, the Andean-Saharan ice age was marked by a mass extinction, the second most severe in Earth’s history.

The die-off was surpassed only by the gargantuan Permian extinction 250 million years ago. But as the ecosystem recovered after the freeze, it expanded, with land plants becoming common over the course of the Silurian period. And those plants may have caused the next great ice age.

Plants invade the land
360 to 260 million years ago

Like the Cryogenian glaciation, the Karoo ice age featured two peaks in ice cover that may well have been distinct ice ages. They took place in the Mississipian period, 359 to 318 million years ago, and again in the Pennsylvanian 318 to 299 million years ago.

These ice ages may have been the result of the expansion of land plants that followed the Cryogenian. As plants spread over the planet, they absorbed CO2 from the atmosphere and released oxygen (PDF). As a result CO2 levels fell and the greenhouse effect weakened, triggering an ice age.

There is some evidence that the ice came and went in regular cycles, driven by changes in Earth’s orbit. If true, this would mean that the Karoo ice age operated in much the same way as the current one.

Antarctica freezes over
14 million years ago

Antarctica wasn’t always a frozen wasteland. It wasn’t until around 34 million years ago that the first small glaciers formed on the tops of Antarctica’s mountains. And it was 20 million years later, when world-wide temperatures dropped by 8 °C, that the glaciers’ ice froze onto the rock, and the southern ice sheet was born.

This temperature drop was triggered by the rise of the Himalayas. As they grew higher they were exposed to increased weathering, which sucked CO2 out of the atmosphere and reduced the greenhouse effect.

The northern hemisphere remained relatively ice-free for longer, with Greenland and the Arctic becoming heavily glaciated only around 3.2 million years ago.

Latest advance of the ice
2.58 million years ago

The Quaternary glaciation started just a few million years ago – and is still going on. So its history is relatively recent, in geological terms, and can be studied in far more detail than the others’. It’s evident that the ice sheets have gone through multiple stages of growth and retreat over the course of the Quaternary.

During “glacial” stages, the temperature was low and ice extended far away from the poles. During “interglacials”, the temperature was somewhat warmer and the ice retreated. Brief, inconclusive periods of advancing ice – typically lasting less than 10,000 years – are called “stadials”; conversely, periods when the ice retreated, but only briefly, are called “interstadials”.

The main trigger for the Quaternary glaciation was the continuing fall in the level of CO2 in the atmosphere due to the weathering of the Himalayas. However, the timing of the glacials and interglacials was driven by periodic changes in Earth’s orbit that change the amount of sunshine reaching various parts of the planet. The effect of these small orbital changes was amplified by positive feedbacks, such as changes in greenhouse gas levels.

During the first two-thirds of the Quaternary, the ice advanced and retreated roughly every 41,000 years – the same tempo as the changes in the tilt of Earth’s axis. About a million years ago, the ice switched to a 100,000-year cycle for reasons that were until recently a mystery. Now more detailed information about the timing of the ice’s movements may have helped glaciologists find an answer.

To make matters more complicated still, the ice didn’t advance and retreat simultaneously all around the world. Often it would begin advancing on one continent, with the others only being covered thousands of years later, and then linger on a few continents several millennia after it had disappeared from the others.

So there were actually many overlapping glaciations within the Quaternary, each separately named: the Bavelian and Cromerian complexes of glacials and interglacials; the Elsterian glacial; the Holsteinian interglacial and the Saalian glaciation, among others.

Between 130,000 and 114,000 years ago, the ice retreated during the Eemian interglacial – and then advanced again to create the glacial that most people know as “the ice age”.

Our ice age
110,000 to 12,000 years ago

The cool temperatures of the Quaternary may have allowed our brains to become much larger than those of our of hominid ancestors. While that’s still open to debate, it’s plausible that the most recent glacial period left its mark on our species.

Neanderthals, with whom we shared the planet until just before the last glacial maximum, 20,000 years ago, may have struggled to survive as the rising and falling ice ate away at their habitat – although many other explanations for their extinction have been suggested. What is beyond doubt is that Homo sapiens survived and turned to farming soon after the ice retreated, setting the stage for the rise of modern civilisation.

As the glacial period drew to a close and temperatures began to rise, there were two final cold snaps. First, the chilly “Older Dryas” of 14,700 to 13,400 years ago transformed most of Europe from forest to tundra, like modern-day Siberia. After a brief respite, the Younger Dryas, between 12,800 to 11,500 years ago, froze Europe solid within a matter of months – probably as a result of meltwater from retreating glaciers shutting down the Atlantic Ocean’s “conveyor-belt” current, although a cometary impact has also been blamed.

Twelve thousand years ago, the great ice sheets retreated at the beginning of the latest interglacial – the Flandrian – allowing humans to return to northern latitudes. This period has been relatively warm, and the climate relatively stable, although it has been slightly colder than the last interglacial, the Eemian, and sea levels are currently at least 3 metres lower – differences that are being closely scrutinised by researchers keen to understand how our climate will develop.

But this respite from the ice is likely to prove short-lived, at least in geological terms. Human effects on the climate notwithstanding, the cycle will continue to turn, the hothouse period will some day come to an end – and the ice sheets will descend again.





And here is another lil tidbit...


Sahara Desert Was Once Lush and Populated

At the end of the last Ice Age, the Sahara Desert was just as dry and uninviting as it is today. But sandwiched between two periods of extreme dryness were a few millennia of plentiful rainfall and lush vegetation.

During these few thousand years, prehistoric humans left the congested Nile Valley and established settlements around rain pools, green valleys, and rivers.

The ancient climate shift and its effects are detailed in the July 21 issue of the journal Science.

When the rains came

Some 12,000 years ago, the only place to live along the eastern Sahara Desert was the Nile Valley. Being so crowded, prime real estate in the Nile Valley was difficult to come by. Disputes over land were often settled with the fist, as evidenced by the cemetery of Jebel Sahaba where many of the buried individuals had died a violent death.


But around 10,500 years ago, a sudden burst of monsoon rains over the vast desert transformed the region into habitable land.

This opened the door for humans to move into the area, as evidenced by the researcher's 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites.

"The climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany.

Frolicking in pools

In the Egyptian Sahara, semi-arid conditions allowed for grasses and shrubs to grow, with some trees sprouting in valleys and near groundwater sources. The vegetation and small, episodic rain pools enticed animals well adapted to dry conditions, such as giraffes, to enter the area as well.

Humans also frolicked in the rain pools, as depicted in rock art from Southwest Egypt.

In the more southern Sudanese Sahara, lush vegetation, hearty trees, and permanent freshwater lakes persisted over millennia. There were even large rivers, such as the Wadi Howar, once the largest tributary to the Nile from the Sahara.

"Wildlife included very demanding species such as elephants, rhinos, hippos, crocodiles, and more than 30 species of fish up to 2 meters (6 feet) big," Kroepelin told LiveScience.

A timeline of Sahara occupation [See Map]:

• 22,000 to 10,500 years ago: The Sahara was devoid of any human occupation outside the Nile Valley and extended 250 miles further south than it does today.

• 10,500 to 9,000 years ago: Monsoon rains begin sweeping into the Sahara, transforming the region into a habitable area swiftly settled by Nile Valley dwellers.

• 9,000 to 7,300 years ago: Continued rains, vegetation growth, and animal migrations lead to well established human settlements, including the introduction of domesticated livestock such as sheep and goats.

• 7,300 to 5,500 years ago: Retreating monsoonal rains initiate desiccation in the Egyptian Sahara, prompting humans to move to remaining habitable niches in Sudanese Sahara. The end of the rains and return of desert conditions throughout the Sahara after 5,500 coincides with population return to the Nile Valley and the beginning of pharaonic society.

Both articles address the fact of the changing climate as a natural occurrence. There is nothing man has done to bring it about, nor is there anything man can do to stop it.

Perhaps there's some troglodyte living in a cave somewhere that actually doesn't know about ice ages and warming and cooling trends. This isn't news.

Just as obviously humans before the Industrial Revolution had no influence on that. But you can't sit in your easy chair an flatly declare we don't in the present day, simply because it's what you would like to be true. The fact is you have nowhere near the perspective to make such an assessment. At all. That's just delusions-of-omniscience arrogance.

As is the deliberate conflation of "weather" with "climate".

Actually we can. There is zero empirical evidence that we have any effect on global temperature. None. On the other hand locally there is a very well documented, but ignored by the climatologists, urban heat island effect.

Actually we can't. Absence of evidence is not evidence of absence. You're basically claiming you know what the final score is going to be after two minutes of the first quarter. Then when there actually is a final score you'll scratch your head going "well now that shouldn't have happened".

As far as urban heat islands, "ignored" really? Maybe by that troglodyte in a cave who's never seen a city but everybody who's ever been to one knows all about it. I learned it as a child, as did most people.

 

[westwall]

Here's some more reading for ya.....

The history of ice on Earth

The history of ice on Earth


By Michael Marshall

Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age.

But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years.

In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the poles and there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over.

Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain.



Snowball Earth
2.4 to 2.1 billion years ago

The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms.

The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect.

Deep freeze
850 to 630 million years ago

During the 200 million years of the Cryogenian period, the Earth was plunged into some of the deepest cold it has ever experienced – and the emergence of complex life may have caused it.

One theory is that the glaciation was triggered by the evolution of large cells, and possibly also multicellular organisms, that sank to the seabed after dying. This would have sucked CO2 out of the atmosphere, weakening the greenhouse effect and thus lowering global temperatures.

There seem to have been two distinct Cryogenian ice ages: the so-called Sturtian glaciation between 750 and 700 million years ago, followed by the Varanger (or Marinoan) glaciation, 660 to 635 million years ago. There’s some evidence that Earth became a snowball at times during the big freezes, but researchers are still trying to work out exactly what happened.

Mass extinction
460 to 430 million years ago

Straddling the late Ordovician period and the early Silurian period, the Andean-Saharan ice age was marked by a mass extinction, the second most severe in Earth’s history.

The die-off was surpassed only by the gargantuan Permian extinction 250 million years ago. But as the ecosystem recovered after the freeze, it expanded, with land plants becoming common over the course of the Silurian period. And those plants may have caused the next great ice age.

Plants invade the land
360 to 260 million years ago

Like the Cryogenian glaciation, the Karoo ice age featured two peaks in ice cover that may well have been distinct ice ages. They took place in the Mississipian period, 359 to 318 million years ago, and again in the Pennsylvanian 318 to 299 million years ago.

These ice ages may have been the result of the expansion of land plants that followed the Cryogenian. As plants spread over the planet, they absorbed CO2 from the atmosphere and released oxygen (PDF). As a result CO2 levels fell and the greenhouse effect weakened, triggering an ice age.

There is some evidence that the ice came and went in regular cycles, driven by changes in Earth’s orbit. If true, this would mean that the Karoo ice age operated in much the same way as the current one.

Antarctica freezes over
14 million years ago

Antarctica wasn’t always a frozen wasteland. It wasn’t until around 34 million years ago that the first small glaciers formed on the tops of Antarctica’s mountains. And it was 20 million years later, when world-wide temperatures dropped by 8 °C, that the glaciers’ ice froze onto the rock, and the southern ice sheet was born.

This temperature drop was triggered by the rise of the Himalayas. As they grew higher they were exposed to increased weathering, which sucked CO2 out of the atmosphere and reduced the greenhouse effect.

The northern hemisphere remained relatively ice-free for longer, with Greenland and the Arctic becoming heavily glaciated only around 3.2 million years ago.

Latest advance of the ice
2.58 million years ago

The Quaternary glaciation started just a few million years ago – and is still going on. So its history is relatively recent, in geological terms, and can be studied in far more detail than the others’. It’s evident that the ice sheets have gone through multiple stages of growth and retreat over the course of the Quaternary.

During “glacial” stages, the temperature was low and ice extended far away from the poles. During “interglacials”, the temperature was somewhat warmer and the ice retreated. Brief, inconclusive periods of advancing ice – typically lasting less than 10,000 years – are called “stadials”; conversely, periods when the ice retreated, but only briefly, are called “interstadials”.

The main trigger for the Quaternary glaciation was the continuing fall in the level of CO2 in the atmosphere due to the weathering of the Himalayas. However, the timing of the glacials and interglacials was driven by periodic changes in Earth’s orbit that change the amount of sunshine reaching various parts of the planet. The effect of these small orbital changes was amplified by positive feedbacks, such as changes in greenhouse gas levels.

During the first two-thirds of the Quaternary, the ice advanced and retreated roughly every 41,000 years – the same tempo as the changes in the tilt of Earth’s axis. About a million years ago, the ice switched to a 100,000-year cycle for reasons that were until recently a mystery. Now more detailed information about the timing of the ice’s movements may have helped glaciologists find an answer.

To make matters more complicated still, the ice didn’t advance and retreat simultaneously all around the world. Often it would begin advancing on one continent, with the others only being covered thousands of years later, and then linger on a few continents several millennia after it had disappeared from the others.

So there were actually many overlapping glaciations within the Quaternary, each separately named: the Bavelian and Cromerian complexes of glacials and interglacials; the Elsterian glacial; the Holsteinian interglacial and the Saalian glaciation, among others.

Between 130,000 and 114,000 years ago, the ice retreated during the Eemian interglacial – and then advanced again to create the glacial that most people know as “the ice age”.

Our ice age
110,000 to 12,000 years ago

The cool temperatures of the Quaternary may have allowed our brains to become much larger than those of our of hominid ancestors. While that’s still open to debate, it’s plausible that the most recent glacial period left its mark on our species.

Neanderthals, with whom we shared the planet until just before the last glacial maximum, 20,000 years ago, may have struggled to survive as the rising and falling ice ate away at their habitat – although many other explanations for their extinction have been suggested. What is beyond doubt is that Homo sapiens survived and turned to farming soon after the ice retreated, setting the stage for the rise of modern civilisation.

As the glacial period drew to a close and temperatures began to rise, there were two final cold snaps. First, the chilly “Older Dryas” of 14,700 to 13,400 years ago transformed most of Europe from forest to tundra, like modern-day Siberia. After a brief respite, the Younger Dryas, between 12,800 to 11,500 years ago, froze Europe solid within a matter of months – probably as a result of meltwater from retreating glaciers shutting down the Atlantic Ocean’s “conveyor-belt” current, although a cometary impact has also been blamed.

Twelve thousand years ago, the great ice sheets retreated at the beginning of the latest interglacial – the Flandrian – allowing humans to return to northern latitudes. This period has been relatively warm, and the climate relatively stable, although it has been slightly colder than the last interglacial, the Eemian, and sea levels are currently at least 3 metres lower – differences that are being closely scrutinised by researchers keen to understand how our climate will develop.

But this respite from the ice is likely to prove short-lived, at least in geological terms. Human effects on the climate notwithstanding, the cycle will continue to turn, the hothouse period will some day come to an end – and the ice sheets will descend again.





And here is another lil tidbit...


Sahara Desert Was Once Lush and Populated

At the end of the last Ice Age, the Sahara Desert was just as dry and uninviting as it is today. But sandwiched between two periods of extreme dryness were a few millennia of plentiful rainfall and lush vegetation.

During these few thousand years, prehistoric humans left the congested Nile Valley and established settlements around rain pools, green valleys, and rivers.

The ancient climate shift and its effects are detailed in the July 21 issue of the journal Science.

When the rains came

Some 12,000 years ago, the only place to live along the eastern Sahara Desert was the Nile Valley. Being so crowded, prime real estate in the Nile Valley was difficult to come by. Disputes over land were often settled with the fist, as evidenced by the cemetery of Jebel Sahaba where many of the buried individuals had died a violent death.


But around 10,500 years ago, a sudden burst of monsoon rains over the vast desert transformed the region into habitable land.

This opened the door for humans to move into the area, as evidenced by the researcher's 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites.

"The climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany.

Frolicking in pools

In the Egyptian Sahara, semi-arid conditions allowed for grasses and shrubs to grow, with some trees sprouting in valleys and near groundwater sources. The vegetation and small, episodic rain pools enticed animals well adapted to dry conditions, such as giraffes, to enter the area as well.

Humans also frolicked in the rain pools, as depicted in rock art from Southwest Egypt.

In the more southern Sudanese Sahara, lush vegetation, hearty trees, and permanent freshwater lakes persisted over millennia. There were even large rivers, such as the Wadi Howar, once the largest tributary to the Nile from the Sahara.

"Wildlife included very demanding species such as elephants, rhinos, hippos, crocodiles, and more than 30 species of fish up to 2 meters (6 feet) big," Kroepelin told LiveScience.

A timeline of Sahara occupation [See Map]:

• 22,000 to 10,500 years ago: The Sahara was devoid of any human occupation outside the Nile Valley and extended 250 miles further south than it does today.

• 10,500 to 9,000 years ago: Monsoon rains begin sweeping into the Sahara, transforming the region into a habitable area swiftly settled by Nile Valley dwellers.

• 9,000 to 7,300 years ago: Continued rains, vegetation growth, and animal migrations lead to well established human settlements, including the introduction of domesticated livestock such as sheep and goats.

• 7,300 to 5,500 years ago: Retreating monsoonal rains initiate desiccation in the Egyptian Sahara, prompting humans to move to remaining habitable niches in Sudanese Sahara. The end of the rains and return of desert conditions throughout the Sahara after 5,500 coincides with population return to the Nile Valley and the beginning of pharaonic society.

Both articles address the fact of the changing climate as a natural occurrence. There is nothing man has done to bring it about, nor is there anything man can do to stop it.

Perhaps there's some troglodyte living in a cave somewhere that actually doesn't know about ice ages and warming and cooling trends. This isn't news.

Just as obviously humans before the Industrial Revolution had no influence on that. But you can't sit in your easy chair an flatly declare we don't in the present day, simply because it's what you would like to be true. The fact is you have nowhere near the perspective to make such an assessment. At all. That's just delusions-of-omniscience arrogance.

As is the deliberate conflation of "weather" with "climate".

Actually we can. There is zero empirical evidence that we have any effect on global temperature. None. On the other hand locally there is a very well documented, but ignored by the climatologists, urban heat island effect.

Actually we can't. Absence of evidence is not evidence of absence. You're basically claiming you know what the final score is going to be after two minutes of the first quarter. Then when there actually is a final score you'll scratch your head going "well now that shouldn't have happened".

As far as urban heat islands, "ignored" really? Maybe by that troglodyte in a cave who's never seen a city but everybody who's ever been to one knows all about it. I learned it as a child, as did most people.

Wow. You just failed science 101. If you postulate a theory, but can provide no empirical evidence to support it, the theory FAILS.

 

[JustAnotherNut]

Here's some more reading for ya.....

The history of ice on Earth

The history of ice on Earth


By Michael Marshall

Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age.

But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years.

In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the poles and there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over.

Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain.



Snowball Earth
2.4 to 2.1 billion years ago

The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms.

The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect.

Deep freeze
850 to 630 million years ago

During the 200 million years of the Cryogenian period, the Earth was plunged into some of the deepest cold it has ever experienced – and the emergence of complex life may have caused it.

One theory is that the glaciation was triggered by the evolution of large cells, and possibly also multicellular organisms, that sank to the seabed after dying. This would have sucked CO2 out of the atmosphere, weakening the greenhouse effect and thus lowering global temperatures.

There seem to have been two distinct Cryogenian ice ages: the so-called Sturtian glaciation between 750 and 700 million years ago, followed by the Varanger (or Marinoan) glaciation, 660 to 635 million years ago. There’s some evidence that Earth became a snowball at times during the big freezes, but researchers are still trying to work out exactly what happened.

Mass extinction
460 to 430 million years ago

Straddling the late Ordovician period and the early Silurian period, the Andean-Saharan ice age was marked by a mass extinction, the second most severe in Earth’s history.

The die-off was surpassed only by the gargantuan Permian extinction 250 million years ago. But as the ecosystem recovered after the freeze, it expanded, with land plants becoming common over the course of the Silurian period. And those plants may have caused the next great ice age.

Plants invade the land
360 to 260 million years ago

Like the Cryogenian glaciation, the Karoo ice age featured two peaks in ice cover that may well have been distinct ice ages. They took place in the Mississipian period, 359 to 318 million years ago, and again in the Pennsylvanian 318 to 299 million years ago.

These ice ages may have been the result of the expansion of land plants that followed the Cryogenian. As plants spread over the planet, they absorbed CO2 from the atmosphere and released oxygen (PDF). As a result CO2 levels fell and the greenhouse effect weakened, triggering an ice age.

There is some evidence that the ice came and went in regular cycles, driven by changes in Earth’s orbit. If true, this would mean that the Karoo ice age operated in much the same way as the current one.

Antarctica freezes over
14 million years ago

Antarctica wasn’t always a frozen wasteland. It wasn’t until around 34 million years ago that the first small glaciers formed on the tops of Antarctica’s mountains. And it was 20 million years later, when world-wide temperatures dropped by 8 °C, that the glaciers’ ice froze onto the rock, and the southern ice sheet was born.

This temperature drop was triggered by the rise of the Himalayas. As they grew higher they were exposed to increased weathering, which sucked CO2 out of the atmosphere and reduced the greenhouse effect.

The northern hemisphere remained relatively ice-free for longer, with Greenland and the Arctic becoming heavily glaciated only around 3.2 million years ago.

Latest advance of the ice
2.58 million years ago

The Quaternary glaciation started just a few million years ago – and is still going on. So its history is relatively recent, in geological terms, and can be studied in far more detail than the others’. It’s evident that the ice sheets have gone through multiple stages of growth and retreat over the course of the Quaternary.

During “glacial” stages, the temperature was low and ice extended far away from the poles. During “interglacials”, the temperature was somewhat warmer and the ice retreated. Brief, inconclusive periods of advancing ice – typically lasting less than 10,000 years – are called “stadials”; conversely, periods when the ice retreated, but only briefly, are called “interstadials”.

The main trigger for the Quaternary glaciation was the continuing fall in the level of CO2 in the atmosphere due to the weathering of the Himalayas. However, the timing of the glacials and interglacials was driven by periodic changes in Earth’s orbit that change the amount of sunshine reaching various parts of the planet. The effect of these small orbital changes was amplified by positive feedbacks, such as changes in greenhouse gas levels.

During the first two-thirds of the Quaternary, the ice advanced and retreated roughly every 41,000 years – the same tempo as the changes in the tilt of Earth’s axis. About a million years ago, the ice switched to a 100,000-year cycle for reasons that were until recently a mystery. Now more detailed information about the timing of the ice’s movements may have helped glaciologists find an answer.

To make matters more complicated still, the ice didn’t advance and retreat simultaneously all around the world. Often it would begin advancing on one continent, with the others only being covered thousands of years later, and then linger on a few continents several millennia after it had disappeared from the others.

So there were actually many overlapping glaciations within the Quaternary, each separately named: the Bavelian and Cromerian complexes of glacials and interglacials; the Elsterian glacial; the Holsteinian interglacial and the Saalian glaciation, among others.

Between 130,000 and 114,000 years ago, the ice retreated during the Eemian interglacial – and then advanced again to create the glacial that most people know as “the ice age”.

Our ice age
110,000 to 12,000 years ago

The cool temperatures of the Quaternary may have allowed our brains to become much larger than those of our of hominid ancestors. While that’s still open to debate, it’s plausible that the most recent glacial period left its mark on our species.

Neanderthals, with whom we shared the planet until just before the last glacial maximum, 20,000 years ago, may have struggled to survive as the rising and falling ice ate away at their habitat – although many other explanations for their extinction have been suggested. What is beyond doubt is that Homo sapiens survived and turned to farming soon after the ice retreated, setting the stage for the rise of modern civilisation.

As the glacial period drew to a close and temperatures began to rise, there were two final cold snaps. First, the chilly “Older Dryas” of 14,700 to 13,400 years ago transformed most of Europe from forest to tundra, like modern-day Siberia. After a brief respite, the Younger Dryas, between 12,800 to 11,500 years ago, froze Europe solid within a matter of months – probably as a result of meltwater from retreating glaciers shutting down the Atlantic Ocean’s “conveyor-belt” current, although a cometary impact has also been blamed.

Twelve thousand years ago, the great ice sheets retreated at the beginning of the latest interglacial – the Flandrian – allowing humans to return to northern latitudes. This period has been relatively warm, and the climate relatively stable, although it has been slightly colder than the last interglacial, the Eemian, and sea levels are currently at least 3 metres lower – differences that are being closely scrutinised by researchers keen to understand how our climate will develop.

But this respite from the ice is likely to prove short-lived, at least in geological terms. Human effects on the climate notwithstanding, the cycle will continue to turn, the hothouse period will some day come to an end – and the ice sheets will descend again.





And here is another lil tidbit...


Sahara Desert Was Once Lush and Populated

At the end of the last Ice Age, the Sahara Desert was just as dry and uninviting as it is today. But sandwiched between two periods of extreme dryness were a few millennia of plentiful rainfall and lush vegetation.

During these few thousand years, prehistoric humans left the congested Nile Valley and established settlements around rain pools, green valleys, and rivers.

The ancient climate shift and its effects are detailed in the July 21 issue of the journal Science.

When the rains came

Some 12,000 years ago, the only place to live along the eastern Sahara Desert was the Nile Valley. Being so crowded, prime real estate in the Nile Valley was difficult to come by. Disputes over land were often settled with the fist, as evidenced by the cemetery of Jebel Sahaba where many of the buried individuals had died a violent death.


But around 10,500 years ago, a sudden burst of monsoon rains over the vast desert transformed the region into habitable land.

This opened the door for humans to move into the area, as evidenced by the researcher's 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites.

"The climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany.

Frolicking in pools

In the Egyptian Sahara, semi-arid conditions allowed for grasses and shrubs to grow, with some trees sprouting in valleys and near groundwater sources. The vegetation and small, episodic rain pools enticed animals well adapted to dry conditions, such as giraffes, to enter the area as well.

Humans also frolicked in the rain pools, as depicted in rock art from Southwest Egypt.

In the more southern Sudanese Sahara, lush vegetation, hearty trees, and permanent freshwater lakes persisted over millennia. There were even large rivers, such as the Wadi Howar, once the largest tributary to the Nile from the Sahara.

"Wildlife included very demanding species such as elephants, rhinos, hippos, crocodiles, and more than 30 species of fish up to 2 meters (6 feet) big," Kroepelin told LiveScience.

A timeline of Sahara occupation [See Map]:

• 22,000 to 10,500 years ago: The Sahara was devoid of any human occupation outside the Nile Valley and extended 250 miles further south than it does today.

• 10,500 to 9,000 years ago: Monsoon rains begin sweeping into the Sahara, transforming the region into a habitable area swiftly settled by Nile Valley dwellers.

• 9,000 to 7,300 years ago: Continued rains, vegetation growth, and animal migrations lead to well established human settlements, including the introduction of domesticated livestock such as sheep and goats.

• 7,300 to 5,500 years ago: Retreating monsoonal rains initiate desiccation in the Egyptian Sahara, prompting humans to move to remaining habitable niches in Sudanese Sahara. The end of the rains and return of desert conditions throughout the Sahara after 5,500 coincides with population return to the Nile Valley and the beginning of pharaonic society.

Both articles address the fact of the changing climate as a natural occurrence. There is nothing man has done to bring it about, nor is there anything man can do to stop it.

Perhaps there's some troglodyte living in a cave somewhere that actually doesn't know about ice ages and warming and cooling trends. This isn't news.

Just as obviously humans before the Industrial Revolution had no influence on that. But you can't sit in your easy chair an flatly declare we don't in the present day, simply because it's what you would like to be true. The fact is you have nowhere near the perspective to make such an assessment. At all. That's just delusions-of-omniscience arrogance.

As is the deliberate conflation of "weather" with "climate".

So then explain just what we humans have done in the last 300 years to contribute to the Global Climate Change......and include links to back it up.

 

[Pogo]

Here's some more reading for ya.....

The history of ice on Earth

The history of ice on Earth


By Michael Marshall

Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age.

But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years.

In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the poles and there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over.

Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain.



Snowball Earth
2.4 to 2.1 billion years ago

The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms.

The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect.

Deep freeze
850 to 630 million years ago

During the 200 million years of the Cryogenian period, the Earth was plunged into some of the deepest cold it has ever experienced – and the emergence of complex life may have caused it.

One theory is that the glaciation was triggered by the evolution of large cells, and possibly also multicellular organisms, that sank to the seabed after dying. This would have sucked CO2 out of the atmosphere, weakening the greenhouse effect and thus lowering global temperatures.

There seem to have been two distinct Cryogenian ice ages: the so-called Sturtian glaciation between 750 and 700 million years ago, followed by the Varanger (or Marinoan) glaciation, 660 to 635 million years ago. There’s some evidence that Earth became a snowball at times during the big freezes, but researchers are still trying to work out exactly what happened.

Mass extinction
460 to 430 million years ago

Straddling the late Ordovician period and the early Silurian period, the Andean-Saharan ice age was marked by a mass extinction, the second most severe in Earth’s history.

The die-off was surpassed only by the gargantuan Permian extinction 250 million years ago. But as the ecosystem recovered after the freeze, it expanded, with land plants becoming common over the course of the Silurian period. And those plants may have caused the next great ice age.

Plants invade the land
360 to 260 million years ago

Like the Cryogenian glaciation, the Karoo ice age featured two peaks in ice cover that may well have been distinct ice ages. They took place in the Mississipian period, 359 to 318 million years ago, and again in the Pennsylvanian 318 to 299 million years ago.

These ice ages may have been the result of the expansion of land plants that followed the Cryogenian. As plants spread over the planet, they absorbed CO2 from the atmosphere and released oxygen (PDF). As a result CO2 levels fell and the greenhouse effect weakened, triggering an ice age.

There is some evidence that the ice came and went in regular cycles, driven by changes in Earth’s orbit. If true, this would mean that the Karoo ice age operated in much the same way as the current one.

Antarctica freezes over
14 million years ago

Antarctica wasn’t always a frozen wasteland. It wasn’t until around 34 million years ago that the first small glaciers formed on the tops of Antarctica’s mountains. And it was 20 million years later, when world-wide temperatures dropped by 8 °C, that the glaciers’ ice froze onto the rock, and the southern ice sheet was born.

This temperature drop was triggered by the rise of the Himalayas. As they grew higher they were exposed to increased weathering, which sucked CO2 out of the atmosphere and reduced the greenhouse effect.

The northern hemisphere remained relatively ice-free for longer, with Greenland and the Arctic becoming heavily glaciated only around 3.2 million years ago.

Latest advance of the ice
2.58 million years ago

The Quaternary glaciation started just a few million years ago – and is still going on. So its history is relatively recent, in geological terms, and can be studied in far more detail than the others’. It’s evident that the ice sheets have gone through multiple stages of growth and retreat over the course of the Quaternary.

During “glacial” stages, the temperature was low and ice extended far away from the poles. During “interglacials”, the temperature was somewhat warmer and the ice retreated. Brief, inconclusive periods of advancing ice – typically lasting less than 10,000 years – are called “stadials”; conversely, periods when the ice retreated, but only briefly, are called “interstadials”.

The main trigger for the Quaternary glaciation was the continuing fall in the level of CO2 in the atmosphere due to the weathering of the Himalayas. However, the timing of the glacials and interglacials was driven by periodic changes in Earth’s orbit that change the amount of sunshine reaching various parts of the planet. The effect of these small orbital changes was amplified by positive feedbacks, such as changes in greenhouse gas levels.

During the first two-thirds of the Quaternary, the ice advanced and retreated roughly every 41,000 years – the same tempo as the changes in the tilt of Earth’s axis. About a million years ago, the ice switched to a 100,000-year cycle for reasons that were until recently a mystery. Now more detailed information about the timing of the ice’s movements may have helped glaciologists find an answer.

To make matters more complicated still, the ice didn’t advance and retreat simultaneously all around the world. Often it would begin advancing on one continent, with the others only being covered thousands of years later, and then linger on a few continents several millennia after it had disappeared from the others.

So there were actually many overlapping glaciations within the Quaternary, each separately named: the Bavelian and Cromerian complexes of glacials and interglacials; the Elsterian glacial; the Holsteinian interglacial and the Saalian glaciation, among others.

Between 130,000 and 114,000 years ago, the ice retreated during the Eemian interglacial – and then advanced again to create the glacial that most people know as “the ice age”.

Our ice age
110,000 to 12,000 years ago

The cool temperatures of the Quaternary may have allowed our brains to become much larger than those of our of hominid ancestors. While that’s still open to debate, it’s plausible that the most recent glacial period left its mark on our species.

Neanderthals, with whom we shared the planet until just before the last glacial maximum, 20,000 years ago, may have struggled to survive as the rising and falling ice ate away at their habitat – although many other explanations for their extinction have been suggested. What is beyond doubt is that Homo sapiens survived and turned to farming soon after the ice retreated, setting the stage for the rise of modern civilisation.

As the glacial period drew to a close and temperatures began to rise, there were two final cold snaps. First, the chilly “Older Dryas” of 14,700 to 13,400 years ago transformed most of Europe from forest to tundra, like modern-day Siberia. After a brief respite, the Younger Dryas, between 12,800 to 11,500 years ago, froze Europe solid within a matter of months – probably as a result of meltwater from retreating glaciers shutting down the Atlantic Ocean’s “conveyor-belt” current, although a cometary impact has also been blamed.

Twelve thousand years ago, the great ice sheets retreated at the beginning of the latest interglacial – the Flandrian – allowing humans to return to northern latitudes. This period has been relatively warm, and the climate relatively stable, although it has been slightly colder than the last interglacial, the Eemian, and sea levels are currently at least 3 metres lower – differences that are being closely scrutinised by researchers keen to understand how our climate will develop.

But this respite from the ice is likely to prove short-lived, at least in geological terms. Human effects on the climate notwithstanding, the cycle will continue to turn, the hothouse period will some day come to an end – and the ice sheets will descend again.





And here is another lil tidbit...


Sahara Desert Was Once Lush and Populated

At the end of the last Ice Age, the Sahara Desert was just as dry and uninviting as it is today. But sandwiched between two periods of extreme dryness were a few millennia of plentiful rainfall and lush vegetation.

During these few thousand years, prehistoric humans left the congested Nile Valley and established settlements around rain pools, green valleys, and rivers.

The ancient climate shift and its effects are detailed in the July 21 issue of the journal Science.

When the rains came

Some 12,000 years ago, the only place to live along the eastern Sahara Desert was the Nile Valley. Being so crowded, prime real estate in the Nile Valley was difficult to come by. Disputes over land were often settled with the fist, as evidenced by the cemetery of Jebel Sahaba where many of the buried individuals had died a violent death.


But around 10,500 years ago, a sudden burst of monsoon rains over the vast desert transformed the region into habitable land.

This opened the door for humans to move into the area, as evidenced by the researcher's 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites.

"The climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany.

Frolicking in pools

In the Egyptian Sahara, semi-arid conditions allowed for grasses and shrubs to grow, with some trees sprouting in valleys and near groundwater sources. The vegetation and small, episodic rain pools enticed animals well adapted to dry conditions, such as giraffes, to enter the area as well.

Humans also frolicked in the rain pools, as depicted in rock art from Southwest Egypt.

In the more southern Sudanese Sahara, lush vegetation, hearty trees, and permanent freshwater lakes persisted over millennia. There were even large rivers, such as the Wadi Howar, once the largest tributary to the Nile from the Sahara.

"Wildlife included very demanding species such as elephants, rhinos, hippos, crocodiles, and more than 30 species of fish up to 2 meters (6 feet) big," Kroepelin told LiveScience.

A timeline of Sahara occupation [See Map]:

• 22,000 to 10,500 years ago: The Sahara was devoid of any human occupation outside the Nile Valley and extended 250 miles further south than it does today.

• 10,500 to 9,000 years ago: Monsoon rains begin sweeping into the Sahara, transforming the region into a habitable area swiftly settled by Nile Valley dwellers.

• 9,000 to 7,300 years ago: Continued rains, vegetation growth, and animal migrations lead to well established human settlements, including the introduction of domesticated livestock such as sheep and goats.

• 7,300 to 5,500 years ago: Retreating monsoonal rains initiate desiccation in the Egyptian Sahara, prompting humans to move to remaining habitable niches in Sudanese Sahara. The end of the rains and return of desert conditions throughout the Sahara after 5,500 coincides with population return to the Nile Valley and the beginning of pharaonic society.

Both articles address the fact of the changing climate as a natural occurrence. There is nothing man has done to bring it about, nor is there anything man can do to stop it.

Perhaps there's some troglodyte living in a cave somewhere that actually doesn't know about ice ages and warming and cooling trends. This isn't news.

Just as obviously humans before the Industrial Revolution had no influence on that. But you can't sit in your easy chair an flatly declare we don't in the present day, simply because it's what you would like to be true. The fact is you have nowhere near the perspective to make such an assessment. At all. That's just delusions-of-omniscience arrogance.

As is the deliberate conflation of "weather" with "climate".

So then explain just what we humans have done in the last 300 years to contribute to the Global Climate Change......and include links to back it up.

I've never taken that position. That would be as arrogant as what you did.

 

[JustAnotherNut]

I've never taken that position

didn't you just say this? Aren't you saying that before 300 years ago (Industrial Revolution) humans had no effect BUT we do in the present day have an effect? I was asking you to explain just what we have contributed to the Global Climate Change and provide some facts to back it up.

Just as obviously humans before the Industrial Revolution had no influence on that. But you can't sit in your easy chair an flatly declare we don't in the present day,

 

[Old Rocks]

Here's some more reading for ya.....

The history of ice on Earth

The history of ice on Earth


By Michael Marshall

Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age.

But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years.

In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the poles and there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over.

Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain.



Snowball Earth
2.4 to 2.1 billion years ago

The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms.

The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect.

Deep freeze
850 to 630 million years ago

During the 200 million years of the Cryogenian period, the Earth was plunged into some of the deepest cold it has ever experienced – and the emergence of complex life may have caused it.

One theory is that the glaciation was triggered by the evolution of large cells, and possibly also multicellular organisms, that sank to the seabed after dying. This would have sucked CO2 out of the atmosphere, weakening the greenhouse effect and thus lowering global temperatures.

There seem to have been two distinct Cryogenian ice ages: the so-called Sturtian glaciation between 750 and 700 million years ago, followed by the Varanger (or Marinoan) glaciation, 660 to 635 million years ago. There’s some evidence that Earth became a snowball at times during the big freezes, but researchers are still trying to work out exactly what happened.

Mass extinction
460 to 430 million years ago

Straddling the late Ordovician period and the early Silurian period, the Andean-Saharan ice age was marked by a mass extinction, the second most severe in Earth’s history.

The die-off was surpassed only by the gargantuan Permian extinction 250 million years ago. But as the ecosystem recovered after the freeze, it expanded, with land plants becoming common over the course of the Silurian period. And those plants may have caused the next great ice age.

Plants invade the land
360 to 260 million years ago

Like the Cryogenian glaciation, the Karoo ice age featured two peaks in ice cover that may well have been distinct ice ages. They took place in the Mississipian period, 359 to 318 million years ago, and again in the Pennsylvanian 318 to 299 million years ago.

These ice ages may have been the result of the expansion of land plants that followed the Cryogenian. As plants spread over the planet, they absorbed CO2 from the atmosphere and released oxygen (PDF). As a result CO2 levels fell and the greenhouse effect weakened, triggering an ice age.

There is some evidence that the ice came and went in regular cycles, driven by changes in Earth’s orbit. If true, this would mean that the Karoo ice age operated in much the same way as the current one.

Antarctica freezes over
14 million years ago

Antarctica wasn’t always a frozen wasteland. It wasn’t until around 34 million years ago that the first small glaciers formed on the tops of Antarctica’s mountains. And it was 20 million years later, when world-wide temperatures dropped by 8 °C, that the glaciers’ ice froze onto the rock, and the southern ice sheet was born.

This temperature drop was triggered by the rise of the Himalayas. As they grew higher they were exposed to increased weathering, which sucked CO2 out of the atmosphere and reduced the greenhouse effect.

The northern hemisphere remained relatively ice-free for longer, with Greenland and the Arctic becoming heavily glaciated only around 3.2 million years ago.

Latest advance of the ice
2.58 million years ago

The Quaternary glaciation started just a few million years ago – and is still going on. So its history is relatively recent, in geological terms, and can be studied in far more detail than the others’. It’s evident that the ice sheets have gone through multiple stages of growth and retreat over the course of the Quaternary.

During “glacial” stages, the temperature was low and ice extended far away from the poles. During “interglacials”, the temperature was somewhat warmer and the ice retreated. Brief, inconclusive periods of advancing ice – typically lasting less than 10,000 years – are called “stadials”; conversely, periods when the ice retreated, but only briefly, are called “interstadials”.

The main trigger for the Quaternary glaciation was the continuing fall in the level of CO2 in the atmosphere due to the weathering of the Himalayas. However, the timing of the glacials and interglacials was driven by periodic changes in Earth’s orbit that change the amount of sunshine reaching various parts of the planet. The effect of these small orbital changes was amplified by positive feedbacks, such as changes in greenhouse gas levels.

During the first two-thirds of the Quaternary, the ice advanced and retreated roughly every 41,000 years – the same tempo as the changes in the tilt of Earth’s axis. About a million years ago, the ice switched to a 100,000-year cycle for reasons that were until recently a mystery. Now more detailed information about the timing of the ice’s movements may have helped glaciologists find an answer.

To make matters more complicated still, the ice didn’t advance and retreat simultaneously all around the world. Often it would begin advancing on one continent, with the others only being covered thousands of years later, and then linger on a few continents several millennia after it had disappeared from the others.

So there were actually many overlapping glaciations within the Quaternary, each separately named: the Bavelian and Cromerian complexes of glacials and interglacials; the Elsterian glacial; the Holsteinian interglacial and the Saalian glaciation, among others.

Between 130,000 and 114,000 years ago, the ice retreated during the Eemian interglacial – and then advanced again to create the glacial that most people know as “the ice age”.

Our ice age
110,000 to 12,000 years ago

The cool temperatures of the Quaternary may have allowed our brains to become much larger than those of our of hominid ancestors. While that’s still open to debate, it’s plausible that the most recent glacial period left its mark on our species.

Neanderthals, with whom we shared the planet until just before the last glacial maximum, 20,000 years ago, may have struggled to survive as the rising and falling ice ate away at their habitat – although many other explanations for their extinction have been suggested. What is beyond doubt is that Homo sapiens survived and turned to farming soon after the ice retreated, setting the stage for the rise of modern civilisation.

As the glacial period drew to a close and temperatures began to rise, there were two final cold snaps. First, the chilly “Older Dryas” of 14,700 to 13,400 years ago transformed most of Europe from forest to tundra, like modern-day Siberia. After a brief respite, the Younger Dryas, between 12,800 to 11,500 years ago, froze Europe solid within a matter of months – probably as a result of meltwater from retreating glaciers shutting down the Atlantic Ocean’s “conveyor-belt” current, although a cometary impact has also been blamed.

Twelve thousand years ago, the great ice sheets retreated at the beginning of the latest interglacial – the Flandrian – allowing humans to return to northern latitudes. This period has been relatively warm, and the climate relatively stable, although it has been slightly colder than the last interglacial, the Eemian, and sea levels are currently at least 3 metres lower – differences that are being closely scrutinised by researchers keen to understand how our climate will develop.

But this respite from the ice is likely to prove short-lived, at least in geological terms. Human effects on the climate notwithstanding, the cycle will continue to turn, the hothouse period will some day come to an end – and the ice sheets will descend again.





And here is another lil tidbit...


Sahara Desert Was Once Lush and Populated

At the end of the last Ice Age, the Sahara Desert was just as dry and uninviting as it is today. But sandwiched between two periods of extreme dryness were a few millennia of plentiful rainfall and lush vegetation.

During these few thousand years, prehistoric humans left the congested Nile Valley and established settlements around rain pools, green valleys, and rivers.

The ancient climate shift and its effects are detailed in the July 21 issue of the journal Science.

When the rains came

Some 12,000 years ago, the only place to live along the eastern Sahara Desert was the Nile Valley. Being so crowded, prime real estate in the Nile Valley was difficult to come by. Disputes over land were often settled with the fist, as evidenced by the cemetery of Jebel Sahaba where many of the buried individuals had died a violent death.


But around 10,500 years ago, a sudden burst of monsoon rains over the vast desert transformed the region into habitable land.

This opened the door for humans to move into the area, as evidenced by the researcher's 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites.

"The climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany.

Frolicking in pools

In the Egyptian Sahara, semi-arid conditions allowed for grasses and shrubs to grow, with some trees sprouting in valleys and near groundwater sources. The vegetation and small, episodic rain pools enticed animals well adapted to dry conditions, such as giraffes, to enter the area as well.

Humans also frolicked in the rain pools, as depicted in rock art from Southwest Egypt.

In the more southern Sudanese Sahara, lush vegetation, hearty trees, and permanent freshwater lakes persisted over millennia. There were even large rivers, such as the Wadi Howar, once the largest tributary to the Nile from the Sahara.

"Wildlife included very demanding species such as elephants, rhinos, hippos, crocodiles, and more than 30 species of fish up to 2 meters (6 feet) big," Kroepelin told LiveScience.

A timeline of Sahara occupation [See Map]:

• 22,000 to 10,500 years ago: The Sahara was devoid of any human occupation outside the Nile Valley and extended 250 miles further south than it does today.

• 10,500 to 9,000 years ago: Monsoon rains begin sweeping into the Sahara, transforming the region into a habitable area swiftly settled by Nile Valley dwellers.

• 9,000 to 7,300 years ago: Continued rains, vegetation growth, and animal migrations lead to well established human settlements, including the introduction of domesticated livestock such as sheep and goats.

• 7,300 to 5,500 years ago: Retreating monsoonal rains initiate desiccation in the Egyptian Sahara, prompting humans to move to remaining habitable niches in Sudanese Sahara. The end of the rains and return of desert conditions throughout the Sahara after 5,500 coincides with population return to the Nile Valley and the beginning of pharaonic society.

Both articles address the fact of the changing climate as a natural occurrence. There is nothing man has done to bring it about, nor is there anything man can do to stop it.

Perhaps there's some troglodyte living in a cave somewhere that actually doesn't know about ice ages and warming and cooling trends. This isn't news.

Just as obviously humans before the Industrial Revolution had no influence on that. But you can't sit in your easy chair an flatly declare we don't in the present day, simply because it's what you would like to be true. The fact is you have nowhere near the perspective to make such an assessment. At all. That's just delusions-of-omniscience arrogance.

As is the deliberate conflation of "weather" with "climate".

So then explain just what we humans have done in the last 300 years to contribute to the Global Climate Change......and include links to back it up.

Very easy to do. First, we have increased the GHGs in the atmosphere very significantly. CO2 by over 40%, CH4 by about 250%. Second, we know from the absorption spectra of CO2 and CH4 that they absorb longwave IR, and warm the atmosphere, and, by back radiaton, the ground.

And here is a presentation to the AGU by one of the top scientists and glaciaologists on earth, Dr. Richard Alley that discusses the known historical affect of CO2;



You see, GHGs don't care whether they came from a Trapp volcanic eruption cooking coal seams, or mankind burning fossil fuels, they simply do what the physics say they should do.