Arctic heat

[ding]

Do you believe that human GHG emissions are the primary cause of warming observed over the last 100 years?

No. I believe they do have an effect though. Why do I believe that? Because temperatures did not reach the level predicted by radiative forcing of CO2.

How much do you believe temperatures have risen?

 

[Crick]

I believe this is accurate:

https://www.nasa.gov/sites/default/files/thumbnails/image/2016temperature.png

 

[ding]

I believe this is accurate:

https://www.nasa.gov/sites/default/files/thumbnails/image/2016temperature.png

Ok, and how much associated temperature does radiative forcing predict using the starting and ending CO2 levels for this time period?

 

[Crick]

To which component of radiative forcing do you refer?

 

[ding]

To which component of radiative forcing do you refer?

Ok, so 1.68 C, right?

 

[Crick]

If you actually want an answer to your question, you're going to have to supply the particular prediction to which you refer and the actual start and end dates of the "period" you mention. Given that isotopic analysis shows virtually every bit of increased CO2 in the atmosphere is the result of fossil fuel combustion and methane and CFCs are also there as a direct or indirect result of other human activity and the warming it has produced, I would say that virtually all of the warming seen since 1750 is the result of the Greenhouse effect acting on atmospheric GHGs whose levels have been increased almost solely due to human activity. Solar activity is down. If you have another source, please let us know.

Ps: I would have said ~1C was closer than 1.68C. Where did you find that number?

 

[ding]

If you actually want an answer to your question, you're going to have to supply the particular prediction to which you refer and the actual start and end dates of the "period" you mention. Given that isotopic analysis shows virtually every bit of increased CO2 in the atmosphere is the result of fossil fuel combustion and methane and CFCs are also there as a direct or indirect result of other human activity and the warming it has produced, I would say that virtually all of the warming seen since 1750 is the result of the Greenhouse effect acting on atmospheric GHGs whose levels have been increased almost solely due to human activity. Solar activity is down. If you have another source, please let us know.

Ps: I would have said ~1C was closer than 1.68C. Where did you find that number?

Sorry, that was 1.68 W/m2 in the table in post #44. Which equates to 1.26 C. If we use C= 5.35*ln400/280*.75 we get 1.43 C. This assumes that CO2 is the only forcing and it still overestimate the temperature gain that you posted in post #46.

 

[Crick]

So, what's your point?

 

[ding]

So, what's your point?

That their models are flawed.

 

[CrusaderFrank]

Is there any lab work at all showing how a 120ppm increase in CO2 will raise temperature by 1C?

 

[ScienceRocks]

Is there any lab work at all showing how a 120ppm increase in CO2 will raise temperature by 1C?

Physics and models..There's no way to do what you're saying in a fish tank.

 

[ding]

Is there any lab work at all showing how a 120ppm increase in CO2 will raise temperature by 1C?

There is a GHG effect. This we know for sure, but the largest effect is at very low concentrations. That's because there is a logarithmic relationship between CO2 concentration and associated temperature. Which means that as CO2 concentration increases the incremental temperature associated with the CO2 increase diminishes. So a 120 ppm increase from 0 to 120 would have a much bigger impact (19.21 C) than a 120 ppm increase from 280 to 400 ppm (24.04 - 19.21 = 1.43 C)

 

[Old Rocks]

Is there any lab work at all showing how a 120ppm increase in CO2 will raise temperature by 1C?

There is a GHG effect. This we know for sure, but the largest effect is at very low concentrations. That's because there is a logarithmic relationship between CO2 concentration and associated temperature. Which means that as CO2 concentration increases the incremental temperature associated with the CO2 increase diminishes. So a 120 ppm increase from 0 to 120 would have a much bigger impact (19.21 C) than a 120 ppm increase from 280 to 400 ppm (24.04 - 19.21 = 1.43 C)

View attachment 99694

View attachment 99697

Please, link to your source.

 

[Old Rocks]

Ding, which models showed what we are seeing in the Arctic right now? Seems to me that the models have all been on the conservative side in relation to the cryosphere.

 

[ding]

Is there any lab work at all showing how a 120ppm increase in CO2 will raise temperature by 1C?

There is a GHG effect. This we know for sure, but the largest effect is at very low concentrations. That's because there is a logarithmic relationship between CO2 concentration and associated temperature. Which means that as CO2 concentration increases the incremental temperature associated with the CO2 increase diminishes. So a 120 ppm increase from 0 to 120 would have a much bigger impact (19.21 C) than a 120 ppm increase from 280 to 400 ppm (24.04 - 19.21 = 1.43 C)

View attachment 99694

View attachment 99697

Please, link to your source.

Ok.

Radiative forcing - Wikipedia

Carbon dioxide radiates within a narrow frequency spectrum. The first parts per million has the strongest effect. The more CO2 you add, the smaller the outcome. Each additional doubling has the same effect on temperature. From 0 to 280 ppm the increase is the same as from 280 to 560, and the same as from 560 to 1120, and so on. It’s like adding layers of blankets when it really cold. The first one does most of the work. The logarithmic relationship is accepted by the IPCC and is used in their models.

Guy Callendar, an English engineer, was the first person to discuss this in paper he wrote in 1938.

The Carbon Dioxide Greenhouse Effect

Forcing due to atmospheric gas[edit]
For a greenhouse gas, such as carbon dioxide, radiative transfer codes that examine each spectral line for atmospheric conditions can be used to calculate the change ΔF as a function of changing concentration. These calculations can often be simplified into an algebraic formulation that is specific to that gas.

For instance, the simplified first-order approximation expression for carbon dioxide is:

where C is the CO2 concentration in parts per million by volume and C0 is the reference concentration.[6] The relationship between carbon dioxide and radiative forcing is logarithmic[7] and thus increased concentrations have a progressively smaller warming effect.

A different formula applies for other greenhouse gases such as methane and N2O (square-root dependence) or CFCs (linear), with coefficients that can be found e.g. in the IPCC reports.[8]

To convert forcing to temperature, multiple F which is in W/m^2 times 0.75 which is in degrees C per W/m^2

 

[ding]

Ding, which models showed what we are seeing in the Arctic right now? Seems to me that the models have all been on the conservative side in relation to the cryosphere.

I'm glad you brought that up. Global warming is an inaccurate term. It really should be called polar warming. I suspect all of the models will show increased polar temperatures at the polar region. The question I have is the time between CO2 change and temperature change. This is why I don't believe that CO2 drives the climate. It reinforces the climate.

 

[Old Rocks]

Just polar heating? Then how do you explain the worldwide recession of the alpine glaciers?

 

[ding]

Just polar heating? Then how do you explain the worldwide recession of the alpine glaciers?

You are an idiot. The temperature changes are mainly at the polar regions. That's where the greatest changes will occur. If you don't believe me go ask your high priests of climate religion.

 

[Old Rocks]

Yes, of course, the greatest changes occur in the polar regions. But the alpine glaciers are going away, also. And that will have major effects in areas dependent on summer melt for agriculture. And, of course, the melting of the alpine glaciers adds a bit to the sea level rise.

 

[ding]

Yes, of course, the greatest changes occur in the polar regions. But the alpine glaciers are going away, also. And that will have major effects in areas dependent on summer melt for agriculture. And, of course, the melting of the alpine glaciers adds a bit to the sea level rise.

That's what happens in an interglacial period. Nothing new there.