CrusaderFrank
Diamond Member
- May 20, 2009
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- #81
Correct. CO2 is a miniscule GHG compared to water vapor which is THE dominant GHG.It is late so I will check this in the morning. But to understand you correctly you disagree with:
"Carbon dioxide (CO2) is the primary greenhouse gas emitted through human activities. In 2010, CO2 accounted for about 84% of all U.S. greenhouse gas emissions from human activities."
Carbon Dioxide Emissions | Climate Change | US EPA
Say good-night to Cleo with the solar fan for me.
In the real world, CO2 accounts for about 20% of global warming, which is only "miniscule" when seen through crazy denier cult eyes. Of course, the really important point is that CO2 is a 'forcing' that doesn't just raise temperatures on its own but also causes 'feedbacks', of which water vapor is one, such that the temperature increase created by the increased CO2 levels causes more water to evaporate thus raising the water vapor levels in the atmosphere which increases the greenhouse effect, further raising the temperatures.
Climate myths: CO2 isn't the most important greenhouse gas
New Scientist
by David L Chandler
(excerpts)
Water is a major greenhouse gas too, but its level in the atmosphere depends on temperature. Excess water vapour rains out in days. Excess CO2 accumulates, warming the atmosphere, which raises water vapour levels and causes further warming. Firstly, there is the greenhouse effect, and then there is global warming. The greenhouse effect is caused by certain gases (and clouds) absorbing and re-emitting the infrared radiating from Earth's surface. It currently keeps our planet 20°C to 30°C warmer than it would be otherwise. Global warming is the rise in temperatures caused by an increase in the levels of greenhouse gases due to human activity.
Water vapour is by far the most important contributor to the greenhouse effect. Pinning down its precise contribution is tricky, not least because the absorption spectra of different greenhouse gases overlap. At some of these overlaps, the atmosphere already absorbs 100% of radiation, meaning that adding more greenhouse gases cannot increase absorption at these specific frequencies. For other frequencies, only a small proportion is currently absorbed, so higher levels of greenhouse gases do make a difference. This means that when it comes to the greenhouse effect, two plus two does not equal four. If it were possible to leave the clouds but remove all other water vapour from the atmosphere, only about 40% less infrared of all frequencies would be absorbed. Take away the clouds and all other greenhouses gases, however, and the water vapour alone would still absorb about 60% of the infrared now absorbed.
By contrast, if CO2 alone was removed from the atmosphere, only 15% less infrared would be absorbed. If CO2 was the only greenhouse gas, it would absorb 26% of the infrared currently absorbed by the atmosphere. A simplified summary is that about 50% of the greenhouse effect is due to water vapour, 25% due to clouds, 20% to CO2, with other gases accounting for the remainder. But the overall quantities of these other gases are tiny. Even allowing for the relative strength of the effects, CO2 is still responsible for two-thirds of the additional warming caused by all the greenhouse gases emitted as a result of human activity. Water vapour will play a huge role in the centuries to come, though. Climate models, backed by satellite measurements, suggest that the amount of water vapour in the upper troposphere (about 5 to 10 kilometres up) will double by the end of this century as temperatures rise. This will result in roughly twice as much warming than if water vapour remained constant. Changes in clouds could lead to even greater amplification of the warming or reduce it - there is great uncertainty about this. What is certain is that, in the jargon of climate science, water vapour is a feedback, but not a forcing.
So, it's H2O as the primary GHG dwarfing CO2.
Thank you for that.
"Even allowing for the relative strength of the effects, CO2 is still responsible for two-thirds of the additional warming caused by all the greenhouse gases emitted as a result of human activity" Translation, CO2 is still a rounding error but with tricky sentence structure we can make it appear that its responsible for 2/3 of the warming