Clouds are indeed one of the more difficult aspects of climate to model. Low clouds can indeed reflect sunlight back into space. However high clouds can provide an insulating effect and retain heat in the atmosphere. That is why cloudy nights are usually less cold than clear nights.Josh wrote: ↑Sat Jun 17, 2023 2:51 pmI agree with #5:Ken wrote: ↑Sat Jun 17, 2023 2:33 pmWhich part of the following do you disagree with?
1. That CO2 has inherent "greenhouse" effects that trap heat in the atmosphere rather than allowing it to radiate back out to outer space?
2. That the atmospheric concentrations of greenhouse gases affects the earth's climate?
3. That humans are increasing the concentrations of greenhouse gases in the atmosphere through their industrial activities?
4. That a warming climate will have negative affects and costs for both human civilization and the environment?
5. CO2 can also cause cooling from increased cloud cover where the sun's rays are radiated back into space; the earth has a lot of self-regulating mechanisms so that it does not enter runaway feedback loops. (If it didn't, the earth's oceans and atmosphere would have boiled off a long time ago.)
6. There is plenty of evidence in the fossil record, etc. that CO2 concentrations may have been much larger in the past.
But what you are missing is the fact that a warmer atmosphere is likely to have less clouds because a warmer atmosphere can absorb more water vapor. Clouds are not water vapor in gas form. They are composed of droplets of liquid water that have condensed when warmer air cools, but that are not yet large enough for gravity to pull them back to earth in the form of rain or snow. A hotter atmosphere can hold more water vapor without forming clouds. And those water molecules themselves act as greenhouse gases just like CO2.
For those reasons, climate models actually predict fewer low clouds over tropical regions as the planet warms and more high clouds over high latitude arctic regions, both of which could accelerate warming, not reduce it. But again, it is a complex and difficult thing to model because there are so many variables.
As for the fossil record? There is also evidence from the fossil record that every mass extinction going back to the Permian extinction was related to atmospheric climate change. In fact research into the Permian extinction, which wiped up perhaps 90% of life on earth, suggests that it was directly caused by both methane and carbon dioxide emissions.
So if you want to rely on the fossil record, it tells us that greenhouse gases can indeed cause mass extinctions. As well as the flooding of the continents and also ice ages.
