Re: Is Global Warming going to precipitate an Ice Age?

[Frederick Sparber]

One could envision a natural 25,000 year cycle of global warming caused by

methane and CO2 release due to biological activity and fires with subsequent ice ages .

 

Would water vapor from oxidation of methane (CH4) produce a high

altitude cloud formation/ice albedo?

 

Are we speeding up such a cycle?

 

 

http://www.physicalgeography.net/fundamentals/7f.html

 

http://nsidc.org/arcticmet/patterns/feedback_loops.html

Temperature—Cloud Cover—Radiation Feedbacks

" Feedbacks between temperature, cloud cover and radiation are potentially important agents of climate change. However, they are not well understood and research in this area is active."

" It is thought that if climate warms, evaporation will also increase, in turn increasing cloud cover. Because clouds have high albedo, more cloud cover will increase the earth's albedo and reduce the amount of solar radiation absorbed at the surface. Clouds should therefore inhibit further rises in temperature. This temperature—cloud cover—radiation feedback is negative as the initial temperature change is dampened."

" However, cloud cover also acts as a blanket to inhibit loss of longwave radiation from the earth's atmosphere. By this process, an increase in temperature leading to an increase in cloud cover could lead to a further increase in temperature - a positive feedback."

" Knowing which process dominates is a complex issue. Cloud type plays a strong role, as do cloud water content and particle size. Another factor is whether the cloud albedo is higher or lower than that of the surface. Research indicates that the effect of this feedback in the Arctic may be different than in other latitudes. Except in summer, arctic clouds seem to have a warming effect. This is because the blanket effect of clouds tends to dominate over reductions in shortwave radiation to the surface caused by the high cloud albedo."

Frederick