Is CO2 the most significant greenhouse gas?
Those that believe that the increase in CO2 will have little effect on the climate (hypothesis 2), have this opinion, as they believe that water vapour not CO2 is the most important greenhouse gas. Soon et al. (1999), suggest that climate change prediction models do not handle water vapour feedback correctly, however substantial research in to water vapour feedback has taken place since these claims were made back in 1999 (Held and Soden, 2000; Hall and Manabe, 1999). The paper also argues that cooling from negative feedback as a result of greenhouse gases will even out temperatures after an initial increase. Low altitude cloud cover is an example of a negative feedback process. Additional water vapour in the atmosphere increases cloud cover, which acts to cool the earth ( http://www.newscientist.com ). Critics also stress that greenhouse gases are present naturally, and in the past have helped keep the earth at ambient temperature for life to exist and thrive. The greenhouse gases are
