On Jan 17, 5:03 pm, Michael Lewis <[email protected]> wrote: > The problem with these kinds of studies is that they exhibit > correlation, not cause and effect. We don't know which came first, > temperature rise or CO2 concentration rise. In fact, much of the data > suggests that temperature rise precedes CO2 rise by 200 to 800 years in > some cases.
It is fairly clear that the warming that takes us out of glacial periods is caused by changes in the eccentricity of the Earth's orbit which results in the planet receiving more solar isolation. But the increase in temperature is far greater than the changes in solar energy can explain. It seems that the warming is amplified by subsequent releases of carbon dioxide from the warmer ocean. This explains why the rise in CO2 follows the rise in temperature, and also why the rise is so steep. The increase in temperature causes more CO2 and more CO2 causes the temperature to rise. There is a runaway temperature rise caused by the positive feedback from the greenhouse effect of carbon dioxide. > Alastair wrote: > > My spin is that without the Arctic sea ice, which did not exist in the > > Pliocene, then we will get an abrupt rise of between 2 to 4C. The > > rise will be even higher the closer to the North Pole you live. > > Arctic sea ice is a symptom, not a cause. Yes, the albedo changes, > but has little effect on sea temperatures at northern latitudes. The melting of the Arctic sea ice is a symptom of the increase in carbon dioxide. However, just as carbon dioxide is not the initial cause of the exit from a glacial but leads to a rapid warming, so too the melting of the sea ice is not an initial cause. However, when the sea ice disappears there will be rapid warming as the planet tries to adjust to the loss of albedo. It can only do that by creating more cloud, and cloud does not seem to increase in a linear fashion with increase in surface temperature. Moreover, cloud is a strong greenhouse agent. Thus after the cloud increases to balance the radiation at the top of the atmosphere (TOA) the temperature at the surface may be considerably than at present. Prof. Ray Pierrehumbert discusses the difference between the TOA balance and the surface temperature here: http://www.realclimate.org/index.php/archives/2010/01/plass-and-the-surface-budget-fallacy/ > The fact that scientists and politicians rapidly change their > conclusions and interpretations of data does not mean climate change > will be rapid as well. Climate change is what it is. It is not really true that scientists and politicians rapidly change their minds. No one likes to admit that they are wrong, whether they are scientists, politicians or just ordinary people like you and me! In fact in the previous post to RealClimate http://www.realclimate.org/index.php/archives/2010/01/the-carbon-dioxide-theory-of-gilbert-plass/ Gavin shows how thinking on greenhouse induced climate change is still the same as in 1950s. > We still don't know what's happening with Greenland and Antarctica. > Some parts are cooling, some parts are warming. Some glaciers are > receding some are advancing. Time will tell. There are some anomalies in Antarctica due to the ozone hole but otherwise glaciers are melting everywhere else in the world. The sceptics love to point out those anomalies, since it justifies their continued use of their beloved SUV, but it is just spin. The fact is that climate is spinning out of control, and there is now no prospect that Obama can stop it, far less persuade the Chinese to come on board :-( Cheers, Alastair. -- You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/globalchange
