A broad summary of the real data supporting global warming concerns is available at:
Larry’s blindspots

1) Antarctic data suggests temperatures and greenhouse gas concentrations have been closely linked over the last 200,000 years with a 12 degree change corresponding to factor of 2 variations in GHG concentrations.

2) The rise in human CO2 emissions corresponds to a rise in CO2 concentration over the last 150 years from about 285 ppmv to 360 ppmv with the majority occurring in the last 50 years. This is after a 900 year period of stability.

3) Global mean temperatures have risen 1 degC over the last 150 years with most during the last 50 years (About half what one would expect if the global change was 1/4 the change seen in Antarctica for a similar change in CO2=see details below).

GHG and Antarctic Temperatures

An obvious correlation between the GHGs methane (CH4) and carbon dioxide (CO2) over the last 200,000 years exists based on the data presented on page 2 from the 1994 IPCC conference. This data indicates Antarctic temperatures have varied over about a 12 degree range with concentrations of CO2 and CH4 varying by about a factor of 2. The CO2 levels are about 500 times higher than CH4 levels. No computer models here, just real data. Now this data does not prove that CO2 caused the warming or even methane. Temperature changes could possibly have cause atmospheric composition changes, but this data alone is strong evidence for a correlation between all three.

Lab data clearly indicates both CO2 and CH4 are greenhouse gases. This independent observation indicates that increasing either Methane or CO2 should increase temperature and be the driving forces. Lab data also indicates that Methane is a far stronger GHG than CO2. I’ve read that in several sources but don’t know how much stronger. Based on several small temperature spikes in the graph that seem to correlate more with the methane than CO2 I’d guess CH4 is at least several hundred times stronger in order to have the observed impact of a similar scale to CO2 at 1/500 the concentration. However if GWP stands for global warming potential or something with a similar meaning CH4 is listed as 21 times as strong as CO2 on page 5.

To summarize from lab data and the Antarctic data we have good reason to believe CO2 and/or CH4 have contributed strongly to global warming in the past. Temperature could be part of an overall positive feedback loop enforcing the three way correlation but the wondering nature of the data does not indicate such a loop. Of concern to me personally is why CO2 and Methane should be linked. Does rising CO2 drive CH4 up, the reverse, or does a natural force drive both? We now know there are sources of methane in the ocean that would could released as ocean temperatures warm accelerating the warming caused by CO2 alone. This suggests to me that CO2 is the primary driving force with a secondary addition from methane. I have read of concern over the ocean stores of methane being released by GW but not any tie to this Antarctic data.

Global mean temperatures varied as much as 3 degrees C over the same period with the coming and going of ice ages. This data indicates we see major climactic changes with modest mean temperature changes with temperature ranges increasing towards the poles. It also suggests roughly a 1/4 correlation between antarctic temperature changes and global averages.

CO2 Emissions and Concentrations

To go from what CO2 and CH4 can do to what we are doing requires looking at pages 3,4, and 21. The rise in CO2 concentration also appears to correlate with emissions. Temperature changes also seem to correlate although not as clearly. The Two CO2 graphs clearly contradict the “our emissions are two small to matter” argument. That argument overlooks the fact that natural systems are clearly fairly balanced over the short term based on the 1000-year data graph and Earth’s general climactic history of stability over thousand year time scales. We are also talking about small concentrations of CO2 having strong impacts. The amount of CO2 we have added is consistent with the rise measured (try the math) but I guess that is just another inconvenient coincidence for many.

Plugging in the laboratory data for CO2 and CH4 into energy balances based on CO2 and Methane levels should be easy. The hard part is predicting how much of GHG emissions remain in the atmosphere. The data clearly show we should be concerned about our CO2 emissions. The fact that our models are not yet proven enough to concretely predict what will happen is no reason to ignore the real data showing increasing CO2 concentrations are likely to lead to global warming.

Now while I consider predictions of actual effects far more speculative than that continued increases in CO2 will cause global warming, the predictions based on our best understanding are also available at the link above and are rather worrisome in many ways.

Now lets play a little Occam’s razor and try to find the simplest explanation for all the correlations in 1, 2 , and 3.

Debating what we should do about the situation and weighing the costs of doing nothing versus the costs of doing something makes since. Sticking our heads in the sand in denial does not.

Regards,
Mark