The way that climate change is argued is often rather inventive and repeatedly lacking in any proof of a causal relationship between the factors being considered, there is no more tenuous relationship than the one claimed for CO2 and temperature, the piece I quote below postulates a different cause for climate change and it also suggests a strategy that will undoubtedly be attractive to many AGW enthusiasts of the Latte sipping variety.
Statistical climate reconstruction techniques using the CLIVAR model produced accurate temperature anomalies for Middle America and Valley of Mexico region for various time periods. Several independent proxy data sets, including the invaluable new Codex data on sacrificial frequencies and corn yield, were used to derive estimates of regional spatial temperature covariance patterns (corrected for atmospheric absorption) and amplitude changes in them through time. A modified principal component analysis technique was used to optimise this combination of spatial and temporal information. Verification statistics obtained from data subsets confirmed the validity of the CLIVAR reconstructions.
The reconstructions confirm, on the balance of probabilities, that the major forcing agent determining regional temperature anomalies was the frequency of human sacrifice. Cooler periods, for example, showed an impressive causal connectivity with (lagging) high sacrificial numbers. Sacrificial frequency also directly influenced local rainfall patterns and corn yields.
There were other intriguing outcomes too. For example, young male sacrifices were statistically the largest percentile and tended to drive cooler weather, while female sacrifice produced warmer weather. The meteorological outcomes of child and animal sacrifice were less clear, and probably masked by the adult groups.
Recent research by David Lobell and Christopher Field concluded that wheat, maize and barley yields decline with increased temperatures. Annual global temperatures have increased by about 0.04 degrees since 1980, with even larger changes in some regions. This has had a negative impact on crop yields and produced serious losses.
I would suggest though that if they are really genuine in their belief in AGW that the Latte sippers should all put their names down to be the new sacrifices on the altar of Gaia, and if they refuse then we will know that their faith is somewhat shallow.