Global Temperature: What Is The Issue?

The fundamental question is not whether global temperatures have risen from the 1970s to the 1990s. The rise is demonstrably true. The question is whether the rise in temperature represents a cycle or a long-term (in geological terms) trend. The IPCC concludes (point 1) that the rise represents a long-term trend and (point 2) that the rising trend is physically caused by increase in CO2, which (point 3) is based on a geological-environmental theory that atmospheric CO2 levels are the driver of climate change over geological time periods. The reason that some observers are skeptical of the IPCC conclusions (1 and 2) is that it is a very long inferential jump from the evidence regarding temperature rise from 1970s to 1990s to the IPCC conclusions to the CO2 theory (point 2). Points 1 and 2 are based on correlational analyses that are subject to serious anomalies (e.g., sunspot cycle, El nino cycle). Repeating and reillustrating the facts about the rise in temperatures of the recent decades does nothing to make the IPCC conclusions more credible. It is not serious scientific debate to argue that charts of the temperature rise prove any hypotheses about causation; it is only political hectoring that demeans science.