IPCC Dec 2012

The IPCC continues to work on its Fifth Assessment Report Climate Change 2013: The Physical Science Basis. https://www.ipcc-wg1.unibe.ch/

As usual, there are conflicting reports about the science. 

Some claim the IPCC projections have been accurate. For a detailed analysis, look here: http://www.skepticalscience.com/contary-to-contrarians-ipcc-temp-projections-accurate.html
 
Others disagree. The Wall St. Journal published an editorial by Matt Ridley that evaluates early reports from Nic Lewis. http://online.wsj.com/article/SB10001424127887323981504578179291222227104.html?mod=opinion_newsreel#

I found Mr. Ridley's concluding paragraph reasonable and consistent with my own views, to an extent. Excerpts from his piece are in Georgia font.

The scientists at the IPCC next year have to choose whether they will admit—contrary to what complex, unverifiable computer models indicate—that the observational evidence now points toward lukewarm temperature change with no net harm. On behalf of all those poor people whose lives are being ruined by high food and energy prices caused by the diversion of corn to biofuel and the subsidizing of renewable energy driven by carboncrats and their crony-capitalist friends, one can only hope the scientists will do so.

Contrary to Mr Ridley's rhetoric, though, I think it's important to subsidize renewable energy projects, purely to advance the science. Certainly the corn-ethanol program has been a fiasco, and the mandates to utilities are creating unjustified windfalls and inefficiencies. Still, I think scientific progress requires investments that are not necessarily economically viable at the present. It's the forced commercialization of intermediate technology that is irrational and counterproductive, like the many windmills I've seen that have been abandoned long before their projected useful lives because maintenance costs are too high and the equipment itself is obsolete.

Here are excerpts from Mr. Ridley's comments on the science. Obviously, since the information is not yet public, I can't comment on the accuracy of these statements, but they do seem consistent with the actual data that has been made public over the years, which is inconsistent with the IPCC's projections:

In short: We can now estimate, based on observations, how sensitive the temperature is to carbon dioxide. We do not need to rely heavily on unproven models. Comparing the trend in global temperature over the past 100-150 years with the change in "radiative forcing" (heating or cooling power) from carbon dioxide, aerosols and other sources, minus ocean heat uptake, can now give a good estimate of climate sensitivity.

The conclusion—taking the best observational estimates of the change in decadal-average global temperature between 1871-80 and 2002-11, and of the corresponding changes in forcing and ocean heat uptake—is this: A doubling of CO2 will lead to a warming of 1.6°-1.7°C (2.9°-3.1°F).

This is much lower than the IPCC's current best estimate, 3°C (5.4°F)....

Next he brings up a point made by Cass Sunstein years ago. Sunstein observed that global warming will benefit North America and China, which was one reason why the U.S. and China were not focusing on climate change as much as other countries. Some people were skeptical of that. Now, with years of observational evidence, it appears there's a factual basis for Sunstein's conclusion (which is not really his, but given his political affiliation, he attracted considerable attention to this view). 

A cumulative change of less than 2°C by the end of this century will do no net harm. It will actually do net good—that much the IPCC scientists have already agreed upon in the last IPCC report. Rainfall will increase slightly, growing seasons will lengthen, Greenland's ice cap will melt only very slowly, and so on....

In my view, the IPCC has long reflected more of a focus on environmental justice than on pure science, and the observational data bears this out. While the precautionary principle is a valid consideration, it has been stretched to the breaking point by exaggerated claims and predictions (see Al Gore). I do think there's a legitimate argument for policies that promote economic and environmental justice, but to base the argument on faulty science is a huge mistake. So I like the way Mr. Ridley asks the bottom line question:

The big question is this: Will the lead authors of the relevant chapter of the forthcoming IPCC scientific report acknowledge that the best observational evidence no longer supports the IPCC's existing 2°-4.5°C "likely" range for climate sensitivity? Unfortunately, this seems unlikely—given the organization's record of replacing evidence-based policy-making with policy-based evidence-making, as well as the reluctance of academic scientists to accept that what they have been maintaining for many years is wrong....

It will be fascinating to see how the IPCC treats the observational evidence. To date, they haven't done a very good job acknowledging evidence inconsistent with their projections, let alone adapting their official statements to reflect this evidence.