Contaminated Global Warming Data

Hot cities, not CO2, cause urban thermometers to rise

Ross McKitrick, Financial Post Published: Wednesday, December 05, 2007

Below is the famous graph of "global average surface temperature," or "global temperature" for short. (please follow post title link to view graph) The data come from thermometers around the world, but between the thermometer readings and the final, famous, warming ramp, a lot of statistical modelling aims at removing known sources of exaggeration in the warming trend. In a new article just published in the Journal of Geophysical Research -- Atmospheres, a co-author and I have concluded that the manipulations for the steep post-1980 period are inadequate, and the above graph is an exaggeration. Along the way, I have also found that the United Nations agency promoting the global temperature graph has made false claims about the quality of its data.

Carbon Dioxide and the Ocean Sink. David B. Benson

In addition to the changing ocean sink, drought and heat wave conditions may change the uptake of carbon on land. The infamously hot summer of 2003 in Europe for example cut the rate of photosynthesis by 50%, dumping as much carbon into the air as had been taken up by that same area for the four previous years [Ciais et al., 2005].

The warming at the end of the last ice age was prompted by changes in Earth's orbit around the sun, but it was greatly amplified by the rising CO2 concentration in the atmosphere. The orbits pushed on ice sheets, which pushed on climate. The climate changes triggered a strong positive carbon cycle feedback which is, yes, still poorly understood.

Now industrial activity is pushing on atmospheric CO2 directly. The question is when and how strongly the carbon cycle will push back.