United Nations: Warming of the climate system is unequivocal | Letter
Published 1:10 pm Friday, June 26, 2015
As a coordinating lead author on the Intergovernmental Panel on Climate Change (IPCC) report cited by Roger Clarke-Johnson’s June 12 rebuttal of Mark Vossler’s comments on climate change, I am troubled by Mr. Clarke-Johnson’s characterization of the report and those that express genuine concern for our planet.
He failed to mention that the very first overarching conclusion of the report is that “warming of the climate system is unequivocal,” meaning the changes are a scientific fact not a belief. The second conclusion is that “each of the last 3 decades has been successively warmer at the Earth’s surface than any preceding decade.” Furthermore, the report states with 95 percent confidence that human activity, primarily burning of fossil fuels, is the dominant cause of the observed warming since the mid-20th century.
There are two points to consider with respect to the slowing of the global surface temperature mentioned in the rebuttal. First, we all know that there is a lot of natural variability in temperatures. That variability still occurs even as heat trapping greenhouse gases continue to accumulate. At times that natural variability can work to slow the surface air temperature warming caused by human activities. At other times, however, the natural variability can work to speed up the long-term trend. Don’t let a period of slow warming lull you into thinking that the long-term warming is not really happening.
Second, we tend to focus on surface air temperature because that is the most obvious thing we notice when we walk outside. However, warming air only accounts for about 1 percent of the heat accumulation from rising greenhouse gases. About 3 percent goes into melting ice in the glaciers and Polar Regions, about 3 percent goes into warming land and about 93 percent goes into warming the ocean. It is true that warming air temperatures have been variable with strong warming at times and slower warming at other times, but when we look at all the pieces the relentless accumulation of heat in the Earth has continued without fail.
Christopher Sabine, Redmond
