September 15, 2013
On September 27, the Intergovernmental Panel on Climate Change (IPCC) will release part of their fifth assessment report on climate change. For the first time since 1990, this report will scale back the hysteria on global warming.
Matt Ridley at The Wall Street Journal viewed a few leaks from the 31-page document and talked to one of the senior climate scientists. The temperature rise due to man-made carbon dioxide is lower than their prediction in 2007. Originally a three degrees Celsius increase was predicted, but that number is now expected to be between 1-2.5 degrees Celsius.
Specifically, the draft report says that “equilibrium climate sensitivity” (ECS)—eventual warming induced by a doubling of carbon dioxide in the atmosphere, which takes hundreds of years to occur—is “extremely likely” to be above 1 degree Celsius (1.8 degrees Fahrenheit), “likely” to be above 1.5 degrees Celsius (2.4 degrees Fahrenheit) and “very likely” to be below 6 degrees Celsius (10.8 Fahrenheit). In 2007, the IPPC said it was “likely” to be above 2 degrees Celsius and “very likely” to be above 1.5 degrees, with no upper limit. Since “extremely” and “very” have specific and different statistical meanings here, comparison is difficult.