Fact-free he began and fact-free he remains.
Herewith, some observations on Professor Jeffrey Sachs’sto my of his of the recent State Department of the proposed Keystone XL pipeline in the context of greenhouse gas (GHG) emissions. A summary of his original criticism of Keystone XL is as follows:
• “The world is on a trajectory to raise the mean global temperature by at least 3 degrees C by the end of the century.”
• “The world is experiencing a rapidly rising frequency of extreme climate-related events such as heat waves.”
• “The Keystone pipeline is crucial to the global carbon budget,” that is, an effort to limit the use of fossil fuels to an amount that would yield a global temperature increase of no more than 2 °C.
In my critique, I argued that the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5) presents no temperature data — that is, an actual temperature trend, which is the only definition of the phrase “on a trajectory” that is meaningful analytically — even remotely consistent with Sachs’s assertion of a temperature trajectory yielding an increase of “at least 3 degrees C by the end of the century.” I pointed out that the data on tornado, hurricane, and cyclone activity, wildfires, sea-level increases, droughts, and flooding are inconsistent with the assertion of “a rapidly rising frequency of extreme climate-related events.” I added that the data on the Arctic ice cover are ambiguous, in part because the satellite record begins in 1979, that is, at the outset of the warming period that began in the late 1970s and continued through 1998. I noted also that it is not plausible to argue that Keystone XL “is crucial to the global carbon budget” (about which more below) given the vanishingly small contribution of the proposed pipeline to aggregate GHG emissions even under the most extreme assumptions.