Going through this week’s issue of Nature magazine, which arrived in my in-box yesterday, the following short squib in their “research highlights” section appears:
Warming, but not as much
The climate system may be less sensitive to greenhouse-gas warming than many models have predicted.
Nathan Gillett and his co-workers at Environment Canada in Victoria, British Columbia, analysed how well the latest Canadian Earth System Model tracked temperature changes attributable to volcanoes, man-made aerosols and rising greenhouse-gas emissions. They adjusted the model using temperature records from 1851 to 2010 — 60 years of data more than most previous analyses. The model predicted a short-term increase of 1.3–1.8 °C for a doubling of atmospheric carbon dioxide levels, which is low in the range of estimates from previous forecasts.
Nature links to the original article in Geophysical Research Letters (subscription required for the complete article unfortunately, though you can read the abstract), entitled “Improved constraints on 21st-century warming derived using 160 years of temperature observations.” It is a typically dense article filled with all of the usual qualifiers, but several things make this a bombshell and a blow to the catastrophist narrative. First, this study was conducted by the Canadian Centre for Climate Modelling and Analysis of Environment Canada, which is Canada’s EPA, so the climate campaigners can’t use their favorite talking point that this comes from a private, fossil-fuel funded skeptic outfit. Second, there is no disguising that the finding of this model, along with recent similar studies, that global warming is overestimated by roughly a factor of two in the usual models the IPCC uses. The authors appear to know that this is politically incorrect, and add the usual caveats at the end to mitigate the implications of their findings: “[W]e find that [the model’s] multi-decadal internal climate variability is lower than that in other models. We therefore recommend caution in interpreting the scaled projections derived from this single model. . .” The authors appear duty-bound to include that the full range of possible warming could be 1.2 – 4.3 degrees C, but the body of their study and the strength of their main conclusions do not give much support for this.
This is merely the latest in a series of recent climate modeling studies that conclude that the standard “consensus” forecast of the amount of warming to be expected by a doubling of carbon dioxide has been dramatically overestimated. Which is just about par for the course with most environmental scares. As more studies like this dribble out from the scientific community, eventually we’ll reach the proverbial “tipping point” beloved of so many climate alarmists—only it won’t tip the way they think.