Critique of the IPCC’s Summary for Policymakers

Scientists Craig D. Idso, Robert M. Carter, S. Fred Singer, and Willie Soon have released a lengthy critique of the recently published Intergovernmental Panel on Climate Change (IPCC) Summary for Policymakers (SPM).

They note that “the IPCC has retreated from at least 11 alarmist claims promulgated in its previous reports or by scientists prominently associated with the IPCC. The SPM also contains at least 13 misleading or untrue statements, and 11 further statements that are phrased in such a way that they mislead readers or misrepresent important aspects of the science.”

You can download the 18-page critique here.  Below I summarize some alarmist claims that the IPCC has retreated from or downplayed.

The IPCC finally concedes that there has been a 15-year “pause” in global warming in spite of carbon dioxide increasing by 7 percent.  The IPCC also concedes that the rate of global warming has decelerated since 1951 although carbon dioxide has increased 26 percent since that time.

The “hockey stick” has disappeared.  The IPCC now admits there was a Medieval Warm Period that was just as warm as late 20th Century temperatures.

In a contradiction to its own climate models, the IPCC now admits that Antarctic sea ice has been increasing by 1- to 2 percent per decade since 1979.

The IPCC admits that its climate models did not predict nor can they reproduce the recent lack of warming.

For the first time, the IPCC admits that solar factors may play a determinative role in short-term climate variability.

The IPCC has decreased the lower number in the range for equilibrium climate sensitivity, i.e., the amount of warming they expect to result from a doubling of atmospheric CO2.  However, unlike in previous reports, the IPCC did not publish a “best guess” of what the actual number is. The lower value brings the sensitivity closer to what has been estimated by many non-IPCC scientists.

The IPCC now has “low confidence” that global warming will result in dangerous increases in the magnitude or frequency of extreme climatic events including cyclones and droughts.

As I’ve shown in a previous post, the IPCC does not now think that warming will release carbon dioxide from permafrost nor do they think that there will be a catastrophic release of methane from clathrates in the ocean.

See also:

The great Arctic methane scare, again

IPCC AR5 climate report may be dead on arrival

Book Review: Into the Dustbin, an assessment of the IPCC and its chairman

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