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The IPCC’s weather report is a major setback for warmists looking for the smoking cigarette butts of global warming

Only a week to go before the United Nations Framework Convention on Climate Change (UNFCCC) begins in Durban, South Africa, where world governments will again attempt to draft a global plan to control carbon emissions so as to stave off catastrophic man-made global warming. At the moment, however, the world’s governments seem more intent on warding off catastrophic government-made fiscal disasters. If for no other reason, Durban is heading for the dustbin of UN climate meetings.

But distraction with economic and fiscal crises isn’t the only reason Durban seems doomed. Another issue would be what looks like a growing realism in climate science, including within the Intergovernmental Panel on Climate Change (IPCC), the science arm of the UN climate machinery. In a summary report last Friday, the ­IPCC rang climate alarm bells on extreme weather events that weren’t all that alarming.

The report summarized the “key findings” of a Special Report on Managing the Risks of Extreme Events and Disasters, to be released next February. For warmists looking for the smoking cigarette butts of climate change, the report was a major setback. Despite a few headlines that mostly exaggerated its findings, the report actually concluded there was little or no evidence of man-made global warming to date as measured in extreme-weather events. As for the future, nothing much can be expected for another 20 or 30 years. The big impacts were projected way off at the end of the 21st century.

The report was so lame as a climate-warning device that Media Matters, the U.S. watchdog group, observed Monday that it was “almost totally ignored” by the TV networks. Not a word on CNN, Fox, MSNBC, ABC or CBS. Media Matters’ concern was that the key headline message — warning of more extreme heat waves, floods, droughts and storms — had failed to reach the people.

That the report’s message was missed is beyond dispute, but the message missed is not the one Media Matters wanted to hear. Take, for example, the report’s treatment of hurricanes. David Suzuki and other green activists have often claimed that hurricanes like Katrina are the product of man-made global warming and human consumption of carbon-emitting fossil fuels produced by evil oil companies. But the new IPCC report said it did not have evidence that there has been an increase in hurricane activity or intensity. In the language of the IPCC, “There is low confidence in any observed long-term (i.e. 40 years or more) increase in tropical cyclone activity (i.e. intensity, frequency, duration), after accounting for past changes in observing capabilities.”

Headlines such as “Katrina not likely caused by global warming” or “Hurricanes not on rise” could have been written off this report. As for major rain/precipitation events, the report said there have been “statistically significant trends” in some regions, although those trends have shown decreases in events as well as increases. Droughts are also hard to identify. There is “medium confidence” that “some regions” have experienced more intense and longer droughts, but in “some regions” droughts have become “less frequent, less intense or shorter.”

Floods around the world are often cited in media as evidence of global warming. But the IPCC report downplays its support for this idea.

There is limited to medium evidence available to assess climate-driven observed changes in the magnitude and frequency of floods at regional scales because the available instrumental records of floods at gauge stations are limited in space and time, and because of confounding effects of changes in land use and engineering.

No wonder the TV networks ignored the story: Most of their extreme-weather coverage over the last few years blaming global warming appears to have been wrong.

Watering the message down even further was the IPCC’s upfront definition of what it means by climate change: “Climate change may be due to natural internal processes or external forcings, or to persistent anthropogenic changes in the composition of the atmosphere or in land use.” In this definition, man-made climate change brought on by carbon emissions amounts to only one part of the system. The role of natural forces is likely larger than carbon emissions.

If the recent past evidence of man-made global warming is thin, what about the future? Here again, the IPCC report offers little headline fodder.

Projected changes in climate extremes under different emissions scenarios generally do not strongly diverge in the coming two to three decades, but these signals are relatively small compared to natural climate variability over this time frame. Even the sign of projected changes in some climate extremes over this time frame is uncertain. For projected changes by the end of the 21st century, either model uncertainty or uncertainties associated with emissions scenarios used becomes dominant, depending on the extreme.

Not exactly a green light for governments and politicians in Durban to charge ahead with radical carbon-reduction schemes and targets. If carbon emissions are causing global warming, extreme events won’t be showing up for another 20 or 30 years. Beyond that, the models are tricky. Still, the IPCC produced a number of projections that some extreme events would increase. It is “virtually certain” that warm daily temperature extremes will occur in the 21st century. But it is “likely that the global frequency of tropical cyclones [hurricanes] will either decrease or remain essentially unchanged.”

For some, the new report is a welcome change. Roger Pielke Jr., a long-time critic of IPCC climate models, said: “The IPCC should be congratulated for delivering a message that cannot have been comfortable to deliver. The IPCC has accurately reflected the scientific literature on the state of attribution with respect to extreme events — it is not there yet, not even close, for events such as floods, hurricanes, tornadoes, bushfires and on other topics there remain enormous uncertainties. That is just the way that it is, so that is indeed what the IPCC should have reported.”

The real “extreme event,” however, may be the IPCC report itself, a pre-Durban warning of pending climate catastrophes that is short on catastrophes. It’s an IPCC science document that doesn’t give the UN policymaking arm meeting in Durban enough hot science to justify action.

Financial Post, 22 November 2011