Skeptic lobbyists GWPF ‘cherrypick’ IPCC report to ‘make it sound benign’

  • 22 Nov 2011, 13:30
  • Verity Payne

The Intergovernmental Panel on Climate Change (IPCC) last week released the Summary for Policymakers for its latest report - the 'Special Report for Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation' (SREX). The report evaluates the role of climate change in extreme weather events, and discusses how best to minimise exposure and vulnerability to extreme weather events.

Media coverage of the report varied considerably. The Guardian, for example, focused on the conclusion that some extreme weather events, such as heatwaves and heavy rainfall, have been happening more frequently as climate has changed over recent decades, and are expected to increase in coming decades. They pointed out that the report is less confident about changes in some other extreme weather events, including tornadoes and tropical storms.

The BBC's Richard Black took a similar line, also discussing the difficulties in attributing specific extreme weather events to climate, but noting that overall trends in extreme weather events can be assessed. Black also suggested that the recent scrutiny the IPCC has received has helped to improve quality control, quoting Professor Chris Field, Working Group II co-chairman:

"I think that the quality control procedures that we used in this report were very carefully constructed and very carefully executed - I feel very good about the overall level of quality and scrutiny."

On the other hand, the Australian might have been reading different research. They majored on uncertainty in the projections in a piece headlined 'Climate change effects unknown: IPCC report'. The article began

"Great uncertainty remains about how much of an impact climate change will have on future extreme weather events".

The effect of this was to imply that, across the board, scientists don't know how extreme weather will be affected by climate change. In fact, they have different levels of confidence about making predictions for different kinds of weather.

So for example the IPCC's review of the scientific literature says it is "virtually certain" (implying 99 to 100 percent likelihood) that temperature extremes will increase over the 21st century, it is "very likely" (implying 90 to 100 percent likelihood) that heat waves will continue to increase, and it is also "very likely" that average global sea level rise will contribute to increasing extreme coastal high water levels.

On the other hand, scientists have less understanding of other types of extreme weather like tropical cyclones or changes in drought patterns. The summary suggests just 'medium' or 'low' confidence that droughts will intensify over the 21st century, depending on the region.

Cherrypicking uncertainty

The increasingly prominent climate skeptic lobbyists the Global Warming Policy Foundation (GWPF) wasted no time in offering their own interpretation of the SREX report:

"According to a preliminary report released by the IPCC, there will be no detectable influence of mankind's influence on the Earth's weather systems for at least thirty years, and possibly not until the end of this century.

"...Surveying the state of scientific knowledge IPCC scientists say they cannot determine if mankind's influence will result in more, or fewer, extreme weather events over the next thirty years or more."

Notable in the Australian was a quote from GWPF director Benny Peiser, who ignored the IPCC's more definitive conclusions to selectively focus on the uncertainty in the scientific predictions - which they have done repeatedly in the past.

"Global Warming Policy Foundation director Benny Peiser said the overall message was 'there was not a strong empirical link between anthropogenic climate change and weather events'.

"'It is unlikely there will be one for 20 to 30 years,' he said.

"He said any suggestion that recent weather events could be directly linked to climate change went directly against the general scientific consensus."

We asked one of the report's lead authors whether this was a reasonable interpretation of the report. Professor David Easterling, Chief of the Scientific Services Division at NOAA's National Climatic Data Center, told us that the GWPF's take on the SREX Summary for Policymakers was a "gross over-simplification".

The SREX report notes that expected changes in some kinds of weather extremes may be masked by natural climate variability over the next twenty or thirty years, particularly for things like tropical cyclones, which don't show clear changes so far.

But it also states that there are other kinds of extreme weather events like heatwaves and heavy precipitation which have already increased in length (heatwaves) and frequency (both heatwaves and heavy precipitation) over recent decades.

Professor Easterling noted that while natural fluctuations in the climate mean spotting changes in some weather patterns is more difficult in the short term,

"...For many other [extreme events], especially temperature-related extremes and heavy precipitation increases, the signal is already there, so they are cherry picking to make it sound benign."

Finally, a plea to the IPCC

As noted, the summary report was published on Friday, with the full report (which the summary, er, summarises) out in February next year. Perhaps there is a good bureaucratic reason for this three month gap, but in the modern age of the internet when people (rightly) want to be able to check the reasoning and sources on material to the fullest extent possible, this is a practice that could do with changing.

This is particularly important as the summary documents are agreed by representatives of governments involved in the IPCC process. In this context, being able to see the full report becomes particularly important as it allows consideration of the scientific material itself. Making the full report available at the same time as the summary - or publishing the summary after the report is released, if necessary - would allow more transparent consideration of the organisation's work.


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