On August 1st 2012, John Christy once again testified before the US Congress in a Senate hearing on climate issues. His written testimony is here and his verbal testimony is here. Christy's latest testimony consisted entirely of five climate myths, four of which we debunked in a previous post. In this post we will examine Christy's comments regarding the link between climate change and extreme weather.
Soon after Christy's testimony, Roger Pielke Jr. and Steve McIntyre weighed in by attacking the largely correct testimony from Christopher Field, while turning blind eye to Christy's grossly misleading testimony that contained myths regarding extreme weather events. Unfortunately, this sort of behavior by Pielke Jr. is not uncommon and several climate scientists have been the victim of similar efforts (for example, Coumou and Rahmstorf, James Hansen and others). To this end, Pielke Jr. uses an oft-repeated strategy that involves misdirection, bait and switch and knocking down strawmen arguments that he has constructed.
Christy spent much of his testimony denying that global warming is causing more extreme weather events, claiming that the extremes we have recently experienced are simply "Mother Nature". Christy also referenced a couple of record local cold and snow events in his verbal testimony. This is of course a misleading strawman argument; global warming does not eliminate either cold or snowfall records.
There are numerous examples of increased extreme weather frequency already being attributed to humans in the published peer-reviewed scientific literature. For example, Pall et al. (2011):
"Here we present a multi-step, physically based ‘probabilistic event attribution’ framework showing that it is very likely that global anthropogenic greenhouse gas emissions substantially increased the risk of flood occurrence in England and Wales in autumn 2000"
"Here we show that human-induced increases in greenhouse gases have contributed to the observed intensification of heavy precipitation events found over approximately two-thirds of data-covered parts of Northern Hemisphere land areas."
"All the four forms of the PDSI show widespread drying over Africa, East and South Asia, and other areas from 1950 to 2008, and most of this drying is due to recent warming. The global percentage of dry areas has increased by about 1.74% (of global land area) per decade from 1950 to 2008."
"Therefore, it is concluded that the influence of anthropogenic forcing has had a detectable influence on extreme temperatures that have impacts on human society and natural systems at global and regional scales"
"Here, we review the evidence and argue that for some types of extreme — notably heatwaves, but also precipitation extremes — there is now strong evidence linking specific events or an increase in their numbers to the human influence on climate. For other types of extreme, such as storms, the available evidence is less conclusive, but based on observed trends and basic physical concepts it is nevertheless plausible to expect an increase."
The key point is hiding behind Christy's attempts to obfuscate by focusing solely on convincing Congress that recent extreme weather events are consistent with Mother Nature. While it is very difficult to attribute individual weather events to global warming, we do know that climate change will 'load the dice' and result in more frequent extreme weather events.
Roger Pielke Jr. has also joined Christy's obfuscation on extreme weather by attacking the testimony from Christoper Field on the subject, which he accomplished through a bait and switch misdirection strategy, misrepresenting what Field actually said and then attacking his built-up strawman.
For example, as Field noted,
"the link between climate change and the kinds of extremes that lead to disasters is clear."
Pielke's response to this correct point by Field is a perfect example of his misdirection. The information discussed by Field comes from the IPCC Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX), on which Field was a Co-Chair. When Field accurately describes the SREX findings about extreme weather hazards, Pielke Jr. misrepresents it as a claim about financial losses, for example responding to Field's quote above about the link between climate change and extreme weather with this quote (emphasis added):
"There is medium evidence and high agreement that long-term trends in normalized losses have not been attributed to natural or anthropogenic climate change"
In reality, Field has accurately described the conclusions of the SREX. For example, the SREX says:
"It is likely that anthropogenic influences have led to warming of extreme daily minimum and maximum temperatures at the global scale. There is medium confidence that anthropogenic influences have contributed to intensification of extreme precipitation at the global scale. It is likely that there has been an anthropogenic influence on increasing extreme coastal high water due to an increase in mean sea level."
and
"Extreme weather and climate events, interacting with exposed and vulnerable human and natural systems, can lead to disasters."
These quotes quite clearly support Field's comments. In the most absurd case of Pielke misdirection, Field accurately reports the SREX findings on extreme precipitation events, which Pielke Jr. purports is a misrepresentation because of something that report said about flood losses. Put simply, the distinction between precipitation and floods is not a hard one to make, nor is the distinction between flood events and associated losses. In fact these are fundamental distinctions for Pielke Jr.'s area of expertise.
On hurricanes, Pielke ridicules Field for saying that "For several of these categories of disasters, the strength of any linkage to climate change, if there is one, is not known...The evidence on hurricanes is mixed". In fact, Field uses almost the exact same language as page 159 of SREX (emphasis added):
"Different methods for estimating undercounts in the earlier part of the North Atlantic tropical cyclone record provide mixed conclusions"
Pielke again uses a sleight of hand claiming that (emphasis added) "IPCC was unable to attribute any trend in tropical cyclone disasters to climate change". But Field was specifically talking about "linkages to climate change", a subtle but important difference to what Pielke is saying. As for how tropical cyclone activity will respond to a warming planet, the literature is as Field notes "mixed". Pielke also makes an assertion about disasters based on an SREX quote dealing with impacts (emphasis added):
"The statement about the absence of trends in impacts attributable to natural or anthropogenic climate change holds for tropical and extratropical storms and tornados"
An increased frequency of disasters will not necessarily lead to an increase in impacts, for example if technology improves to offset the losses caused by disasters. Therefore Pielke has not even demonstrated a lack of attribution in cyclone disasters, and has certainly not disproven Field's claim about a linkage between cyclones and climate change.
On drought, Field quoted almost verbatim from the SREX summary for policymakers, noting:
"The report identified some areas where droughts have become longer and more intense (including southern Europe and West Africa), but others where droughts have become less frequent, less intense, or shorter."
Here is the associated quote from the SREX:
"There is medium confidence that some regions of the world have experienced more intense and longer droughts, in particular in southern Europe and West Africa, but in some regions droughts have become less frequent, less intense, or shorter, for example, in central North America and northwestern Australia."
Pielke Jr. suggests that Field misrepresented what the SREX said by pulling a quote from a different section on the report and noting that it is not the same - no kidding. This is undoubtedly an honest mistake from Pielke, but when accusing someone of "misleading US Congress" as Pielke Jr. has accused Field of doing, one should really be sure that the accusation is accuate. It took all of a 30-second word search for us to find the section Field quotes in the SREX.
Pielke also says that "Field conveniently neglected in his testimony to mention that one place where droughts have gotten less frequent, less intense or shorter is ... the United States" ("central North America" in the quote above). However, Pielke conveniently neglects to share the SREX conclusions regarding future drought changes:
"There is medium confidence that droughts will intensify in the 21st century in some seasons and areas, due to reduced precipitation and/or increased evapotranspiration. This applies to regions including...central North America".
This conclusion is supported by Dai (2010), for example:
"Regions like the United States have avoided prolonged droughts during the last 50 years due to natural climate variations, but might see persistent droughts in the next 20–50 years"
In the comments on his post, Pielke Jr. argued that droughts are not disasters. That of course depends on your definition of "disaster", but just this year,
"more than half of all U.S. counties - 1,584 in 32 states - have been designated primary disaster areas this growing season, the vast majority of them mired in a drought that's considered the worst in decades."
In addition, there are the impacts to the poor as food becomes more expensive as crops are damaged by drought.
Sadly, Steve McIntyre tripled down on these myths by both repeating Pielke's strawman attacks on Field and by inventing a new conspiracy theory that the draft IPCC Fifth Assessment Report (AR5) is "hiding" discussions of past mega-droughts. We cannot address this conspiracy in detail since the AR5 is still in draft form. However, suffice it to say that the latest draft version actually has more information about North American mega-droughts than the previous version, including Figure 5.12 which now depicts the severity duration and frequency of droughts in North America.
The real irony here is that Pielke Jr. and McIntyre falsely accuse Field of misleading Congress while completely ignoring that John Christy actually did mislead Congress in the very same hearing. In fact, Pielke and McIntyre double and triple down on Christy's myth that human activities are not contributing to extreme weather events, which is really just a distraction from the fact that human-caused climate change will certainly cause many types of extreme weather to occur more frequently in the future. This series of events illustrates that Pielke Jr. and Steve McIntyre do not seem willing to apply their 'skepticism' and 'auditing' to climate contrarians.
There is a silver lining in this cloud of obfuscation - climate contrarians appear to be retreating more and more away from the "it's not happening" and "it's not us" myths, toward the "it's not bad" fallback position.
However, this means we must be increasingly vigilant when faced with misleading arguments like Christy's and Pielke's that climate change is nothing to worry about. It has taken decades to transition away from the former two myths - we cannot afford to allow the contrarian obfuscation regarding the consequences of climate change to be as efffective in delaying action to reduce greenhouse gas emissions. We simply don't have the time for this nonsense anymore.
Note: this post has been adapted into the Intermediate rebuttal to the myth 'extreme weather isn't caused by global warming'.
Posted by Albatross on Thursday, 9 August, 2012
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