IPCC Sides With Roger Pielke, Jr.

New AR 5 Report Confirms Pielke's Conclusions on Disasters

The new United Nations Intergovernmental Panel on Climate Change (IPCC) report released Monday, March 31 confirms representations of the climate science made by a University of Colorado-Boulder scientist who wrote a controversial column for Nate Silver’s new media company, FiveThirtyEight.com, two weeks ago.

Roger Pielke, Jr., an environmental studies professor at CU-Boulder, and a Senior Fellow at the Breakthrough Institute, argued that the rising cost of natural disasters is explained by more wealth in harm’s way and not by increasing frequency or intensity of natural disasters and extreme weather.

The release of the new UN IPCC report — Climate Change 2014:Impacts, Adaptation, and Vulnerability (Working Group II Fifth Assessment Report)— affirms Pielke’s argument, which was the point of contention with his critics:

"Economic growth, including greater concentrations of people and wealth in periled areas and rising insurance penetration, is the most important driver of increasing losses... loss trends have not been conclusively attributed to anthropogenic climate change."

The IPCC report released this week backs up a special report on climate and disasters published in 2012. That report — “Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation” — is known as the “SREX.” That report cites Pielke’s work 43 times. Beyond the IPCC, Pielke’s work continues to be heavily cited in the scientific literature.

That IPCC report affirmed the methods that Pielke, his coauthors and other researchers used to normalize data over long periods of time. One of the criticisms of Pielke made in the popular media over the last two weeks has been that Pielke ignores improvements in buildings, technologies, and disaster preparedness. In fact, the methodologies used by Pielke are standard, transparent, and understood, by IPCC reviewers.

Below are the critical passages pertaining to the controversy over Pielke.

Working Group II AR5:

  • “Economic growth, including greater concentrations of people and wealth in periled areas and rising insurance penetration, is the most important driver of increasing losses.” (AR5 10.7.3)
  • “Apart from detection, loss trends have not been conclusively attributed to anthropogenic climate change; most such claims are not based on scientific attribution methods.” (AR5 10.7.3)
  • “…increased probabilities of upward shifted accumulated loss [from tropical cyclones] might be detectable by 2025 at earliest, whereas a significant loss trend might emerge much later (Emanuel, 2011); (Crompton et al., 2011).” (AR5 10.7.3)
  • “The observed rise in US normalized insured flood losses (Barthel and Neumayer, 2012) may partly correspond to very likely increased heavy precipitation events in central North America (WG1-, while the evidence for climate driven changes in river floods is not compelling (WG1-” (AR5 10.7.3)


  • “Most studies of long-term disaster loss records attribute these increases in losses to increasing exposure of people and assets in at-risk areas (Miller et al., 2008; Bouwer, 2011), and to underlying societal trends – demographic, economic, political, and social – that shape vulnerability to impacts (Pielke Jr. et al., 2005; Bouwer et al., 2007). Some authors suggest that a (natural or anthropogenic) climate change signal can be found in the records of disaster losses (e.g., Mills, 2005; Höppe and Grimm, 2009), but their work is in the nature of reviews and commentary rather than empirical research.” (SREX
  • “There is medium evidence and high agreement that long-term trends in normalized losses have not been attributed to natural or anthropogenic climate change (Choi and Fisher, 2003; Crompton and McAneney, 2008; Miller et al., 2008; Neumayer and Barthel, 2011).” (SREX
  • “The absence of trends in impacts attributable to natural or anthropogenic climate change holds for tropical and extratropical storms and tornados (Boruff et al., 2003; Pielke Jr. et al., 2003, 2008; Raghavan and Rajesh, 2003; Miller et al 2008; Schmidt et al., 2009; Zhang et al., 2009; see also Box 4-2). (SREX
  • Most studies related increases found in normalized hurricane losses in the United States since the 1970s (Miller et al., 2008; Schmidt et al., 2009; Nordhaus, 2010) to the natural variability observed since that time (Miller et al., 2008; Pielke Jr. et al., 2008). Bouwer and Botzen (2011) demonstrated that other normalized records of total economic and insured losses for the same series of hurricanes exhibit no significant trends in losses since 1900.” (SREX
  • “The major factor increasing the vulnerability and exposure of North America to hurricanes is the growth in population (see, e.g., Pielke Jr. et al., 2008) and increase in property values, particularly along the Gulf and Atlantic coasts of the United States.” (SREX
  • “There is low confidence in any observed long-term (i.e., 40 years or more) increases in tropical cyclone activity (i.e., intensity, frequency, duration), after accounting for past changes in observing capabilities. (SREX 3.3.2, 3.3.3, 3.4.4, 3.4.5)
  • It is likely that there has been a poleward shift in the main Northern and Southern Hemisphere extratropical storm tracks. There is low confidence in observed trends in small spatial-scale phenomena such as tornadoes and hail because of data inhomogeneities and inadequacies in monitoring systems.” (SREX 3.3.2, 3.3.3, 3.4.4, 3.4.5)
  • “Based on a variety of model simulations, the expected long-term changes in global tropical cyclone characteristics under greenhouse warming is a decrease or little change in frequency concurrent with an increase in mean intensity. One of the challenges for identifying these changes in the existing data records is that the expected changes predicted by the models are generally small when compared with changes associated with observed short-term natural variability. Based on changes in tropical cyclone intensity predicted by idealized numerical simulations with CO2-induced tropical SST warming, Knutson and Tuleya (2004) suggested that clearly detectable increases may not be manifest for decades to come. Their argument was based on a comparison of the amplitude of the modeled upward trend (i.e., the signal) in storm intensity with the amplitude of the interannual variability (i.e., the noise). The recent high-resolution dynamical downscaling study of Bender et al. (2010) supports this argument and suggests that the predicted increases in the frequency of the strongest Atlantic storms may not emerge as a clear statistically significant signal until the latter half of the 21st century under the SRES A1B warming scenario.” (SREX 3.4.4)