The full IPCC Special Report on Extremes is out today, and I have just gone through the sections in Chapter 4 that deal with disasters and climate change.
Kudos to the IPCC — they have gotten the issue just about right, where “right” means that the report accurately reflects the academic literature on this topic. Over time good science will win out over the rest — sometimes it just takes a little while.
A few quotable quotes from the report (from Chapter 4):
- “There is medium evidence and high agreement that long-term trends in normalized losses have not been attributed to natural or anthropogenic climate change”
- “The statement about the absence of trends in impacts attributable to natural or anthropogenic climate change holds for tropical and extratropical storms and tornados”
- “The absence of an attributable climate change signal in losses also holds for flood losses”
The report even takes care of tying up a loose end that has allowed some commentators to avoid the scientific literature:
“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.”
With this post I am creating a handy bullshit button on this subject (pictured above). Anytime that you read claims that invoke disasters loss trends as an indication of human-caused climate change, including the currently popular “billion dollar disasters” meme, you can simply call “bullshit” and point to the IPCC SREX report.
You may find yourself having to use the bullshit button in locations that are supposed to be credible, such as Nature Climate Change and the New York Times. This might may feel uncomfortable at first, because such venues are generally credible, but is absolutely necessary to help certain corners of science and the media to regain their credibility. The siren song of linking disasters to human-caused climate change exerts a strong pull for activists in all settings, but might be countered by the widespread and judicious use of the disaster and climate change bullshit button.