One of the first articles on Nate Silver’s highly anticipated data-driven news site used flawed data to make its conclusions, according to some of the nation’s top climate scientists.
Silver’s FiveThirtyEight published its first article about climate change on Wednesday, entitled “Disasters Cost More Than Ever — But Not Because of Climate Change.” But climate scientists are condemning the article and its author, Roger Pielke Jr., saying he ignored critical data to produce a “deeply misleading” result.
The crux of Pielke’s article is this: Extreme weather events are costing us more and more money, but that is not because climate change is making extreme weather more frequent or intense. The reason we are losing more money, rather, is because we have more money to lose. Pielke came to this conclusion by measuring rising disaster damage costs alongside the rising global Gross Domestic Product. He also cited a U.N. climate report, along with his own research, to assert that extreme weather events have not been increasing in frequency or intensity.
“Pielke’s piece is deeply misleading, confirming some of my worst fears that Nate Silver’s new venture may become yet another outlet for misinformation when it comes to the issue of human-caused climate change,” said Michael Mann, director of the Earth System Science Center at Pennsylvania State University. “Pielke uses a very misleading normalization procedure that likely serves to remove the very climate change-related damage signal that he claims to not be able to find.”
His story in FiveThirtyEight is one that he has written before, in Chapter 7 of his 2011 book “The Climate Fix.” Just like in his article, the chapter argues that increased wealth and development is the principal cause of increased monetary losses from extreme weather events — not more extreme weather from climate change.
But just as Pielke’s article has been written before, so too it has been criticized before. Dr. Kevin E. Trenberth, a distinguished senior climate scientist at the National Center for Atmospheric Research, has criticized Pielke’s data for its simplistic nature. Simply showing that an increase in damage has corresponded to an increase in wealth ignores the fact that communities are now more prepared than ever for extreme storms, Trenberth wrote at the time.
Trenberth says data on increased disaster preparation measures should, to some degree, cancel out Pielke’s findings.
“This is the same old wrong Roger,” Trenberth said by e-mail. “He is demonstrably wrong and misleads.”
Mann agrees that the data analysis is too simplistic. “Pielke, in this case, continues to use an extremely controversial ‘normalization’ procedure when analyzing these data,” he told Climate Progress in an e-mail. “That procedure assumes that damages increase with population but it completely ignores technological innovations (sturdier buildings, hurricane-resistant structures, better weather forecasting, etc.) that have served to reduce societal vulnerability, thus likely masking some of the aggravating impacts of climate change.”
Pielke’s article also says that intensifying weather events can’t be causing more damage, because they aren’t occurring in the first place. Pielke cites the fifth IPCC’s report, which he said showed “little evidence of a spike in the frequency or intensity of floods, droughts, hurricanes and tornadoes.”
“In fact, today’s climate models suggest that future changes in extremes that cause the most damage won’t be detectable in the statistics of weather (or damage) for many decades,” Pielke wrote, citing his own research.
Some have pointed out that Pielke’s own study does not support the claim that he makes from it — that the most damaging extremes won’t be detectable in weather statistics for many decades. The 3-year-old research involves only rare, land-falling tropical cyclones, and looks only at the damage data from those cyclones. The study also explicitly ignores future rising sea-levels from climate change, which research from the National Oceanic and Atmospheric Administration has shown highly contributes to damaging storm surges.
Dr. John Abraham, a thermal science professor at the University of St. Thomas famous for his formation of the Climate Science Rapid Response Team, criticized Pielke’s assessment of the IPCC’s report. “You should know that we have already detected significant increases in Atlantic hurricane intensity, in extreme heat waves, large precipitation events and regional droughts,” Abraham wrote in an e-mail to Nate Silver expressing his disdain for the article, forwarded to Climate Progress.
“It’s ludicrous to say that extremes have not increased, and they have certainly increased in ways that are completely consistent with expectations based on atmospheric physics and climate model projections in response to increasing greenhouse gases,” Jennifer Francis, a research professor at Rutgers University’s Institute of Marine and Coastal Science who specializes in the connection between climate change and extreme weather, said.
Abraham also added that it wasn’t clear what Pielke meant when he said the IPCC hadn’t found evidence for a “spike” in extreme weather intensity. “If it means a statistically significant increase, then [Pielke] is wrong,” he wrote. “The report has identified changes to extreme weather including the intensity of Atlantic hurricanes, regional droughts and floods.” Pielke asserts those are not significant drivers of disaster costs.
“This post is surprisingly sloppy,” Abraham said. “I wouldn’t accept this kind of writing from my own students, even undergraduates.”
Because Pielke has been repeatedly criticized as inaccurate and misleading by some of the nation’s foremost climate scientists, debate over his pieces for Silver’s FiveThirtyEight will likely continue.
After this post was published Wednesday, Pielke expressed strong disagreement with the scientists’ assertions, saying they were factually inaccurate and partially represented a personal vendetta against him.
“Please realize that you are using untruths to attack the reputation of someone who you know nothing about,” he said by e-mail. “If you actually did some real reporting you might be surprised at what you find.”
Pielke particularly took issue with Mann’s claim that Pielke “completely ignores technological innovations (sturdier buildings, hurricane-resistant structures, better weather forecasting, etc.)” when analyzing disaster damage and its cause. Pielke said he has considered mitigation data in previous work, but has found through four of his own research papers not mentioned in the FiveThirtyEight article that there were no strong effects on the data.
In one paper, for example, Pielke says that even though stronger building codes have been shown to be able to reduce losses from hurricanes by more than 40 percent, those types of codes “have only been implemented in recent years and in some cases vary signiﬁcantly on a county-by-county basis.” This means that stronger building codes are unlikely to change the results on overall loses, he says.
His studies found that data on mitigation efforts had an effect on losses from U.S. earthquakes and Australian tropical cyclones, but not on U.S. hurricanes, tornadoes, or global floods, he said.
“Seriously, there are lots of important issues to debate about climate change,” he said. “You guys really want to make a big deal out of this?”
Nine days after this post was published, Nate Silver released a response to the criticisms contained in this and other articles regarding Pielke’s use of data.
In it, Silver wrote that he was sympathetic towards concerns surrounding Pielke’s central thesis, and concerns surrounding the way FiveThirtyEight covers climate. He said he would commission an article to rebut Pielke’s claims, and publish it on FiveThirtyEight in the coming weeks.
“All journalism relies on trust — between reporters and sources, between editors and writers, between a publication and its readers. Any time that trust is undermined, it’s a huge concern for us,” Silver wrote. “We thank you for your continued feedback. We’re listening and learning.”