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Roger Pielke Jr. @RogerPielkeJr
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1⃣Last night I gave my first public lecture on extreme weather since being "investigated" by Rep. Raul Grijalva in 2015. In the lecture I tell a story and present updated, consensus science on extreme weather. Let's get started ...
2⃣I started with a disclosure of everyone I've voted for in presidential elections since 1988. I also included who I supported in 1980 (John Anderson, of course), the first election I can remember actually following, when I was 12 and in 7th grade.
3⃣I start with the Wikileaks releases of John Podesta's emails in 2016.
I turned up in them. I know. It's nuts.
In them a staffer at the Center for American Progress emailed Podesta and billionaire Tom Steyer to brag about getting me removed as a writer for Nate Silver's 538.
4⃣The email revealed an organized campaign by CAP against me. It was one they had been pursuing for years. The CAP email opened a lot of people's eyes to some ugly behaviors.
5⃣Beginning in 2007, CAP wrote more than 161 articles critical of me, many spreading false and incorrect representations of my views. They averaged an article a week in 2008 and 2009. The must have really thought I was important to put 7 different writers on my beat!
6⃣But before getting further on all that, let's start a bit further back. Before proceeding, here are two quick answers to questions that this talk does not dwell on.
7⃣I started studying extreme events in 1993 (that's me 25 yrs ago) when I began a post-doc at NCAR on a project focused on lessons learned in Hurricane Andrew & the Midwest floods of 1993. I worked for the one and only @MickeyGlantz who was one of my most significant mentors 🙏
8⃣I can actually tell you the apex of my career studying extreme events. On March 15, 2006 I received an award from the NAS & gave a lecture to a huge audience at the Smithsonian Natural History Museum in DC. My work was viewed to be important, novel and ... legitimate.
9⃣Two months later, An Inconvenient Truth came out, focused on politicizing extreme weather in the climate debate. Extreme weather had always been part of the debate, but it was becoming more central as advocates tried to make climate more relevant to the public.
1⃣0⃣That same May, 2006 I was busy organizing a major international workshop in partnership with @MunichRe in Hohenkammer, Germany. We wanted to assess the science of disasters and climate change as input to the upcoming IPCC AR4 report.
1⃣1⃣Our focus was sharp. We wanted to assess scientific understandings on the causes of the trend shown in the data below. Why were disasters getting more costly? We started by thinking that we'd produce a "consensus dissensus" report, but we wound up all in 100% consensus.
1⃣2⃣The Hohenkammer workshop (page archived here:…) involved 32 participants & we comissioned 24 background papers. We produced a summary published in Science (…) including the workshop's 20 consensus statements.
1⃣3⃣The three consensus statements most relevant to this talk are below, with a key takeaway highlighted in red. If increasing disaster losses were the result of climate change due to GHG emissions, we could not detect that. It was not a close call, it was unanimous.
1⃣4⃣So when the IPCC AR4 came out, I excitedly looked to see what role our efforts in Hohenkammer played in their report.
1⃣5⃣I went to Section " Summary of disasters and hazards" only to be blindsided. The report cited "one study" that was apparently at odds with what we had concluded in our assessment. How could 32 experts have all missed this "one study"? What fools we were (I thought).
1⃣6⃣Looking closer, the IPCC AR4 included a mysterious graph that seemed to link rising global temperatures with increasing catastrophe losses. It was mysterious because I'd never seen it before. It was referenced to Muir-Wood et al. 2006, which seemed familiar . . .
1⃣7⃣&1⃣8⃣The paper was the one listed below ...
Hey! That was one of the papers we had commissioned for the Hohenkammer workshop. But I knew it did not include that mysterious graph nor any analysis of temperatures and disasters. That is really weird, I thought.
1⃣9⃣Long story short. The graph was slipped into the IPCC by one of its authors (& Hohenkammer workshop attendee) who miscited it to the white paper in order to circumvent the IPCC deadline for publications. He expected the figure and analysis to appear in a future publication.
2⃣0⃣That future paper was eventually published, well after the IPCC AR4 came out. And what did it say? Have a seat and read the below. That is right. It said the opposite of what had been claimed in the IPCC AR4. Whoopsy.
2⃣1⃣That seemed like a big deal & it was
The Sunday Times (@Jonathan__Leake) did a very good news story on it.
I was called by @larsonchristina (then at FP) who asked if she could interview me. Sure I said.
That resulted in the hit job below, turning me into a climate "denier."
2⃣2⃣The Center for American Progress amplified the hit job & continued a campaign of delegitimization of me & my work. It was relentless.
In 2015 Pulitzer Prize winner Paige St. John quoted me innocuously, only to have others calling for her to be fired for doing so. She wrote:
2⃣3⃣But science goes on. In 2012 the IPCC Special report on Extreme (SREX) arrived at the eact same conclusion as we had at Hohenkammer. Of course they did, that is what the science, evidence, data all show. Key conclusion:
2⃣4⃣Despite the IPCC consensus aligned w/ (& indeed drawing upon my & colleagues work) the delegitimization efforts intensified.
In 2015 I was the subject of an Congressional "investigation" (w/ 6 other academics), accused of secretly taking Exxon money. (Cue evil music here)
2⃣5⃣I cannot describe how penal, professionally & personally, it is to be identified as the subject of a congressional investigation.
I suppose that was the entire point.
(Note: I never have taken any money from energy companies. I was of course cleared in the "investigation.")
2⃣6⃣The basis for the "investigation" was ostensibly that the President's science advisor, John Holdren thought I had made "serious misstatements." Here is the letter Rep. Grijalva sent to my university president as part of the investigation.
2⃣7⃣The reality is Dr. Holdren got caught out, as we say in Colorado, a little forward on his skis, in comments abt disasters & climate change, articulating the Al Gore version not the IPCC. I had testified to the IPCC version before the Senate in 2013 ()
2⃣8⃣&2⃣9⃣In February 2014, Dr. Holdren made some strong (and scientifically dubious) statements about the linkage of the CA drought and climate change, which he was confronted with before the Senate a few weeks later.
3⃣0⃣My 2013 testimony, relying on IPCC, was cited to Dr Holdren & he freaked. He wrote a protest-too-much 6-page screed about me (which reads like a bad blog post) and posted it on White House website.
I guest it served its purpose, it led to me being investigated by Congress.
3⃣1⃣&3⃣2⃣OK one more, to close the loop with Wikileaks where we started this sordid series. In 2015 I was hired to write for Nate Silver's 538. I was hoping to write about sports, they asked me to write some science stuff also. No problem, I said.
3⃣3⃣You can see in the figure below, from that Time photo, high above Nate's left shoulder is "Climate Change Disaster." In retrospect, it was an accurate descriptor of what came next.
3⃣4⃣I proposed to 538 to write abt the SREX summary statement on disaster losses (below), which wasn't new, but was solid science, supported by data & peer-reviewed science. Plus I had written about it many times before. A nice uncontroversial starting point. Ha, that is funny.
3⃣5⃣538 has some very good editors and I thought that the piece came out really well. It is still solid today. Here it is (…)
Little did I know that CAP was on the case, behind the scenes.
3⃣6⃣There was a major freakout, no doubt partly motivated by Nate's enemies in the media (who could care less about me), plus the CAP kneecappers working behind the scenes, plus assorted trolls who like a good witch burning.
It was wild. It was pretty lonely for a long while.
3⃣7⃣There was a CAP-funded internet campaign. Oddly, almost all of the participants in that campaign have disappeared off of Twitter 9I've looked). I suspect many were what we now call bots (they had long numbers on their handles). But it worked, props to them.
3⃣8⃣I lost my job at 538. I became a fundraising ad for CAP (below). I did find this offensive. $10? Only $10? WTF? My scalp is worth 2 maybe 3 times that.
Anyway, score a "Victory for Climate Truth!"
That was the story part.
When I return, likely in the AM, we will turn to science & evidence. I'll present the latest assessment report findings & updated data on trends in global & US weather extremes. The science is still cool even with the drama
3⃣9⃣OK, let's pick this up, leave the drama behind and move on to some science, data, evidence. Here is the focus of Part 2:
4⃣0⃣As I prepared my summer 2013 testimony, President Obama said this on his weekly radio address. I knew it was incorrect and that helped motivate me to write a short book on the subject. I voted for him, twice (and would have 3x!), but that was no excuse to bite my tongue.
4⃣1⃣Of course, everyone these days likes to politicize the weather. Here is Senator Inhofe in the Senate with a snowball. I don't know what he is saying but I'd wager its wrong. My expertise is in disasters and climate change, so let's look at the science in that area.
4⃣2⃣Here are the assessment reports that I draw from, the most recent IPCC reports and the US National Climate Assessment released late last year. I'll also share updated primary data from multiple official sources. Buckle in ...
4⃣3⃣The strongest evidence for long-term increases in the incidence of extreme weather can be found with heat waves, globally (but as we shall see, not in the US). Even here the science is rather nuanced and the confidence expressed by the IPCC is "medium".
4⃣4⃣There is also some evidence that extreme precipitation has increased in some places around the world. IPCC again is quite nuanced and expresses "medium" confidence. Be careful, "extreme precipitation" is a technical term and does not equal flooding.
4⃣5⃣Next hurricanes, a very popular extreme.
Here is the most recent published update of our normalized hurricane loss dataset (from…) which shows that after adjusting for more people & wealth, losses show no trend. But is is accurate? Let's check next...
4⃣6⃣We use climate data to evaluate our economic normalization.
Trends in independent datasets should match up, if they don't, there is a bias.
Below are trends in US hurricanes & Cat3+
No trends in either. A good match.
Our normalization is unbiased compared to climate data🙏
4⃣7⃣This figure from @philklotzbach (a classic W Gray viz) shows FL and US east coast major hurricanes.
Over the past half-century, the US has been lucky compared to the more distant past, even with the big storms of recent years.
4⃣8⃣The Atlantic has just a small subset of tropical cyclones & those that hit the US an even smaller subset. So here is global data on TCs from @RyanMaue since 1970. Lots of variability, no clear trend.
4⃣9⃣Here is data on all tropical cyclones of hurricane force that hit land, updated (thx @RyanMaue) to 2017 from our 2012 paper (…)
Discussed in more detail here:…
Global data dates to 1970 but goes back further for individual basins
5⃣0⃣What about flooding related to landfalling hurricanes? (we documented this can be a big deal:…)
A paper out this month looks at TC flooding in the US (…)
They find no trends.
5⃣1⃣These data are robust & explain why the IPCC concluded that there is not compelling evidence for increasing TCs worldwide or in the US, or increasing intensities of TCs. They may yet increase in freq & strength, but not as yet. It's not a difficult call.
5⃣2⃣How about floods? Similarly, IPCC found no evidence to support claims of increasing floods globally.
More recent evidence supports this conclusion, e.g.:
5⃣3⃣A group of authors of the IPCC SREX with expertise in flooding summarized their views in a 2014 paper (…) with their bottom line conclusions below:
5⃣4⃣Data shared by EPA (via USGS) indicates that more places in the US have seen decreases in floods than increases. Here is that EPA page:…
5⃣5⃣If we look at flood losses as a proportion of US GDP there is some good news to report, it has dropped significantly. The mix of reasons (e.g., climate, flood policy, development patterns, GDP composition) are complex, but this is very good for the US.
5⃣6⃣FEMA data also reflects the lack of increases in US flooding⬇️
5⃣7⃣The IPCC SREX found no evidence of increasing tornadoes or hail. Long-term data for these phenomena is not great (to put it mildly).
5⃣8⃣Below is updated data on normalized US tornado losses, from our 2013 paper (here:…)
As with hurricanes, we compared the normalization to climate data & are confident that it is unbiased. Some big years, but no increasing trend.
5⃣9⃣Here is data from 2012-2017 on tornadoes from NOAA WCM (here: There is legitimate debate about this data & inflation-adjustments, but it is safe to conclude that overall 2012-2017 tornado incidence was below long-term average. Lucky us, once again.
6⃣0⃣According to NOAA, 2018 has started out pretty average, you can track US tornado counts daily (thx @NOAA🙏) here almost daily:
6⃣1⃣Drought. Lots of people are surprised to learn what the IPCC has concluded on drought. Little evidence to suggest that it has increased worldwide or in the US. Please read the below and then we will next look at some data & a more recent assessment report.
➡️Here is some data for the US (via EPA… …)
➡️And here also is a global perspective via satellite data (Hao et al… …)
No clear trends, which helps to explain why the IPCC concluded as it did.
6⃣4⃣The most recent climate assessment report is the US National Climate Assessment released last year by the Trump admin, but most work was done under Obama. The report's release was accompanied by a lot of media attention. Few actually read it. I did so you don't have to. . .
6⃣5⃣Below are some direct quotes from the assessment & a graph it included on temperature extremes in the US. Cold snaps down, heat waves down (!) & warm spells down then up. Winter storms up since 1950 ... more in next slide ...
6⃣6⃣Here are more bottom-line conclusions from the 2017 US NCA. These conclusions support everything I've reported in this long talk so far. They are also contrary to a lot of media reporting & statements by activist scientists.
This is what the science says & it's solid⬇️
6⃣7⃣So after this massive thread we come to the conclusions.
Have disasters become more costly because of human-caused climate change?
The answer is clear: ➡️No⬅️
It's not a welcome conclusion in some powerful circles.
But it is what the science says.
6⃣8⃣After the Wikileaks release revealed the behind-the-scenes campaign against me, the elected (4Ds & 5Rs) @CUBoulder Board of Regents voted unanimously in support of academic freedom, motivated by my experiences (…)
It was a strong statement of support🙏
6⃣9⃣Thanks for reading along. Feel free to share comments, I'll read them all.

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