Seattle meteorologist Cliff Mass sparks controversy by delving into heat wave climate science


On Thursday, June 24, as the record-breaking North West heat wave approached, Cliff Mass released a forecast he found it hard to believe. On Monday, temperatures near the western foothills of the Cascades would exceed 108 degrees and they would reach 104 degrees and above around Puget Sound.

“The predicted event is so extreme and so beyond expectations that my natural inclination is to dismiss it” Mass wrote. “But I can not.”

His blog succinctly captured the historic event about to unfold in the kind of post that helped make Mass, a professor in the Department of Atmospheric Sciences at the University of Washington, one of the most influential meteorologists in the world. the region.

After the heat wave, he quickly assumed a much more controversial role as a vocal critic of scientists who claim climate change plays a significant role in extreme weather events.

In an article from July 6, Mass said that without global warming we “would still have had the most severe heat wave of the last century.” In a follow-up post on July 13, he lambasted as “Deeply flawed” a World Weather Attribution report by a team of 27 international scientists who concluded that the heat wave would have been virtually impossible without man-made climate change.

His blog posts serve as an online megaphone for Mass, who says he collects some 20,000 views on a typical day, and has received more than half a million views during certain weather events.

His recent posts have come at a time when the governments of Puget Sound and others in our region are scrambling to better prepare for such events. The heat wave contributed to the deaths of at least 125 people, according to preliminary data from the state’s health ministry. And Mass has been strongly rejected by scientists involved in the report as well as other climatologists who say his ridicule increasingly makes him an outlier among scientists assessing the impacts of global warming.

World Weather Attribution researchers, using statistical analyzes, estimated the probability of this summer’s heat wave to be one in 1,000 in today’s world, but would have been at less 150 times more unlikely in pre-industrial times. From the 2040s, their report said such events could happen somewhere in the world every five to ten years.

In their models, the overall global impact of climate change looks like a roll of the dice that can increase the intensity of extreme temperature events like the Northwest heat wave. In this case, they found that climate change had intensified the heat in the Seattle area from around 4 degrees to 108 degrees, dramatically increasing the risk of death, according to one. rebuttal document six of the scholars prepared in response to mass.

The perspective of the masses is different.

He concluded that climate change did not play a central role in an event largely caused by the natural variability of our regional weather. He notes that the temperature has climbed more than 40 degrees above the normal maximum and that climate change has only added a few degrees, so “a unique and record-breaking heat wave” would have occurred even without global warming. In his blog, he sets out a golden rule that, based on this analysis, the greater the temperature rise during an extreme event, the weaker the role of climate change, and blames the World Weather report Attribution of “misinforming millions of people”.

Mass says his reviews are based on a deep knowledge of the complex mix of oceans, mountains, and atmospheric flows that help produce the weather for the Northwest, as well as the climate models he runs.

Faron Anslow, a climatologist at the University of Victoria and co-author of the report, says he respects Mass’s forecasting abilities but not his climate analysis. He says Mass’s rejection of the report “makes it clear how far out of his element Cliff is.”

Nick Bond, a state climatologist and professor at UW who teaches a course with Mass, said the report team used recognized statistical methods to examine these types of events. “What they show makes sense to me – that the frequency and intensity of these events is increasing – although I wouldn’t take the exact numbers as gospel,” Bond said.

Gavin schmidt, NASA’s senior climate advisor, in a series of tweets, wrote “some people continue to be wrong about the connection to climate change” and referred to Mass.

Schmidt called Mass’s Golden Rule “nonsense.”

“And that’s important, because if you’re someone who is going to be making decisions about the future, you have to know that it could happen again,” said Schmidt, who was not part of the World Weather Attribution team. , in an interview.

A controversial figure

Mass says he thinks climate change – caused by greenhouse gases from burning fossil fuels and other human sources – is a problem. He is convinced that this will result in more frequent heat waves and extremes later this century, and says that “humanity should work to reduce emissions.” But he says his research leads him to conclude that in western Washington – due to weakening easterly winds that bring indoor heat – these will be less intense than others predicted. And he doubts there will be a repeat of the temperatures encountered during this summer’s heatwave over the next few decades.

“I don’t think we’re facing any existential threat,” Mass said. “But it is not a good idea to play with the climate of the planet.”

Mass has at times gotten into very public disputes with other scientists, such as questioning the findings of a study on mountain snowpack decline in the West. He has also often derided the news media – including the Seattle Times – for headlines and reporting that he says exaggerates the threat of climate change.

Mass started his blog in 2008, focusing on problems in public mathematics education, and since then he has often ventured beyond meteorology.

In one March 13, 2020, blog post, he concluded that the coronavirus situation “is much less apocalyptic than some suggest.” He noted that COVID-19 deaths in the United States at that time numbered 36. He compared that to 61,000 flu deaths in 2017-18. “The coronavirus is not even in the same league as the flu… we haven’t closed universities, businesses and more over the flu.”

The death toll from the coronavirus now exceeds 600,000 people.

Mass, in a recent interview, said “of course (COVID-19) is worse than the flu,” but maintains his analysis as correct at the time.

Mass also commented on the impacts of vandalism during the protests. In August 2020, Mass, who is Jewish, wrote, “Seattle has Kristallnacht (s) and the photos of what happened in the past few weeks are eerily similar to those from 80 years ago. ” Crystal night was a pogrom against German Jews and an attack on their property carried out by the Nazis in 1938.

The blog post elicited a strong reaction, especially from his colleague at UW, Daniel Bessner, associate professor of American foreign policy, who told the university daily The Daily: “To compare the destruction of ‘a one-act Starbucks in 2020 that foreshadowed genocide, reflects analogical reasoning not fully reflected. Tacoma-based KNKX has ditched a mass radio segment over what the station called a “sensational and misleading” comparison.

Mass, who removed the reference from his blog, later said he was not referring to protesters at large, but to those who destroyed property.

Mass said his take on the pandemic and the protests was irrelevant to his take on climate science.

An isolated view

The World Weather Attribution report that caught Mass’s attention is the result of an initiative launched in 2014 to try to provide real-time analysis of extreme heat and other events to assess the role of climate change. .

The report says the Northwest heat wave could have been the equivalent of statistical bad luck worsened by climate change, or that there could have been something – beyond global warming – that made such an event more likely. Their report indicates that this possibility, although not indicated in the models, deserves further investigation.

These quick documents aim to capture the attention of the media while events are still fresh on people’s minds. Anslow notes that most of these reports have subsequently passed peer review and been published in scientific journals.

Mass has long been critical of how climatologists describe the results of probabilistic models that analyze climate change.

In 2017, for example, he used his blog to speak out against efforts to link powerful Hurricane Harvey, which triggered record rainfall in Texas and caused $ 125 billion in damage, to climate change. His analysis found that human-induced global warming played an “unimportant role in this disaster.”

In the aftermath of the hurricane, a peer-reviewed study published in the Proceedings of the National Academy of Science found that warming since the late 20th century had increased the likelihood of such an event six-fold.

Mass said he was sticking to his analysis. “You would have had a devastating effect no matter what,” he said.

As he responds to the heat wave report, Mass has stepped up those attacks. In emails to Anslow, he accuses the team of having developed a “science of attribution that makes virtually all extreme weather conditions much more likely to occur in the event of global warming.”

Mass says he’s working on a document to document what he says are “the fundamental flaws” of this approach. He said it will be submitted for peer review and publication.

Anslow said he would welcome such a review, provided it is peer reviewed.


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