Major New Paper in Nature: Climate Change Increase; Intensity and Frequency of Heatwaves; 1/4 “Virtually Impossible” Otherwise; “Carbon Majors” Accounted for Half of Intensity Increase

Nature has just published a blockbuster new paper on the role of anthropogenic activity in heatwaves from 2000 to 2019. Many articles attribute increasingly wild weather, as in more severe heatwaves, more intense rain producing more floods, and out-of-season temperatures (both hot winters and weird cold snaps in summers). In our daily Links, we’ve highlighted only a comparatively small portion of way-out-of-band events, as well as their impact, from flood deaths to pests and pathogens becoming common in areas where they were formerly absent to significant falls in farm output. Because there are so many of these events now, it seems as if only the ones that produce a catastrophic death count, like flooding in the Punjab or central Texas, or extensive wildfires, such as in Europe and Canada, get much attention outside their region. Yet in a 10 day heatwave in Europe over the summer, 2,300 died, which is 1,500 more that would likely have succumbed otherwise. Extreme heat is also producing or worsening droughts. The image below is from the UN’s World Population Review:

Even with the seemingly overwhelming evidence of climate change, like disappearing glaciers, there’s still a rearguard trying to attribute it to something other than fossil fuel emissions, say solar activity. But courts are siding against that view. From a new KFF Health News story, Climate Activists Cite Health Hazards in Bid To Stop Trump From ‘Unleashing’ Fossil Fuels:

In 2023, a group of 16 young Montanans won a much-heralded climate change case that said the state had deprived them of a “clean and healthful environment,” a right enshrined in Montana’s constitution.

Their victory in Held v. Montana, later upheld by the state Supreme Court, resounded across the country, showing that young people have a stake in the issue of climate change, advocates say. Yet, state policies to address the causes of climate change in Montana — home to large coal, oil, and natural gas deposits — haven’t changed in the wake of the case.

On Sept. 17, some of those plaintiffs are scheduled to appear in federal court to request that U.S. District Judge Dana Christensen block a series of President Donald Trump’s executive orders on energy issues. They argue the orders violate their Fifth Amendment rights and will cause nearly 200,000 additional deaths over the next 25 years and lead to more heart, respiratory, and other health problems. They are joined by other plaintiffs ages 7 to 24 from California, Florida, Hawaii, and Oregon, and are backed by the climate-focused nonprofit Our Children’s Trust….

The plaintiffs are asking the court to declare Trump’s three related executive orders — “Unleashing American Energy,” “Declaring a National Energy Emergency,” and “Reinvigorating America’s Beautiful Clean Coal Industry” — unconstitutional and to block their implementation. They also claim that Trump has overstepped his authority by attempting to undo laws such as the Clean Air Act. A coalition of 14 states’ attorneys general has also filed a lawsuit against the order that declares an energy emergency.

Trump came into office in January primed to support traditional energy sources and to back off efforts to usher in an era of renewable energy, which he claims are not viable. He has also issued orders rolling back environmental regulations. “We are driving a dagger into the heart of the climate change religion to drive down the cost of living for American families, unleash American energy, bring auto jobs back to the U.S., and more,” Environmental Protection Agency Administrator Lee Zeldin said in a March news release.

In July, the EPA proposed repealing its 2009 “endangerment finding” that concluded climate-warming gases “endanger both the public health and the public welfare of current and future generations.”

Actions like this have been successfully challenged in the past. However, some hope that the Held v. Montana ruling will bolster the position of climate-action-seeking plaintiffs.

As much as the judiciary pretends that it rules based on the law alone, interpretations change with shifts in prevailing opinion and with new information challenging the wording of statute and older decisions. So the Nature paper below is important not just in and of itself, but for its potential to move the goalposts by drawing stronger causal links between human action and global warming. The paper, Systematic attribution of heatwaves to the emissions of carbon majors, is too large to embed in this post, so I hope readers will take the time to review it. Its other important contribution is estimating the impact of the biggest fossil fuel emission bad actors. Its abstract:

Extreme event attribution assesses how climate change affected climate extremes, but typically focuses on single events. Furthermore, these attributions rarely quantify the extent to which anthropogenic actors have contributed to these events,. Here we show that climate change made 213 historical heatwaves reported over 2000–2023 more likely and more intense, to which each of the 180 carbon majors (fossil fuel and cement producers) substantially contributed. This work relies on the expansion of a well-established event-based framework1. Owing to global warming since 1850–1900, the median of the heatwaves during 2000–2009 became about 20 times more likely, and about 200 times more likely during 2010–2019. Overall, one-quarter of these events were virtually impossible without climate change. The emissions of the carbon majors contribute to half the increase in heatwave intensity since 1850–1900. Depending on the carbon major, their individual contribution is high enough to enable the occurrence of 16–53 heatwaves that would have been virtually impossible in a preindustrial climate. We, therefore, establish that the influence of climate change on heatwaves has increased, and that all carbon majors, even the smaller ones, contributed substantially to the occurrence of heatwaves. Our results contribute to filling the evidentiary gap to establish accountability of historical climate extremes.

Much of the analysis is over my pay grade, but below are some key graphics:

I hope you will read and circulate this paper. It looks to represent an important step forward in the climate change debate by not only looking at severity of outcomes but also responsible parties.