A Takeover of the IPCC
The IPCC's longstanding framework for detection and attribution looks DOA in AR7
This is Part 7 in the THB series Weather Attribution Alchemy. The first six installments can be found linked at the bottom of this post. —RP
The Intergovernmental Panel on Climate Change (IPCC) has just released the names of its authors for its seventh assessment report (AR7). The author list for its Chapter 3 — Changes in regional climate and extremes, and their causes — suggests strongly that the IPCC will be shifting from its longstanding focus on detection and attribution (D&A) of extreme events to a focus on “extreme event attribution” (EEA).
Let’s first briefly clarify how these concepts are different and why the difference matters.
The IPCC D&A framework follows from its definition of “climate change” as a change in the statistics of weather over long time periods, typically many decades. Detection refers to identifying such a change. Attribution refers to identifying causes of that change. For most extreme weather phenomena, the IPCC has not achieved detection or attribution with high confidence and does not expect to for most this century.
In part due to the IPCC’s failure to achieve D&A for most types of extreme events, the notion of EEA was invented to connect specific weather events with changes in climate and characterized as an effort to get into the media and support climate litigation. Most EEA work is published outside of the scientific literature, announced by press release, and is typically contrary to peer-reviewed research on extreme events.
The D&A framework is scientifically rigorous, consistent with the IPCC”s definition of climate change, and treats extreme events in the same manner as other phenomena, like global temperatures and sea level rise. The EEA approach is scientifically problematic, inconsistent with the IPCC’s findings on extreme weather, and is explicitly grounded in climate advocacy.
The IPCC AR6 was decidedly lukewarm to freezing cold on the notion of EEA, and emphasized the traditional D&A framework. Those days may now be over.
World Weather Attribution (WWA) co-founder Frederika Otto has been put in charge of the chapter, along with another academic who focuses on extreme event attribution.
Otto explains today:
I’m a coordinating lead author. This means leading the chapter, and ultimately being responsible for making it happen. It’ll be a lot of work, but it also gives a lot of opportunity to shape the structure and focus of the chapter.
The chapter’s author list shows that it is stacked with people who focus on extreme event attribution — far out of proportion to their presence in the field. With the help of Google Scholar and ChatGPT I created the table below, which shows that 9 of the chapter’s 20 authors focus their research on extreme event attribution. Two of the three coordinating lead authors focus on EEA. Few of the authors, if any, have expertise in the IPCC’s conventional framework for detection and attribution, and some have no publications on either detection or attribution.
Of note, in addition to Otto, the chapter includes a second WWA collaborator. The Bezos Earth Fund partially funds WWA along with the U.S. National Academy of Sciences ongoing study of extreme event attribution. At least five of the 20 chapter authors have participated in some way in that study.
Let’s look at a specific example of differences between conventional IPCC D&A research and EEA and why it matters. Consider the following claims about flooding in Pakistan:
World Weather Attribution (WWA) in the media (6 Aug 2025): “Every tenth of a degree of warming will lead to heavier monsoon rainfall, highlighting why a rapid transition from fossil fuels to renewable energy is so urgent.”
The WWA analysis (not peer-reviewed, issued as a press release) claimed: “Historical trends associated with global warming in observational datasets show the 30-day maximum rainfall over the study region is now approximately 22% more intense . . . heavy rainfall events such as this one are expected to become more frequent and intense.”
In contrast, a new peer-reviewed study on detecting and attributing possible changes in monsoon rainfall in Pakistan (9 July 2025) concluded: “[U]nderstanding how climate change affects monsoon regions in South Asia is not straightforward, contrary to what some media commentators suggested when reporting the Pakistan floods in 2022.”
That same study on projections of heavy rainfall in the future: “[O]ur experiments show that a future anthropogenic increase in CO2 concentrations would not necessarily lead to a further exacerbation of Pakistan rainfall; instead, a non-significant reduction by approximately 5% of the ensemble mean rainfall has been found.”
A 2022 study of flood incidence in Pakistan: “Annual maximum flows exhibited negative trends at 15 (10 significant) stations while positive trends were shown by 7 (2 significant) between 1981 and 2016 . . . Counter to common belief, the most profound and decreasing pattern of flows was observed in summer.”
These different claims are impossible to reconcile.
Flooding in Pakistan has increased. Flooding in Pakistan has not increased.
Monsoon rainfall will certainly increase. Monsoon rainfall will likely decrease.
Reducing future carbon dioxide emissions will directly modulate monsoon behavior. Future carbon dioxide emissions are unlikely to be a significant factor in future monsoon behavior.
The composition of the IPCC AR7 chapter on extreme events may give us a preview of how such contradictory claims might be reconciled by the author team.
Media reports on EEA perhaps offer a preview of the next IPCC. For instance, just yesterday the New York Times reported on Pakistan’s floods and sees no scientific tensions or uncertainties, as it follows the lead of WWA:
Once a Source of Life and Renewal, Monsoon Brings Death to Pakistan
. . . climate change has brought a catastrophic new normal to the country . . . The monsoon season, once revered as a source of life and renewal, has brought death and devastation across large parts of Pakistan, a South Asian nation of 250 million people. Monsoons have killed more than 700 people nationwide since the season began in late June. This increasingly frequent pattern is forcing Pakistan to reckon with a new reality: Destruction brought by extreme weather has become the norm, not the exception.
In reality, there is no “new normal.” Pakistan has long been one of the most flood prone and flood impacted nations on the planet. Hamidifar and Nones (2023) looked at 70 years of flooding around the world and found:
The maximum number of flood events corresponds to India, China, Indonesia, Pakistan, Brazil, and Vietnam. . . However, the highest fatalities correlated to flooding events were reported in India, China, Pakistan, Bangladesh, Japan, and Iran . .
The table below shows that Pakistan has a long history of large loss of life related to flooding across the low-lying nation, reflecting enormous vulnerabilities in a region prone to extremes, even in the absence of strong trends.
Extreme events have become a political football. Climate advocacy has emphasized connecting extreme events with climate change, promoting the idea that “every tenth of degree” of global temperature increase is associated with more extreme events and more disasters. If only we reduce emissions, the argument goes, we can also modulate extreme weather. In this logic, every extreme event becomes about energy use, and not about exposure, vulnerability, and the local decisions that have seen disaster deaths drop to their lowest in human history. EEA has been central to such advocacy.
Scentific assessment can be challenging in the best of circumstances. When an assessment is taken over to serve politics it ceases to be an assessment and turns into something else.
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Read more about extreme event attribution in the THB series, Weather Attribution Alchemy:
Part 1: A new THB series takes a close look at extreme weather event attribution
Part 3: Tricks of the Trade
Part 4: Climate Science Whiplash
Part 6: Behind the Curtain, Inside World Weather Attribution
Comments welcomed! I especially invite the 20 IPCC AR7 Chapter 3 authors to share their reactions to this post, which I am happy to publish. Other IPCC contributors are welcome to join in as well. Here at THB we value debate, discussion, and respectful disagreement.
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Every time I start to get optimistic that real science is going to shape the dialogue stuff like this happens. Sad day. Thanks for the update.
So much for the high standards of IPCC Science.
Roger, do you still think that if the IPCC didn't exist that someone would have to invent it?
I guess Jim Skea (new IPCC Chair) is either asleep at the switch or he is part of the problem.