Jan Lenaerts

EU impotence extends to decarbonisation

If you read one thing about Iran & geopolitics & economic fallout & climate, make it this @martinsandbu.ft.com column

Nature Report, Killed by Trump, Is Released Independently

When the US govt terminated the National Nature Asst, @phillevin.bsky.social + the author team were determined not to let that stop them.

They re-organized, set up an advisory committee, found funding…and now the brand new Nature Record is open for public comment. 👏🌳👏🌲

Check it out (link below)!

Trump Is Attacking Climate Science. Scientists Are Fighting Back. It’s easy, looking at the past year, to see the damage the administration has done. But researchers are also stepping up, trying to fill the gaps.

One year in the federal assault on climate science — a review and prospective

We need a global assessment of avoidable climate-change risks To understand the urgency of emissions reductions, policymakers and citizens need a full analysis of what is at stake.

Major threats to our well being from climate change can be avoided, or hugely reduced, by rapid action.

Our Nature comment calls for a global risk assessment, effectively communicated to governments, the media and the public, to make clear what is at stake.

www.nature.com/articles/d41...

The Complexity Cascade: Why Physical Risk Models Diverge — and What Governance Needs to Do About It Physical climate risk vendors often provide very different assessments for the same assets. This article explains the sources of these differences and how banks can utilize model governance to manage ...

Why do physical risk vendors produce divergent estimates for the same properties? The core reason is a complexity cascade in which modeling choices compound. Robust model governance is needed to make those choices transparent and decision useful for banks. www.garp.org/risk-intelli...

Why the western US is running out of water, in one chart Cows are draining the Colorado River.

Cows are draining the Colorado River. www.vox.com/future-perfe...

This is very impressive work, filling a gap of allowing public access to super-granular, high-quality, and transparent climate risk information . Thanks @carbonplan.org !

Thanks for your work on this @zacklabe.com @climatecentral.org !

A map of the US with each 2025 billion-plus dollar weather and climate disaster geo-located on it. Source: Climate Central

After the US admin cancelled the $B Climate + Weather Disaster dataset, @climatecentral.org hired the scientists who ran it and set it back up.

Now the 2025 numbers are in: it's 3rd highest year on record and highest year w/o land-falling hurricanes.

More: www.climatecentral.org/climate-serv...

After reviewing nearly 200 applications from prospective grad students and postdocs over the past few months for a couple different 🧪⚒️ postings, here are some tips, at least as they apply to North American positions. I hope they help future applicants. Share with your networks. 🧵

It’s simply not possible to overstate how important NCAR is to US and world science. We need to fight this with everything we’ve got.

NCAR is a unique & valuable asset - far more than a climate model, or observations, or technology, or training ground, or gathering space. It covers weather, space weather, data, climate, paleo-climate, and everything in-between. It's building is an icon, but it's iconic status goes far beyond that.

NCAR is quite literally our global mothership.

Everyone who works in climate and weather has passed through its doors and benefited from its incredible resources.

Dismantling NCAR is like taking a sledgehammer to the keystone holding up our scientific understanding of the planet.

Unbelievable.

Zillow’s climate risk reversal looks like a setback. It’s really a wake‑up call. When private models sow confusion, it’s a flashing warning sign that Washington needs to fix federal flood maps,

Zillow’s climate score rollback is a wake-up call: build open, future‑conditions federal flood maps -- gold‑standard, trustworthy data for building codes, mortgages, and our future. Column today: open.substack.com/pub/susanpcr...

A reminder, in light of that NYT story today, about skill and spread across climate analytics providers:

Getting good climate info in the hands of individuals would be highly valuable. Just not convinced we're actually there yet.

Consulting* with experts, of course.

Better yet: consisting with experts who know the local conditions and have the experience to interpret, adapt, and translate “global-scale” climate risk outputs to locally reliable information. Modeling quality is one, local applicability is another. Above all, honest communication is essential!

IMO - this should become part of any regular due diligence in the real estate business. Of course, accurate information is important, but climate risk models are hard to interpret, subject to large uncertainties, and risks hard to communicate (probability vs risk vs occurrence vs intensity).

As both banks and insurance industry will start to use v granular information for their decision making, too, (which will impact people living or buying in the most vulnerable places most), it is becoming increasingly important for individuals to be informed on climate risks.

Zillow Removes Climate Risk Scores From Home Listings

The discussion on accuracy here is somewhat moot. I find it most intriguing that this information does seem to go into and does impact individual customer decision making and even house sale price (paper here www.nber.org/papers/w33119).
www.nytimes.com/2025/11/30/c...

New text @cop30brazil.bsky.social provides a glimpse of where #COP30 might land.

Some reflections on references to science and evidence. /1

unfccc.int/sites/defaul...

A line graph shows the time series of Arctic mean surface temperature anomalies for each October from 1850 through 2025. There is a long-term increasing trend and large year-to-year variability. The mean surface temperature anomaly in October 2025 was 3.78°C for this region. Anomalies are computed relative to a 1910-2000 climate baseline. All data is from NOAA/NESDIS/NCEI NOAAGlobalTemp v6.0.0 on this graphic.

A line graph shows the time series of Antarctic mean surface temperature anomalies for each October from 1850 through 2025. There is a long-term increasing trend and large year-to-year variability. The mean surface temperature anomaly in October 2025 was 1.43°C for this region. Anomalies are computed relative to a 1910-2000 climate baseline. All data is from NOAA/NESDIS/NCEI NOAAGlobalTemp v6.0.0 on this graphic.

Was there any coverage of the recent record warmth in both the Arctic and Antarctic? Multiple global datasets now confirm these records, and I think it's really quite striking.

Here's some very quick plots showing NOAAGlobalTempv6 data from October too. And see my earlier posts.

Happy to share our experience organizing the 2022 Firn Workshop! @tridatta.bsky.social

Assessing future cyclone speeds at the same location across climate analytics vendors. For the same spot, high risk properties range from sub-tropical storm to Cat 5.

Absolutely fantastic study comparing anonymized outputs of climate analytics models.

Everyone loves to bag on flood (rightly so), but can we talk about how the spread here is "30mph breeze to Cat 5 hurricane" www.fca.org.uk/publication/... HT @ruarirhodes.bsky.social

Our 400+ page comment on the DOE climate working group report is now out.

Our conclusion: The merchants of doubt are back, and they're coming for climate science.

This resonates a lot with me. The tipping points topic is one of the most popular ones for private sector, but is largely irrelevant for their short- to medium-term (20 yrs is typically way too far out!) decision making process around climate resilience and adaptation www.nature.com/articles/s41...