Zeke Hausfather

Reminds me of when we first published Berkeley Earth and found it more or less independently validated NOAA's homogenization of US temperature records:

The @metoffice.gov.uk use weather station observations to reconstruct changes in UK average temperature since 1884.

@copernicusecmwf.bsky.social produce the ERA5 reanalysis which reconstructs global weather every hour back to 1950 using a weather forecast model.

Their estimates agree. Just sayin'.

And here is the percentage of the world's land area setting a new all-time monthly maximum temperature record in each decade:

Around 78% of the world has seen all-time maximum monthly temperature records set since the year 2000, with 38% set in past five years alone. In a new analysis over at The Climate Brink I take a look at where and when records were set: www.theclimatebrink....

Met office and Berkeley Earth estimates were pretty spot on. Others were a tad low but the result will be well within error bars.

No necessarily. It’s quite possible that 2026 will be a bit cooler than 2025, particularly if La Niña conditions continue to develop; we will need to wait and see!

September 2025 was the third warmest September on record at 1.47C above preindustrial levels in ERA5, behind only the prior two years (2023 and 2024).

With 9 months of the year now in, I estimate 2025 will approximately tie with 2023 for the second warmest year on record at ~1.48C.

Pope Leo hits out at critics of global warming In his first major statement on climate change, the pontiff criticises those who minimise climate change.

"God will ask us if we have cultivated and cared for the world that he created for the benefit of all and for future generations, and if we have taken care of our brothers and sisters - what will be our answer, my dear friends?"

Is this the most embarrassing error in the DOE Climate Working Group Report? mistaking detection for emergence

My latest on The Climate Brink:

Is this the most embarrassing error in the DOE Climate Working Group Report?

The DOE CWG authors confuse detection and attribution with emergence.

Climate-linked escalation of societally disastrous wildfires Climate change and land mismanagement are creating increasingly fire-prone built and natural environments. However, despite worsening fire seasons, evidence is lacking globally for trends in socially ...

Published today: our new paper showing a 44-year trend of increasing global wildfire disasters (fatalities and economic losses) due to climate change-induced extreme weather. www.science.org/doi/10.1126/...

I’m using the latest calibrated constrained ensemble (so that might be where differences are coming from), and I’m perturbing an underlying scenario (SSP2-4.5) by 40 GtCO2 and differencing that from an unperturbed scenario, if that helps.

Homeowners denounce SB 79 vote - Beverly Press & Park Labrea News Legislation awaits governor’s signature

A bunch of toxic LA NIMBYs are whining about SB 79, the amazing housing bill the CA legislature passed recently.

It's on the governor's desk, and reportedly he's getting cold feet. Hey @gavinnewsom.bsky.social, please have some spine on the most important issue in your state. Just sign it.

The relative flattening of CO2 emissions over the last decade is probably the most clearly visible indicator here...

Yep, while there is a growing literature on emissions and climate outcomes under current policy scenarios (and we can more firmly rule out things like 5x more coal by 2100 globally), current policies represent neither a ceiling nor floor on future emissions: journals.sagepub.com/doi/10.1177/...

I’m partial to this one from my 2022 Nature piece with @climatefran.bsky.social: www.nature.com/articles/d41...

This Expert Working Group on Climate Change and Health in the United States comprises 114 scientists with experience researching various dimensions of the health effects of climate change. We are submitting this public comment in response to the proposed reconsideration of the Endangerment Finding and Greenhouse Gas Vehicle Standards. Our overall conclusion is that EPA is incorrect in its assessment of uncertainties in the 2009 Endangerment Finding as a reason to reconsider the rule, given that the scientific evidence since that time reduces the uncertainty regarding health harms from climate change stemming from greenhouse gas emissions. Greenhouse gas emissions, by altering the climate and disrupting earth systems, pose a clear and indisputable danger to human health and well-being.

Another expert review of the science behind the endangerment finding, this time from health professionals.

they conclude that CO2 emissions "pose a clear and indisputable danger to human health and well-being."

drive.google.com/fil...

The AR7 will include both emissions pathways consistent with current policies and a more pessimistic pathway where policies in place today are reversed and clean energy expansion is restricted.

my takeaway from climate week nyc is that "climate storytelling" is a little too much "we must reimagine our deepest souls in relationship to mother nature and the moral abyss of the polycrisis into which we must now stare" and not enough "ok but get a heat pump"

It’s analogous to current policies, but 2050 temperatures are similar (a few tenths of a degree warmer) in a worst case SSP3-7.0 emissions scenario. It’s later in the century that they more substantially diverge.

SSP3-7.0 is ~0.1C warmer by 2050 but not that meaningfully different. It diverges more late century.

I, um, do? bsky.app/profile/haus...

We need to strive to be accurate regardless of the moment, otherwise we are not scientists.

For reference, here are the three models that show 3C by 2050; they are more than a tad off from reality today!

So while climate change is accelerating in recent years, its a stretch to argue that we could end up with 3C global warming relative to preindustrial by 2050, even if its quite possible we end up at 3C or more by 2100 unless we rapidly reduce emissions.

However, if we constrain CMIP6 to match recent observed global temperatures, we see no models reaching 3C until at least 2060: www.carbonbrief.org/...

If we look a the full ensemble of CMIP6 models we see a small number (3 of 37 models) reaching 3C by 2050. However, these three have both too much historical warming (~2.2C in 2024) and what an unrealistically high climate sensitivity (>5C per doubling CO2) as we noted here: www.nature.com/artic...

Last week the German Meteorological Society warned that "the 3-degree limit could be exceeded as early as 2050".

While not possible to fully rule out, the assessed warming scenarios we published in the IPCC AR6 report find this to be extremely unlikely.

The undeniable science of extreme weather Dr. Kevin Trenberth explains how global warming is supercharging droughts, floods, and storms

On The Climate Brink, Kevin Trenberth writes about the undeniable science of extreme weather

Oddly enough @davidho.bsky.social also convinced me to get a gravel bike. Just brought it in yesterday to go tubeless!

When I say the US has bet its post-pandemic economy on AI while China has bet its on green energy, this is what I mean: Here, AI related companies account for 75% of S&P 500 returns since ChatGPT's launch. In China, green tech accounts for one quarter of GDP growth.