This month’s open thread for climate related topics.

The post Unforced Variations: Mar 2026 first appeared on RealClimate .

The EPA has announced its final* ruling on the CO2 Endangerment Finding. *not even close to final. Notably, they have completely abandoned any reliance on the DOE’s CWG report. The EPA is not relying on new findings by the Administrator with respect to global climate change concerns under CAA section 202(a)(1) as a basis for […]

The post EPA’s final* ruling on CO2 first appeared on RealClimate .

For the first time, the Federal Judicial Center (FJC) commissioned a chapter on climate science for the manual they put out (with the NASEM) for judges, the Reference on Scientific Evidence (4th Edition). This week, a month after it was published, they pulled the chapter out after being pressured by 27 Republican Attorneys General. You […]

The post The Climate Science reference they don’t want Judges to read first appeared on RealClimate .

At a public event debating the DOE CWG report, Steve Koonin embarrasses himself further. This week there was a bit of a peculiar event at the Civitas Institute at UT Austin, with three of the CWG authors (John Christy, Steve Koonin and Ross McKitrick) being rebutted by Andy Dessler (working solo). The event itself was […]

The post Koonin’s Continuing Calumnies first appeared on RealClimate .

This month’s open thread about climate topics. Try to be substantive and respectful to other commenters. Note: Comments that are abusive and/or repetitive to the point of tedium will be moderated. If you’ve made the same point ten times already in the thread, and people are still arguing with you, repeating it another ten times […]

The post Unforced variations: Feb 2026 first appeared on RealClimate .

Our various graphics and model-observation comparisons have been updated with 2025 data. There are a few version updates that make some difference (particularly in sea ice extent), but the basic story is similar to last year. Feel free to comment and/or suggest changes for the future, including potential new comparisons.

The post 2025 Updates first appeared on RealClimate .

New email releases from the EDF/UCS lawsuit against the DOE provide a rarely-seen behind the curtain look at how the climate contrarians work. The new releases of non-governmental emails were ordered released by the judge in the case and illustrate clearly the desire for the five scientists of the Climate Working Group (CWG) (and their […]

The post A peek behind the curtain… first appeared on RealClimate .

There has been a frenzy around artificial intelligence and deep machine learning (AI/ML) since the “ChatGPT Moment” in 2022, and AI/ML is for sure going to affect us all. It strikes me that this buzz also looks more like a science fiction story (utopy/dystopy) than the old-fashion Clondyke goldrush craze.  “AI will not replace you. […]

The post AI/ML climate magic? first appeared on RealClimate .

This month’s open thread. We’re not great ones for New Year’s resolutions, but let’s try. How about we resolve to stay substantive, refrain from abusing one another, and maintaining a generosity of spirit when interacting with others? Lots of things get updated in January and we’ll try and keep up, though possibly with less fanfare […]

The post Unforced variations: Jan 2026 first appeared on RealClimate .

The Paris Agreement temperature limits are a little ambiguous and knowing where we are is tricky. The desire to keep global temperature rises since the pre-industrial, ideally below 1.5ºC and definitely below 2.0ºC, is a little bit complicated by the lack of definition in what constitutes the pre-industrial, uncertainties in what the temperature was in […]

The post 1.5ºC and all that first appeared on RealClimate .