Robert Rohde

2025 data quietly released by EPA shows harmful increases in dangerous air pollution attributable to Trump, personally, with 6 TX power plants that Trump exempted from stronger safeguards, for example, experiencing an astonishing 48% increase in sulfur-dioxide emissions collectively in 2025. 1/

Bar chart showing the history of polling on US concern about global warming.

While the US Government may have abruptly decided to ignore global warming, public sentiment remains largely unchanged.

As of Dec. 2025, about 2/3 of the US public continues to be either somewhat or very worried about global warming.

climatecommunication.yale.edu/app/uploads/...

Time series chart of carbon dioxide in the atmosphere showing the IS92a scenario and the observed changes from Mauna Loa.

So how is the fight against global warming going?

Well, compared to a business-as-usual scenario made 30 years ago, we have slightly slowed the rate at which carbon dioxide is accumulating in the atmosphere.

Technically that's progress, I guess, but we need it to stop increasing entirely.

AI generated illustration of two frogs in a pot of boiling water on a stove. One frog says to the other "Don't worry. The stove is not real."

Everyone always forgets to mention the other frog...

I made it.

Time series plot of carbon dioxide levels over the last 10,000 years, combining ice core measurements and direct air measurements.

Human civilization arose under a stable atmosphere of 260-280 ppmv of carbon dioxide.

Then, humans learned to utilize the power of fossil fuels.

In a geologic blink, fossil fuel burning has increased atmospheric carbon dioxide levels by more than 50%.

Scientists thought they understood global warming. Then the past three years happened. The last 30 years are the fastest warming period since 1880, according to a Washington Post analysis of NASA data. By John Muyskens and Shannon Osaka

Excellent @washingtonpost.com piece on the signs that global warming is accelerating by @shannonosaka.bsky.social and @johnmuyskens.bsky.social, featuring @hausfath.bsky.social @rarohde.bsky.social @cjsmith.eu

www.washingtonpost.com/climate-envi...

How well can we quantify when 1.5 °C of global warming has been exceeded? Abstract. Parties to the 2015 Paris Agreement agreed to limit the long-term increase in global average temperature to well below 2 °C and pursue efforts to keep temperatures below 1.5 °C relative to p...

New discussion paper just dropped that’s taken shall we say a little work to get this far … essd.copernicus.org/preprints/es... please be kind. Not on an at all sensitive topic in the slightest.

I'm not really sure. Obviously it depends on precise, well-calibrated, robust, and stable radiometers in space, and ideally several at the same time for cross-validation.

But I'm not close enough to say what the remaining key technical challenges are.

Now, forcings due to additional greenhouse gases are clearly larger than the observed solar changes.

But total solar irradiance remains a pretty important boundary condition for all climate and climate change work.

One would think that we would have solar variation nailed down better by now.

Plot showing all the different satellite TSI results since 1980 as well as sunspot observations.

I understand why it is hard.

Total solar irradiance is ~1361 W/m², so measuring a ~1 W/m² change is less than a 0.1% change.

And it can only be done with satellites, which often degrade and get replaced, requiring the synthesis of many (sometimes inconsistent) measurements.

Time series chart showing a 365-day moving average of 4 different estimates of the changes in total solar irradiance.

It is wild to me that in 2025 the question of how much does solar output change during a solar cycle still comes with a ~20% measurement uncertainty.

I feel this too.

Honestly, Section 4 is mostly there to provide a path of succession when the President is physically unable to serve but is not dead (e.g. comatose or otherwise medically incapacitated).

‘Shattered’: US scientists speak out about how Trump policies disrupted their careers Researchers lay bare the human toll of lay-offs, funding cuts and attacks on science one year after the president’s return to the White House.

We're one year in. The speed, scope and severity of what's happening to American science is beyond anything we've seen before. The reliability of the Federal science and technology enterprise and the people within it, has been shattered. www.nature.com/articles/d41...

Presumably they didn't export either. I'll check later.

Something's apparently wrong with our automated export process.

I'm going to update the tables manually later today.

For further discussion, see yesterday's thread and
@berkeleyearth.org's Annual Report.

bsky.app/profile/did:...

Comparison of annual average global mean temperature 1970-2025 and the expected warming from greenhouse gases.

Nearly linear warming over recent decades is in line with what models expect based on the observed history of greenhouse gases that have been added to the atmosphere.

But the warming experienced in 2023, 2024, and 2025 suggest additional factor(s) are having an effect.

12-month moving average of global mean temperature from 1965 to 2025, with the linear trend 1970-2019 highlighted and the upward divergence in recent years.

For 50 years, global warming had a very consistent trend (+0.19 °C/decade) with a boring, predictable range of natural variations around it.

During the last three years, we've broken out above that range, suggesting the pace of change has quickened.

Global Temperature Report for 2025 - Berkeley Earth 2025 was the 3rd warmest year on Earth since direct observations began, and recent warming appears to be moving faster than expected.

For more background on 2025 temperatures from a climate context, please see @berkeleyearth.org's annual report:

berkeleyearth.org/global-tempe...

Annual average time series of global mean temperature 1850-2025 and the projected range for 2026.

2026 seems likely to deliver more of the same.

Warmth well above 20th century averages, and probably similar to 2025, but only a modest (10%) chance of a new record.

A switch to El Niño later this year is possible, but if so, would probably impact 2027 more than 2026.

Diagram showing 10-year segments of different factors and their anticipated effect on global mean temperature

So, in 2025, we had:

Warming from increased greenhouse gases
Warming from reduced marine sulfur
Cooling from La Niña
Warming from an active solar cycle
Warming(?) from Hunga Tonga

And arrive at the third warmest year in the modern record.

A recent modeling attempting to simulate the full impact of the volcano suggests that the eruption might have initially created modest cooling only to be followed by modest warming after the sulfur aerosols had dissipated.

juser.fz-juelich.de/record/10491...

Reality can be messy.

Water vapor is a strong greenhouse gas, and so its excess (especially in the normally dry upper atmosphere) could lead to warming.

At the same time Hunga Tonga unleashed sulfur aerosols that would be expected to lead to cooling.

The net effect is... complicated.

7-day moving average of upper atmosphere water vapor content 2005-2025.

Unlike the lower atmosphere, where water vapor typically persists for only 1-2 weeks before raining out, the upper atmosphere takes years to dissipate any excess water vapor.

Hunga Tonga provided an unprecedented natural experiment for upper atmosphere water vapor.

In addition to the reduction of marine sulfur air pollution, the other X factor in recent years is the January 2022 eruption of the Hunga Tonga volcano.

An eruption that provided a never before seen boost in upper atmosphere water vapor content.

x.com/RARohde/stat...

In 2025, we actually started and ended the year with a mild La Niña event. This contrasts with the El Niño of 2023/2024.

But for the cooling provided by La Niña, 2025 likely would have been warmer.

But even with a La Niña, 2025 was above the long-term trend line.

Ultimately, removing sulfur air pollution simply reveals the warming that Earth would have had anyway from added greenhouse gases, if we hadn't also been polluting the air with sulfur.

However, removing that sulfur does still provide a bit a shock/jump.

Map of annual average temperature anomalies in 2025 compared to 1950-1980 averages.

Natural variability still plays a role, but the reduction in marine sulfur air pollution (and associated reduction in low cloud cover) likely contributed to the North Pacific heatwave we saw last year, and the North Atlantic heatwaves of 2023/2024.