Bizarro Arctic Sea Ice

Arctic Sea Ice is acting weird. Here's the volume as modeled by PIOMAS. {Really this is just an excuse for me to try datawrapper.de, because Excel charts have never looked good and by now look like something from the late 1900s.} But it is strange how the SIV has been basically flat for the last 15 years. (Arctic sea ice extent is just as unusual.) 

Here is a conference presentation screen capture I captured from the leading PIOMAS modeler in Sept 2014:

I think this was from a Cliff Maas blog post or comment I read in 2017, but can't find it exactly. The screen capture looks like it's from a conference. 

Anyway it's very wrong. Actually the decline, linearly regressed, is about 1/1.5, now 1/6.  

Lesson?: beware of making climate predictions unless it's about mean global surface temperature, and even then ENSOs mess you up.

--

So why is there a "pause" in Arctic melting? This paper on ESS Open Archive (?) goes into it. It's not peer reviewed, which is unfortunate. Given that, here's the abstract:

So it's maybe worse, going back 20 years (to 2005). Could last 5-10 more years. (Not convenient, given my lifespan.) 

So, internal variability, which is nearly impossible to explain to deniers.

Conquering the Universe

"Just because some of us can read and write and do a little math, that doesn't mean we deserve to conquer the Universe."

Kurt Vonnegut

CO2 > 430 ppm

Atmospheric carbon dioxide has cracked the 430 ppm level at the Mauna Loa Observatory in on Hawaii. 

Here's NOAA's daily source for the data; the image above is from Daily CO2.

In fact, atmospheric CO2 at MLO peaked this year at 431.13 ppm on 27-April-2025. Last year it peaked at 428.59 ppm on 26-April-2024. That's only a 2.45 ppm increase, maybe a touch below the recent average, maybe due to the relative ENSO states. 2024 as a year (not a season) was somewhat on the La Nina-side, with this year slightly towards the El Nino-side. (I think.)

So, it's not clear if next year will break 435 ppm. Anyway the fascists might have stopped all US scientific measurements by then. (Yes, I know it's measured at many other places around the globe, but as far as I know none of them has the longevity of the Mauna Loa data.)

"They Haven't Started and We're Almost Done"

Suppressing the Costs of Climate Change

The fascists have decided to stop keeping track of the costs of climate change. Free link to NY Times story.

If you don't keep track of it, it's like it doesn't exist. This is hard for me to wrap my head around at the moment.

50 Years at 0.30°C/decade

The 50-year linear trend for the Hadley Central England Temperature (HadCET) is a very healthy worrisome 0.30°C/decade.

Without including any autocorrelation, because I don't feel like calculating it today, the 2-sigma uncertainty is 0.07°C/decade.

Over 50 years that's an increase of 1.52°C (2.73°F).

Also, the 10-year moving average reached a record high in April at 10.7°C. (That's an absolute number, not an anomaly.) 

HadCET is measured over a fairly broad area of...central England...bounded by an approximate triangle from Lancaster in the north of England to Bristol in the southwest to London in the southeast. Former homes of such famous people as Gollum (well, actor Andy Serkis), Blackbeard the Pirate and Charles the Darwin, son of Robert, a wealthy society doctor and financier, and grandson of Erasmus the Darwin, a (inhale) "natural philosopher, physiologist, slave-trade abolitionist, inventor, freemason, and poet" (exhale). 

Via Wikipedia.

Caught Only Half the Time

Meowthematics >> Mathematics
byu/Ok-Cap6895 inmathmemes

The Dispossessed

“If you can see a thing whole,” he said, “it seems that it’s always beautiful. Planets, lives…But close up, a world’s all dirt and rocks. And day to day, life’s a hard job, you get tired, you lose the pattern. You need distance, interval. The way to see how beautiful the earth is, is to see it as the moon. The way to see how beautiful life is, is from the vantage point of death.”

Ursula K. Le Guin, The Dispossessed

A really great book.

Latest SST

If you need an update on the latest sea surface temperatures, this is from Zack Labe on Bluesky:

2024: Record high CO2 energy emissions

2024 global energy-related CO2 emissions were a record high, at 37.8 Gt, according to the International Energy Administration (IEA). That's an annual increase of 1.0%.

In 2024, CO2 emissions from fuel combustion grew by around 1% or 357 Mt CO2, while emissions from industrial processes declined by 2.3% or 62 Mt CO2. Emissions growth was lower than global GDP growth (+3.2%), restoring the decades-long trend of decoupling emissions growth from economic growth, which had been disrupted in 2021.

Natural gas emissions rose by around 2.5% (180 Mt CO₂) in 2024, making it the largest contributor to global carbon emissions growth. This increase was driven by higher consumption in China, the United States, the Middle East, and India.

This is disappointing:

Global coal emissions rose by 0.9% (135 Mt CO₂) in 2024. The increase was primarily fuelled by growing coal consumption in China, India and Southeast Asia, while demand declined in advanced economies, particularly in the United States and the European Union.

 

Climate Sensitivity from Paleoclimate Data

Here's a graph from Skinner 2012 that I've never seen before and I'm surprised I've never seen it before--the climate sensitivity from many climate events, warming and cooling, in the distant past:

This is from 

"A Long View on Climate Sensitivity," Luke Skinner

Science 24 Aug 2012, Vol. 337, Issue 6097, pp. 917-919

https://science.sciencemag.org/content/337/6097/917/tab-figures-data

(paywalled). The individual climate sensitivities--the amount of global warming that may be expected as a result of a doubling of the atmospheric carbon dioxide (CO2) concentration--vary, in part because every climate event starts in a different climate and so won't trace the same warming path as any other. Still there's apparently not a lot of variation between events. 

The author gives 12 pairs of data for the different in supplementary material (also paywalled). From it I get a best linear fit to this graph of 

ΔT/ΔF = 0.704°C/(W/m²)

which, using the definition of climate sensitivity λ 

gives, for a doubling of temperature

where α is this proportionality constant equal to 5.35 W/m². Plugging in the numbers

and that quite enough LaTeX for one day. (Like all physics graduate students, I used to be a wiz in LaTeX back then.)

The IPCC 6AR gives a climate sensitivity of 2.5 - 4.0°C, so there is some agreement.