One sentence in the article especially caught my eye.
This warmth is especially apparent in the oceans, where key indicators of climate change are now accelerating.
They don't say which indicators, but I assume ocean heat content (OHC) is a prominent one.
I used to think, based on the data, that it was indeed accelerating. But from my amateurish calculations, it looks like the OHC in the 0-2000 meter range (top half) has stopped accelerating. It had a peak in the first quarter of last year, and the last three readings are below that. OK, ENSOs and whatnot. A very recent peak isn't important or interesting.
Here are the data:
The leading coefficient of the second-degree polynomial is now 0.037 ZJ/yr2 (ZJ=zetajoules=1021 joules). But it has a 2-sigma uncertainty of 0.044 ZJ/yr2, calculated by the standard linear regression (with no autocorrelation, which would only make the error bars higher (I think)).
The 0-2000 m acceleration is twice this coefficient, and in more typical units is 0.0046 ± 0.0055 (W/m2)/yr. So it's not statistically significant at the 2-sigma level.
The 0-700 m acceleration is statistically significant at 0.0088 ± 0.0004 (W/m2)/yr.
I don't have data on the lower half of the ocean. I don't even know if it exists, though I have seen a few papers years ago that it's warming, though at a much slower rate. (Now I can't find them.)
Don't know if this means anything--the ocean heat is still increasing strongly, of course. I could calculate that, but I'm not going to right now because I'm tired. Maybe tomorrow. Likely the recent OHCs are messed up wonky because of the big El Nino than the small La Nina.
Just wanted to put up my the little calculations, to justify the time it took to build the spreadsheet. (Really, I just like making spreadsheets & keeping track of the basic climate data).
Cheers.
8 comments:
Aviso gives an acceleration of 0.11+/-0.05mm/year.
https://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level.html#c15723
Colorado gives 0.083+/-0.025mm/year. But it only goes up to 2023.
https://sealevel.colorado.edu/
Aviso give a rate of increase of of 2.1mm/yr for the first ten years of their record and 4.1mm/yr for the last ten years. Crudely that's an acceleration of 0.09mm/yr.
Everyone has big error bars, suggesting noisy data, with a lot of short term variations in both the rate of rise and the acceleration
Had you seen this?
https://sealevel.nasa.gov/news/282/nasa-analysis-shows-unexpected-amount-of-sea-level-rise-in-2024/
Very awesome!!! When I seek for this I found this website at the top of all blogs in search engine.
Your blog provided us with valuable information to work with
EM: are you maybe looking at sea level rise? Because that has units of mm/yr, and its acceleration would have units of mm/yr^2. But ocean heat content has units of joules, and the units of its acceleration are J/yr^2.
I did see that link, yes, but thanks for pointing it out. I meant to blog about it and still should. I have several items of news piled up to blog; I might just post citations and links without a discussion of every item.
I played about with there numbers a few years ago.
IIRC one zeettajoule (10^21 Joules) of increased ocean heat content leads to 360 cubic kilometres of thermal expansion.and raises sea level by 1mm.
Whether you measure the rate of change in joules/yr, cubic kilometres/yr or mm/yr probably depends on where your data comes from. In each case the acceleration is about 1% of the rate of change.
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