The ocean takes up anthropogenic CO₂ emissions, 26% on average over the past decade. The #GlobalCarbonBudget 2024 confirms that the ocean sink increased in 2023 after 3 years of stagnation due to rare triple La Niña event. 2023 was an El Niño year, with an expected increase in the sink. 🔽 🌊 1/10 - ThreadSky

jhauck.bsky.social • 144 days ago

The ocean takes up anthropogenic CO₂ emissions, 26% on average over the past decade.

The #GlobalCarbonBudget 2024 confirms that the ocean sink increased in 2023 after 3 years of stagnation due to rare triple La Niña event. 2023 was an El Niño year, with an expected increase in the sink.

🔽
🌊 1/10

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joceansan.bsky.social•144 days ago

Thanks for this great summary @jhauck.bsky.social and all the work behind!

Do we know why observations decreased so much? Less observational programs? Less ship time? I wonder if anybody has looked into the reasons of this worrying decline...

jhauck.bsky.social•144 days ago

It is missing funding for routine observations that would need to be operationalized. Funding agencies prefer to fund innovative exciting short-term projects. Entire lines of ships of opportunity stopped.

jhauck.bsky.social•144 days ago

In view of increasing atmospheric CO₂ and absence of La Niña, what else could the ocean sink do as to increase in 2024?

That's what is projected here.

2/10

jhauck.bsky.social•144 days ago

Clearly, the CO₂ effect dominates over the climate effect in the ocean. Yet, climate change and variability reduces the ocean carbon sink, by about 6% over the past decade.

Often people think this is a warming effect, but changing wind patterns actually matter more ...

3/10

jhauck.bsky.social•144 days ago

...due to a feedback that limits the reduced carbon uptake in response to warming.

more on the climate effect here: https://bsky.app/profile/jhauck.bsky.social/post/3kmgf4bejqc2m

4/10

jhauck.bsky.social•144 days ago

The ocean sink is quite well behaved this year and the best estimates from models and observation-based estimates lie well within the uncertainty of the joint best estimate, as @davidho.bsky.social noted.

5/10

https://bsky.app/profile/davidho.bsky.social/post/3lasyimpfas2g

jhauck.bsky.social•144 days ago

Dependent on the chosen period, the trends now agree as well (within their uncertainties). The trend in the observation-based estimates is lower than in previous years.
Nicolas Mayot and the UEA team just had a nice 🌊 paper constraining the trend in the ocean sink:
https://www.nature.com/articles/s41467-024-52641-7

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jhauck.bsky.social•144 days ago

Of course, the difference in the decadal mean estimate of the ocean carbon sink is still too large for comfort, and this is further emphasized when including an oxygen-based estimate.

7/10

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