Composite model-based estimate of the ocean carbon sink from 1959 to 2022

<p>The ocean takes up around one-quarter of anthropogenically emitted carbon and is projected to remain the main carbon sink once global temperatures stabilize. Despite the importance of this natural carbon sink, estimates of its strength over the last decades remain uncertain, mainly due to t...

Full description

Saved in:
Bibliographic Details
Main Author: J. Terhaar
Format: Article
Language:English
Published: Copernicus Publications 2025-03-01
Series:Biogeosciences
Online Access:https://bg.copernicus.org/articles/22/1631/2025/bg-22-1631-2025.pdf
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850066322691457024
author J. Terhaar
J. Terhaar
author_facet J. Terhaar
J. Terhaar
author_sort J. Terhaar
collection DOAJ
description <p>The ocean takes up around one-quarter of anthropogenically emitted carbon and is projected to remain the main carbon sink once global temperatures stabilize. Despite the importance of this natural carbon sink, estimates of its strength over the last decades remain uncertain, mainly due to too few and unevenly sampled observations and shortcomings in ocean models and their setups. Here, I present a composite model-based estimate of the annually averaged ocean carbon sink from 1959 to 2022 by combining the higher-frequency variability of the annually averaged estimates of the carbon sink from ocean models in hindcast mode and the long-term trends from fully coupled Earth system models. Ocean models in hindcast mode reproduce the observed climate variability, but their spin-up strategy likely leads to long-term trends that are too weak, whereas fully coupled Earth system models simulate their own internal climate variability but better represent long-term trends. By combining these two modelling approaches, I keep the strength of each approach and remove the respective weaknesses. This composite model-based estimate of the ocean carbon sink from 1959 to 2022 is <span class="inline-formula">125±8</span> Pg C and is similar in magnitude to the best estimate of the Global Carbon Budget but 70 % less uncertain.</p>
format Article
id doaj-art-fb71d778c1f547a0b7163768bb409caf
institution DOAJ
issn 1726-4170
1726-4189
language English
publishDate 2025-03-01
publisher Copernicus Publications
record_format Article
series Biogeosciences
spelling doaj-art-fb71d778c1f547a0b7163768bb409caf2025-08-20T02:48:46ZengCopernicus PublicationsBiogeosciences1726-41701726-41892025-03-01221631164910.5194/bg-22-1631-2025Composite model-based estimate of the ocean carbon sink from 1959 to 2022J. Terhaar0J. Terhaar1Climate and Environmental Physics, Physics Institute, University of Bern, Bern, SwitzerlandOeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland<p>The ocean takes up around one-quarter of anthropogenically emitted carbon and is projected to remain the main carbon sink once global temperatures stabilize. Despite the importance of this natural carbon sink, estimates of its strength over the last decades remain uncertain, mainly due to too few and unevenly sampled observations and shortcomings in ocean models and their setups. Here, I present a composite model-based estimate of the annually averaged ocean carbon sink from 1959 to 2022 by combining the higher-frequency variability of the annually averaged estimates of the carbon sink from ocean models in hindcast mode and the long-term trends from fully coupled Earth system models. Ocean models in hindcast mode reproduce the observed climate variability, but their spin-up strategy likely leads to long-term trends that are too weak, whereas fully coupled Earth system models simulate their own internal climate variability but better represent long-term trends. By combining these two modelling approaches, I keep the strength of each approach and remove the respective weaknesses. This composite model-based estimate of the ocean carbon sink from 1959 to 2022 is <span class="inline-formula">125±8</span> Pg C and is similar in magnitude to the best estimate of the Global Carbon Budget but 70 % less uncertain.</p>https://bg.copernicus.org/articles/22/1631/2025/bg-22-1631-2025.pdf
spellingShingle J. Terhaar
J. Terhaar
Composite model-based estimate of the ocean carbon sink from 1959 to 2022
Biogeosciences
title Composite model-based estimate of the ocean carbon sink from 1959 to 2022
title_full Composite model-based estimate of the ocean carbon sink from 1959 to 2022
title_fullStr Composite model-based estimate of the ocean carbon sink from 1959 to 2022
title_full_unstemmed Composite model-based estimate of the ocean carbon sink from 1959 to 2022
title_short Composite model-based estimate of the ocean carbon sink from 1959 to 2022
title_sort composite model based estimate of the ocean carbon sink from 1959 to 2022
url https://bg.copernicus.org/articles/22/1631/2025/bg-22-1631-2025.pdf
work_keys_str_mv AT jterhaar compositemodelbasedestimateoftheoceancarbonsinkfrom1959to2022
AT jterhaar compositemodelbasedestimateoftheoceancarbonsinkfrom1959to2022