Assessing the lifetime of anthropogenic CO<sub>2</sub> and its sensitivity to different carbon cycle processes
<p>Although it is well-established that anthropogenic <span class="inline-formula">CO<sub>2</sub></span> emitted into the atmosphere will persist for a long time, the duration of the anthropogenic climate perturbation will depend on how rapidly the excess <...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2025-06-01
|
| Series: | Biogeosciences |
| Online Access: | https://bg.copernicus.org/articles/22/2767/2025/bg-22-2767-2025.pdf |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849685571543236608 |
|---|---|
| author | C. Kaufhold C. Kaufhold M. Willeit B. Liu B. Liu A. Ganopolski |
| author_facet | C. Kaufhold C. Kaufhold M. Willeit B. Liu B. Liu A. Ganopolski |
| author_sort | C. Kaufhold |
| collection | DOAJ |
| description | <p>Although it is well-established that anthropogenic <span class="inline-formula">CO<sub>2</sub></span> emitted into the atmosphere will persist for a long time, the duration of the anthropogenic climate perturbation will depend on how rapidly the excess <span class="inline-formula">CO<sub>2</sub></span> is removed from the climate system by different biogeochemical processes. The uncertainty around the long-term climate evolution is therefore linked to not only the future of anthropogenic <span class="inline-formula">CO<sub>2</sub></span> emissions but also our insufficient understanding of the long-term carbon cycle. Here, we use the fast Earth system model CLIMBER-X, which features a comprehensive carbon cycle, to examine the lifetime of anthropogenic <span class="inline-formula">CO<sub>2</sub></span> and its effects on the long-term evolution of atmospheric <span class="inline-formula">CO<sub>2</sub></span> concentration. This is done through an ensemble of 100 000-year-long simulations, each driven by idealized <span class="inline-formula">CO<sub>2</sub></span> emission pulses. Our findings indicate that depending on the magnitude of the emission, 75 % of anthropogenic <span class="inline-formula">CO<sub>2</sub></span> is removed within 197–1820 years of the peak <span class="inline-formula">CO<sub>2</sub></span> concentration (with larger cumulative emissions taking longer to remove). Approximately 4.3 % of anthropogenic <span class="inline-formula">CO<sub>2</sub></span> will remain beyond 100 <span class="inline-formula">kyr</span>. We find that the uptake of carbon by land, which has only been considered to a small extent in previous studies, has a significant long-term effect, storing approximately 4 %–13 % of anthropogenic carbon by the end of the simulation. Higher-emission scenarios fall on the lower end of this range, as increased soil respiration leads to greater carbon loss. For the first time, we have quantified the effect of dynamically changing methane concentrations on the long-term carbon cycle, showing that its effects are likely negligible over long timescales. The timescale of carbon removal via silicate weathering is also reassessed here, providing an estimate (80–105 <span class="inline-formula">kyr</span>) that is significantly shorter than some previous studies due to higher climate sensitivity, stronger weathering feedbacks, and the use of a spatially explicit weathering scheme, leading to faster removal of anthropogenic <span class="inline-formula">CO<sub>2</sub></span> in the long term. Furthermore, this timescale is shown to have a non-monotonic relationship with cumulative emissions. Our study highlights the importance of adding model complexity to the global carbon cycle in Earth system models to accurately represent the long-term future evolution of atmospheric <span class="inline-formula">CO<sub>2</sub></span>.</p> |
| format | Article |
| id | doaj-art-e30b8e4d6f354e6e945f3520fac7077c |
| institution | DOAJ |
| issn | 1726-4170 1726-4189 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj-art-e30b8e4d6f354e6e945f3520fac7077c2025-08-20T03:23:06ZengCopernicus PublicationsBiogeosciences1726-41701726-41892025-06-01222767280110.5194/bg-22-2767-2025Assessing the lifetime of anthropogenic CO<sub>2</sub> and its sensitivity to different carbon cycle processesC. Kaufhold0C. Kaufhold1M. Willeit2B. Liu3B. Liu4A. Ganopolski5Department of Earth System Analysis, Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, P.O. Box 601203, 14412 Potsdam, GermanyInstitute of Physics and Astronomy, Universität Potsdam, Potsdam, GermanyDepartment of Earth System Analysis, Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, P.O. Box 601203, 14412 Potsdam, GermanyUniversität Hamburg, Hamburg, GermanyMax Planck Institute for Meteorology, Hamburg, GermanyDepartment of Earth System Analysis, Potsdam Institute for Climate Impact Research (PIK), Member of the Leibniz Association, P.O. Box 601203, 14412 Potsdam, Germany<p>Although it is well-established that anthropogenic <span class="inline-formula">CO<sub>2</sub></span> emitted into the atmosphere will persist for a long time, the duration of the anthropogenic climate perturbation will depend on how rapidly the excess <span class="inline-formula">CO<sub>2</sub></span> is removed from the climate system by different biogeochemical processes. The uncertainty around the long-term climate evolution is therefore linked to not only the future of anthropogenic <span class="inline-formula">CO<sub>2</sub></span> emissions but also our insufficient understanding of the long-term carbon cycle. Here, we use the fast Earth system model CLIMBER-X, which features a comprehensive carbon cycle, to examine the lifetime of anthropogenic <span class="inline-formula">CO<sub>2</sub></span> and its effects on the long-term evolution of atmospheric <span class="inline-formula">CO<sub>2</sub></span> concentration. This is done through an ensemble of 100 000-year-long simulations, each driven by idealized <span class="inline-formula">CO<sub>2</sub></span> emission pulses. Our findings indicate that depending on the magnitude of the emission, 75 % of anthropogenic <span class="inline-formula">CO<sub>2</sub></span> is removed within 197–1820 years of the peak <span class="inline-formula">CO<sub>2</sub></span> concentration (with larger cumulative emissions taking longer to remove). Approximately 4.3 % of anthropogenic <span class="inline-formula">CO<sub>2</sub></span> will remain beyond 100 <span class="inline-formula">kyr</span>. We find that the uptake of carbon by land, which has only been considered to a small extent in previous studies, has a significant long-term effect, storing approximately 4 %–13 % of anthropogenic carbon by the end of the simulation. Higher-emission scenarios fall on the lower end of this range, as increased soil respiration leads to greater carbon loss. For the first time, we have quantified the effect of dynamically changing methane concentrations on the long-term carbon cycle, showing that its effects are likely negligible over long timescales. The timescale of carbon removal via silicate weathering is also reassessed here, providing an estimate (80–105 <span class="inline-formula">kyr</span>) that is significantly shorter than some previous studies due to higher climate sensitivity, stronger weathering feedbacks, and the use of a spatially explicit weathering scheme, leading to faster removal of anthropogenic <span class="inline-formula">CO<sub>2</sub></span> in the long term. Furthermore, this timescale is shown to have a non-monotonic relationship with cumulative emissions. Our study highlights the importance of adding model complexity to the global carbon cycle in Earth system models to accurately represent the long-term future evolution of atmospheric <span class="inline-formula">CO<sub>2</sub></span>.</p>https://bg.copernicus.org/articles/22/2767/2025/bg-22-2767-2025.pdf |
| spellingShingle | C. Kaufhold C. Kaufhold M. Willeit B. Liu B. Liu A. Ganopolski Assessing the lifetime of anthropogenic CO<sub>2</sub> and its sensitivity to different carbon cycle processes Biogeosciences |
| title | Assessing the lifetime of anthropogenic CO<sub>2</sub> and its sensitivity to different carbon cycle processes |
| title_full | Assessing the lifetime of anthropogenic CO<sub>2</sub> and its sensitivity to different carbon cycle processes |
| title_fullStr | Assessing the lifetime of anthropogenic CO<sub>2</sub> and its sensitivity to different carbon cycle processes |
| title_full_unstemmed | Assessing the lifetime of anthropogenic CO<sub>2</sub> and its sensitivity to different carbon cycle processes |
| title_short | Assessing the lifetime of anthropogenic CO<sub>2</sub> and its sensitivity to different carbon cycle processes |
| title_sort | assessing the lifetime of anthropogenic co sub 2 sub and its sensitivity to different carbon cycle processes |
| url | https://bg.copernicus.org/articles/22/2767/2025/bg-22-2767-2025.pdf |
| work_keys_str_mv | AT ckaufhold assessingthelifetimeofanthropogeniccosub2subanditssensitivitytodifferentcarboncycleprocesses AT ckaufhold assessingthelifetimeofanthropogeniccosub2subanditssensitivitytodifferentcarboncycleprocesses AT mwilleit assessingthelifetimeofanthropogeniccosub2subanditssensitivitytodifferentcarboncycleprocesses AT bliu assessingthelifetimeofanthropogeniccosub2subanditssensitivitytodifferentcarboncycleprocesses AT bliu assessingthelifetimeofanthropogeniccosub2subanditssensitivitytodifferentcarboncycleprocesses AT aganopolski assessingthelifetimeofanthropogeniccosub2subanditssensitivitytodifferentcarboncycleprocesses |