Carbon–climate feedbacks accelerate ocean acidification
Carbon–climate feedbacks have the potential to significantly impact the future climate by altering atmospheric CO<sub>2</sub> concentrations (Zaehle et al. 2010). <br><br> By modifying the future atmospheric CO<sub>2</sub> concentrations, the carbon–climate f...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-03-01
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| Series: | Biogeosciences |
| Online Access: | https://www.biogeosciences.net/15/1721/2018/bg-15-1721-2018.pdf |
| Summary: | Carbon–climate feedbacks have the potential to significantly
impact the future climate by altering atmospheric CO<sub>2</sub> concentrations
(Zaehle et al. 2010).
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By modifying the future atmospheric CO<sub>2</sub> concentrations, the
carbon–climate feedbacks will also influence the future ocean acidification
trajectory. Here, we use the CO<sub>2</sub> emissions scenarios from four
representative concentration pathways (RCPs) with an Earth system model to
project the future trajectories of ocean acidification with the inclusion of
carbon–climate feedbacks.
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We show that simulated carbon–climate feedbacks can significantly impact the
onset of undersaturated aragonite conditions in the Southern and Arctic
oceans, the suitable habitat for tropical coral and the deepwater saturation
states. Under the high-emissions scenarios (RCP8.5 and RCP6), the
carbon–climate feedbacks advance the onset of surface water under saturation
and the decline in suitable coral reef habitat by a decade or more. The
impacts of the carbon–climate feedbacks are most significant for the medium-
(RCP4.5) and low-emissions (RCP2.6) scenarios. For the RCP4.5 scenario, by
2100 the carbon–climate feedbacks nearly double the area of surface water
undersaturated with respect to aragonite and reduce by 50 % the surface
water suitable for coral reefs. For the RCP2.6 scenario, by 2100 the
carbon–climate feedbacks reduce the area suitable for coral reefs by 40 %
and increase the area of undersaturated surface water by 20 %. The
sensitivity of ocean acidification to the carbon–climate feedbacks in the low
to medium emission scenarios is important because recent CO<sub>2</sub> emission
reduction commitments are trying to transition emissions to such a scenario.
Our study highlights the need to better characterise the carbon–climate
feedbacks and ensure we do not underestimate the projected ocean
acidification. |
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| ISSN: | 1726-4170 1726-4189 |