Details:

Journal Title:
Environmental Research Letters
Personal Author:
McKinley, Galen A ; Bennington, Val ; Meinshausen, Malte ; Nicholls, Zebedee
McKinley, Galen A ; Bennington, Val ; Meinshausen, Malte ; Nicholls, Zebedee Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research)
Description:
The ocean has absorbed about 25% of the carbon emitted by humans to date. To better predict how much climate will change, it is critical to understand how this ocean carbon sink will respond to future emissions. Here, we examine the ocean carbon sink response to low emission (SSP1-1.9, SSP1-2.6), intermediate emission (SSP2-4.5, SSP5-3.4-OS), and high emission (SSP5-8.5) scenarios in CMIP6 Earth System Models and in MAGICC7, a reduced-complexity climate carbon system model. From 2020–2100, the trajectory of the global-mean sink approximately parallels the trajectory of anthropogenic emissions. With increasing cumulative emissions during this century (SSP5-8.5 and SSP2-4.5), the cumulative ocean carbon sink absorbs 20%–30% of cumulative emissions since 2015. In scenarios where emissions decline, the ocean absorbs an increasingly large proportion of emissions (up to 120% of cumulative emissions since 2015). Despite similar responses in all models, there remains substantial quantitative spread in estimates of the cumulative sink through 2100 within each scenario, up to 50 PgC in CMIP6 and 120 PgC in the MAGICC7 ensemble. We demonstrate that for all but SSP1-2.6, approximately half of this future spread can be eliminated if model results are adjusted to agree with modern observation-based estimates. Considering the spatial distribution of air-sea CO2 fluxes in CMIP6, we find significant zonal-mean divergence from the suite of newly-available observation-based constraints. We conclude that a significant portion of future ocean carbon sink uncertainty is attributable to modern-day errors in the mean state of air-sea CO2 fluxes, which in turn are associated with model representations of ocean physics and biogeochemistry. Bringing models into agreement with modern observation-based estimates at regional to global scales can substantially reduce uncertainty in future role of the ocean in absorbing anthropogenic CO2 from the atmosphere and mitigating climate change.
Keywords:
[+]
General Environmental Science Public Health, Environmental And Occupational Health Renewable Energy, Sustainability And The Environment
Source:
Environmental Research Letters, 18(4), 044011
DOI:
https://doi.org/10.1088/1748-9326/acc195
ISSN:
1748-9326
Format:
PDF
Publisher:
IOP Publishing
Document Type:
Journal Article
Funding:
Grant no. NA20OAR4310340
License:
https://creativecommons.org/licenses/by/4.0/
Rights Information:
CC BY
Compliance:
Library
Main Document Checksum:
[+]
urn:sha256:b11cce93f144a19865561c0f4f47bd5a3156c7d89f3c90bf81dc816f948fd698
Download URL:
https://repository.library.noaa.gov/view/noaa/58888/noaa_58888_DS1.pdf
File Type:

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