Open AccessImpact of Solar Radiation Modification on Allowable CO 2 Emissions: What Can We Learn From Multimodel Simulations?
Author(s) -
Plazzotta Maxime,
Séférian Roland,
Douville Hervé
Publication year - 2019
Publication title -
earth's future
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.641
H-Index - 39
ISSN - 2328-4277
DOI - 10.1029/2019ef001165
Subject(s) - environmental science , biosphere , carbon dioxide , carbon cycle , greenhouse gas , carbon fibers , atmosphere (unit) , atmospheric sciences , earth system science , carbon dioxide removal , carbon capture and storage (timeline) , meteorology , climate change , oceanography , chemistry , ecology , materials science , ecosystem , geology , physics , organic chemistry , composite number , composite material , biology
Solar radiation modification (SRM) is known to strengthen both land and ocean carbon uptake because of its impacts on surface temperature, solar radiation, and other potential drivers of the global carbon cycle. However, the magnitude and timing of the response of both land and ocean carbon uptake to SRM and its consequence on allowable CO 2 emissions remain poorly understood. Here we use the results of six Earth system models simulating a continuous stratospheric injection of 5 Tg of sulfur dioxide per year between 2020 and 2069 under the representative concentration pathways 4.5 to investigate the impact of SRM on land and ocean carbon uptake. We find that 50 years of SRM under this protocol increases the allowable CO 2 emissions by 40 ± 19 GtC; 85% of this additional uptake of carbon is stored in the land biosphere and 15% in the ocean. This increase in allowable CO 2 emissions is however not sustainable after the stoppage of SRM. Earth system models predict a mean release of 8 ± 11 GtC of the carbon back to the atmosphere 20 years after the stoppage which is dominated by large uncertainties in the response of the simulated land carbon cycle to rising temperature and solar radiation. We demonstrate that the time scales of carbon dioxide removal (CDR) potential of SRM are smaller than the time scales of the geological storage assumed in well‐established CDR options. This shows that the CDR potential of SRM should be compared to well‐established CDR options with caution.