Regional and global temperature response to anthropogenic SO<sub>2</sub> emissions from China in three climate models
We use the HadGEM3-GA4, CESM1, and GISS ModelE2 climate models to investigate the global and regional aerosol burden, radiative flux, and surface temperature responses to removing anthropogenic sulfur dioxide (SO<sub>2</sub>) emissions from China. We find that the models differ by up...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/9785/2016/acp-16-9785-2016.pdf |
| Summary: | We use the HadGEM3-GA4, CESM1, and GISS ModelE2 climate models to
investigate the global and regional aerosol burden, radiative flux, and
surface temperature responses to removing anthropogenic sulfur dioxide
(SO<sub>2</sub>) emissions from China. We find that the models differ by up to a
factor of 6 in the simulated change in aerosol optical depth (AOD) and
shortwave radiative flux over China that results from reduced sulfate
aerosol, leading to a large range of magnitudes in the regional and global
temperature responses. Two of the three models simulate a near-ubiquitous
hemispheric warming due to the regional SO<sub>2</sub> removal, with similarities
in the local and remote pattern of response, but overall with a
substantially different magnitude. The third model simulates almost no
significant temperature response. We attribute the discrepancies in the
response to a combination of substantial differences in the chemical
conversion of SO<sub>2</sub> to sulfate, translation of sulfate mass into AOD,
cloud radiative interactions, and differences in the radiative forcing
efficiency of sulfate aerosol in the models. The model with the strongest
response (HadGEM3-GA4) compares best with observations of AOD regionally,
however the other two models compare similarly (albeit poorly) and still
disagree substantially in their simulated climate response, indicating that
total AOD observations are far from sufficient to determine which model
response is more plausible. Our results highlight that there remains a large
uncertainty in the representation of both aerosol chemistry as well as
direct and indirect aerosol radiative effects in current climate models, and
reinforces that caution must be applied when interpreting the results of
modelling studies of aerosol influences on climate. Model studies that
implicate aerosols in climate responses should ideally explore a range of
radiative forcing strengths representative of this uncertainty, in addition
to thoroughly evaluating the models used against observations. |
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| ISSN: | 1680-7316 1680-7324 |