Cleaning the air helps cool planet: Cutting smog and soot has an immediate impact on climate change

Cleaning the air helps cool planet

12 December 2008

Emissions cuts offer 'greatest potential for substantial, simultaneous improvements in local air quality and near-term mitigation.'

By Douglas Fischer
Daily Climate

Local and state regulators have new ammunition in the fight to justify expensive air pollution rules: Cutting smog and soot has an immediate impact on climate change.

A study published this week bolsters the link between air quality and climate, finding that across-the-board cuts in air pollution can spur "substantial, simultaneous" improvement in local air quality and near-term mitigation of climate change.

Trimming smog and soot also represents an alternate and far more immediate global warming solution for regulators stymied by the complexities of other greenhouse gases such as carbon dioxide, said Drew Shindell, a climate scientist at NASA’s Goddard Institute for Space Sciences and the lead author of the study.

Tackling air pollution can buy 20 to 30 years worth of mitigation, he said – time that will be needed, if ongoing debates in Poznan, Brussells and Washington D.C. offer any indication – to cut the political and economic knots associated with carbon dioxide.

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ABSTRACT

Shindell et al. 2008

Shindell, D., J.-F. Lamarque, N. Unger, D. Koch, G. Faluvegi, S. Bauer, and H. Teich, 2008: Climate forcing and air quality change due to regional emissions reductions by economic sector. Atmos. Chem. Phys., 8, 7101-7113.

We examine the air quality (AQ) and radiative forcing (RF) response to emissions reductions by economic sector for North America and developing Asia in the CAM and GISS composition/climate models. Decreases in annual average surface particulate are relatively robust, with intermodel variations in magnitude typically <30% and very similar spatial structure. Surface ozone responses are small and highly model dependent. The largest net RF results from reductions in emissions from the North America industrial/power and developing Asia domestic fuel burning sectors. Sulfate reductions dominate the first case, for which intermodel variations in the sulfate (or total) aerosol optical depth (AOD) responses are ~30% and the modeled spatial patterns of the AOD reductions are highly correlated (R=0.9). Decreases in BC dominate the developing Asia domestic fuel burning case, and show substantially greater model-to-model differences. Intermodel variations in tropospheric ozone burdens are also large, though aerosol changes dominate those cases with substantial net climate forcing. The results indicate that across-the-board emissions reductions in domestic fuel burning in developing Asia and in surface transportation in North America are likely to offer the greatest potential for substantial, simultaneous improvement in local air quality and near-term mitigation of global climate change via short-lived species. Conversely, reductions in industrial/power emissions have the potential to accelerate near-term warming, though they would improve AQ and have a long-term cooling effect on climate. These broad conclusions appear robust to intermodel differences.

* http://pubs.giss.nasa.gov/docs/2008/2008_Shindell_etal_3.pdf">Download PDF (Document is 716 kB)

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