Pollute Locally, Heat Globally
That smelly hog factory-farm or power plant down the road from your home might be doing more than offending your nasal passages and depressing neighborhood property values. A new report from the National Oceanic and Atmospheric Administration (NOAA) finds that short-lived, local pollution exerts greater-than-expected effects on the global climate.
It’s not just a little impact, either. The study says that, by 2050, projected growth in short-lived pollutants could be responsible for as much 20 percent of global warming.
“Previous research suggests that the warming of the surface climate by increasing levels of long-lived greenhouse gases has been partially offset by increasing levels of those short-lived particles that reflect sunlight,” said Hiram “Chip” Levy, senior research scientist at NOAA’s Geophysical Fluid Dynamics Laboratory in Princeton, N.J., and co-author of the new report. “This study found that over the 21st century the climate impacts of projected changes in human emissions of short-lived gases may in fact enhance global warming.”
Pollutants like tropospheric ozone and black carbon, both of which last in the atmosphere for just days to weeks, contribute a general warming effect to the global climate (see the accompanying chart). Dust, organic carbon, nitrates and sulfates, on the other hand, exert a cooling effect in the days to week they stay in the air.
Then, of course, there are the long-lasting greenhouse gases: carbon dioxide (which stays in the atmosphere for more than 100 years), nitrous oxide (120 years) and methane (10 years).
“By 2100, changes in the levels of short-lived gases and particles could account for a significant portion of the predicted warming, due to a projected increase in black carbon and ozone and a decrease in sulfate,” said Drew Shindell, a climate scientist at NASA’s Goddard Institute for Space Studies in New York and a co-author of the new report.
In North America, we could help reduce the potential warming effects of short-lived pollutants by cutting emissions from ground-based transportation. Curbing black carbon emissions from power plants — especially high-polluting ones such as those found in parts of Asia — would also benefit the climate.
“To assess potential impacts of air quality management actions on future climate, current decision-making tools must be extended to consider local and global scales concurrently,” said Alice Gilliland, a lead author of the new report and a former physical scientist with NOAA’s Air Resources Laboratory.
NOAA’s Website provides more details about the study and links to other resources here.
