Shaky world economies have forced global warming off the political agenda, but a new twist on the issue could revive its political fortunes.
The initial thrust of environmentalist action was aimed at carbon dioxide emissions, the greenhouse gas emissions generated by electrical plants and large industry. The specter of rising energy prices, factories closing down and workers being laid off dampened enthusiasm in Congress and state legislatures to adopt ideas such as "cap and trade" policies to reduce CO2 emissions.
Because CO2 hangs around in the atmosphere a long time, reductions now wouldn't produce a difference for what seemed like a political eternity.
Since the clock is still running on rising world temperatures, climate scientists and global warming warriors are looking for a new direction that can produce positive results with less political resistance. In an article published by Science, climate scientist Drew Shindell offers a potentially winning strategy.
Shindell, who is with NASA's Goddard Institute for Space Studies at Columbia University, says the environment would be greatly improved by reducing the amount of ozone and soot in the air. Soot and ozone reduction could slow warming by a half degree Celsius by 2050, he says, which would be "an immediate and quite powerful effect on climate both at global and regional scales."
Ozone is generated when methane rises into the atmosphere. According to the Environmental Protection Agency, rotting food in landfills is a major source of methane emissions. Other sources are coal mines, pipelines and livestock waste ponds. Ozone can damage commercial crops and create smog.
Soot or black carbon results from burning wood, charcoal and dung. The United States and many other countries regulate the amount of particulate matter that can be emitted into the air.
Shindell says in addition to the environmental benefits of reducing ozone and soot, there would be significant health benefits. "If you factor in the air quality benefits and their large effects on health, then you find the reductions are really giving you benefits that outweigh costs," Shindell says. One estimate places the cost of reducing ozone and soot to an average of $250 per ton. It is harder to place a value on cleaner air or, for that matter, holding the planet's temperatures relatively constant.
Global warming activists see an advantage in attacking ozone and soot because there are already laws in places in many countries that address ozone and black carbon emissions. Pushing harder to limit or eliminate these emissions probably wouldn't require the arduous task of negotiating and implementing an international treaty – or fighting big utilities and corporations.
More important, the issue of combating greenhouse gases can be framed as more personal. Instead of worrying about losing your job, Americans would see a benefit in cleaning up the air they breathe by relatively modest steps such as recycling food scraps, switching to an electric lawnmower and replacing charcoal grills and wood stoves.