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Renewables Are Faster Fix By Replacing Diesel Soot First

Replacing diesel use with renewable energy or hydrogen will do more to speed efforts to reduce global warming and reduce health problems in the short term than any other measure, according to pollution expert Mark Jacobson.

STANFORD, California, US, 2002-01-04 [SolarAccess.com] Diesel soot particles are not only dirty, smelly, cause respiratory and cardiovascular disease and shorten life, but is a major factor in global warming, says the California professor in a paper to the American Geophysical Union. Reducing soot emissions will slow global warming faster than will reducing carbon dioxide, methane or other greenhouse gases. “If you want to control global warming, the first thing to go after is soot,” he says. The particles of elemental black carbon warm the air by absorbing sunlight and radiating heat to the air, unlike greenhouse gases that do not absorb sunlight but warm the air by absorbing the earth’s heat and radiating it to the air. Soot does this as well. Soot may be the second-leading cause of global warming after carbon dioxide, says Jacobson. Controlling soot will cool climate faster than will controlling CO2 because soot has a very short lifetime in the air, whereas CO2 has a lifetime of 50 to 1,000 years. He explains that soot leaves the atmosphere quickly and no longer has a warming effect. The 1997 Kyoto Protocol of global warming failed to consider soot, which is created by burning diesel fuels, jet fuel, coal, wood and other biomass. Most climate-change models do not consider soot nor its interactions with other atmospheric aerosols or clouds. Jacobson’s developed a computer model over 12 years to consider the impact, and he says net global warming to date is due to warming by greenhouse gases and soot, significantly offset by cooling due to reflective particles such as sulfate and nitrate. Eliminating all soot from fossil fuels could reduce 40 percent of net global warming in three to five years, while he explains that cutting fossil-fuel CO2 emissions by one third would have the same effect after 50 to 200 years. Removing soot would provide enormous health benefits, and Jacobson says studies estimate that health costs due to soot are US$160,000 to $2 million per ton emitted in industrialized nations. Worldwide, five million tons of soot are emitted each year from fossil fuels, according to some estimates. “Within a few decades, oil supplies are predicted to run out, so all oil will be burned, whether as diesel or gasoline,” says Jacobson’s paper. “Since the replacement is likely to be hydrogen fuel, possibly produced from a renewable energy source, the use of diesel from now until that time serves only to exacerbate health and climate problems.”