The fact that over the years black carbon in the air from diesel in California has dropped in and of itself is notable. (See: “Diesel consumption rises, black carbon concentrations drop in California”). But what if the reduction of black carbon from the air had a direct effect on atmospheric concentrations of climate change pollutants being lower, too? That’s right, what if?
“Reductions in emissions of black carbon since the late 1980s, mostly from diesel engines as a result of air quality programs, have resulted in a measurable reduction of concentrations of global warming pollutants in the atmosphere, according to a first-of-its-kind study examining the impact of black carbon on California’s climate,” relates the California Environmental Protection Agency Air Resources Board (ARB) in its “California’s efforts to clean up diesel engines have helped reduce impact of climate change on state, study finds: Clean diesel programs slashed black carbon, a powerful short-term contributor to global warming” news release.
The ARB in the release also pointed out, “Black carbon – tiny soot particles released into the atmosphere by burning fuels – has been linked to adverse health and environmental impacts through decades of scientific research. It is also one of the major short-lived contributors to climate change.”
So, what affect do black carbon particles in the atmosphere have on warming and how do these interrelate with other so-called “warming” and “cooling” particles?
Based on my understanding of what I read in the ARB release in question related to that, characteristic of black carbon is its ability to absorb sunlight rather than to reflect it, thereby making it a warming pollutant. Meanwhile, combined with a host of other polluting particles, some having a cooling effect, when all things are taken into consideration, though, on the whole the overall net effect is atmospheric warming, confirmation of such “based on both observations and computer modeling.” This is what I understand to be the case.
“This confirms the positive impact reducing diesel emissions has on fighting climate change,” the ARB noted.
The study referenced above has the title: “Black Carbon and Regional Climate of California.”
Image above: NASA