What is the Second Biggest Cause of Man-Made Global Warming?

Soot. The Washington Post is reporting a new study in the Journal of Geophysical Research that has concluded that soot from fires, diesels, and power generation is a big factor in recent global warming. As the Post observes:

Soot ranks as the second-largest human contributor to climate change, exerting twice as much of an impact as previously? thought, according to an analysis released Tuesday.

The four-year, 232-page study of black carbon, published in the Journal of Geophysical Research: Atmospheres, shows that short-lived pollution known as soot, such as emissions from diesel engines and wood-fired stoves, has about two-thirds the climate impact of carbon dioxide. The analysis has pushed methane, which comes from landfills and other forces, into third place as a human contributor to global warming.

The good news is that since soot does not stay long in the atmosphere efforts to reduce this kind of health-damaging pollution could reduce man-made global warming by about 1 degree Fahrenheit in the near term. 

By the way, NASA says since 1880 that the planet has warmed by 0.8 degree Celsius (about 1.4 degree Fahrenheit) and that two-thirds of that warming has occurred since 1975. Two-thirds of past warming nets out to about 1 degree Fahrenheit since 1975. Interesting.

I was somewhat bemused by this observation in the Post article:

Veerabhadran Ramanathan, an atmospheric scientist at the Scripps Institution of Oceanography at the University of California at San Diego, identified black carbon in 2008 as the second-biggest human contributor to climate change. But many researchers questioned his analysis because it was based on observations rather than computer modeling.

Computer modeling trumps empirical observations? Really?

The next question is: What else might the computer climate models be overlooking?