2010-09-20 06:50:202 interesting papers on the cooling effects of black carbon
John Cook


Interesting results on cooling effect of black carbon. First models predict black carbon (soot) may cause cooling:


Observations confirm this:


2010-09-20 07:46:22interesting
Dana Nuccitelli
Yeah, interesting results.  The IPCC thought that the radiative forcing from black carbon was small.  But then a study by Ramanathan concluded it was around 1 W/m2, which is about two-thirds of the CO2 forcing and would make it the second-largest contributor to global warming.  But then this study said that when you include cloud effects, black carbon actually has a net negative forcing.  So it's all over the place!
2010-09-20 07:51:13
Rob Painting
This will disappoint the skeptics.
2010-09-20 20:17:59
Ari Jokimäki

Sorry, I think I missed something. The abstract in that AGU-link mentions aerosols but not black carbon specifically. I don't have access to the full paper so is there something said about black carbon in the paper?
2010-09-20 20:51:07I may have jumped the gun on the second AGU paper
John Cook

I think I too eagerly ascribed black carbon to the cooling effect in the AGU paper - it talks about haze particles but there's no indication from the abstract that black carbon is necessarily a player and I don't have the full paper either, to confirm one way or the other. Sorry, should've been watching more carefully.
2010-09-21 02:46:42
Chris Colose

This interpretation isn't quite complete.  Black Carbon warms the atmosphere via its direct radiative effects and this is generally a very robust result.  It does this through absorption of solar radiation, or at the surface, will decrease the albedo.  The first paper doesn't talk about this, they talk about the indirect effects of BC on clouds which involves more subtle effects.  BC can cause a multitude of feedbacks on the water vapor or clouds in that area of varying magnitude or sign, and the net effect varies by location, time of year, etc