We’ve had several essays here at WUWT on the role of Black Carbon soot and its role in affecting surface albedo. Anyone who has ever witnessed “dirty snow” knows that it tends to melt faster than white snow under sunlight because the black carbon on top absorbs more solar energy than the base white snow does. There’s even been some simple citizen science demonstrating this effect in your own back yard. Most of the western world’s industrialization has shifted to China due to environmental regulation, and as we know, China hasn’t paid much attention to pollution control as seen by the satellite photo at right and the many photos we’ve seen from the ground showing air pollution in China, for example, in Beijing.
While this paper is based on a modeling of black carbon interaction with the atmosphere and albedo, the premise is fairly straightforward, and wouldn’t likely have as many variables as many long term climate models. I think it is worth considering because unlike some long term climate models, we also have observational feedback that suggests black carbon is a real problem. The good news is that is a much easier problem to solve as conventional pollution control is a mature technology.
In the recently published Fahey et al, from the U.S. National Oceanic and Atmospheric Administration (NOAA) where they did atmospheric sampling over a four year period, the lead author said, “This study confirms and goes beyond other research that suggested black carbon has a strong warming effect on climate, just ahead of methane.”
Then there was Lau et al from NASA, another modeling study which suggests that Soot is having a big impact on Himalyan temperature – as much or more than GHG’s
This new paper from Lee and Kim says similar things using different methods.
Radiative effect of black carbon aerosol on seasonal variation in snow depth in the Northern-Hemisphere
In this research, we studied the effects of black carbon (BC) aerosol radiative forcing on seasonal variation in the Northern Hemisphere (NH) using numerical simulations with the NASA finite-volume General Circulation Model (fvGCM) forced with monthly varying three-dimensional aerosol distributions from the Goddard Ozone Chemistry Aerosol Radiation and Transport Model (GOCART). The results show that atmospheric warming due to black carbon aerosols subsequently warm the atmosphere and land surfaces, especially those over Eurasia. As a result, the snow depth in Eurasia was greatly reduced in late winter and spring, and the reduction in snow cover decreased the surface albedo. Our surface energy balance analysis shows that the surface warming due to aerosol absorption causes early snow melting and further increases surface-atmosphere warming through snow/ice albedo feedback. Therefore, BC aerosol forcing may be an important factor affecting the snow/ice albedo in the NH.
Indeed, spring snow cover in Eurasia seems to be down markedly according to this plot from Rutgers Snow Lab:
I don’t have access to the new Lee and Kim paper, but I do have access to some stunning examples of black carbon existing where it should not, in Greenland:
Meltwater stream flowing into a large moulin in the ablation zone (area below the equilibrium line) of the Greenland ice sheet. (Image courtesy Roger J. Braithwaite, The University of Manchester, UK via GISS)
Of course images like this one at left showing water tumbling down a huge moulin are being held up with gloom and doom scenarios that say Greenland’s Ice is melting “faster than expected” and we’ll get six feet of sea level rise from it along with a 10-15°F temperature rise by the year 2100.
Perhaps. But, moulins have existed since Greenland had ice, they are just part of the natural landscape and processes. They aren’t “new” to our time.
One of the photos we don’t often get to see was also circulated in the email, by somebody who lives in Greenland and knows what this is really all about.
It’s a real eye opener:
In the winter a huge among of snow are accumulated on the Ice (2-3 meters, sometimes more) and we are not talking about 1 or 2 square-miles, it’s about 100.000′s of square miles (up to 1 million) on the Westside of the Ice cap and a similar picture on the Eastside… when the melting season starts in april-sep… the meltwater has to go somewhere, and for sure it goes downhill in huge meltwater rivers.
The black stuff on the bottom of the lakes is carbon dust and pollution in general… but not from one year, but several decades (the topographical conditions don’t change from year to year). On a flight over the Ice Cap a sky clear day, you can see hundreds of huge lakes with the black spot on the bottom.
Here in Kangerlussuaq, on the edge of the Ice Cap, we have several burst from edge-lake, all the water (millions of tonnes) in the river passing through the settlement in a day or two.
The Vikings (Eric the Red) is about Medieval warm period…. the Hockey-stick mystery!!!
Med venlig hilsen
Svend Erik Hendriksen
And in that same Nat Geo collection that the photo above came from, you can see this photo also:
From National Geographic: At the bottom of an ice canyon, cryoconite—fine brown and black dust carried by wind—spatters the edges of sutured crevasses, places where meltwater flooded massive cracks in the ice and then froze. Photo: James Balog
h/t to Dr. Roger Pielke Sr. for the Lee and Kim paper.
[UPDATE] I trust that Anthony won’t mind if I add some more information about black carbon, from the EPA.
Note the large differences between US and global sources. Domestic/residential, from the use of coal and wood for heating and cooking, is only 3.6% of the US emissions, but it is a full quarter of the global emissions. Going the other way, transport (mainly diesel vehicles) is more than half the US total, while it’s about a fifth of the global total.
Regards to all,