I waffled between the above title and "
WHAT," but decided that the former would probably be less confusing. Getting to the point, I recently came across the following two papers (well,
one paper and
one call to arms for the modelers) dealing with what, according to the author, are some of the only ice core records of Arctic black carbon deposition. Before reading these, I had just sort of assumed that the levels of soot deposited on the Arctic ice (both on the Arctic ocean and on the GIS) had roughly followed the rate of carbon dioxide emissions: low towards the end of the 19th century, rising all the way up through the 20th to a peak in the 21st.
Not so much, apparently.
The authors conclude that this pattern is a result of the very short atmospheric lifetime of soot and prevailing winds which tend to originate over North America--which makes sense, I suppose, but even so I'm astounded that China hasn't had more of an impact. It is noted in the paper that their measurements here are by no means to be taken as representative of the Arctic Ocean in general, and of course the timeseries leaves out the last twelve years, which have seen quite a boom in industrialization in the East. All the same, I find this very surprising. Intriguing, too, from a forcing perspective, as it might indicate that the role of black carbon in the recent dramatic Greenland melts might be lower than generally thought, if it was this much higher in the past. That, of course, implies a much larger role for CO2 in the matter, and a tougher job ahead of us when it comes to reducing global temperatures (given how much harder it is to cut CO2 emissions than it is to cut soot emissions), but I'm not familiar enough with the literature to feel comfortable making any definite speculations on that point. Y'all's thoughts on this? Do any of you happen to know of any other research that's been done measuring the quantity of black carbon deposited per year over the 20th century and before?
