The odds are poor that humanity will ever curtail CO2 emissions sufficiently fast against even the mid-case global warming scenarios forecast by climatologists. A possible near-term remedy, however, has been found in the form of a simple pollution abatement strategy in the mitigation of airborne soot. Airborne soot falls from the air in a matter of weeks, so its abatement is far more efficacious - in terms of tangible environmental benefits - than first migitating CO2 emissions.
Recent studies now show that soot - in the air as aerosol brown clouds and on the ice as dirty snow - has contributed a significant amount to global warming in both the air on and on the ground. Over the vast Pacific soot-ladened brown clouds have been recently found to cause up to 40 percent (60 percent of CO2's effect) of the obseved warming anomalies, alone accounting for 12 percent of all of the Earth's ongoing global warming. In the Arctic its current effects are seen to be equal to that of CO2 in that small region but its long-term effects are nearly 20 percent of all global warming in the past two centuries.
Soot mitigation would then be a vital stopgap measure that needs to be discussed openly and progress made in implementing this completely feasible and cost-effective climate change and pollution reduction strategy.
The role of sootfall in the progressive decimation of Arctic and Subarctic ice has been long known, accounting for nearly 90 percent of the boreal thaw -- accounting for nearly 20 percent of all sesquicentennial global warming.
The discovery that airborne soot is in fact causing as much warming as it does, however, was made almost by accident in a field study using small robotic airplanes flying over the Indian Ocean. These field data - collected in situ - were contrary to the conventional view that soot-ladened brown clouds only dimmed the Earth's surface and hence inhered a net cooling effect, whereas in fact the net effect is to heat the air beyond the ground-dimming effect.
The reasons for this misunderstanding were manifold: The associated whitish sulfates were wrongly assumed to impart albedo (reflectivity) to the brown clouds, canceling out the heat-absorptive properties of black carbon (soot, or for short, B.C.). Indeed it was found that sulfates actually impart heat into the airborne soot particles via visible near-infrared light. The discovery itself could not have been made without actual field data collected - in situ - from within the brown clouds, since the actual effect was masked from both space satellites as well as ground instruments.
The issue of masking is interesting because prior to the discovery (made Summer, 2007) climatologists had long believed that the surface-dimming effects of sooty brown clouds was in fact masking global warming from CO2 and other greenhouse gases. This clearly implicated greenhouse gases as possessing far more ongoing warming potential that could be unleashed by sudden reductions in aerosol pollution. Instead it appears that soot was implicating CO2 for more than its due as extra heating anomalies are originating in the sooty brown clouds themselves.
Corroborating this are the joint testimonies of two very conventional climate researchers: Drs. V. Ramanathan and Charlie Zender.Dr. Zender has essentially stated this: That with the albedo-blunting effects of soot being equal to that of extant CO2 warming the benefits of significant soot mitigation in the Arctic would be like cutting CO2 levels by a two thirds (or more). The magnitude of global warming in the Arctic approaches that of 20 percent of all sesquicentennial global warming, and amending the Arctic melt through soot abatement has a far greater impact than mitigating CO2 emissions in an equivalent region elsewhere in the world. The recovery of the boreal ice environs holds many benefits, not least of which would be the continued wellbeing of Polar Bear populations. The heat-reflective properties of a relatively pristine and bright Arctic and Subarctic -- the entire boreal environment -- would reject far more heat from the sun, thereby aiding significantly in slowing climate change.
Dr. Ramanathan makes similar points that the the efficacy of soot mitigation is such that we can broaden the window of opportunity up to 20 years against climate change by simply cleaning up industrial sources of soot. Soot mitigation has an immediate effect as opposed to waiting 50 years for the effects of an equivalent reduction of CO2 to finally have an effect.
The joint testimonies of Dr. V. Ramanthan & Dr. Charlie Zender before Rep. Henry Waxman's subcommittee, Q4 2007:
Summary:
http://oversight.house.gov/story.asp?ID=1550
The video:
http://oversight.house.gov/story.asp?ID=1639
Transcript:
http://oversight.house.gov/documents/20071127165326.pdf
Prepared statements:
http://oversight.house.gov/documents/20071018110734.pdf
Many environmental organizations are well aware of the evidence against soot in the Arctic and its net heating effects in the air but have chosen to focus on CO2 reductions. If activists and politicians are to be taken for their word, however, to subsume the evidence against soot under the rubric of "carbon emissions" for fear of diluting the message about CO2 would be an act of brinksmanship.
Is this is in fact what the environmental activists have done in hopes of getting the bigger prize of CO2 reductions? To trumpet the environmental stresses suffered by polar bears without mentioning sootfall in the Arctic and Subarctic is contradictory to the stated goal of protecting the boreal environment of the bears as well as climate remediation, especially considering the real-world risk of continued greenhouse gas emissions.
Again, the odds are not good that societies will mitigate greenhouse gas emissions at rate sufficient to head off any rate of warming that can pose any real risk. The belief that it's possible to do otherwise may well run up hard against the vast inertia of human society as industrialized countries grapple with trade deficits and other cost overheads while developing nations ramp up industry and big agriculture in pursuit of feeding and advancing the lives of their increasing multitudes.
The first big step is to mitigate soot so to buy time against both the potential for accelerated global warming as well as letting all the wrinkles in climate science even out. Along with a potential fall in solar output, soot mitigation may be the great reprieve that humanity can use to buy time in the pursuit of reducing greenhouse gas emissions. If, however, societies don't take the opportunity to mitigate soot, the opportunity may be lost.
It would be a pointless and foolish mistake to miss the opportunity (and incur other opportunity costs) all because of activist politics.
Comments