NILU workshop: Short-lived pollutants and Arctic climate
Arctic temperatures have increased at almost twice the global average rate over the past 100 years [IPCC, 2007]. Warming in the Arctic has been accompanied by an earlier onset of spring melt, a lengthening of the melt season, and changes in the mass balance of the Greenland ice sheets and extent of Arctic sea ice. Impacts of ice loss include reduction of the Earth’s albedo, a positive feedback which leads to further warming. Timescales for a collapse of the Greenland ice sheet and a transition to a seasonally ice-free Arctic are highly uncertain as are the regional and global impacts.
Arctic warming is primarily a manifestation of global warming such that reducing global-average warming will reduce Arctic warming and the rate of melting. Reductions in the atmospheric burden of CO2 are the backbone of any meaningful effort to mitigate climate forcing. But, even if swift and deep reductions were made, given the long lifetime of CO2, the reductions may not be achieved in time to delay a rapid melting of the Arctic. Hence, the goal of constraining the length of the melt season and, in particular, delaying the onset of spring melt, may best be achieved by targeting shorter-lived climate forcing agents which also impact Arctic climate. Addressing these species has the advantage that emission reductions will be felt immediately. These agents include methane, tropospheric ozone, and tropospheric aerosols.
An initial workshop was held at NASA`s Goddard Institute for Space Sciences (GISS) in New York and attendance was by invitation only. The workshop was highly successful, and a report about the outcome of this workshop was recently submitted to Atmospheric Chemistry and Physics Discussion (available here).
The success of this initial workshop led to the decision that a series of follow-up workshops shall be held during the course of the International Polar Year. These workshops will be open to all scientists, and the second workshop is to be held at NILU on November 5-7.
In connection with the scientific workshop, a follow-on policy conference, to overlap the workshop for a half day with a subsequent full day of discussions on November 8, is in the initial planning stages. The policy discussions, to take place under Chatham House rules, would explore the potential implications of these research findings for the international climate regime, including the possibility for an Arctic-specific initiative given the urgent need to slow current melting; international support for intensified research efforts; and potential early mitigation efforts.
The goal of the workshops are to assess the current understanding of the impact of short lived pollutants on Arctic climate and to outline research that is needed to further our understanding. The NILU workshop is to be held before the bulk of the IPY measurement season in order to inform, coordinate, and improve measurement and modeling activites during IPY. Maximizing the scientific knowledge gained from IPY activities will depend on integrating measurement and modeling activities so a primary objective of these workshops will be to promote focused discussion between those doing field measurements and those following up with modeling.