Page - 7 - in options, Volume winter 2015/2016

research news 7winter 2015/2016 + optionswww.iiasa.ac.at iiasa research Long term impacts of cutting short‑lived climate pollutants IIASA research has shown that climate and air pollution are closely linked from an economic and policy standpoint. Measures to reduce air pollution could bring climate benefits by reducing emissions of short-lived climate pollutants that contribute to climate change, but remain in the atmosphere for  a  much shorter time than CO2. In a new study, IIASA researcher Joeri Rogelj and colleagues examined how reducing short-lived climate pollutants would affect the carbon budget: the amount of CO2 emissions that could still be released in the next century while limiting global warming to 2°C compared to pre-industrial levels. The study, published in the journal Environmental Research Letters, found that reducing methane emissions stringently in the second half of the century could increase the size of the carbon budget for meeting the 2°C target by 2100 by about 20%. This  can slightly relax the very tight limits on CO2, but  emissions still need to reach net zero by the end of the century. Strict controls on pollutants such as black carbon, by contrast, had only a small impact on the carbon budget of  around 5%. “To limit global warming to any level, the total amount of CO2 emissions needs to be limited to a certain budget,” says Rogelj. “We  knew that warming from non-CO2 gases like methane or some air pollutants can influence the size of this carbon budget. The question was, how much?” KL Further information Rogelj J, Meinshausen M, Schaeffer M, Knutti R, Riahi K (2015). Impact of short-lived non-CO2 mitigation on carbon budgets for  stabilizing global warming. Environmental Research Letters 10(7):075001 [doi:10.1088/1748-9326/10/7/075001]. Joeri Rogelj rogelj@iiasa.ac.at Targeting short‑lived pollutants to benefit climate and air quality A new study looking into short-lived pollutants reveals measures to substantially improve air quality as well as fight climate change. These results, from the major EU-funded ECLIPSE project, have now been published in the journal Atmospheric  Chemistry and Physics. IIASA researchers developed the emissions scenarios for air  pollution and greenhouse gases that were used in the analysis, and identified mitigation measures for reducing short-lived climate pollutants. They also assessed how such measures would impact health in Europe and Asia. They find that targeting short-lived pollutants could simultaneously boost air quality, reduce health impacts from air pollution, and bring climate benefits. “Beyond measures in the oil and gas sector, there are also other important opportunities to reduce methane emissions from coal mining, municipal waste treatment, and gas distribution, for  example, as well as black carbon emission reductions through elimination of high-emitting vehicles, use  of cleaner biomass cooking and heating stoves, replacement of kerosene wick lamps with LED lamps, and other measures,” says IIASA researcher Zbigniew Klimont, who led the institute’s contribution to the study. “There is no doubt that the most important factor causing climate warming is CO2 emissions and this must be the prime target of our climate policies. Yet, there is merit in not completely ignoring other climate forcers, which could affect the rate of warming, particularly over the next few decades,” says  Andreas  Stohl of the Norwegian Institute for Air Research, who led the study. “And what is probably even more important: targeting these substances would lead to large improvements in global air quality.” KL Further information Stohl A, Aamaas B, Amann M, et al. (2015). Evaluating  the climate and air  quality  impacts of short-lived pollutants. Atmospheric Chemistry and Physics 15(18):10529–10566 [doi:10.5194/acp-15-10529-2015]. Zbigniew Klimont klimont@iiasa.ac.at § Markus Amann amann@iiasa.ac.at