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ECLIPSE Report Summary

Project reference: 282688
Funded under: FP7-ENVIRONMENT

Periodic Report Summary 2 - ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants)

Project Context and Objectives:
ECLIPSE aims to develop and assess effective emission abatement strategies for short-lived climate agents in order to provide sound scientific advice on how to mitigate climate change while improving the quality of air. Current climate policy does not consider a range of short-lived gases and aerosols, and their precursors (including nitrogen oxides, volatile organic compounds, sulphate, and black carbon). These nevertheless make a significant contribution to climate change and directly influence air quality. There are fundamental scientific uncertainties in characterizing both the climate and air quality impacts of short-lived species and many aspects (for example, the regional dependence) are quite distinct to those for the longer-lived climate gases already included in the Kyoto Protocol. ECLIPSE brings together 11 institutes with established and complementary expertise for a closely
co-ordinated 3 year programme. It will build on existing knowledge and use state-of-the-art chemistry and climate models to improve understanding of key atmospheric processes (including the impact of short-lived pecies on cloud properties) and characterize existing uncertainties; evaluate model simulations of short-lived species and their long-range transport using ground-based and satellite observations;perform case studies on key source and receptor regions (focused on Southeastern Europe, China and the Arctic); quantify the radiative forcing and climate response due to short-lived species, incorporating the dependence on where the species are emitted; refine the calculation of climate metrics, and develop novel metrics which, for example, nsider rate of climate warming and go beyond using global-mean quantities; clarify possible win-win and trade-off situations between climate policy and air quality policy; identify a set of concrete cost-effective abatement measures of short-lived species with large co-benefits.

Project Results:
ECLIPSE had a unique systematic concept for designing a realistic and effective mitigation scenario for short-lived climate pollutants (SLCPs: methane, aerosols and ozone, and their precursor species) and quantifying its climate and air quality impacts, and this paper presents the results in the context of this overarching strategy. The first step in ECLIPSE was to create a new emission inventory based on current legislation (CLE) for the recent past and until 2050. Substantial progress compared to previous work was made by including previously un-accounted types of sources such as flaring of gas associated with oil production, and wick lamps. These emission data were used for present-day reference simulations with four ad-vanced Earth system models (ESMs) and six chemistry transport models (CTMs). The model simulations were compared with a variety of ground-based and satellite observational data sets from Asia, Europe and the Arctic. It was found that the models still underestimate the measured seasonality of aerosols in the Arctic but to a lesser extent than in previous studies. Problems likely related to the emissions were identified for Northern Russia and India, in par-ticular. To estimate the climate impacts of SLCPs, ECLIPSE followed two paths of research: The first path calculated radiative forcing (RF) values for a large matrix of SLCP species emissions, for different seasons and regions independently. Based on these RF calculations, the Global Temperature change Potential metric for a time horizon of 20 years (GTP20) was calculated for each SLCP emission type. This climate metric was then used in an integrated assessment model to identify all emission mitigation measures with a beneficial air quality and short-term (20-year) climate impact. These measures together defined a SLCP mitigation (MIT) scenario. Compared to CLE, the MIT scenario would reduce global methane (CH4) and black carbon emissions by about 50% and 80%, respectively. For CH4, measures on shale gas production, waste management and coal mines were most important. For non-CH4 SLCPs, elimination of high emitting vehicles and wick lamps, as well as reducing emissions from gas flaring, coal and biomass stoves, agricultural waste, solvents and diesel engines were most important. These measures lead to large reductions in calculated surface concentrations of ozone and particulate matter. We estimate that in the EU the loss of statistical life expectancy due to air pollution was 7.5 months in 2010, which will be reduced to 5.2 months by 2030 in the CLE scenario. The MIT scenario would reduce this value by another 0.9 months to 4.3 months. Substantially larger reductions due to the mitigation are found for China (1.8 months) and India (11-12 months). The climate metrics cannot fully quantify the climate response. Therefore, a second research path was taken. Transient climate ensemble simulations with these ESMs were run for the CLE and MIT scenarios, to determine the climate impacts of the mitigation. In these simulations, the CLE scenario resulted in a surface temperature increase of 0.70±0.14 K between the years 2006 and 2050. For the decade 2041-2050, the warming was reduced by 0.22±0.7 K in the MIT scenario, and this result was in almost exact agreement with the response calculated based on the emission metrics (reduced warming of 0.22±0.9 K). It was also expected from the metrics that non-CH4 SLCPs would contribute ~22% to this response and CH4 78%, however this could not be fully confirmed by the transient simula-tions, which attributed about 90% of the temperature response to CH4 reductions, for reasons discussed in the paper. Nevertheless, an important conclusion is that our mitigation basket as a whole would lead to clear benefits for both air quality and climate. The climate response from BC reductions in our study is smaller than reported previously, largely because we find a strong semi-direct effect offsetting the direct BC aerosol radiative effect. The temperature responses to the mitigation were generally stronger over the continents than over the oceans, and with a warming reduction of 0.44 K (0.39-0.49) largest over the Arctic. Our calculations suggest particularly beneficial climate responses in Southern Europe, where the surface warm-ing was reduced by about 0.3 K and precipitation rates were increased by about 15 (6-21) mm/yr (more than 4% of total precipitation) from spring to autumn. Thus, the mitigation could help to alleviate expected future drought and water shortages in the Mediterranean area.
Potential Impact:
The final results from ECLIPSE will guide policymakers on the impact of changes in short-lived climate forcing agent emissions on climate and air quality. They will allow comparison of these forcings with long-lived climate forcings (such as CO2) and feed into assessments of measures aimed at improving air quality and the impact of these measures on climate change.

At the end of ECLIPSE, we will have:

• explored the suitability of different climate metrics for short- and long-term climate targets and decided upon the most suitable metrics.
• extended the GAINS model to include climate metrics in the optimization as an additional environmental constraint in the search for cost-effective portfolios of emission reductions, in addition to constraints (targets) on human health and vegetation.
• produced emission data that has been adopted by several other EU projects and many researchers worldwide for their work.
• defined a basket of SLCF emission reduction measures in Europa and China that is designed to maximize the co-benefits between air quality policy and climate policy and minimize tradeoffs between the two.
• evaluated the set of regional and global air quality and climate models used in the project both in the emission source regions (Europe, China) as well as in one remote region (the Arctic).
• estimated the impact of the basket of measures on climate and air quality, using a small ensemble of climate models.
• produced a substantial number of peer-reviewed publications, which will collectively make a large impact on this research field located between climate and air chemistry research, as well as between environmental science and policy.

The final results, i.e., the portfolio of specific measures that maximize co-benefits between greenhouse gas mitigation and air pollution reduction goals will inform decision makers within Europe (e.g., the European Commission), in China, and at the global scale under the Climate and Clean Air Coalition (CCAC). Especially in this context, it is conceivable that the ECLIPSE analysis will reveal additional measures that are not yet considered by the CCAC.

List of Websites:


Stohl, Andreas (Senior scientist)
Tel.: +47 6389 8035
Fax: +47 6389 8050
Record Number: 168804 / Last updated on: 2015-09-04
Information source: SESAM