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High Level Sub-regional Consultation on Advancing Action on Short-Lived Climate Pollutants (SLCPs) In Southeast and Northeast Asia 19 Aug 2014, Bangkok, Thailand. SLCP and other air pollutants: an introduction for policy makers. Jun-ichi Kurokawa
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High Level Sub-regional Consultation on Advancing Action on Short-Lived Climate Pollutants (SLCPs) In Southeast and Northeast Asia 19 Aug 2014, Bangkok, Thailand SLCPand other air pollutants:an introduction forpolicy makers Jun-ichi Kurokawa Asia Center for Air Pollution Research (ACAP), Niigata, Japan
Background NOx CO2 Regional shares of global anthropogenic emissions of NOx and CO2 in 2008 (EDGAR 4.2 for NOx; CDIAC for CO2) • Emissions of air pollutants and green house gases in East Asia covering Northeast and Southeast Asia have already exceeded those in European and North American continent. • This situation brings about not only serious urban and regional air pollution, but also prompted concerns on emissions in East Asia from the view of global climate change.
What are Short-Lived Climate Pollutants (SLCPs)? • Reduction of CO2 emissions does not help to mitigate climate change until 2050. • Reduction of emissions of BC and CH4 will bring a relatively rapid climate response. • Decrease of SLCPs coupled with CO2 could lead to both the mid-term (2030-50) mitigation of climate change and the 2℃ capping in 2100. UNEP & WMO (2011) Long-lived Climate Pollutants (LLCPs) CO2: 60% < 100 yr; 25% > 1000 yr SLCPs are agents which have relatively short lifetime in the atmosphere and have a warming influence on climate.
Black Carbon (BC) • BC is a tiny black particle and major component of PM2.5, which has adverse effects on human health and ecosystems. • BC has a strong warming effect both in the atmosphere and on ice and snow. • As an air pollutant: • Leading environmental cause of poor health and premature death such as cardiovascular mortality. • Affecting ecosystem health. • As a warming agent: • Absorbing solar radiation and converting it to heat • Increasing the melting rate of ice and snow CCAC (2014)
BC emissions Sector share of anthropogenic emissions* in Global total, China, and SE Asia Global (GAINS) in 2005 China (REAS 2.1) in 2008 SE Asia (REAS 2.1) in 2008 * Open biomass burning emissions are not included in these graphs. [Tg/year] [Tg/year] Comparison between anthropogenic and open biomass burning emissionsin SE Asia Trends of anthropogenic emissions in China and SE Asia (REAS 2.1) • Residential combustion is major emissions source in East Asia. • Contribution from industry sector (coal combustion, production of cokes and bricks, etc.) is also large in China. • Majority of emissions in transport sector is from diesel vehicles. • Open biomass burning is important especially in Southeast Asia.
Methane (CH4) • CH4 is over 20 times more potent than CO2as GHGs. • CH4 has indirect impacts on human health and ecosystems through its role as the primary precursor of tropospheric O3. Global (EDGARv4.2) China (REAS 2.1) Southeast Asia (REAS 2.1) F_ = Fugitive emissions Sector share of anthropogenic emissions of Global total, China, and SE Asia in 2008 • Major emission sources are agriculture, fossil fuel production and distribution, and waste treatment. • In China, coal mining is the largest source. • Oil and gas production and distribution as well as agricultural activities are estimated to be important emissions source in SE Asia.
Hydrofluorocarbons (HFCs) • HFCs are man-made fluorinated GHGs. • There is no impact on human health and ecosystem. • HFC-134a has 1430 times more damaging influence on the climate system than CO2. China 70% Japan 25% Global Consumption by sector in 2010 CCAC (2014) HFCs emissions in 2008 EDGARv4.2 • HFCs currently represent only a small fraction of the total GHGs, but emissions of high-global warming potential (GWP) HFCs are rising very quickly. • A recent study concluded that replacing high-GWP with low-GWP alternatives could avoid 0.1℃ of warming by 2050.
Tropospheric Ozone (O3) • O3 is a secondary gas (not directly emitted). • Tropospheric O3 is formed by sunlight-driven oxidation of precursor gases (CH4, CO, NMVOCs, and NOx). • Tropospheric O3 is the 3rd most important contributor to the human enhancement of the GHGs effects. • Tropospheric O3 is a harmful air pollutant adversely affecting public and ecosystem health. • O3 can make a transboundary air pollution problem. CCAC (2014) • Differences as O3 precursors: • CH4 and CO is important for tropospheric O3 in global scale. • NOx and NMVOCs is more effective for high surface O3.
Adverse impacts of O3 (Lelieveld et al., ACP, 2013) Regional ratios of respiratory mortality (persons) related to O3 in 2005 Majority of mortality related to O3 is clearly in Asian region, especially China and India. CCAC (2014) • Regional and urban ozone pollution in East Asia is more serious than in Europe and North America. • Social incentives for controlling air pollution of O3 as well as PM2.5 are expected to be stronger in East Asia.
Tropospheric O3 and Surface O3 Warming • Only reduction of NOx will lead to increase of CH4, which increase net radiative forcing. • However, if NMVOCs and CO are reduced at the same time with NOx, O3 will be decreased without increase of net radiative forcing. • (Fry et al., JGR, 2012) EA: East Asia, EU: Europe and North Africa NA: North America, SA: South Asia Cooling -20% CH4 -20% NOx -20% NOx/NMVOCs/CO Effects of reducing anthropogenic EMs on Radiative forcing • Reduction of CH4 is effective for long-termdecrease of tropospheric (global) O3. • For immediate reduction of urban/regional surface O3, controlling NOx/NMVOCs is needed. • Both of NOx/NMVOC and CH4 reduction are important and should be considered in East Asia especially in heavily polluted areas.
NOxand NMVOCsemissions Global (EDGARv4.2) China (REAS 2.1) Southeast Asia (REAS 2.1) Sector share of NOx emissions in 2008 Sector share of NMVOCs emissions in 2008 Global (EDGARv4.2) China (REAS 2.1) Southeast Asia (REAS 2.1) • For China, majority NOx emissions is from power plants, and those from industry and transport are comparable.Road transport is major emission source in Southeast Asia. • NMVOCs emissions from road vehicles and solvent and paint use have large contributions in China. Contributions from road vehicles as well as biofuel combustion are large in Southeast Asia.
Benefits of Mitigating SLCPs UNEP and WMO (2011) identified 16 cost effective SLCPs control measures such as for cook stoves, diesel vehicles, coal mines, municipal waste, etc. CCAC (2014)
Summary • For near-term mitigation of climate change, reduction of SLCPs that have relatively short lifetime in the atmosphere and have warming influence on climate such as BC, CH4, HFCs, and O3 is essential. • SLCPs have adverse impacts on human health and ecosystem including agriculture (food security) as well as climate change. • Emissions of SLCPs in East Asia covering Northeast and Southeast Asia have already exceeded or at least been comparable to those in European and North American continent. • Social incentives for controlling air pollution of O3 as well as PM2.5 are expected to be stronger in East Asia. • In East Asia, both of NOx/NMVOC and CH4 reduction are important and should be considered especially in heavily polluted area. • Benefits of SLCP control measures for East Asia are estimated to be larger than other regions.