Co-benefits of climate mitigation on air quality and human health in Asian countries

Mairs-FE IPO, Hancheng Dai newly published paper:

Title: Co-benefits of climate mitigation on air quality and human health in Asian countries

Authors:Yang Xie a,b , Hancheng Dai c, ? , Xinghan Xu d , Shinichiro Fujimori b,d , Tomoko Hasegawa b , Kan Yie,Toshihiko Masui b , Gakuji Kurata d
Abstract: Climate change mitigation involves reducing fossil fuel consumption and greenhouse gas emissions, which is expensive, particularly under stringent mitigation targets. The co-benefits of reducing air pollutants and improving human health are often ignored, but can play significant roles in decision-making. In this study, we quantified the co-benefits of climate change mitigation on ambient air quality and human health in both physical and monetary terms with a particular focus on Asia, where air quality will likely be degraded in the next few decades if mitigation measures are not undertaken. We used an integrated assessment framework that incorporated economic, air chemistry transport, and health assessment models. Air pollution reduction through climate change mitigation under the 2 °C goal could reduce premature deaths in Asia by 0.79 million (95% confidence interval: 0.75–1.8 million) by 2050. This co-benefit is equivalent to a life value savings of approximately 2.8 trillion United States dollars (USD) (6% of the gross domestic product [GDP]), which is decidedly more than the climate mitigation cost (840 billion USD, 2% of GDP). At the national level, India has the highest potential net benefit of 1.4 trillion USD, followed by China (330 billion USD) and Japan (68 billion USD). Furthermore, in most Asian countries, per capita GDP gain and life value savings would increase with per capita GDP increasing. We robustly confirmed this qualitative conclusion under several socioeconomic and exposure response function assumptions.

Research reveals the co-beneļ¬ts of achieving 2-degree targets outpace the cost significantly in Asia
This study indicates that climate mitigation entails co-benefits in air quality improvement in all Asian countries with noticeable reduction in PM2.5 and, to a less extent, reduction in ozone pollution. The air quality improvement could prevent 0.79 million premature deaths, save 30 billion USD in health expenditures, and provide a 170 billion USD economic benefit from an increased labor supply in 2050. Meanwhile, the co-benefit is equivalent to a life value saving of approximately 2.8 trillion USD in Asia, which is three times the climate mitigation cost (840 billion USD).

The majority of countries around the world have submitted greenhouse gas (GHG) reduction targets to the Paris Agreement. However, policymakers generally hesitate to set more ambitious mitigation targets concerning the associated economic costs: the more ambitious the 2-degree mitigation target, the higher the cost would be.
However, such considerations ignore the other side of the coin: the co-benefits of climate change mitigation on improvement in air pollution and human health could be significant. This study quantified such co-benefits in both physical and monetary terms with a particular focus on Asia.

An integrated assessment framework that combined three models was adopted: an air quality model, a health assessment model, and a macroeconomic model.
The air quality model was used to simulate the annual average PM2.5 and daily 8 h maximum ozone concentrations in 2005 and 2050 in both baseline and mitigation scenarios. The health assessment model quantified both physical and monetized health impacts due to outdoor air pollution, which are categorized as morbidity and mortality. Furthermore, health impacts were converted into work time loss, which was used as a change in the labor participation rate in the economic model to identify the macroeconomic impacts.

Finally, cost-benefit analyses were conducted to investigate the net benefit of climate mitigation in different regions of Asia.

GHG/air pollutant emission could be reduced due to the active mitigation policy. Under a stringent but achievable climate mitigation goal, the PM2.5 concentrations could be reduced in most parts of Asia compared to the scenario without any mitigation target by 2050. However, climate mitigation will have diverse effects on ozone pollution in 2050, such as the slight increase in central and eastern parts of China.

Climate mitigation could evidently help to avoid premature death. In Asia, the avoided mortality is predicted to be 0.79 million in 2050 and its monetized life value savings are approximately 1.7 trillion USD (3% of GDP). India has the largest number of avoided premature deaths (0.46 million) and life value savings of approximately 720 billion USD (7% of GDP), followed by China which has a relatively high number of avoided premature deaths (0.22 million) and life value savings of approximately 720 billion USD (3% of GDP). The amount of avoided premature deaths in other Asian countries are much lower than in India and China.

Climate mitigation could reduce the morbidity risk in all Asian countries. It is found that the risk of getting air pollution-related illness will drop to 20% under the mitigation scenario in all Asian countries in 2050, compared to the 29% in 2005. The trend is most noticeable in China (30% reduced to 13%), Japan (32% reduced to 20%) and India (45% reduced to 32%). India still has the highest air pollution-related morbidity risk rate for a long-term period, and Japan has a relatively higher morbidity risk owing to its aging population. In other Asian countries, morbidity risk from air pollution is lower than the above three countries.

Climate mitigation could save medical expenditure related to air pollution. Additional medical expenditures attributable to ambient air pollution in all Asian countries amounted to 13 billion USD in 2005 and will grow significantly, particularly in developing regions. For example, health expenditures due to air pollution in Asia in 2050 will reach approximately 44 billion USD under the climate mitigation scenario. At the regional level, China’s total health expenditure will grow from 5.5 billion USD to 9.1 billion USD, and that of India will grow from 3.5 billion USD to 22 billion USD. The expenditure reduction due to climate mitigation will amount to 12 billion USD in Asia, 3.6 billion USD of which in China, 6.5 billion USD in India and 0.33 billion USD in Japan.

Air pollution also causes work time loss due to both mortality and morbidity, and affect the macroeconomic output. Because of the climate mitigation policy, the work loss time will decline by 2050 in most parts of Asia, including China (drop to 2.0 h in 2050), India (drop to 3.8 h in 2050), Japan (drop to 1.0 h in 2050), and 1.1 h in the rest of Asia in 2050.

The results also show that developing countries in Asia would experience greater economic gain in terms of gains in GDP, VSL (value of statistical life), and medical expense from climate mitigation, than developed countries. On the other side, we found that in most Asian countries, when the per capita GDP increases, per capita GDP gain and VSL gain also increase. However, per capita expenditure savings are not significantly correlated with per capita GDP. Conversely, in Japan, the per capita GDP gain and expenditure savings decrease as per capita GDP increases, whereas the per capita VSL does not change, which is quite different from the trends in other countries in Asia.

Through cost-benefit analysis, the net benefit from climate mitigation is positive in Asia as a whole, as well as in most Asian countries. The climate mitigation cost in Asia in 2050 is 840 billion USD (or 1.8% of GDP). However, the benefit is approximately three times the mitigation cost. At the regional aspect, although China had the highest climate mitigation cost (510 billion USD in 2050, 61% of Asia), the benefits from climate mitigation in China could outweigh the costs. Regarding India, its co-benefits will be eight times the cost under the mitigation scenario in 2050. Besides, developing countries in Asia could receive more benefits from climate mitigation.The full paper could be download here: