Action to cut greenhouse gas emissions could save millions of lives because of the cleaner air that would result.
There are strong links between the problems of climate change and air pollution, in particular the fact that emissions from fossil fuel combustion contribute significantly to both problems. Consequently, measures to abate emissions of greenhouse gases may show strong co-benefits in terms of less air pollution and vice versa.
Policies that result in a reduced demand for coal in the electricity sector will simultaneously lower the emissions of the major greenhouse gas, carbon dioxide, and of traditional air pollutants such as sulphur, nitrogen oxides and fine particles. Similarly, policies to limit transport demand and congestion will improve air quality and at the same time lower emissions of greenhouse gases (GHG). There are however also examples of measures that may help alleviate one problem, but exacerbate the other.
It is important to take into account these co-effects when deciding on appropriate policy actions in response to one or both of these problems. A recent study by the Netherlands Environment Agency investigated the consequences of the interrelationship between policies on climate change and policies on air pollution. The interrelations between these two policy areas were investigated from three different perspectives (or windows):
- Climate change window: Policies primarily aiming at the mitigation of global climate change not only reduce emissions of GHG but also reduce emissions of air pollutants, which yields co-benefits in terms of improved air quality;
- Air pollution window: Policies primarily aiming at the mitigation of (local) air pollution not only reduce emissions of air pollutants, but also reduce emissions of GHG, yielding co-benefits in terms of reduced global climate change;
- Integrated approach: Policies that simultaneously aim to mitigate climate change and (local) air pollution, yielding an optimised combination of reductions in emissions ofgreenhouse gases and air pollutants.
One of the main messages of the report is that a stringent global climate policy will lead to considerable improvements in local air quality and consequently improve health. Measures to reduce the global emissions of greenhouse gases to 50 per cent of 2005 levels, by 2050, can reduce the number of premature deaths from air pollution by 20–40 per cent.
However, if countries continue the trend of increasing energy use as in “businessas- usual”, then population growth, ageing demographics and increased urbanisation will cause premature deaths from air pollution to increase by 30 per cent in the industrialised (OECD) countries, and 100 per cent outside the OECD.
According to the study, there is indeed a synergy between the two policy areas, and an integrated strategy tackling climate change and air pollution is likely to reduce the overall policy costs and generate a net welfare benefit at the global level.
Although the indirect benefits of climate policy – improved air quality and public health – provide an additional incentive for countries to participate in a future climate agreement, current estimates indicate that they are too small to fully outweigh the costs of climate policy.
For example, in 2050, the costs of such a climate policy in China – under which greenhouse gas emissions are 80 per cent lower than the “business-as-usual” trend without a stringent climate policy – could amount to 6.5 per cent of the country’s GDP, while the benefits were estimated to be equivalent to 4.5 per cent of GDP. However, these benefits could also be achieved through a more targeted air quality policy. In China, such a targeted air quality policy could achieve the same air quality improvements by 2050 at a cost of 1.8 per cent of GDP
The study also shows that a stringent air quality policy can lead to a reduction in emissions of greenhouse gases. For example, if China pursues a stringent air pollution control policy to reduce the number of premature deaths from air pollution by 70 per cent (compared with a “business-as-usual” trend without such a policy), this policy will lower GDP in 2050 by 7 per cent. The air quality benefits would be equivalent to 7.5 per cent of GDP, while greenhouse gas emissions would be 40 per cent lower.
Christer Ågren
Co-benefits of climate policy (2009). PBL report no. 500116005. 75 pp. By J. Bollen, C. Brink, H. Eerens and T. Manders. Published by and available from the Netherlands Environment Agency, http://pbl.nl/en/index.html