Multiple benefits from climate change mitigation: assessing the evidence
Climate change mitigation yields multiple benefits – or ‘co-benefits’ – in addition to the reduction of greenhouse gas emissions. Many co-benefits, such as diminished local air pollution resulting from reduced use of fossil fuels, occur in the short run, are relatively certain to be achieved, and are primarily enjoyed by the country doing the abatement. This stands in stark contrast to the benefits of climate change mitigation. As the world proceeds with the implementation of the Paris Agreement, a focus on the multiple benefits of mitigation can motivate a more ambitious approach to reducing greenhouse gas emissions.
This report assesses what is known about potential co-benefits across multiple domains: environmental, economy-wide, and sector-specific. It then reports on empirical results on co-benefits, in particular the application of integrated assessment models (IAMs) to simulate co-benefits over the course of the century. The following chapter analyses a key policy question – if governments aim to reduce local air pollution damages, are there greater benefits from using traditional pollution control measures or moving to greener zero-emission energy sources? The final two chapters deal with creating co-benefits through strengthening public investment management, and policy reforms that can foster the application of co-benefits analysis to development decisions.
- Abating greenhouse gas emissions reduces harm to health caused by local and regional air pollution. The health co-benefits of CO2 mitigation could be large, conservatively estimated at over US$100/tonne CO2 abated in high-income countries and US$50/tonne CO2 abated in middle-income countries.
- There are variations in the control of local air pollutants and in the evidence for economy-wide benefits from climate change mitigation. The degree of control of local air pollutants from electric power generation has a fairly direct effect on the potential for co-benefits from CO2
- Energy efficiency measures and actions to reduce short-lived climate pollutants are producing health- and food-related co-benefits. Model results for 2030 suggest that health benefits from reduced ozone and PM2.5 exposure could be as large as 5 per cent of global GDP, while many countries could also enjoy substantial increases in crop yields.
- Policy decisions should be made on the basis of social cost–benefit analysis, where costs include economic costs such as the health damages from local air pollution externalities.
- An important distinction needs to be made between low-income countries and the rest. Ensuring that the poorest countries in the world are sheltered, both from harmful climate change (through adaptation) and from the high costs of adapting and abating, must be part of any collective action.