To ask the Secretary of State for Energy and Climate Change with reference to his consultation on the Renewable Heat Incentive, if he will (a) estimate the cumulative emissions of black carbon from biomass boilers by 2020 and (b) assess the likely effects on global warming of the black carbon emitted from those boilers by 2020.
We recognise that, compared with most climate gases, black carbon is a powerful warming agent (a 100-year global warming potential approximately 650 times that of carbon dioxide ) but it has a very short average lifetime (residence time) in the atmosphere (up to a week or two). It is removed by rain and snowfall, and through direct deposition on land surfaces and the surface of the ocean. We are working collaboratively within the United Nations Economic Commission for Europe's convention on long-range transboundary air pollution to examine the significance of black carbon.
Estimates are not currently available on black carbon emissions from biomass boilers in the UK. However, we expect that the proposed emission standards to be introduced under the RHI will have a significant impact in reducing concentrations of black carbon compared to the current situation.