Greenhouse Effect (Hansard, 24 January 1992)

Mr. Alan W. Williams
To ask the Secretary of State for the Environment what is his Department's estimate of the contribution to the greenhouse effect from(a) the combustion of fossil fuels in Britain and (b) the escape of natural gas into the environment during the production and processing of North sea gas and its distribution to the consumer.

§ Mr. Baldry
Revised figures for annual United Kingdom emissions of greenhouse gases up to 1990 will be published in late February or early March in the 14th edition of the "Digest of Environmental Protection and Water Statistics". The new estimates indicate that in 1990 United Kingdom emissions of CO₂ from fossil fuel combustion were about 2.6 per cent. of world emissions. Current estimates of world methane emissions from natural gas production are uncertain within a factor of at least two. United Kingdom emissions in 1990 can therefore be estimated only very approximately at between 1–7 per cent. and 3 per cent. of world emissions from this source.
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Mr. Alan W. Williams
To ask the Secretary of State for the Environment what figures he has on the relative efficiency of absorption of infra-red radiation leading to the greenhouse effect for(a) carbon dioxide, (b) nitrogen dioxide, (c) methane and (d) chlorofluorocarbons.

§ Mr. Baldry
The relative impact of greenhouse gases is only partly explained by their radiation absorption properties. Differences in concentration, atmospheric lifetime and secondary effects on the concentration of other gases are also important.
To take account of all these factors, the intergovernmental panel on climate change (IPCC) developed the concept of the global warming potential (GWP).
Initial tentative GWP values for a wide range of substances were published in the panel's first scientific assessment, copies of which have been placed in the Library of the House.
The IPCC, in a supplementary report which will be made public within a few months, will give revised GWPs for the main greenhouse gases. However the summary of the assessment, published recently, indicates that there is now greater uncertainty in the calculation of GWPs.