To ask the Secretary of State for the Environment what gases, other than carbon dioxide, are thought to contribute to the greenhouse effect; what is their percentage currently in the atmosphere; and which sources, man-made and natural, are the main causes for emissions of these gases.

Greenhouse gases, excluding carbon dioxide, their current (1988) average atmospheric concentration and the main sources believed to be responsible for their emissions are set out in the booklet "Global Climate Change"; copies of which may be found in the House Library.