The researchers from the Grantham Research Institute on Climate Change and the Environment and the Centre for Climate Change Economics and Policy conclude that about US$400 billion should be spent worldwide on ‘green’ policies and investments which also help economic recovery and lay the foundations of sustainable low-carbon growth. The report, ‘An outline of the case for a ‘green’ stimulus’, points out that this sum represents about 20 per cent of the US$2 trillion, or 4 per cent of global gross domestic product, that governments might spend in the next 18 months on fiscal stimulus packages to lessen the economic downturn.