Forty of the world's leading climate change scientists united in a call to global leaders, demanding greater action on climate change. The statement, instigated by WWF and endorsed by recognised climate luminaries such as Sir John Houghton, former chair of the Intergovernmental Panel on Climate Change (IPCC), calls for industrialised countries to make a commitment at the UN Climate summit in Copenhagen, to cut carbon emissions by at least 40% below 1990 levels by 2020, in order to keep temperatures below 2�C and avoid dangerous climate change. "As the UK government rallies the EU to step up to the mark ahead of Copenhagen, it is time for Gordon Brown and other world leaders to turn words into action" said Keith Allott, Head of Climate Change at WWF-UK. "Industrialised nations need to prove that their pledge to keep the world below 2�C is not mere grandstanding. They must commit to global emissions cuts of at least 40% by 2020; anything less will lead to a weak global agreement and leave the world wide open to the worst impacts of climate change." Saleem Huq, one of the signatories, IPCC author and Senior Fellow in Climate Change at the International Institute for Environment and Development, said: "The scientific evidence now indicates that even a rise in temperature of two degrees will entail considerable hardships for poor and vulnerable people around the world, especially those living on low lying islands and coasts. So a 40% reduction in emissions is the very least required to provide a better chance of avoiding devastation for these countries and communities."