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The level in the atmosphere of carbon dioxide, the principal greenhouse gas, stood at 280 parts per million by volume (ppm) before the Industrial Revolution, in about 1780. The level of CO2 in the atmosphere today stands at 382ppm

£200bn, or 1 per cent of global GDP, must be spent every year to get carbon dioxide levels to "stabilise" at 550ppm. This figure will rise as world GDP increases, and could be three to four times as large by 2050

40 per cent of the world's species would face extinction if temperatures rose by 2C

200 million people are at risk of being driven from their homes by flood or drought by 2050

6C is a "plausible" estimate of how much world temperatures could rise by the end of the century if greenhouse gas emissions are unchecked

60 million more Africans could be exposed to malaria if world temperatures rise by 2C

35 per cent drop in crop yields across Africa and the Middle East is expected if temperatures rise by 3C

200 million more people could be exposed to hunger if world temperatures rise by 2C

550 million more people could be at risk of hunger if world temperatures rise by 3C

4 million square kilometres of land, home to one-twentieth of the world's population, is threatened by floods from melting glaciers

35,000 Europeans died in the 2003 heatwave, an event likely to become 'commonplace'

4 billion people could suffer from water shortage if temperatures rise by 2C