Two men are to run marathons in extreme climates to highlight global warming.
Sean Cornwell and Ed Stumpf will endure temperatures ranging from -30C to 40C when they compete in races at the North Pole and in the Sahara desert.
The pair, both from London, plan to run wrapped in clingfilm to symbolise how carbon emissions suffocate the world.
They also hope to collect one million "action pledges" on their EarthFireIce website which encourages people to help the environment in their daily lives.
The Sahara Marathon is held in southern Algeria on 26 February with 200 runners expected to take part.
The North Pole Marathon takes place on 6 April with 50 competitors expected.
Mr Cornwell, 32, of Pimlico, and Mr Stumpf, 29, of Balham, set up their website to prompt people into taking action to reduce their impact on the environment.