Doomsday: How 4C temperature rise this century will change world beyond recognition and threaten human survival
By Claire Bates
Last updated at 3:21 PM on 26th February 2009
Alligators bask off the English coast, the Saharan desert stretches far into Europe and just 10 per cent of humans are left on the planet.
No, this is the doomsday scenario being predicted by scientists if global temperatures make a predicted rise of 4C in the next 100 years. Some fear it could happen as early as 2050.
Rivers from the Danube to the Rhine would be reduced to a trickle while melting glaciers and storm surges would drown coastal regions under two metres of water. More if parts of Antarctica were to melt.
Trying to prevent desertification. Some experts predict that by 2100 deserts would take over most of Africa and stretch into Europe
While 4C does not sound like very much, the New Scientist magazine, has said it could easily occur.
A report in 2007 by the Intergovernmental Panel on Climate Change, whose conclusions are generally accepted as conservative, predicted a rise of between 2C and 6.4C this century.
In August of 2008 Bob Watson, former chair of the IPCC, warned that the world should prepare for 4C of warming.
As part of their research into the article the New Scientist spoke to leading climate experts from around the world to create a map of how our world might look 4C warmer.
Many were optimistic that humans would survive but would have to adapt to vastly altered circumstances. Vast numbers would have to migrate and there would have to be a world effort to redistribute resources.
As a huge swathe of desert started to spread out from the equator, humans would migrate north and south towards the poles, knocking down national boundaries.
'We need to look at the world afresh and see it in terms of where the resources are, and then plan population around that,' Peter Cox from the University of Exeter said.
Humans will become mostly vegetarian with most animals being eaten to extinction by desperate people.
A glaciers melt, sea levels are expected to rise by 2m this century
Large chunks of Earth's biodiversity would vanish because they could not adapt in such a short time.
In the world's oceans, numbers of fish would drop dramatically as acid levels rose because of decreasing plankton.
As the remaining fertile lands would be so precious people would have to live in compact high-rise cities to preserve space for food growing.
Scientists have put forward the prospect of energy being supplied for homes by a giant solar belt running across North Africa, the Middle East and the southern U.S. The New Scientist article also questioned the future of the humankind.
'I think they'll survive as a species all right, but the cull during this century is going to be huge,' former Nasa scientists James Lovelock said.
'The number remaining at the end of the century will probably be a billion or less.'
Workers install solar panels in France. Massive solar panel complexes stretching across countries could be built to provide for the world's energy needs
The last time the world experienced such temperature rises was 55 million years ago when large areas of frozen methane were released from the ocean and filled the atmosphere with carbon, warming the planet by 6C.
Unfortunately humans did not learn any survival lessons from the event as we only evolved a quarter of a million years ago.
Many experts hope our species will continue but warn we are not doing enough to try and prevent a catastrophe.
'In order to be safe, we would have to reduce our carbon emissions by 70 per cent by 2015. We are currently putting in 3 per cent more each year,' said Nobel prizewinning chemist Paul Crutzen.