This is our future - famous cities are submerged, a third of the world is desert, the rest struggling for food and fresh water. Richard Girling investigates the reality behind the science of climate changehttp://www.timesonline.co.uk/tol/news/uk/science/article1480669.eceSix thousand years ago, when the world was one degree warmer than it is now, the American agricultural heartland around Nebraska was desert. It suffered a short reprise during the dust- bowl years of the 1930s, when the topsoil blew away and hundreds of thousands of refugees trailed through the dust to an uncertain welcome further west. The effect of one-degree warming, therefore, requires no great feat of imagination.
"The western United States once again could suffer perennial droughts, far worse than the 1930s. Deserts will reappear particularly in Nebraska, but also in eastern Montana, Wyoming and Arizona, northern Texas and Oklahoma. As dust and sandstorms turn day into night across thousands of miles of former prairie, farmsteads, roads and even entire towns will be engulfed by sand."
What's bad for America will be worse for poorer countries closer to the equator. The Hadley centre calculates that a one-degree increase would eliminate fresh water from a third of the world's land surface by 2100. Again we have seen what this means. Lynas describes an incident in the summer of 2005: "One tributary fell so low that miles of exposed riverbank dried out into sand dunes, with winds whipping up thick sandstorms. As desperate villagers looked out onto baking mud instead of flowing water, the army was drafted in to ferry precious drinking water up the river - by helicopter, since most of the river was too low to be navigable by boat." The river in question was not some small, insignificant trickle in Sussex. It was the Amazon.
While tropical lands teeter on the brink, the Arctic already may have passed the point of no return. Warming near the pole is much faster than the global average, with the result that Arctic icecaps and glaciers have lost 400 cubic kilometres of ice in 40 years. Permafrost - ground that has lain frozen for thousands of years - is dissolving into mud and lakes, "destabilising whole areas as the ground collapses beneath buildings, roads and pipelines". As polar bears and Inuits are being pushed off the top of the planet, previous predictions are starting to look optimistic. "Earlier snowmelt," says Lynas, "means more summer heat goes into the air and ground rather than into melting snow, raising temperatures in a positive feedback effect. More dark shrubs and forest on formerly bleak tundra means still more heat is absorbed by vegetation."
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