What changes can the world expect if we allow global temperatures to rise by 4 degrees C? A new map unveiled today shows the global hot spots likely to see rising sea levels, increased risk of forest fires, dwindling water supplies and melting permafrost, among other dramatic impacts.

With just 45 days to go before international climate change talks begin in Copenhagen, British officials launched the map to highlight the need for the most ambitious deal possible to avoid such dangerous effects.

The map — unveiled by Foreign Secretary David Miliband, Climate and Energy Secretary Ed Miliband and the UK’s Chief Scientist, John Beddington — was developed using the latest peer-reviewed science from the Met Office Hadley Centre and other leading impact scientists. The poster highlights some of the effects that may occur if the global average temperature rises by 4 degrees Celsius above the pre-industrial climate average.

“We cannot cope with a 4 degree world,” said David Miliband. “This map clearly illustrates the scale of the challenge facing us today — climate change is a truly global problem that needs a global solution and it is a solution we have within our grasp. But to tackle the problem of climate change, all of us –  foreign ministries, environment ministries, treasuries, departments of defence and all parts of government and societies — must work together to keep global temperatures to 2 degrees. It is only by doing this that we can minimise the huge security risks presented by a future 4 degree world.”

Ahead of the talks in Copenhagen, the UK government is aiming for an agreement that limits climate change as far as possible to 2 degrees Celsius, believed to be the threshold for catastrophic impact.

“This map shows that the stakes couldn’t be any higher at the Copenhagen talks in December,” said Ed Miliband. “Britain’s scientists have helped to illustrate the catastrophic effects that will result if the world fails to limit the global temperature rise to 2 degrees. With less than 50 days left before agreement must be reached, the UK’s going all out to persuade the world of the need to raise its ambitions so we get a deal that protects us from a 4 degree world.”

The map shows that the effects of a 4 degree average rise will not be spread uniformly across the globe: Land areas will heat up more quickly than oceans, and high latitudes — particularly the Arctic — will see larger temperature increases.

The average land temperature will be 5.5 degrees above pre-industrial levels.

The impacts on human activity shown on the map are only a selection of those that may occur, and highlight the severe effects on water availability, agricultural productivity, extreme temperatures and drought, the risk of forest fire and sea level rise.

Agricultural yields are expected to decrease for all major cereal crops in all major regions of production. Half of all Himalayan glaciers will be significantly reduced by 2050, leading to 23 per cent of China’s population being deprived of the vital dry season glacial melt water source.

“This map developed by the Met Office Hadley Centre, based on the latest climate modelling and peer reviewed science, shows a truly frightening picture of a possible future world in which mankind has failed to act on climate change,” said Beddington. “It is a world we must do all we can to avoid. A 4 degree C rise globally would mean temperature rises far higher than 4 degrees C in many countries and regions, with potentially devastating impacts for people across the planet.”

“If emissions continue at the current rate the global average temperature are likely to rise by 4 degrees Celsius by the end of this century or even substantially earlier,” added Vicky Pope, head of climate change advice at the Met Office. “The science tells us that this will have severe and widespread impacts in all parts of the world, so we need to take action now to reduce emissions to avoid water and food shortages in the future.”

Tags: global warming