The effect of 4-degree climate change
Updated on 22 October 2009
In the build-up to the Copenhagen Climate Change summit, the government has produced a poster showing how the world will be changed by a global temperature increase of 4 degrees Celsius.
The government's current policies are aimed at limiting the increase in temperatures worldwide to 2 degrees Celsius.
The poster shows that a 4 degree average rise will not be spread uniformly across the globe. The land will heat up more quickly than the sea, and high latitudes, particularly the Arctic, will have 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.
Click here to launch a full-screen interactive version of the map
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 the population of China being deprived of the vital dry season glacial melt water source.
The Foreign Secretary David Miliband said: "We cannot cope with a 4 degree
world. 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."
Ed Miliband, Energy and Climate Change secretary said:
"This map shows that the stakes couldn't be any higher at the Copenhagen talks
in December. 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."
Vicky Pope, Head of Climate Change Advice at the Met Office says: "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. 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."
Professor Chris Rapley CBE, director of the Science Museum and Professor of Climate Science at University College London said: "The map provides graphic evidence of the dramatic transformation of our world that a 4 degree global temperature rise would trigger. It leaves no doubt of the paramount importance of a successful outcome of the Copenhagen negotiations."
