climate change

The world heated up by about 0.6 degrees last century, and the 1990s were the warmest decade on record, the International Panel on Climate Change (IPCC) says.

Scientists say average global temperatures have varied by less than one degree since the dawn of human civilisation, although they fluctuated much more before that. The IPCC predicts a global rise of between 1.4C and 5.8C by the year 2100.

Rising temperatures are thought to cause sea levels to rise as the oceans expand and polar ice melts. The IPCC says sea levels rose between 10 and 20cm worldwide during the 20th Century. It predicts a further rise of between 9cm and 88cm by 2100.

According to the IPCC, North Pole sea-ice has thinned by 40% in recent decades in summer and autumn. Global snow cover has shrunk by 10% since the 1960s and mountain glaciers have also retreated.

Most mainstream scientists believe that increased emissions of greenhouse cases, particularly carbon dioxide, are contributing to the warming of the planet. This graph shows how carbon dioxide levels have increased as the world has industrialised.

This map, from the UK’s Hadley Centre, assumes that current emissions trends continue, with moderate economic growth and few measures to reduce emissions. It predicts the greatest rises in northern polar regions, India, Africa and parts of South America.

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