Global warming 'set to speed up to rates not seen for 1,000 years'

By 2020 the average temperature rise per decade will be 0.25C in the northern hemisphere, more than double the 900 years preceding the 20th century

People need to brace themselves for accelerating climate change that could alter the way we live even over short time scales, scientists have warned.

New evidence suggests the rate at which temperatures are rising in the northern hemisphere could be 0.25C per decade by 2020 - a level not seen for at least 1,000 years.