The United Nations Intergovernmental Panel on Climate Change (IPCC) has released a new report on anthropogenic climate change. The findings of the report include the following:
• The world's average surface temperature has increased by around 0.74°C over the past 100 years (1906 - 2005). A warming of about 0.2°C is projected for each of the next two decades.
• The best estimates for sea-level rise due to ocean expansion and glacier melt by the end of the century (compared to 1989 - 1999 levels) have narrowed to 28 - 58 cm, versus 9 - 88 cm in the 2001 report, due to improved understanding. However, larger values of up to 1 m by 2100 cannot be ruled out if ice sheets continue to melt as temperature rises.
• Sea ice is projected to shrink in both Arctic and Antarctic regions. Large areas of the Arctic Ocean could lose year-round ice cover by end of the 21st century if human emissions reach the higher end of current estimates. The extent of Arctic sea ice has already shrunk by about 2.7 per cent per decade since 1978, with the summer minimum declining by about 7.1 per cent per decade.
• Snow cover has decreased in most regions, especially in spring. The maximum extent of frozen ground in winter/spring season decreased by about 7 per cent in the Northern Hemisphere over the latter half of the 20th century. The average freezing date for rivers and lakes in the Northern Hemisphere over the past 150 years has arrived later by some 5.8 days per century, while the average break-up date has arrived earlier by 6.5 days per century.
• It is "very likely" that precipitation will increase at high latitudes and "likely" it will decrease over most subtropical land regions.