states:
At the continental, regional, and ocean basin scales, numerous long-term changes in climate have been observed. These include changes in Arctic temperature and ice, widespread changes in precipitation amounts, ocean salinity, wind patterns and aspects of extreme weather including droughts, heavy precipitation, heat waves and the intensity of tropical cyclones.

More Detailed observations from the report:
Widespread changes in extreme temperatures have been observed over the last 50 years. Cold days and cold nights and frost have become less frequent, while hot days, hot nights, and heat waves have become more frequent.

Since 1900, increased precipitation has occured over many large regions, while increased drying has been observed in the Sahel, the Mediterranean, southern Africa, and parts of southern Asia. More intense and longer droughts have been observed over wide areas since the 1970s, particularly in the tropics and subtropics. Increased drying linked with higher temperatures and decreased precipitation have contributed to changes in drought. Changes in sea temperatures, wind patterns, and decreased snowpack and snow cover have been linked to drought.

There is observational evidence for an increase of intense tropical cyclone activity in the North Atlantic since 1970, correlated with increases in tropical sea temperatures. Mid-latitude winds have strengthened in both hemispheres since the 1960s. A discussion of global warming effects on hurricanes is provided on another zFacts page.

Data shows that Arctic sea ice extent has shrunk by 2.7% per decade since 1978. The area covered by seasonally frozen ground has decreased in the Northern Hemisphere by about 7% since 1900.

http://zfacts.com/p/810.html | 01/18/12 07:18 GMT
Modified: Sun, 06 May 2007 00:33:13 GMT