All Over Bar the Boiling

“extreme weather events” might increase in number and intensity, as global temperatures rise due to climate change. Heat records were broken in France and Switzerland; the United States had the highest number of tornadoes on record in May; hundreds of Indians died in a heatwave and extreme rains drenched Sri Lanka, the WMO noted.

These record extreme events (high temperatures, low temperatures and high rainfall amounts and droughts) all go into calculating the monthly and annual averages which, for temperatures, have been gradually increasing over the past 100 years. New record extreme events occur every year somewhere in the globe, but in recent years the number of such extremes have been increasing. According to recent climate change scientific assessment reports of the joint WMO/UNEP Intergovernmental Panel on Climate Change (IPCC), the global average surface temperature has increased since 1861. Over the 20th century the increase has been around 0.6?C. This value is about 0.15?C larger than that estimated by the previous reports. New analyses of proxy data for the Northern Hemisphere indicate that the increase in temperature in the 20th century is likely to have been the largest in any century during the past 1000 years. It is also likely that, in the Northern Hemisphere, the 1990s were the warmest decade and 1998 the warmest year. While the trend towards warmer globally averaged surface temperatures has been uneven over the course of the last century, the trend for the period since 1976 is roughly three times that for the past 100 years as a whole. Global average land and sea surface temperatures in May 2003 were the second highest since records began in 1880. Considering land temperatures only, last May was the warmest on record.