Regional overviews show that a variety of extreme weather events across the globe, supported by new research, added further weight to the concerns expressed by the Intergovernmental Panel on Climate Change (IPCC) and many others that climate change is already having an impact on the environment

According to the United States National Oceanic and Atmospheric Administration (NOM), 2003 was the third warmest year on record. Average temperatures for the year were above average by as much as 1.7° C for large parts of Asia, Europe, and the western United States. Warmer-than-average temperatures were also recorded in much of South America, Australia, Canada and parts of Africa. However, widespread areas of cooler-than-average temperatures were experienced in the eastern United States, western Asia, and coastal areas of Australia (NOM 2003).

1979	2003
Figure 1: Dramatic changes in Arctic sea ice since 1979. The loss of Arctic sea ice may be caused by warming Arctic temperatures that result from greenhouse gas build-up in the atmosphere.
Source: NASA/Goddard Space Flight Center Scientific Visualization Studio

In September, scientists from the United States and Canada announced that the largest ice-shelf in the Arctic had broken up. The Ward Hunt Ice-shelf (see also Polar section), to the north of Canada´s Ellesmere Island, split into two main parts, with other large blocks of ice also pulling away from the main sections
(Mueller and others 2003). The news only added to the growing number of reports in recent years of melting in the Polar Regions. For example, trends of perennial sea ice in the Arctic declining at a rate of nine per cent per decade, which were found from studies conducted in 2002, persisted in 2003. Researchers suspect that the loss of Arctic sea ice may be caused by changing atmospheric pressure patterns over the Arctic that move sea ice around, and by warming Arctic temperatures that result from greenhouse gas buildup in the atmosphere. The two images (Figure 1) show a comparison of Arctic sea ice extent in 1979 and 2003.

There were also reports of glaciers shrinking at a rapid rate in Nepal as well as in Bolivia, while the Patagonian glaciers in Chile and Argentina were found in October 2003 to be melting so fast that they were actually contributing to sea level rise (Combs and others 2003). And in the Antarctic, it was discovered that the Pine Island Glacier, one of the continent’s biggest, had lost 31 km3 of ice since 1992, and could be lost to the ocean in a few hundred years if present rates of thinning continue (BAS 2003).

While not all cases of extreme weather events can be attributed to climate change, there was certainly an abundance of such phenomena in 2003. A record summer heatwave affected Europe. The all-time maximum temperature record in the United Kingdom was broken on 10 August, when the mercury reached 38.1° C at Gravesend in Kent. France had its warmest summer on record, with a heatwave that the National Institute of Health and Medical Research blamed for 14 802 deaths in the country (Boyer and others 2003).

Temperatures also soared across southern Asia in late May and June. During a 20-day heatwave, maximum temperatures climbed to 45–50° C, and more than 1 500 deaths occurred in India (NOAA 2003).

In China, widespread flooding left four million people homeless after torrential rains hit the country’s eastern provinces in July. And there was no let up in reports of extreme weather as 2003 drew to an end, with major floods reported in southeastern France and southern Brazil, while a freak thunderstorm struck Melbourne, Australia, all within the space of a few days.