This year is on track to be the third warmest over the past century and a half, the size of the Antarctic ozone hole matched an all-time high and the extent of Arctic sea ice neared a record low, according to new figures from the United Nations World Meteorological Organization (WMO).
Global surface temperature for 2003 is expected to be 0.45 C (centigrade) above the 1961-90 annual average, according to records maintained by WMO members, making the year the third warmest, just behind 2002 with 0.48 C. The warmest year was 1998 with 0.55 C.
Calculated separately for both hemispheres, the 2003 temperatures for the Northern Hemisphere (0.57 C) and for the Southern Hemisphere (0.33 C) are both likely to the third warmest since instrumental records began in 1861, the Geneva-based agency said in preliminary findings pending an updated report to be published in March.
It noted that the rate of change since 1976 was roughly three times that for the past 100 years as a whole, and analyses of proxy data for the Northern Hemisphere indicate that late twentieth century warmth was unprecedented for at least the past millennium.
Measurements for Antarctica showed that the ozone hole reached 28 million square kilometres in September, matching the all-time record of September 2000 and in marked contrast to last year when the hole split in two and was the smallest in more than a decade. Ozone shields the world from cancer-causing ultraviolet radiation.
Arctic sea ice, meanwhile, dropped to 5.4 million square kilometres in September, nearly as low as the record 5.3 million square kilometres of 2002. The low sea ice of recent years is consistent with new analyses of satellite data showing significant warming of the Arctic region in the 1990s compared to the 1980s, WMO said.
The agency catalogued the year’s weather in various parts of the world, ranging from European heat waves that saw the warmest temperatures on record in several countries to record warmth in Australia that produced wildfires, continued drought in much of southern Africa, and above normal rainfall in most of the Sahelian region of western Africa.