GENEVA, (WMO) - The global surface temperature for all of 2003 is expected to be +0.45°C above the 1961-90 annual average, according to the records maintained by Members of the World Meteorological Organization (WMO). This value makes 2003 the third warmest year just behind 2002 (+0.48°C). The warmest year remains 1998 (+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 be the third warmest in the instrumental record from 1861 to present.

The high temperatures recorded over land influenced the overall values in 2003. Europe experienced unprecedented heat during June, July and August. The Mediterranean and Near East region (40-30N, 20W-60E) had the warmest land and Sea Surface Temperature (SST) anomaly on record for June and July. The Northern Hemisphere had the warmest land and SST anomaly on record for September and October.

The global surface temperature has increased since the beginning of the instrumental record in 1861. Over the 20th century the increase was greater than 0.6°C. The rate of change for the period since 1976 is roughly three times that for the past 100 years as a whole. Analyses of proxy data for the Northern Hemisphere indicate that late 20th century warmth is unprecedented for at least the past millennium. In the Northern Hemisphere, the 1990s were the warmest decade and 1998 the warmest year in the past 1000 years.


Strong regional temperature differences

Much of Europe was affected by heat waves during the summer (June, July, August) of 2003. Nationwide seasonal temperatures were warmest on record in Germany, Switzerland, France and Spain. The heat wave resulted from a zone of strong high pressure over Western Europe related to a marked ridge of high pressure in the large-scale upper atmospheric wind flow. Such “blocking highs" that persist for many days are not rare in Europe during summer. They usually bring warm and sunny weather. However, in this situation heated air from the south reinforced the strength and persistence of the heat wave.

At many locations, temperatures rose above 40°C. In France, Italy, The Netherlands, Portugal, the United Kingdom and Spain, over 21,000 additional deaths were attributed to the unrelenting heat. Spain, Portugal, France and countries in Central and Eastern Europe suffered from intense forest fires. In the European Alps, the average thickness loss of glaciers reached about 3 metres water equivalent, which was nearly twice as much as during the previous record year 1998 (1.6 metres).

During summer, temperatures across parts of Europe were consistently 5°C warmer than average for several months. The heat waves extended to other parts of the Northern Hemisphere, with near-record temperatures observed in Canada and the United States (including Hawaii and Alaska), China and parts of Russia. In contrast to the summer warmth over large parts of the Northern Hemisphere, extremely low temperatures with wet conditions persisted from northern China to Japan during July and August.

In India, Pakistan and Bangladesh, this year’s pre-monsoon heat wave brought peak temperatures in May of between 45°C and 49°C. May is usually the warmest month of the year in India and heat waves often occur prior to the onset of the summer monsoon, but this year's heat was particularly harsh. At least 1500 people died in India due to the hot weather. This contrasted strongly with the extremely low temperatures observed in northern India in January. Maximum temperatures then were 4 to 5°C below normal, which resulted in more than 1900 fatalities. In the neighbouring countries of Pakistan, Nepal and Bangladesh, the combination of cold weather and persistent fog claimed hundreds of lives in January.

During the Northern Hemisphere winter, large areas in central and Eastern Europe saw episodes of very cold temperatures. January temperatures in the Russian Federation reached –45°C. For the third year in a row Mongolia experienced a cycle of dry summer/cold winter with devastating effects on livestock. During austral winter, a cold wave in the Peruvian highlands resulted in more than 200 deaths as temperatures in areas above 4000m dropped below –20°C in July.


Relief in some drought regions

The year began with a moderate El Niño in the equatorial Pacific Ocean, which quickly faded to neutral conditions by April. The effects of El Niño persisting into early 2003 included drier than normal conditions over Australia and extremely dry conditions in southern parts of Africa.

Dry conditions and record warmth in Australia promoted wildfires that devastated parts of the southeast. A massive complex of bushfires, which burned for 59 days during January and February, destroyed over 3 million hectares. Despite near normal rainfall, the impacts of the drought remained for much of 2003.

In Africa, drought conditions continued to affect much of Botswana, Zimbabwe, parts of South Africa and Mozambique in early 2003. The amount of October ’02 - January ‘03 accumulated rainfall in Maputo was the lowest received since 1951/52. Areas in northern Mozambique, eastern Zimbabwe, southern Malawi, and eastern Zambia did benefit from above-normal precipitation during the rainy season, but much of the rainfall was produced by tropical cyclones and often was accompanied by flooding. The erratic rainy season had varying effects on crops, but led to an overall increase in production in the area. Above normal rainfall throughout most of the Sahelian region of western Africa improved the drought situation in this area as well. Consequently, grain and cotton harvests were also above normal in most countries. In eastern Africa, the drought in northern parts of Ethiopia and Eritrea continued to hurt agriculture and food security.

Near year’s end, moderate to extreme drought affected 37% of the contiguous United States, in some areas for the fourth or fifth year in a row, leading to water shortage. The most costly wildfires on record in the USA occurred in Southern California in late October. British Columbia (Canada) experienced the most costly wildfires ever during summer. Then heavy autumn rainfall ended the drought conditions, but brought flooding to the area.

Rain and snowfall brought relief from drought conditions in Afghanistan that had built up over the past four years. Improved rainfall helped fill water reservoirs that had been dry for years.


Abundant rainfall and flooding in many areas

As in other years, the Asian summer monsoon, which typically lasts from June to September, brought heavy rain and flooding to parts of Pakistan, northern India, Nepal and Bangladesh. The Ganges River reached its highest level since 1975 causing hundreds of flood-related deaths. However, total rainfall in India was near normal (102% of the long term average) and the monsoon rains were well distributed throughout the season and the country.

Heavy monsoon rains also brought flooding to China’s Yellow River basin and some of its tributaries between June and October. The death toll in China reached almost 2000, which was lower than that of earlier events in 1991 and 1998. Part of the flooded area had been affected by the worst drought in 50 years earlier in the year. Viet Nam and Thailand saw heavy rains and severe flooding during their rainy season, particularly in October.

In Brazil, torrential rains in January brought flooding to Rio de Janeiro, triggering deadly mudslides. The Argentine province of Santa Fe experienced serious flooding in late April/early May, leading to a drop in agricultural production and adverse effects on water quality.

In Africa, heavy seasonal rains in April led to flooding in Kenya and southern parts of Ethiopia and Somalia, with similar conditions in western Eritrea and northeast Sudan in July. Some areas experienced the wettest conditions in 70 years.

Snowstorms in February brought numerous new 24-hour snowfall and storm total records to the eastern United States, resulting in a number of weather-related deaths. In November, rainfall records were set in portions of coastal British Columbia as up to 470mm of rain in a six-day period caused the worst flooding in a century.

The Northern Hemisphere snow cover extent for 2003 was the second greatest on record.


Above normal number of hurricanes, typhoons and tropical cyclones

This year’s Atlantic hurricane season saw the development of 16 named storms, well above the 1944-96 average of 9.8, but consistent with a marked increase in the annual number of tropical systems since the mid 1990s. Seven of the named storms were classified as hurricanes and three of those were 'major' (category three or higher on the Saffir-Simpson scale). Hurricane Isabel hit North Carolina as one of the strongest on record. Hurricane Juan was the worst hurricane to hit Halifax, Nova Scotia in modern times, and Hurricane Fabian was the most destructive hurricane to hit Bermuda in more than 75 years.

In the Eastern Pacific, the hurricane season began slowly, though 16 named storms had developed by the beginning of December. This value is slightly greater than in previous years, but close to the 1966-1996 average of 16.4. While none of the storms reached hurricane strength until late August, seven storms had reached hurricane strength by October 31st, with one of those reaching 'major' status.

For the Northwest Pacific, activity was slightly depressed in 2003 with only 20 named storms observed in the western North Pacific, which is below the 1971 to 2000 average of 25.4. Twelve of them reached typhoon intensity. Typhoon ‘Maemi’ passed over southern Japan and made landfall on the Korean Peninsula on September 12, resulting in more than 130 deaths and massive property damage.

For the South West Indian Ocean basin, the cyclone season was active with an above normal number of named storms over the entire basin. In Sri Lanka, heavy rainfalls in May from Tropical Cyclone 01B exacerbated already wet conditions, resulting in flooding and landslides and killing at least 250 people. The flooding is considered the worst to affect the region in 50 years.


Antarctic ozone hole unusually large

A comprehensive analysis of integrated ground-based and satellite measurements over and near Antarctica show that the maximum size of the ozone hole (28 million square kilometers) was reached in late September, matching the all time record size reported for September 2000. This is in stark contrast to the ozone hole last year, which split in two during late September and was the smallest in more than a decade. As it had in the year 2000, the ozone hole in 2003 dissipated earlier than usual.


Low Arctic sea ice extent

Northern Hemisphere sea ice extent was 5.4 million square kilometers in September 2003, which was nearly as low as the record low of 5.3 million square kilometers set in September 2002. The low sea ice extent observed in recent years is consistent with new analyses of satellite data, which show that the Arctic region warmed significantly in the 1990s compared to the 1980s.


Information Sources

This preliminary information for 2003 is based on observations up to the end of November from a network of land-based weather stations, ships and buoys. The data are collected and disseminated on a continuing basis by the National Meteorological and Hydrological Services of the WMO Member countries.

It should be noted that following established practice, WMO’s global temperature analyses are based on data sets maintained by the Hadley Centre of the Met Office, UK, and the Climatic Research Unit, University of East Anglia, UK as well as another authoritative global surface temperature data set, which is maintained by the USA Department of Commerce’s National Oceanic and Atmospheric Administration (NOAA). Results from these two data sets are comparable; both datasets indicate that 2003 will likely be the third warmest year globally.

More extensive, updated information will be made available in the annual WMO Statement on the Status of the Global Climate in 2003, to be published in early March 2004.

(*A joint Press Release issued in collaboration with the Hadley Centre of the Met Office, UK, the Climatic Research Unit, University of East Anglia, UK, and in the USA: NOAA's National Environmental Satellite and Data Information Service and NOAA's National Weather Service. Other contributors were from the WMO Member countries Australia, Canada, France, Germany, India, Japan, Mauritius, the Netherlands, New Zealand, Norway, Spain, Sweden, Switzerland as well as the International Research Institute in New York, the Drought Monitoring Centre in Nairobi, the World Glacier Monitoring Service in Zürich and the AGRHYMET Centre in Niamey).