Geneva, 16 December 2008 (WMO) – The year 2008 is likely to rank as the 10th warmest year on record since the beginning of the instrumental climate records in 1850, according to data sources compiled by the World Meteorological Organization (WMO). The global combined sea-surface and land-surface air temperature for 2008 is currently estimated at 0.31°C/0.56°F above the 1961-1990 annual average of 14.00°C/57.2°F. The global average temperature in 2008 was slightly lower than that for the previous years of the 21st century due in particular, to the moderate to strong La Niña that developed in the latter half of 2007.

The Arctic Sea ice extent dropped to its second-lowest level during the melt season since satellite measurements began in 1979. Climate extremes, including devastating floods, severe and persistent droughts, snow storms, heatwaves and cold waves, were recorded in many parts of the world.

This preliminary information for 2008 is based on climate data from networks of land-based weather stations, ships and buoys, as well as satellites. The data are continuously collected and disseminated by the National Meteorological and Hydrological Services (NMHSs) of WMO’s 188 Members and several collaborating research institutions. Final updates and figures for 2008 will be published in March 2009 in the annual WMO Statement on the Status of the Global Climate.

WMO’s global temperature analysis is based on two complementary sources. One is the combined dataset maintained by both the Hadley Centre of the UK Meteorological Office, and the Climatic Research Unit, University of East Anglia, UK. The other dataset is maintained by the US Department of Commerce’s National Oceanic and Atmospheric Administration (NOAA).

Regional temperature anomalies

2008 again was a year with above-average temperatures all over Europe. A large geographical domain, including north-western Siberia and part of the Scandinavian region, recorded a remarkably mild winter. January and February were very mild over nearly all of Europe. Monthly mean temperature anomalies for these months exceeded +7°C in some places in Scandinavia. In most parts of Finland, Norway and Sweden, winter 2007/08 was the warmest recorded since the beginning of measurements. In contrast, the boreal winter was remarkably cold for a large part of Eurasia extending eastward from Turkey to China. Some places in Turkey had their coldest January nights in nearly 50 years. This extreme cold weather caused hundreds of casualties in Afghanistan and China.

February was a cold month across most of the USA Midwest, with average daily temperatures ranging from 4.0°C to 5.0°C below normal in some areas.

A very cold episode, due to an early Antarctic air mass outbreak, occurred in May in southern South America, particularly in central Argentina, where the minimum temperature dropped below –6°C in some locations, breaking annual absolute minimum temperature records. Conversely, mean July temperatures were more than +3°C above average in large parts of Argentina, Paraguay, southeast Bolivia and southern Brazil, making it the warmest July in the last 50 years for many locations. Also, November broke historical temperature records in association with an unusual heatwave. Central Argentina, including Buenos Aires city, had its warmest November in the last 50 years.

In March, southern Australia experienced a record heatwave that brought scorching temperatures across the region. Adelaide experienced its longest running heatwave on record, with 15 consecutive days of maximum temperatures above 35°C. Also, several heatwaves occurred in south-eastern Europe and the Middle East during April, associated with a very warm spring observed, not only in this region but also in a large part of the rest of Europe and Asia.

Prolonged drought

At the end of July, most parts of the Southeast of North America were classified as having moderate to exceptional drought, based on the US Drought Monitor. The continuous dry conditions across northern and central California hindered efforts to contain numerous large wildfires.

Southern British Columbia in Canada experienced its fifth driest period in 61 years. In Europe, Portugal and Spain had their worst drought winter in decades.

In South America, a large part of Argentina, Uruguay and Paraguay experienced a prolonged and intense drought during most of 2008, which caused severe damage to agriculture.

Dry conditions in south-eastern Australia reinforced long-term drought over much of that region, with Victoria having its ninth-driest year on record. These conditions exacerbated severe water shortages in the agriculturally important Murray-Darling Basin, resulting in widespread crop failures in the area. September and October, in particular, were exceptionally dry in this region.

Flooding and intense storms

In January, 1.3 million square kilometres (km2) in 15 provinces in southern China were covered by snow and experienced persistent low temperature and icing. This weather affected the daily life of millions of people who suffered from disruptions of transport, energy supply and power transmission, as well as damage to agriculture.

In Canada, several all-time snowfall records were set during winter reaching more than 550 centimetres (cm) in many locations, including Quebec City. The accumulation of snow was heavy enough to cause numerous roofs to collapse, killing at least four people. In Toronto, the 2007/2008 winter was the third snowiest on record in the 70 year of snow measurement records. At the end of January, Prince Edward Island was struck by one of the worst ice storms in decades.  Nearly 95 per cent of the province lost power for a time.

In the United States of America, heavy April rainfall combined with previously saturated ground and snowmelt resulted in widespread major flooding that affected Missouri and southern Indiana. During the month of June, daily precipitation records were broken in many parts of Iowa, Illinois, Wisconsin and Missouri. Also, this year was one of the top 10 years for tornado-related fatalities (123 total) since reliable records began in 1953. According to statistics, from January to August, 1 489 tornadoes were recorded, marking a record since 1953.

In Germany, between May and September, a large number of strong thunderstorms with heavy rain, tornadoes and hail storms were observed, causing some casualties and significant damages.

Sub-Saharan Africa, including West and East Africa, was affected by heavy rains, which caused the worst-ever recorded flooding in Zimbabwe and affected more than 300 000 people in West Africa during the monsoon season.

In northern Africa, heavy and extended rainfall during the period of September to November affected Algeria and Morocco, causing important infrastructure damage and several casualties in many cities and villages. Extreme rainfall intensities were recorded in northern provinces of Morocco with up to 200 millimetres (mm) of rainfall in less than six hours. Within the same climate anomaly context and period, intense rainfall was also recorded in south-western Europe. In Valencia, Spain, a total rainfall of 390 mm was recorded in 24 hours, of which 144 mm were recorded in less than one hour. In France, heavy and intense rains affected several locations from 31 October to 2 November. In three days, total rainfall reached 500 mm in some locations, which caused severe flooding and flash floods particularly in central and east-central parts of the country.

Several major rain events affected eastern Australia in January and February, causing significant flooding, particularly in Queensland. In November, widespread heavy rains occurred across most of the continent, ending an extremely dry period in central Australia. Associated severe thunderstorms caused damage from winds, hail and flash floods in many places.

In southern Asia, including India, Pakistan and Vietnam, heavy monsoon rains and torrential downpours produced flash floods, killing more than 2 600 people, and displacing 10 million people in India.

In western Colombia, continuous above-normal rainfall resulted in severe flooding that affected at least half a million people and caused extensive damage and landslides during the second half of the year.

In Southern Brazil, heavy rainfall affected Santa Catarina State from 22 to 24 November causing severe flooding and deadly mudslides, which affected 1.5 million people  and resulted in 120 casualties and left 69,000 people homeless.

Weakening of La Niña

The first quarter of 2008 was characterized by a La Niña event of moderate to strong intensity, which began in the third quarter of 2007 and prevailed through May 2008. The large area of cool surface waters over the bulk of the central and eastern equatorial Pacific, combined with warmer-than-normal conditions in the equatorial western Pacific, represented typical La Niña forcing on the global atmosphere; many climate patterns reflected those normally observed during a La Niña event, both in the vicinity of, and remote from, the tropical Pacific. La Niña conditions have gradually weakened from their peak strength in February, and near-neutral conditions prevailed during the later half of 2008.

Tropical cyclones season

The most deadly tropical cyclone recorded in 2008 was Cyclone Nargis, which developed in the North Indian Ocean and hit Myanmar in early May, killing nearly 78 000 people and destroying thousands of homes. Nargis was the most devastating cyclone to hit Asia since 1991 and resulted in the worst natural disaster on record for Myanmar.

A total of 16 named tropical storms formed in the Atlantic including eight hurricanes, five of which were major hurricanes at Category 3 or higher (averages are eleven, six and two, respectively). The 2008 Atlantic hurricane season was devastating, with many casualties and widespread destruction in the Caribbean, Central America and the United States of America. For the first time on record, six consecutive tropical cyclones (Dolly, Edouard, Fay, Gustav, Hanna and Ike) made landfall on the United States of America, and a record three major hurricanes (Gustav, Ike and Paloma) hit Cuba. Hanna, Ike and Gustav were the deadliest hurricanes during the season, causing several hundred of casualties in the Caribbean, including 500 deaths in Haiti.

In the East Pacific, 17 named tropical storms were recorded, of which seven evolved into hurricanes and 2 of them into major hurricanes (averages are sixteen, nine and four, respectively).

In the western North Pacific, 22 named tropical storms were recorded, and 10 of them were classified as typhoons compared to the long-term average of 27 and 14, respectively. Philippines, Cambodia, Laos, Thailand, Vietnam and south-eastern China were the most affected by these events. For the first time since 2001, no named tropical cyclones made landfall in Japan this year.

Antarctic ozone hole larger than in 2007

The ozone hole area reached a maximum of 27 million km2 on 12 September. This is less than in the record year 2006 (more than 29 million km2) but larger than in 2007 (25 million km2). The variation in the size of the ozone hole from one year to another can be, to a large extent, explained by the meteorological conditions in the stratosphere.

Artic sea ice down to second-lowest extent

Arctic sea ice extent during the 2008 melt season dropped to its second-lowest level since satellite measurements began in 1979, reaching the lowest point in its annual cycle of melt and growth on 14 September 2008. Average sea ice extent over the month of September, a standard measure in the scientific study of Arctic sea ice, was 4.67 million km2. The record monthly low, set in 2007, was 4.3 million km2.

Because ice was thinner in 2008, overall ice volume was less than that in any other year.

A remarkable occurrence in 2008 was the dramatic disappearance of nearly one-quarter of the massive ancient ice shelves on Ellesmere Island. Ice 70 metres thick, which a century ago covered 9 000 km2, has been chiselled down to just 1 000 km2 today, underscoring the rapidity of changes taking place in the Arctic. The season strongly reinforces the 30-year downward trend in Artic sea ice extent.

Information sources

This press release was issued in collaboration with the Hadley Centre of the UK Meteorological Office, the Climatic Research Unit, University of East Anglia, UK, and the National Climatic Data Centre, National Environmental Satellite and Data Information Service and National Weather Service of NOAA and the National Snow and Ice Data Centre in the United States of America. Other contributors are the NMHSs of Algeria, Argentina, Australia, Brazil, Canada, China, Colombia, Finland, France, Germany, India, Japan, Morocco, Spain, Sweden, Turkey and Uruguay. The African Centre of Meteorological Applications for Development (ACMAD, Niamey), the Australian Commonwealth Scientific and Industrial Research Organization (CSIRO), the Centro Internacional para la Investigación del Fenómeno El Niño (CIIFEN, Guayaquil, Ecuador), the IGAD Climate Prediction and Applications Centre (ICPAC, Nairobi, Kenya), the SADC Drought Monitoring Centre (SADC DMC, Gabarone, Botswana) and the World Climate Research Programme (WCRP) also contributed.

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For more information please contact:
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