Following established practice, WMO’s global temperature analyses are based on two different datasets. One is the combined dataset maintained by the Hadley Centre of the UK Met Office, and the Climatic Research Unit, University of East Anglia, UK.
The other is maintained by the U.S. Department of Commerce’s National Oceanic and Atmospheric Administration, NOAA. Both indicate that 2006 is likely to be the sixth warmest year globally.
The global mean surface temperature in 2006 was 0.42 degrees Celsius above the 1961-1990 annual average of 14°C or 57.2 degrees Fahrenheit, the United Nations weather agency said.
Since the start of the 20th century, the global average surface temperature has risen 0.7°C, but this rise has not been continuous.
The steepest rise has occurred since 1976, at 0.18°C (.32°F) per decade.
In the northern hemisphere, the 10 year period 1997-2006 averaged 0.53°C above the 1961-1990 mean.
And in the southern hemisphere temperatures averaged 0.27°C above the 1961-1990 mean.
Historic Holes in the Ozone Layer
Ozone depletion in the Antarctic reached a record level on September 25, 2006, with the ozone hole measured as slightly larger than the previous record seen in September 2000.
“From September 21 to 30, 2006, the average area of the ozone hole was the largest ever observed, at 10.6 million square miles,” said Paul Newman, atmospheric scientist at NASA’s Goddard Space Flight Center.
The size and persistence of the 2006 ozone hole area with its record ozone mass deficit of 40.8 megatons can be explained by the continuing presence of near-peak levels of ozone-depleting substances in combination with a particularly cold stratospheric winter, the WMO said.
Low temperatures in the first part of January prompted a 20 percent loss in the ozone layer over the Arctic in 2006, but the ozone loss was not as large as that seen in 2005.
Dr. Neil Harris who helped compile the WMO's first Arctic Ozone Bulletin, issued in September 2006, said, “Thankfully the Arctic ozone loss was not too large in 2006. However with the cold winters becoming colder, it is important to use the international observing network to continue monitoring the Arctic stratosphere each year, so that there can be early warning of large losses.”
The year 2006 continues the pattern of sharply decreasing Arctic sea ice, the WMO said. The average sea ice extent for the entire month of September was 5.9 million square kilometers, the second lowest on record.
Including 2006, the September rate of sea ice decline is now nearly nine percent per decade, or 60,421 km² per year.
Heat Waves and Drought
The beginning of 2006 was unusually mild in large parts of North America and the western European Arctic islands, though there were harsh winter conditions in Asia, the Russian Federation and parts of eastern Europe.
Canada experienced its mildest winter and spring on record and the United States its warmest January-September on record.
Several parts of Europe experienced heat waves with record temperatures in July and August. The July European average land surface air temperature was the warmest on record at 2.7°C above the climatological normal.
September to November was exceptional in large parts of Europe at more than 3°C warmer than the climatological normal from the north side of the Alps to southern Norway.
In Brazil, heat waves were registered from January to March, including a temperature of 44.6°C (112.3°F) in Bom Jesus on January 31, one of the highest temperatures ever recorded in Brazil.
Drought in the south of Brazil caused significant damage to agriculture in the early part of the year with losses of about 11 per cent estimated for the soybean crop yield alone.
Severe drought conditions also affected China. Millions of hectares of crops were damaged in Sichuan province during summer and in eastern China in autumn. Significant economic losses as well as severe shortages in drinking water were other consequences.
Persistent extreme heat affected much of eastern Australia from late December 2005 until early March with many records being set. The second hottest day on record in Sydney was January 1, 2006 with a temperature of 44.2°C (111.6°F).
Spring 2006 from September through November 2006 was Australia’s warmest since seasonal records were first compiled in 1950.
The Australian Bureau of Meteorology today issued a report showing that the period from August to December 2006 was especially warm and dry across the southern half of the country.
Averaged over the Murray-Darling Basin it was the driest such period on record as well as being the second warmest, with much of the central-west and southwest slopes of New South Wales having mean maximum temperatures more than 3°C (5.4°F) above the long-term average.
For many areas in Australia, the lack of adequate rainfall in 2006 added to long-term dry conditions, with large regions having experienced little recovery from the droughts of 2002-2003 and 1997-1998, the WMO reports.
Dry conditions have now persisted for five to 10 years in some areas of Australia and in southwest Western Australia for around 30 years.
In view of these data, the Australian Conservation Foundation, ACF, is calling for much greater action on climate change from the Australian government in 2007.
Both of these new reports provide more compelling evidence that climate change is real and happening now, with Australia already suffering some of the worst impacts, said ACF Climate Change Campaigner Phil Freeman.
“Unless we cut our greenhouse emissions, droughts will become more severe and frequent in parts of Australia,” said Freeman. “The current drought is projected to wipe off billions from the value of farm production alone.”
The ACF says Australia should ratify the Kyoto Protocol, implement laws and targets to reduce our greenhouse pollution by 2020, and ensure that at least 25 percent of Australia’s energy is generated by renewable sources by 2020.
The 2006 average annual temperature for the lower 48 United States is estimated as the third warmest on record, according to scientists at NOAA’s National Climatic Data Center. The year is noted for widespread drought and record wildfires, as well as heavy precipitation and flooding in some parts of the country.
NOAA predicts the 2006-2007 winter will also be warmer than average. 'The prediction for a warmer than normal winter season does not mean we won't have winter weather,' said Mike Halpert, lead seasonal forecaster at the NOAA Climate Prediction Center. 'What it does mean is that on average this will be a milder than average winter across much of the North, with fewer Arctic air outbreaks.'
Long-term drought continued in parts of the Greater Horn of Africa including parts of Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Somalia, and the United Republic of Tanzania. At least 11 million people were affected by food shortages; Somalia was hit by the worst drought in a decade.
Flooding Rains Across Africa, South America
But the Horn of Africa was also hit with severe flooding in 2006, reported to be the region's worst in 50 years. The heavy rains followed a long period of drought and the dry ground was unable to soak up large amounts of rainfall.
The hardest hit areas were in Ethiopia, Kenya and Somalia.
Somalia is undergoing its worst flooding in recent history - some places have received more than six times their average monthly rainfall and hundreds of thousands of people have been affected.
An estimated 723,000 people were affected by devastating floods in Kenya in November 2006. The Tana River, which flows into the Indian Ocean, broke its banks because of heavy rains at its source in the Mount Kenya region.
Heavy rain also caused disastrous floods in Ethiopia in August, claiming more than 600 lives.
Rare heavy rainfall in the Sahara Desert region of Tindouf produced severe flooding in February damaging 70 percent of food stocks and displacing 60,000 people.
In Bilma, Niger, the highest rainfall since 1923 affected nearly 50,000 people throughout August. In the same month, the most extensive rainfall in 50 years brought significant agricultural losses to the region of Zinder, Niger.
Heavy rainfall in Bolivia and Equador in the first months of the year caused severe floods and landslides with tens of thousands of people affected. Torrential rainfall in Suriname during early May produced the country’s worst disaster in recent times.
After 500 mm of torrential rainfall during a five-day period in February, a large-scale landslide occurred in Leyte Island, the Philippines with more than 1,000 casualties.
Only months after the destructive summer flooding in eastern Europe in 2005, heavy rainfall and snowmelt produced extensive flooding along the River Danube in April and the river reached its highest level in more than a century.
Areas of Bulgaria, Hungary, Romania and Serbia were the hardest hit with hundreds of thousands of hectares inundated and tens of thousands of people affected.
Vancouver, Canada experienced its wettest month ever in November with 351 mm, nearly twice the average monthly accumulation.
Persistent and heavy rainfall during May brought historic flooding to the U.S. region of New England described as the worst in 70 years in some areas.
Across the U.S. mid-Atlantic and northeast, exceptionally heavy rainfall occurred in June. Numerous daily and monthly records were set and the rainfall caused widespread flooding which forced the evacuation of some 200,000 people. '
Deadly Cyclones, Typhoons
Landed tropical cyclones caused more than 1,000 fatalities and economic losses of US$10 billion in China, which made 2006 the severest year in a decade.
Typhoon Durian affected some 1.5 million people in the Philippines in November and December 2006, claiming more than 500 lives with hundreds still missing.
During the mild 2006 Atlantic hurricane season, nine named tropical storms developed, one fewer than the average. Only two of those were major hurricanes, registering Category Three or higher on the Saffir-Simpson scale.
In the eastern North Pacific 19 named storms developed, which is well above the average of 16; eleven reached hurricane strength of which six attained major status.
Twelve tropical cyclones developed in the Australian Basin, two more than the long-term average. Tropical cyclone Larry was the most intense at landfall in Queensland since 1918, destroying 80 to 90 percent of the Australian banana crop.
Moderate El Niño
In August, conditions in the central and western equatorial Pacific started resembling typical early stages of an El Niño event. By the end of the year, the typical El Niño warmer than average sea-surface temperatures were established across the tropical Pacific basin.
The El Niño event is expected by global consensus to continue at least into the first quarter of 2007.