The year 2006 is currently estimated to be the sixth warmest on record with prolonged drought in some regions, heavy rainfall and flooding in others and deadly typhoons in south-east Asia, according to the latest update by the United Nations World Meteorological Organization (WMO).The global mean surface temperature is currently estimated to be 0.42 degrees Celsius above the 1961-1990 annual average of 14C (57.2 degrees fahrenheit), according to records maintained by WMO members. Many UN officials, agencies and reports have warned of the human role in producing the greenhouse gases blamed for global warming and the UN-backed Kyoto Protocol seeks to significantly reduce such emissions, but just this week the WMO reported that no firm link can yet be drawn between human-induced climate change and variations in intensity and frequency of tropical cyclones. The year also continues the pattern of sharply decreasing Arctic sea ice, with the September rate declining by some 8.59 per cent every decade, or 60,421 square kilometres per year. The agency will not release final figures for 2006 until March, but preliminary findings show that, averaged separately, temperatures for the northern hemisphere (0.58C above a 30-year mean of 14.6C/58.28F) are likely to be the fourth warmest and for the southern hemisphere (0.26C above a 30-year mean of 13.4C/56.12F) the seventh warmest in the instrumental record from 1861. Since the start of the 20th century, the global average surface temperature has risen approximately 0.7C, but this has not been continuous. Since 1976, the global average has risen sharply, at 0.18C per decade. In both hemispheres, the period 1997-2006 averaged 0.53C and 0.27C above the 1961-1990 mean, respectively. 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, Russia and parts of eastern Europe. Canada experienced its mildest winter and spring on record and the United States its warmest January-September on record. Persistent extreme heat affected much of eastern Australia from late December 2005 until early March with many records being set, with the southern spring the warmest since seasonal records were first compiled in 1950. Heat waves were also registered in Brazil from January until March and in several parts of Europe with record temperatures in July and August. Long-term drought continued in parts of the Greater Horn of Africa including parts of Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Somalia, and Tanzania and at least 11 million people were affected by food shortages. Somalia was hit by the worst drought in a decade. Drought also affected China, southern Brazil, parts of the US while in Australia, lack of rain added to significant longer-term dry conditions. Heavy rains and floods seriously affected North, East and West Africa, including rare heavy rainfall and severe flooding in the Sahara Desert region of Tindouf, as well as Bolivia, Ecuador and Suriname in South America, the Philippines, eastern Europe and the New England region of the US. Floods are said to be the worst in 50 years in the Great Horn of Africa region. Fourteen typhoons developed in south-east Asia, killing thousands of people and causing billions of damage. WMO global temperature analyses are based on the combined dataset from the Hadley Centre of the British Met Office and the Climatic Research Unit, University of East Anglia, and statistics from the US Department of Commerce’s National Oceanic and Atmospheric Administration.