 This year will be among the seven warmest on record, with extreme events including a precipitous thaw of Arctic sea ice, UN data showed on Thursday on the sidelines of a UN climate conference. The study also said that 1998-2007 was the hottest decade since reliable records began around 1850, in further evidence of what the UN Climate Panel calls "unequivocal" warming in recent decades. "What we see is confirmation of this warming trend," Michel Jarraud, head of the World Meteorological Organization (WMO), said during UN climate talks where 190 nations are deadlocked over how to step up action to slow climate change. "This year was in the top seven," he said. The WMO says 1998 was the warmest year followed by 2005, 2001, 2003, 2004 and 2006. Jarraud said it was not yet possible to rank 2007 exactly. The data are based on two sources -- the U.S. National Oceanic and Atmospheric Administration says 2007 is fifth warmest while data from England's University of East Anglia places it seventh. Among extremes, Jarraud noted that the Arctic ice shrank at the end of the northern summer to the smallest since satellite records began in the 1970s, opening the fabled Northwest Passage for a first time and eclipsing a 2005 low by 23 percent. Signs of extreme weather this year include a cyclone in Bangladesh that killed 3,000 people in November, droughts in Australia and China, and floods in Bolivia. England had its wettest summer since records began in 1766. DISASTERS "Natural disasters are a major obstacle to development as they keep happening with increasing frequency," Jarraud said. He said people could not prevent cyclones, for instance, but could mute damage with better forecasting and preparation. The Bali talks, due to end on Friday, are seeking to agree a "roadmap" to launch two years of talks on a new treaty to bind all nations, including the United States and developing nations, more tightly into combating warming. The U.N. climate panel blames human activities, led by burning fossil fuels, for rising temperatures. Jarraud also said that surface temperatures in the northern hemisphere were likely to be the second warmest on record in 2007 while temperatures in the southern hemisphere ranked ninth on record. World temperatures are about 0.74 Celsius (1.2 F) higher than a century ago. "The difference between an Ice Age and an interglacial period like now is 6 Celsius (11 F)," Jarraud said. "We are adding to an already warm period."