High levels of greenhouse gases and the reappearance of the cyclical warming trend El Nino make it likely 2007 will go down as the world's hottest year ever recorded, British climate scientists said Thursday.
Britain's Meteorological Office said there is a 60 per cent chance the average surface temperature of the Earth will match or exceed the current record from 1998.
In 1998, the average temperature was 0.52C over the long-term average of 14 C.
The researchers say the forecast is based on expected greenhouse gas emissions from human activity and the impact of El Nino.
"This new information represents another warning that climate change is happening around the world," the office said.
"Because of the warming due to greenhouse gases, even a moderate warming event is enough to push the global temperatures over the top," said Phil Jones, director of the climatic research unit at the University of East Anglia.
El Nino is the name for an abnormal system of warm currents in the Pacific Ocean that periodically shift east and appear off the west coast of South America, causing a disruption in weather patterns around the world. The El Nino phenomenon occurs irregularly, with the last one happening in 2002.
The current El Nino is considered moderate and will continue for the first few months of 2007. It has already been blamed for droughts in Australia and is seen as at least partly responsible for the unseasonable weather conditions throughout much of Canada this winter.
"El Nino is an independent variable," said Jones. "But the underlying trends in the warming of the Earth is almost certainly due to the release of carbon dioxide into the atmosphere."
Last yearwas the sixth-warmest year on record globally. The world's 10 warmest years have all occurred since 1994 in a temperature record dating back to 1850, according to the United Nations weather agency.
A UN report issued two months ago said greenhouse gases in the atmosphere reached record levels in 2005 and were expected to increase in 2006.
Concentrations of carbon dioxide and nitrous oxide both rose in 2005, the study's authors found.
Developing countries not included
"There is no sign that [the greenhouse gases] are starting to level off," said World Meteorological Organization climate specialist Geir Braathen. "It looks like it will just continue like this for the foreseeable future."
Under the Kyoto accord that went into effect in 2005, 141 nations have committed to reducing emissions by an average of five per cent below 1990 levels by 2012.
But the agreement does not include the world's biggest emitter — the United States — and also excludes developing countries like China and India.
Canada, one of the accord's signatories, has also backed out of its Kyoto commitments. In September 2006, then-federal Environment Minister Rona Ambrose said Canada had no chance of meeting its Kyoto targets.
The Conservative government replaced the Kyoto targets with a Clean Air Act with targets for reducing emissions beginning in 2010.