This year will be the coolest since 1997 but still the tenth hottest in a temperature record dating back 150 years, the World Meteorological Organization (WMO) said on Tuesday.
The global mean temperature for 2008 was 14.3 degrees Celsius, climate scientists at the UK's Met Office Hadley Centre and Climate Research Unit at the University of East Anglia, who compiled data for the WMO, said.
"Human influence, particularly emission of greenhouse gases, has greatly increased the chance of having such warm years," the Met Office's Peter Stott said in a statement.
"Comparing observations with the expected response to man-made and natural drivers of climate change, it is shown that global temperature is now over 0.7 degrees Celsius warmer than if humans were not altering the climate."
Global temperatures vary annually according to natural cycles. For example, they are driven by shifting ocean currents, and scientists say dips do not undermine the case that man-made greenhouse gas emissions are causing long-term global warming.
Chillier weather this year is partly because of a global weather pattern called La Nina that follows a periodic warming effect called El Nino.
The 10 warmest years measured since records began in 1850 have occurred since 1997, with global temperatures for 2000-2008 standing at almost 0.2 degrees Celsius above the average for the decade 1990-1999, the Met Office said.
"Globally this year would have been considered warm, even as recently as the 1970s or 1980s, but a scorcher for our Victorian ancestors," said Oxford University's Myles Allen.
"As a result of climate change, what would once have been an exceptionally unusual year has now become quite normal. Without human influence on climate change we would be more than 50 times less likely of seeing a year as warm as 2008," added Stott.
No comments:
Post a Comment