If you've been hearing that extreme cold spells disprove global warming, don't believe it.
Global temperatures continued rising in 2013 despite the cold snap that hit parts of the US this winter, NASA research shows. Last year tied with 2009 and 2006, making it the seventh warmest year since record-keeping began back in 1880.
The report was released on Tuesday by NASA's Goddard Institute for Space Studies (GISS) in New York. GISS climatologist Gavin Schmidt said such long-term trends are "unusual". The findings
"add to the evidence for ongoing climate change. While one year or one season can be affected by random weather events, this analysis shows the necessity for continued, long-term monitoring."
The average 2013 temperature was 14.6C (58.3 F), and the average global temperature has risen about 0.8C (1.4 F) since 1880, the report shows.
Cold periods do not wipe out the warming trend
Addressing the links between the US cold snap and climate change, US president Obama's Science and Technology Advisor, Dr. John Holdren said:
"If you've been hearing that extreme cold spells disprove global warming, don't believe it. No single weather episode can prove or disprove global climate change."
"Climate is the pattern of weather geographically and over seasons. A growing body of evidence suggests that the kind of extreme cold experienced by the United States is a pattern we can expect to see with increasing frequency as global warming continues."
"Higher than ever" carbon dioxide levels
The report says although weather patterns will always cause fluctuations in average temperatures year on year, the continued increase in greenhouse gas levels in the atmosphere are "driving a long-term rise in global temperatures".
Driven by increasing man-made emissions from fossil fuels, the level of carbon dioxide is at present higher than at any time in the last 800,000 years.
Heat records round the world
While the world experienced relatively warm temperatures in 2013, other countries such as Australia saw the "hottest year on record".
Intense heat and strong winds fuelled an outbreak of hundreds of bushfires and prompted evacuations of aboriginal communities. Argentina experienced "one of the worst heat waves on record".
With the exception of 1998, the 10 warmest years in the 134-year record have all occurred since 2000, with 2010 and 2005 being the warmest years on record.
The analysis produced at GISS is compiled from weather data from more than 1,000 meteorological stations, satellite observations and Antarctic research stations.
Sophie Morlin-Yron is a freelance journalist.
NASA press-release: http://www.nasa.gov/press/2014/january/nasa-finds-2013-sustained-long-term-climate-warming-trend
