Global temperatures last month tied with 1998 and 2005 as the third warmest for a month of May since record-keeping began in 1880, US scientists said Thursday.
Many areas of the world experienced higher-than-average warmth, including most of northern Siberia, western Russia, north and east Europe and central Australia, the National Oceanographic and Atmospheric Administration said.
With a combined average temperature over land and ocean surfaces of 59.79 degrees Fahrenheit (15.46 degrees Celsius), May 2013 also marked the 37th consecutive May and 339th consecutive month with a global temperature above the 20th century average of 58.6 F (14.8 C).
NOAA said the northern hemisphere snow cover for May was the third smallest on record at 6.21 million square miles (16.1 million square kilometers).
"Below-average snow cover was present for both Eurasia and North America. Eurasia had its smallest May snow cover extent on record, while North America had its 20th smallest," it said.
The average May Arctic sea ice extent was 5.06 million square miles, 2.17 percent below the 1981-2010 average, resulting in the 10th smallest monthly May extent on record.
The Antarctic sea ice extent, however, was 4.43 million square miles—the fifth largest May Antarctic sea ice extent on record at 6.33 percent above the 1981-2010 average.
The world's nations are negotiating an agreement that would, by 2020, bind all countries to measurable targets for curbing Earth-warming greenhouse-gas emissions.
The aim is to avoid the most calamitous warming-induced climate effects—worsening droughts, floods, storms and sea-level rise—by meeting a UN goal to limit global warming to two degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels.
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