This winter was the warmest on record worldwide, the government said, the government said Thursday in the latest worrisome report focusing on changing climate.
The report comes just over a month after the Intergovernmental Panel on Climate Change said global warming is very likely caused by human actions and is so severe it will continue for centuries.
The National Oceanic and Atmospheric Administration said the combined land and ocean temperatures for December through February were 1.3 degrees Fahrenheit above average for the period since record keeping began in 1880.
The report said that during the past century, global temperatures have increased at about 0.11 degrees per decade. But that increase has been three times larger since 1976, NOAA's National Climatic Data Center reported.
Most scientists attribute the rising temperatures to so-called greenhouse gases which are produced by industrial activities, automobiles and other processes. These gases build up in the atmosphere and trap heat from the sun somewhat like a greenhouse.
Also contributing to this winter's record warmth was an El Nino, a periodic warming of the tropical Pacific Ocean. It was particularly strong in January — the warmest January ever — but the ocean surface has since begun to cool.
The report noted that in the Northern Hemisphere the combined land and water temperature was the warmest ever at 1.64 degrees above average. In the Southern Hemisphere, where it was summer, the temperature was 0.88 degree above average and the fourth warmest.
The late March date of the vernal equinox noted on most calendars notwithstanding, for weather and climate purposes northern winter is December, January and February.
For the United States, meanwhile, the winter temperature was near average. The season got off to a late start and spring-like temperatures covered most of the eastern half of the country in January, but cold conditions set in in February, which was the third-coldest on record.
For winter, statewide temperatures were warmer than average from Florida to Maine and from Michigan to Montana, while cooler-than-average temperatures occurred in the southern Plains and areas of the Southwest.
For Alaska, both February and winter were warmer than average but far from the record warmth of 2003 and 2001, respectively.