Last year, the globe sweltered through one of the hottest years on record. Global average temperature was 14.47°C (58.03°F), or about 0.57°C (1.03°F) above the 20th century average, according to data presented today by researchers at the National Oceanic and Atmospheric Administration. Record warmth in the continental United States (denoted by dark red in the image) and warmer-than-average temperatures elsewhere (varying shades of red) helped make the year the 10th-warmest since 1880 and the 36th consecutive year marked by a global average temperature falling above the average for the 20th century. All 12 years of the 21st century rank among the 14 warmest in the 133-year interval since record-keeping began, the researchers noted. The year 2012 was on track to be the eighth-warmest year on record before a spate of cold weather struck the Northern Hemisphere in December—a cold spell that resulted in a record amount of snow cover for the hemisphere for that month. One final record worth mentioning: 2012 was the warmest La Niña year yet seen—which is notable because La Niñas, which are typically marked by cooler-than-average sea-surface temperatures in the equatorial Pacific, normally result in lower-than-average global temperature. Data compiled by NASA researchers, who use satellite data to estimate temperatures in regions not covered by weather stations, suggest that 2012 was the ninth-warmest year on record.
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