2007 was another sizzling year for the planet — the warmest year ever recorded for the Earth's land areas, federal scientists at NOAA's National Climatic Data Center reported Tuesday, with an average temperature about 1.84 degrees above the long-term average. Global weather records began in 1880.
For the entire Earth's surface, including the oceans, scientists report that the global temperature was the 5th-warmest on record.
"2007 was very warm in large parts of Asia and the high latitudes of the Northern Hemisphere, including the Arctic," says climatologist Jay Lawrimore of the NCDC. The unusual Arctic warmth led to the lowest amount of sea ice ever recorded.
Highlights of 2007 included an intense heat wave that engulfed western and central Russia in May, the climate center reports. For the first time in 128 years, Moscow experienced sustained May temperatures of 86 degrees or higher. A scorching heat wave in southeastern Europe in June and July prompted record levels of electricity demand and more than 130 wildfires.
In the USA, an August heat wave set more than 2,000 new daily high temperature records. Eight states experienced their warmest August on record. Overall, 2007 was the 10th-warmest year in the USA since records began in 1895, with an annual average temperature of 54.2 degrees, the climate center reported last week.
Lawrimore says that seven of the Earth's eight warmest years on record have occurred since 2001, and 10 of the warmest years have occurred since 1997.
The global average surface temperature has risen more than 1 degree since the start of the 20th century. Most notable, within the past three decades, the rate of warming in global temperatures has been approximately three times greater than the century scale trend.
Most scientists say the release of man-made greenhouse gases into the atmosphere is to blame for the warming trend. "There's no denying that climate change is occurring, and warmer winters and warmer years are more common for that reason," Lawrimore said last year.
The only land area to see cooler-than-average conditions in 2007 waswestern and southern South America, says Lawrimore. Ocean temperatures around the world were the ninth-warmest on record, primarily due to the cooling influence of the La Nina climate pattern.
In a separate study, NASA scientists announced that 2007 tied with 1998 as the Earth's second-warmest on record. NASA researchers analyze global temperature data differently than does NOAA, which accounts for the different ranking.