January through June was the warmest first half of any year in the continental United States since records began in 1895, U.S. government scientists reported Friday.
The average January-June temperature was 51.8 degrees Fahrenheit — 3.4 degrees above the 20th century average, according to preliminary data reported by scientists at the National Climatic Data Center in Asheville, N.C.
Five states — Kansas, Missouri, Nebraska, Oklahoma and Texas — saw record warmth for the period. No state in the continental United States was near or cooler than average, the report stated, although Alaska was 0.55 degrees cooler than the 1971-2000 average.
The 12 months from July 2005 to last June were ranked as the warmest such period at 55.3 degrees, or 2.5 degrees above the 20th century average.
The nation also saw the second warmest June on record.
As of June, 45 percent of the contiguous United States was in moderate-to-extreme drought, an increase of 6 percent from May.
Those dry conditions spawned more than 50,000 wildfires, burning 4 million acres in the continental United States, according to the National Interagency Fire Center. That is almost twice the 10-year average for this time of year.
Globally, January-June was the sixth warmest first half of a year on record, about 0.90 degrees above normal, the center reported.
Average temperatures were warmer in the majority of North America, China and western Europe. Cooler than average temperatures were posted in Alaska, far eastern Europe, and parts of Russia.
Most years of the last decade are among the warmest on record. NASA calculates 2005 global temperatures as the warmest, followed by 1998, 2002, 2003 and 2004.
Many scientists believe humans are at least partly to blame for this warming, arguing that emissions of carbon dioxide from burning fossil fuels adds to Earth's natural greenhouse effect.
Policymakers are divided over whether to use mandatory emission curbs or voluntary efforts to cut back. The Bush administration is for voluntary action that focuses on technological advances, while Europe favors mandatory cuts via the Kyoto climate change treaty.
The Associated Press contributed to this report.