As Julian points out, no one climate event (hurricane, heat wave, frogs falling from the sky) can be definitively pinned on global warming. But lest the round up of scientists in his post below give us all false succor, the trend seems clear.
According to our own government (via MSNBC):
January through June was the warmest first half of any year in the continental United States since records began in 1895. 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.And, it ain't just hot here in the USA.
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.Indeed, 20 of the globe's 21 hottest years on record occurred in the last quarter century.