Is the earth really getting hotter?

Yes. Although local temperatures fluctuate naturally, over the past 50 years the average global temperature has increased at the fastest rate in recorded history. And experts think the trend is accelerating: the 10 hottest years on record have all occurred since 1990. Scientists say that unless we curb global warming emissions, average U.S. temperatures could be 3 to 9 degrees higher by the end of the century.