July hottest month on record in U.S.
NEW YORK. August 10. KAZINFORM July was the hottest month on record in the United States, perhaps due to a combination of global warming and a widespread drought, experts say.
The lower 48 U.S. states experienced an average July temperature of 77.6 degrees Fahrenheit (25.3 degrees Celsius).
That's about 3.3 degrees (1.8 degrees Celsius) above the 20th-century average and the highest July average since record-keeping began in 1895, according to a report released August 8 by the U.S. National Oceanic and Atmospheric Administration (NOAA).
For 2012, July wasn't an anomaly, either. Taken together, the first seven months of the year have been, on average, the warmest January-to-July period on record in the contiguous U.S. states.
Drought conditions in more than 60 percent of the country helped keep temperatures high, explained Kevin Trenberth, a senior scientist at the Boulder, Colorado-based National Center for Atmospheric Research, Kazinform cites National Geographic.
"If it is wet, it tends to be cool, while if it is dry, it tends to be hot," Trenberth said. With no water on the ground, "all the heat goes into raising temperature and not evaporating moisture."
That creates a "powerful feedback loop," since "drought begets drought. And drought causes heat waves," Trenberth said by email.
On its own, the July record "is not such a major feat," Trenberth said. "But the fact that the first seven months of the year is the hottest on record is much more impressive, from a climate standpoint."
The consistent heat "highlights the fact that there is more than just natural variability playing a role: Global warming from human activities has reared its head in a way that can only be a major warning for the future."
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