Here’s an in-depth report from The Washington Post ( Steven Mufson, Chris Mooney, Juliet Eilperin and John Muyskens. Photography by Salwan Georges). Click through and read the whole article and to enjoy the photographs. Here’s an excerpt:
America’s hot spots
Nationwide, trends are clear. Starting in the late 1800s, U.S. temperatures began to rise and continued slowly up through the 1930s. The nation then cooled slightly for several decades. But starting around 1970, temperatures rose steeply.
At the county level, the data reveals isolated 2-degree Celsius clusters: high-altitude deserts in Oregon; stretches of the western Rocky Mountains that feed the Colorado River; a clutch of counties along the northeastern shore of Lake Michigan — home to the famed Sleeping Bear Dunes National Lakeshore near Traverse City.
Along the Canadian border, a string of counties from eastern Montana to Minnesota are quickly heating up.
The topography of warming varies. It is intense at some high elevations, such as in Utah and Colorado, and along some highly populated coasts: Temperatures have risen by 2C in Los Angeles and three neighboring counties. New York City is also warming rapidly, and so are the very different areas around it, such as the beach resorts in the Hamptons and leafy Westchester County.
The smaller the area, the more difficult it is to pinpoint the cause of warming. Urban heat effects, changing air pollution levels, ocean currents, events like the Dust Bowl, and natural climate wobbles such as El Niño could all be playing some role, experts say.
The one U.S. region that has not warmed since 1895: the South, where data in some cases even shows a modest cooling.
The only part of the United States that has not warmed significantly since the late 1800s is the South, especially Mississippi and Alabama, where data in some cases shows modest cooling. Scientists have attributed this “warming hole” to atmospheric cycles driven by the Pacific and Atlantic oceans, along with particles of soot from smokestacks and tailpipes, which have damaging health effects but can block some of the sun’s intensity. Those types of pollutants were curtailed by environmental policies, while carbon dioxide remained unregulated for decades.
Since the 1960s, however, the region’s temperatures have been increasing along with the rest of the country’s.
The Northeast is warming especially fast.