Some of the chemicals that replaced ozone-harming CFCs are long-lived greenhouse gases. At NOAA's lab in Boulder, Colorado, chemist Steve Montzka leads the effort to monitor the concentration of CFC-substitutes and their potential impact on global warming.
At the end of April 2015, almost 60 percent of Oklahoma was experiencing moderate to exceptional drought, and 30 percent of Texas was experiencing drought conditions. But according to the May drought outlook, conditions are likely to improve in the southern Plains this month.
Strong evidence suggests that mountain areas are warming more quickly than lower elevations—with serious consequences for water supplies. But historical weather observations from mountain ranges are limited, leaving scientists with plenty of questions.
In northern Alaska, ponds are shrinking and disappearing as the frozen ground beneath them thaws. The loss may have serious consequences for migratory birds and the subsistence hunters that depend on them.
Thanks to back-to-back storms over the last month, most of the Midwest and North-Atlantic regions are covered by snow. But when was the last time there was snow on the ground in all fifty states—even our most tropical destinations, Florida and Hawaii?
(animation) The Lower 48 United States was 0.5°F above average in 2014, making it the 34th warmest year in the historical record (1895-2014). It was the 18th year in a row with above-average temperature.