How do you determine whether some location, or the nation, is having a truly brutal winter? As it turns out, the story differs depending on whether it’s being told through events, statistics, or opinions.

A team of researchers, including NCAR scientist Carl Schmitt, are climbing high in the Peruvian Andes to assess the extent to which the white ice is being darkened by ash and other particulates that are emitted by nearby industrial operations. The dark particles can accelerate glacial melting, eventually threatening runoff that supplies water for millions of South American residents.

The "waste heat" generated by everyday activities in metropolitan areas alters atmospheric circulation patterns, warming or cooling temperatures across a large region.

Much of the United States has felt winter’s bite this week, with fresh but frigid cold to the east and a weeks-long spell of stagnant, polluted chill to the west.