Years before Congress began debating greenhouse-gas reduction, more than 500 U.S. cities had pledged to reduce their carbon footprints in line with the goals of the Kyoto Protocol. Now American cities are leading the way on adapting to climate change.

The giant comma-shaped storm systems that traverse the Midwest from fall through spring carry more than a few secrets. Radar, lidar, and profiler beams are now slicing through those storms, hunting for small-scale features that normally go unobserved.

If the last few years have seen a so-called quiet Sun, its silence has spoken volumes. Researchers have taken advantage of a raft of new sensors and a special observing campaign to learn much about what happens when the sun temporarily powers down.