Invade Mexico, annex Greenland, reclaim the Panama Canal. Donald Trump is ushering in a new era of American imperial ambition ...

Extensive evidence, including global temperature and sea ice data, shows Earth's climate is changing due to human activity.

Erin Davis/Axios Visuals A week-long, unusually cold Arctic outbreak is set to bring frigid mid-February conditions to most locations east of the Rockies beginning Sunday. Why it matters: This event ...