Angela Lin, 29, was a software engineer at Google who loved to spend time outdoors.

Forests play a major role pulling planet-warming carbon dioxide out of the atmosphere. As the world heats up, some forests are becoming emitters in their own right.

Forest fires are on the rise globally. An increase in severe fire weather is largely responsible.

Strings of radars stretching across Canada were built to give early warnings of Soviet bombers coming over the Arctic. The region now faces a new era of militarization.