Acoustic ecologist Gordon Hempton says natural sounds are disappearing.
The Alaska Republican faces an uphill battle to win a seventh full term.
Column: Overfishing, a potential mollusk invasion, and the rise of slime threaten ocean ecology.
The highest US total is from 1999, which had 676 tornadoes from January to mid-May.
Readers write and tell us what they are reading.
EU report adds urgency to old warnings, NATO to take up discussion next.
An endurance swimmer uses momentum from a world record to draw attention to disappearing polar caps.