Mountain lakes famous for their clarity are slowly changing colour, as long-term monitoring shows many shifting from deep blue toward green.

Satellite records and new ocean measurements are converging on a difficult picture for Arctic sea ice: even in years when winter freezing looks.

Most large fishing vessels broadcast their positions automatically, but a significant share of the world’s fleet goes dark, switching off tracking.

Walking groups and mental health charities are promoting curiosity walks, a small twist on the daily stroll in which the walker sets out to notice.