Evidence that Australia's Great Barrier Reef is experiencing its worst coral bleaching on record has renewed calls for the UN to list it as "in-danger".

Although winter Arctic sea-ice extent has been the smallest on record this year, it is unclear yet whether its volume will also mark a new low.

Dozens of Japanese engineers and scientists are scrambling to save an X-ray satellite - and more than a quarter of a billion dollars of investment - tumbling out of control in space.

Laboratory tests show some varieties of olive trees appear to be resistant to an invasive pathogen that poses a serious risk to Europe's olive industry.