Climate change

There was chaos in Melbourne, where rising temperatures caused power outages, forcing the cancellation of hundreds of trains. Commuters, described as "cooking in the heat", were stuck on trains and trams for hours.

At least 400,000 homes across Victoria remained without power and the state's government is convening to consider limiting electricity use to prevent further blackouts. But there is little respite in sight. Adelaide is preparing for its longest hot spell since 1908, with forecasters tipping temperatures above 107F (38C) for the next seven days.

Meanwhile NATO and various other interested parties are suddenly keen on the Arctic.