We must act immediately to save the Great Barrier Reef | Jules Howard

This spiralling, three-dimensional coral maze is bleached for the second year in a row, but it can recover - if we act immediately

And so it begins: the end of days. The Great Barrier Reef is bleaching for the second year in a row and now, according to the results of helicopter surveys released on Monday, it is the middle part (all 300 miles-plus of it) that is suffering the awful reef stress that comes courtesy of a warming ocean.

Related: Australia's politicians have betrayed the Great Barrier Reef and only the people can save it | David Ritter