The Great Barrier Reef, one of the seven natural wonders of the world, is the largest single structure on earth built by living organisms. A 2012 report showed that thirty percent of  it had already been killed off by ocean warming. Another 20 percent was lost in 2018. Half of the chain has disappeared into bleached, skeletal form, and this entire 2,600 kilometre chain of reefs off the northeast of Australia will all be dead within a decade. Eventually,…