Rising sea temperatures are just one consequence of climate change. This can have drastic effects on marine organisms, and corals are particularly sensitive.
Researchers have found that as the sea gets increasingly warm, coral turns white and dies in a process called 'bleaching'. And it's happening faster than ever - in 2016 Australia's Great Barrier Reef has seen the worst destruction ever recorded.
I'm worried. Corals are crucial to the marine ecosystem. If we don't get global warming under control soon we could lose them for ever.