There are many dangers in a coal mine. Dangerous gases could displace oxygen and make men sick or die. A canary in a cage would be brought into a coal mine along side workers. The canary had a much higher metabolism and would die if conditions got bad. The death of a canary in a coal mine warned men of this invisible and silent danger.
Today coral bleaching events are like that canary. Ocean warming and acidification cause sensitive corals to die. Just two degrees of water temperature rise will kill a reef. Bleaching event frequency is increasing. Our oceans are warming. Ocean warming is a huge event. So we are not talking about a single coal mine. We are talking about the planet.
Opinions about planetary global climate are irrelevant. Talk, debate, and denial do nothing. The canary is dying, but there is no escape from the inevitable changes already taking place.
Another analogy comes to mind. Rearranging deck chairs on the Titanic did nothing to prevent the sinking of the ship. Denial or debate is like rearranging deck chairs.
The Exxon Valdez oil tanker ran into a reef and spilled crude oil into the sea. There was a point in time long before impact that directional inputs could have avoided collision. But after a point in time no inputs could prevent the disaster. It take a long time to change course of a large moving ship. The planet’s climate is slow to respond to inputs. It is slow to change. And it’s effect on humans is unavoidable.