The coral found in the oceans takes 10,000 years to form. A coral reef will grow about 2.5cm per year, and all the time that it has been growing, it has enjoyed the same temperature and the same amount of carbon dioxide dissolved in the water. Since the industrial revolution, humans keep burning fossil fuels to make energy and burning petrol and diesel in cars which is creating lots more carbon dioxide. Most of it is going into the atmosphere, although some of it is dissolving in the oceans.
The whole earth, including the world’s oceans, are warming up because of climate change. The amount of carbon dioxide dissolved in the water is increasing. The change in temperature and amount of carbon dioxide in the water causes the coral to bleach (turn white) and eventually die.
Coral bleaching is known to be responsible for killing approximately 18% of the world’s coral reefs.
This is a problem as coral reefs are home to approximately a quarter of all living things in the ocean and if the corals die back, so will all of these animals. Many species will go extinct.
More coral will bleach and die as climate change gets worse.
In Paris in 2015, 196 countries agreed to keep the global temperature from rising by more than 1.5 degrees Celsius.
If this target is reached, we can expect 16 times more heat waves in our seas and oceans. At the moment, the earth is on track to get even hotter than that; at 2 degrees Celsius of warming, the oceans will see 23 times more heat waves, and if we reach 3.5 degrees of warming, there will be 41 times more heat waves.
All of these will threaten our coral reefs and the plants and animals that depend on them. As coral reefs are home to lots of fish, our fishermen will struggle more and more to make a living from the fish in the ocean.