Coral reefs have their days counted

What is coral reef bleaching?

In 2014 this phenomenon astonished the world, more than 75% of corals around the world lost their color due to the stress caused by such high temperatures. Corals are known to have vibrant and beautiful colors, these are produced by zooxanthellae, microscopic algae that live within corals in a symbiotic relationship. When water temperatures change dramatically, corals become stressed and expel algae, causing them to turn white. When the temperature is not regulated the coral remains white without allowing the algae to return and consequently dies.

Climate change is the main cause of this, as it not only affects the surface but also warms the ocean water. According to the World Wildlife Fund (WWF), "a change in water temperature of as little as two degrees Fahrenheit can cause the coral to expel algae." Low tides, pollution, and excess sunlight are other reasons why corals can turn white.

Why is coral bleaching a concern?

This phenomenon, which happened en masse in 2014, lasted 36 months and is considered the most destructive on record. Despite the event coming to an end, corals around the world remain under constant threat from climate change, which obviously affects ocean temperatures.

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UNEP recently published a report on coral bleaching projections in which they draw attention to the high probability that this massive phenomenon could be normal in the coming decades.

This report shows that "coral bleaching is occurring faster than anticipated and the future health of reefs is closely linked to the reduction of greenhouse gas emissions that warm the oceans."

This is also worrying considering that coral reefs produce 80% of oxygen, which of course is indispensable. It is estimated that climate change can kill 35% of coral around the world.

What can be done?

The report analyzes the phenomenon based on two possible scenarios, the first being countries' economy driven mainly by fossil fuels, and the second being “an“ intermediate ”option whereby countries exceed their current commitments to reduce carbon emissions by 50 % ". It must be taken into account that even if this pact is fulfilled by the end of the century there would be a warming of more than 2 ° C.

In the first scenario, all the corals in the world would suffer this phenomenon at the end of the century. In the second, the phenomenon would be delayed for only 14 years.

According to a UNEP statement, for Leticia Carvalho, head of the organization's Freshwater and Oceans subdivision, “If we do not take action, coral reefs will soon disappear. Before it is too late, humanity must act with urgency, ambition and innovation, based on evidence, to change the future of this ecosystem that sends us warning signals about the impact of climate on the oceans ”.