Australia’s Great Barrier Reef is in major trouble, and it’s because of climate change.
A new study published in the scientific journal Nature shows that an increase in ocean water temperature last year caused the coral reef to undergo widespread “bleaching,” which happens when the coral expels the algae it uses for food.
Coral only does this when water temperature crosses a temperature threshold, as the spike in warm water causes algae to produce toxins. In order to survive, the coral expels the toxin-emitting algae from its interior.
However, while coral can sometimes recover from bleaching by growing new algae, it often doesn’t — starving to death or falling sick instead.
Scientists doubt we’ve seen the last of these bleaching events.
“The chances of the northern Great Barrier Reef returning to its pre-bleaching assemblage structure are slim given the scale of damage that occurred in 2016,” the report’s authors wrote, “and the likelihood of a fourth bleaching event occurring within the next decade or two as global temperatures continue to rise.”
Indeed, as climate change turns water temperatures up a notch, these bleaching events will occur at greater and greater frequencies. As this happens, weedier species will take over and displace older coral species, which take decades to establish themselves.
Still, the study’s authors concede that there may be hope yet if we intervene properly.
“Immediate global action to curb future warming is essential to secure a future for coral reefs,” the report’s authors wrote. “Water quality and fishing pressure had minimal effect on the unprecedented bleaching in 2016, suggesting that local protection of reefs affords little or no resistance to extreme heat. Similarly, past exposure to bleaching in 1998 and 2002 did not lessen the severity of bleaching in 2016.”
While other forms of pollution are damaging the reef, the increase in temperature is the main killer, according to The Washington Post. Coral in cleaner water is dying at the same rate as those in polluted environments.