A new study examines the development of the Australian coral reef since the mid-1990s. The damage is massive, and especially the large corals are hard hit.
Large species that form “branches” and other formations have almost disappeared from the northernmost parts of the reef.
– These make the hooks and hooks that fish and other creatures depend on. When we lose the large three-dimensional corals, the whole ecosystem changes, says Professor Terry Hughes to the news agency AFP.
He has participated in the work on the new study, which was published on Wednesday in the British scientific journal Proceedings of the Royal Society.
Hit by heat wave
Overall, the Great Barrier Reef has lost about half of its coral since 1995, according to researchers. The main reason is global warming and increasingly warmer seawater.
Warmer water leads to more frequent episodes of so-called coral bleaching, which damages the corals. The by far most extensive bleaching took place earlier this year, after a period of extreme temperatures. Corals were hit along the entire length of the reef at 2,300 kilometers.
The consequences of this incident have not been included in the new study, which looks at the development up to 2017.
Bleaching typically occurs during periods when the water is extra hot. The first mass bleaching of the Great Barrier Reef took place in 1998. Then similar incidents occurred in 2002, 2016, 2017 – and now in 2020.
– We are shocked
“We are all shocked at how quickly this has happened,” Terry Hughes told CNN when the reef was hit again earlier this year.
He pointed out that the Great Barrier Reef is now being hit with a frequency that scientists had not expected until the middle of this century.
The warming of the sea is also causing great damage to coral reefs in many other parts of the world. The situation is likely to worsen further, in line with global warming.
The UN Panel on Climate Change has estimated that almost all tropical coral reefs will be lost if the temperature of the earth rises 2 degrees compared to pre-industrial levels.
The consequences will then also be dramatic for the many other species that live on or near coral reefs.
Great natural diversity
The world’s tropical coral reefs in shallow water together cover an area the size of half of France.
Compared to all the world’s oceans, this is a limited area. Nevertheless, it is estimated that 25 percent of all marine species live on or near coral reefs.
In addition to biodiversity, coral reefs are of great economic importance. Hundreds of millions of people have their share of food needs covered by fish that live in areas with coral reefs.
In many tropical areas – including Australia – the reefs also form the basis for extensive tourism.
Although climate change is the biggest threat to coral reefs, it is also affected by harmful fishing practices, pollution and other impacts on the local environment.
In Australia, the Great Barrier Reef has been damaged by both severe storms and eruptions of coral-eating starfish.