Coral reefs are not just a matter of beauty of the oceans, they are also a vital marine ecosystem. These ecosystems harbor about 8000 species of fish. The reefs also protect coastal areas by reducing the power of the waves hitting the coast along with providing source of livelihoods for millions of people.
The sad part of this beautiful and important ecosystem is that they appear fragile to anthropogenic climate change. The warming of the oceans has impacted coral reefs significantly, and the continuation of this warming will further destroy the reefs.
In a latest assessment carried out by the GCRMN (Global Coral Reefs Monitoring Network), an UN-supported global network, a shocking revelation has emerged—about 14% of the world’s coral reefs have been lost in less than a decade, in the period 2009-2018. This equals a staggering 11,700 square kilometres, an area 2.5 times larger than the size of the Grand Canyon National Park.
The GCRMN assessment incorporated data from 40 years, comprising 73 countries and 12,000 sites. The study looked at ten of the world’s coral reef bearing regions and found that the stunning loss is attributable mainly to the phenomenon known as coral bleaching. Coral bleaching occurs when the corals are under stress from the warming of the ocean water and expel the colourful algae. This bleaching makes the corals appear white. The study said that a severe bleaching event of 1998 alone killed about 8% of the corals.
As found in the study, the hardest-hit areas are South Asia, the Western Indian Ocean, Australis, the Pacific, the Gulf and the Gulf of Oman.
Scientists have long anticipated the crisis that the world’s corals are facing. Paul Hardisty, chief executive of the Australian Institute of Marine Science, said in a statement, “There are clearly unsettling trends toward coral loss, and we can expect these to continue as warming persists.”
However, the report also pointed out that there are instances of the reefs appearing resilient to the onslaught of seawater warming, with many of them bearing the potential to recover under the right conditions. The remedy, even in this case, is immediate action to halt global heating.
“A clear message from the study is that climate change is the biggest threat to the world’s reefs, and we must all do our part by urgently curbing global greenhouse gas emissions and mitigating local pressures,” commented Paul Hardisty.
The IPCC’s (Intergovernmental Panel on Climate Change) 6th assessment report published in August clearly stated that the world’s oceans have warmed faster over a century compared to the end of the last deglacial transition, around 11,000 years back.
Even if corals fill less than 1% of the ocean floor, they are home to over 25% of marine biodiversity. The reefs, according to the GCRMN report, account for about 2.7 trillion US dollars annually in goods, services and tourism as well.
However, there are ongoing projects aimed towards the restoration of the coral reefs, for example, the Ocean-shot in the coasts of Antigua and Barbuda, a Caribbean nation. The project uses technology that can mimic the natural reefs and provide opportunities for the corals to grow.