Beijing, October 6 (Xinhua) -- A report released by the Global Coral Reef Monitoring Network (GCRMN) on October 5 shows that due to climate change and other factors, corals and reefs around the globe had decreased by 14 percent between 2009 and 2018. This is equivalent to the extinction of roughly 11,700 square kilometers of coral reefs, according to Reuters.

Aerial photo taken on June 2, 2021 shows the the Great Barrier Reef in Queensland, Australia. In recent years, large-scale coral bleaching has occurred to the Great Barrier Reef due to climate change and other factors. (Photo by Hu Jingchen/Xinhua) 

This report shows that the loss of corals varied greatly in different parts of the world between 2009 and 2018. East Asia witnessed a 5 percent decline during the period, the smallest drop among all the regions, while a reduction as high as 95 percent was observed in the tropics of the eastern Pacific.

According to the report, the survival of corals is already at stake with rising sea surface temperature. “Climate change is the greatest threat to global coral reefs......There is a worrying trend that corals are evidently dwindling. It can be predicted that this trend will go on as climate continues to warm,” said Paul Hardistrie, one of the authors of the report and Director of the Australian Institute of Marine Science (AIMS). 

Aerial photo taken on December 6, 2017 shows Vabbinfaru Island, the Maldives and nearby coral reefs. (Photo by Song Weiwei/Xinhua) 

The report notes that coral reefs serve as an important  marine ecosystem. Although they just cover 0.2 percent of the world’s seabed, at least 25 percent of marine species rely on coral reefs for survival and hundreds of millions of people’s livelihoods are related. Coral reefs annually provide an estimated value of US$ 2.7 trillion in goods and services, including US$ 36 billion in tourism industry. However, coral reefs are one of the most vulnerable ecosystems on earth to human disturbance. Among all the factors, ocean warming caused by global warming has the most serious impact, resulting in massive coral bleaching. The report points out that large-scale coral bleaching constitutes the most destructive factor to global coral reefs. “The coral bleaching event in 1998 alone caused an 8 percent decrease in coral populations worldwide.”

The photo taken on August 17 provided by the Commonwealth Scientific and Industrial Research Organization (CSIRO) of Australia shows that a researcher is exploring the Ningaloo Reef area. (Photo by Xinhua)

According to the report, marine pollution, overfishing, and unsustainable coastal development also threaten the survival of coral reefs.

However, the report highlights that in view of an increase of coral populations in some regions in 2019, the number of corals is expected to return to the previous level, if the threats are alleviated. 

According to Agence France Presse (AFP), the current global average temperature has risen by 1.1 degrees Celsius compared to the period before industrialization. The Intergovernmental Panel on Climate Change (IPCC) previously predicted that 70 percent to 90 percent of corals will die out if the figure hits 1.5 degrees Celsius.