Between 2009 and 2018, the continuous rise in sea temperature cost the world 14 per cent of its coral reefs – that’s more than the size of Australia’s reefs combined – an UN-backed report revealed on Tuesday.
In the Sixth Status of Corals of the World: 2020 Report, experts from the Global Coral Reef Monitoring Network, funded by the UN Environment Programme (UNEP), collected data from more than 300 scientists from 73 countries, over a span of 40 years, including two million individual observations.
It revealed that almost invariably, sharp declines in coral cover, correspond with rapid increases in sea surface temperatures, indicating their vulnerability to temperature spikes, and found that this phenomenon is likely to increase as the planet continues to warm.
Invaluable Ecosystems
Dynamic underwater coral cities support up to 800 different species of hard coral and are home to more than 25 per cent of all marine life, according to the report.
Soft corals bend and sway amongst the craggy mountains of hard corals providing additional homes for fish, snails and other marine creatures.
And reefs harbor the highest biodiversity of any of the world’s ecosystems, making them one of the most biologically complex and valuable on the planet.
Coral Bleaching
However, when waters get too warm, corals released their colorful micro-algae, turning a skeletal white color. Some glowed, by naturally producing a protective layer of neon pigments, before they bleach.
“Bleaching can be thought of as the ocean’s version of the ‘canary in the coral mine’ since it demonstrates corals’ sensitivity to dangerous and deadly conditions”, the Status of Coral Reefs explained.
Algae Takeover
A shift from coral to algae-dominated reefs, reduces the architectural complexity and structural integrity of these habitats, making them less biodiverse and providing fewer goods and services to humans.
According to the report, there has been a steady decrease in hard coral cover since 2010 with the worst impacts occurring in South Asia, Australia, the Pacific, East Asia, the Western Indian Ocean, The Gulf and Gulf of Oman.
Valuing Coral
Although coral reefs in more than 100 countries cover only 0.2 per cent of the seafloor, they underpin the safety, coastal protection, wellbeing, food and economic security of hundreds of millions of people, said the report.
Before and after: Coral bleaching in the Great Barrier Reef., by The Ocean Agency/WL Catlin Seavi
The value of goods and services they provide, is estimated at $2.7 trillion per year, including $36 billion in coral reef tourism.
However, coral reefs are under threat from climate change, ocean acidification, and land-based pollution; as well as sediments from agriculture, marine pollution and overfishing.
“Maintaining the integrity and resilience of coral reef ecosystems is essential for the wellbeing of tropical coastal communities worldwide, and a critical part of the solution for achieving the Sustainable Development Goals (SDGs) under the 2030 Agenda for Sustainable Development”, underscored the Status of Coral Reefs.
Reef Recovery
Despite these gloomy assessments, there is still hope for coral reefs. They are remarkably resilient and can recover in the absence of large-scale disturbances.
After a 1998 mass coral bleaching event, hard coral cover rebounded to pre-1998 levels within a decade.
“If we halt and reverse ocean warming through global cooperation, we give coral reefs a chance to come back from the brink. It will, however, take nothing less than ambitious, immediate and well-funded climate and ocean action to save the world’s coral reefs”, said the report.
This year marks the beginning of the UN Decade of Ocean Science for Sustainable Development and the UN Decade on Ecosystem Restoration, campaigns designed to help protect our seas through scientific advancement and to resuscitate the planet’s declining ecosystems.
Moreover, political leaders will attend the 15th meeting of the Conference of the Parties (CoP) to the Convention on Biological Diversity on Monday and again from 25 April to 8 May next year.
There, world Governments will negotiate a post-2020 global biodiversity framework to map out how humanity will live in harmony with nature in the coming decade.
More Than a Third of Shark Species Threatened with Extinction
More than a third of the world’s sharks and rays are threatened with extinction, according to the International Union for the Conservation of Nature (IUCN).
In a report released earlier this month, the group said the loss is primarily due to overfishing and compounded by ocean pollution and climate change.
“Today’s IUCN Red List update also includes a comprehensive reassessment of the world’s shark and ray species, which reveals 37% are now threatened with extinction, demonstrating that effective management measures are lacking throughout much of the world’s oceans,” the report said. “All of the threatened shark and ray species are overfished, with 31% further affected by loss and degradation of habitat and 10% affected by climate change.”
“We are delighted to see the reassessment of sharks and rays,” said Eimear Nic Lughadha, senior research leader in conservation assessment and analysis at the Royal Botanic Gardens, Kew. “Comprehensive reassessments of ecologically important groups are vital to maintain the value of the Red List as a Barometer of Life. We note striking similarities between the shark and ray statistics and recent estimates for plants: about 2 in 5 are threatened with extinction, and habitat loss and degradation present more immediate threats than climate change.”
The IUCN’s Red List of Threatened Species includes 138,374 species, of which 38,543 are threatened with extinction.
The update was preceded by new research published in the journal Current Biology that analyzed nearly 1,200 species of chondrichthyes, a group of fish including sharks and rays, of which 32% were considered to be “vulnerable,” “endangered” or “critically endangered.”
“That statistic increases to more than one-third (37.5%) if Data Deficient species are assumed to be threatened in the same proportion as assessed species,” the IUCN SSC Shark Specialist Group said in a post following the news.
“This second global assessment of chondrichthyan fishes finds twice as many species threatened as found in the first analysis in 2014 (181). Chondrichthyans now rank second among vertebrates (after amphibians) in terms of extinction threat,” it added.
Chondrichthyes have lived on Earth for hundreds of millions of years and three species have not been seen in nature for several decades, according to the Smithsonian Magazine.
That said, the species are considered to be exceptionally susceptible to overfishing because they tend to grow slowly and produce few offspring and pollution and habitat degradation are key risks.
Climate change currently impacts 10.2% of threatened chondrichthyes, the IUCN’s shark group said.
“The tropics host incredible shark and ray diversity, but too many of these inherently vulnerable species have been heavily fished for more than a century by a wide range of fisheries that remain poorly managed, despite countless commitments to improve,” Colin Simpfendorfer, adjunct professor at James Cook University, said in a statement. “As a result, we fear we will soon confirm that one or more of these species has been driven to extinction from overfishing, a deeply troubling first for marine fishes. We will work to make this study a turning point in efforts to prevent any more irreversible losses and secure long-term sustainability.”
