Photo by The Ocean Agency / Xl Catlin Seaview Survey
The world is figuring out how to move forward in the face of the COVID-19 pandemic by finding newer ways to support economic development, animal and human well being, and ecosystem integrity. As the priority in many parts of the world is to stay home, safe and healthy, work continues to address the ongoing crisis of nature loss which also threatens long-term health and prosperity. In fact, nature, now more than ever, is sending warning signals calling for our attention.
Coral reef scientists predict that bleaching events will be more frequent, more widespread and more severe. For instance, the 2017 Coral Bleaching Futures report by the United Nations Environment Programme (UNEP) predicted, “Increasingly coral bleaching would be among the greatest threats to coral reefs due to climate change.” Annual Severe Bleaching (ASB) is projected to occur within this century for 99 per cent of the world’s coral reefs. The average projected year of ASB is 2043, the report adds.
Great barrier reef, feb 2017. Photo by The Ocean Agency / Coral Reef image bank
Leticia Carvalho, Head of UNEP’s Marine and Fresh Water Branch says: “Scientists have been telling us for a while that coral bleaching events would become more frequent with anthropogenic climate change and warming oceans. Unfortunately, their worst predictions have come to pass. Mass coral bleaching events are like nature’s fire alarm, a stark reminder that climate change is happening and is already impacting our societies and global ecosystem”.
Bleaching occurs when coral—tiny animals that secrete calcium carbonate for protection—become stressed by factors such as warm water or pollution. As a result of the stress, they expel the microscopic symbiotic algae called zooxanthellae, which reside within their tissues. The corals then turn ghostly white; they become ‘bleached’ (watch these coral bleaching explainer videos). The zooxanthellae are the primary food source for corals. If the algae do not return to the corals as soon as possible (or if temperatures get warmer), the corals can die as it happened in the Great Barrier Reef in 2016 and 2017.
Corals have been observed to glow in luminescent colours—blue, yellow and purple— to protect themselves, like a sunscreen, during extreme ocean heat waves before they die. The phenomenon has sparked the Glowing Gone Campaign in which UNEP has partnered with The Ocean Agency, among other leading ocean conservation organizations.
“It is important to remember bleached corals are not dead corals — on mildly or moderately bleached reefs there is a good chance most bleached corals will recover and survive this event. Equally, on severely bleached reefs, there will be higher mortality of corals,” adds the statement from the lead management agency for the Reef. However, some pockets of the Reef remain unaffected.
“Understanding the different responses of coral reefs to bleaching events is critical for managing coral reefs in a changing climate. Coral reefs are naturally resilient ecosystems, and have been observed to recover well after mortality events if they are given the chance to and other stressors are reduced. This means better water quality, reduced pollution, and sustainable fishing,” says Ms Carvalho.
The bleaching event comes at a time when this year’s World Environment Day, celebrated on June 5, is focused on biodiversity. The day calls for increased awareness and understanding of what biodiversity is and how it provides the vital services that sustain all life on earth. Coral have the highest biodiversity of any ecosystem on the planet—even more than a tropical rainforest.
Further, coral protection speaks to the UN Decade on Ecosystem Restoration (2021-2030) geared towards the restoration of degraded and destroyed ecosystems to fight the climate crisis and enhance food security, water supply and biodiversity.