Coral bleaching alerts are out!! According to research findings by CORDIO East Africa (www.cordioea.net), a MarCOSIO partner under the Global Monitoring for Environment and Security http://gmes.africa-union.org/ and Africa Marine and Coastal Operations for Southern Africa https://marcosio.org/ project, the overall coral bleaching risk in Western Indian Ocean (WIO) region in 2023 is quite low.

“This latest forecast may however change in the coming weeks and this will be confirmed in updated alerts,” says James Mbugua who is the coral bleaching alert thematic lead in GMES project “Year 2022 was a relatively cool and quiet year.

No major bleaching was reported in the WIO and cyclone activity was minimal,” adds James. However, the long protracted La Niña conditions in the Pacific that provided a haven for the WIO reefs is transitioning quickly to a neutral El Niño-Southern Oscillation (ENSO).

Coral bleaching is brought about by warming oceans, among other factors, which degrade the reefs. Bleaching is triggered by increase in sea surface temperatures, due to climate change, and is exacerbated by marine pollution and other local threats.

“Coral reefs are critical marine ecosystems that provide protection against erosion, storms and flooding, and shelter coastlines from the damaging effects of wave action and tropical storms. They also provide critical habitats and shelter for many marine organisms including fish, hence the need to protect and conserve them,” explains James.

According to the findings documented in The Sixth GCRMN Status of Coral Reefs of the World: 2020, coral reefs occur in more than 100 countries and territories. And while they cover only 0.2 per cent of the seafloor, they support a quarter of marine species and underpin the safety, coastal protection, wellbeing, food and economic security of hundreds of millions of people.

The findings further reveal that the value of goods and services provided by coral reefs is estimated at US$2.7 trillion per year globally, including US$36 billion in coral reef tourism. It is against this background that GMES & Africa project in partnership with CORDIO East Africa is generating critical data aimed at combating coral reef bleaching.

See January and February 2023 forecasts below:

Coral reefs are endangered

Coral reefs, which are built by live marine organisms, are among the most vulnerable ecosystems to numerous anthropogenic pressures. They face global threats from climate change and ocean acidification. Local impacts from land-based pollution such as input of nutrients and sediments from agriculture have not spared them either.

“The declining ocean health is therefore not conducive for coral reefs,” says James. These ecosystems have not only suffered global impacts but coastal development has also undermined them. The use of destructive fishing techniques and gears, sediments swept along by rivers containing nutrient overloads and pollutants such as pesticides have also contributed significantly to coral reefs decline.

The greatest threat to date is warming waters brought about by human activities. Over the last three decades, bleaching events have increased in frequency and intensity preventing the corals from recovering between disturbances and resulting in a gradual decline to their status. According to the scenarios captured in the Intergovernmental Panel on Climate Change (IPCC’s) special report on the ocean and cryosphere, a 1.5 degrees’ Celsius increase in water temperature in the course of this century could lead to a loss of 70 to 90 per cent of reef areas. This loss would be almost total with a 2 degrees’ increase.

Already, coral reefs in the Western Indian Ocean have been assessed as Vulnerable to collapse in a regional study published in 2021 using the International Union for Conservation of Nature (IUCN) Red List of Ecosystems (see link below). Several coral reef ecoregions within the WIO are assessed as Critically Endangered due to the risk of warming in coming decades. Equally deleterious ecological changes affect ocean and coral health such as acidification, which results from the absorption of human-generated carbon dioxide emissions by the ocean, and the dramatic decline in oxygen levels linked to global warming and accelerated coastal pollution.

Faced with these observations and pessimistic outlook, the Status of Coral Reefs of the World:2020 report produced by the Global Coral Reef Monitoring Network (GCRMN) under the auspices of International Coral Reef Initiative (ICRI), gives us all the more reason to take action.

There is however hope of coral reef recovery if decisive measures are taken to minimize global warming to 1.5 degrees Celsius, to restore degraded coral reef ecosystems, and minimize marine pollution. 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 under the 2030 Agenda for Sustainable Development.

GMES & Africa project is funded by the African Union Commission and the European Union (EU).

For more information on coral bleaching, please click on the links below:

Coral Bleaching

Nature Sustainability Publication