ISRS Consensus on Coral Bleaching and Ocean Acidification

By: Kayla White, UHM MOP Student

The International Society for Reef Studies (ISRS) is the leading coral reef association internationally, made up of coral reef scientists and managers from all over the world. In the International Year of the Reef in 2018, the ISRS called on nations to implement the Paris Agreement and take drastic environmental actions by 2030 in order to keep global warming to a maximum of 1.5 degrees (Celsius) over the pre-industrial period.

Since the beginning of the 20th century, the surface of the world’s oceans has warmed at a faster rate than anything we have recorded in history, including million year-old fossil records. This is because of the changes in the composition of the atmosphere, but mostly because of the carbon dioxide (CO2) increase. Some is out of our control, but we are responsible for the burning of fossil fuels and deforestation which has accelerated over the last 50 years. If this continues at the rate it is, tropical waters will be 3-4 degrees (Celsius) warmer by 2100.

Not only should we worry about coral bleaching, human-induced climate change is bringing about an additional problem: ocean acidification. Ocean acidification is from the increased CO 2 in the atmosphere entering the ocean, reacting mildly, and decreasing the pH. By changing the seawater chemistry, it affects the metabolism, sensory systems, reproductive stages, and calcification of corals and other reef dwellers.

Just like the increased rates of coral bleaching, ocean acidification is taking place at a faster rate than ever seen over the past 65 million years, and maybe even the past 300 million years. Scientists are worried that at the rate the ocean is acidifying, corals and reef organisms won’t have enough time to adapt to their changing environment. This would result in a slower recovery from other impacts like disease, predation and destructive fishing.

Reduction of CO 2 concentrations to the level of recovery to save the coral reef ecosystems will require major initiatives to reduce emissions and our carbon footprint. The Intergovernmental Panel on Climate Change (IPCC) Special Report warns that global warming is likely to grow 1.5 degrees (Celsius) between 2030 and 2052 if we continue as usual. With this in mind, we only have 12 years to make changes and not surpass this limit. Allowing a warming of 2 degree (Celsius) will significantly worsen the risks of disasters like drought, poverty of millions of people, extreme heat and the loss of almost all of our coral reefs.

The IPCC Special Report plans out ways we can achieve this by a combination of land use and technological change. By reforesting, we can turn towards a greater adoption of carbon capture technology. Rapid changes would need to happen, but the cost of not doing anything is much greater. Our coral reefs are a sign of how urgent it is to take action as soon as possible. •

Coral reef. Photo by: Lars Plougman, Flickr.