Coral Reefs Overpowered by Rising Sea Levels

A new study finds fragile marine ecosystems cannot grow fast enough to keep pace with global sea levels rising.

Scientists have discovered a new threat to the global endangered coral systems. They have found that most are inadequate of growing fast enough to compensate for rising sea levels triggered by global warming.

The study suggests that coral systems, which are already suffering severe degradation because the world’s seas are warming and becoming more acidic which could also become overwhelmed by rising oceans.

The new research was led by scientists at Exeter University and published in Nature this week involved studying growth rates for over 200 tropical western Atlantic and Indian Ocean reef systems. It was found that 9% of these reefs had the ability to keep up with even the most optimistic rates of sea level rises forecast by the Intergovernmental Panel on Climate Change. “For many reefs across the Caribbean and Indian Ocean regions, where the study focused, rates of growth are slowing due to coral reef degradation,” said Professor Chris Perry, of Exeter University. “Meanwhile, rates of sea-level rise are increasing – and our results suggest reefs will be unable to keep up. As a result, water depths above most reefs will increase rapidly through this century.”

Sea levels rose by several inches over the past century and measurements show the speed of this increase is now rising significantly. Two key factors are involved is climate change which is making ocean water warmer and so it expands. And as ice sheets and glaciers melt, they increase amounts of water across the world oceans.

At the same time, reefs are being exhausted by ocean warming and also by ocean acidification, triggered as more and more the seas absorb more CO2. These effects lead to bleaching events that kill off vast areas of coral and limits their ability to grow.

“Our predictions, even under the best case scenarios, suggest that by 2100 the inundation of reefs will expose coastal communities to significant threats of shoreline change,” said co-author Prof Peter Mumby of Queensland University.

This point was endorsed by US marine scientist Ilsa Kuffner writing in a separate comment piece for Nature. “The implications of the study are dire. Many island nations and territories are set to quickly lose crucial natural resources.”

Rory Sinclair