A new study led by the University of Exeter emphasizes the alarming rate at which coral reefs could stop growing due to climate change, projecting massive ecological and socio-economic consequences if global temperatures exceed 2°C.
Most coral reefs in the western Atlantic are on the brink of halting growth and could begin to erode significantly by mid-century if global temperatures rise by 2 degrees Celsius above pre-industrial levels, a new study reveals.
An international team led by scientists from the University of Exeter assessed 400 reef sites around Florida, Mexico and Bonaire.
Their findings, published in the journal Nature, suggest that more than 70% of these reefs will cease to grow by 2040, with the figure rising to over 99% by 2100 if warming persists.
“Our research shows that under current CO2 emission scenarios most Atlantic coral reefs will not only stop growing but many will actually be eroding by mid-century,” lead author Chris Perry, a professor at the University of Exeter, said in a news release.
Coral reefs are vital for marine biodiversity, coastal protection and the livelihoods of millions of people. However, climate change coupled with coral disease and deteriorating water quality is diminishing reef growth by killing corals and slowing colony growth rates.
The study combined fossil reef data from the tropical western Atlantic with ecological information from modern reef sites to calculate current and future growth rates. This comprehensive analysis underscores the delicate balance disrupted by global warming.
“Climate change is not only accelerating this decline but also worsening the cascading ecological and socio-economic consequences of their loss,” added co-author Lorenzo Alvarez-Filip from the Universidad Nacional Autónoma de México.
As sea levels rise, the inability of reefs to keep pace will result in increased water depths above reefs, escalating flood risks and altering nearshore ecosystems.
“With reefs and sea levels moving in opposite directions, water depths above reefs will increase — raising flooding risks along vulnerable reef-fronted coasts and fundamentally changing nearshore ecosystems,” Perry added.
The study projects water depth increases of up to 1.2 meters by the end of the century if higher warming rates are realized.
Reef growth is heavily influenced by the quantity and types of living coral. Disease outbreaks, bleaching events triggered by high temperatures, and other factors have drastically reduced key reef-building species.
“We are witnessing an alarming decline in both the abundance and diversity of corals across Atlantic coral reefs,” Alvarez-Filip added.
One potential solution is coral restoration combined with effective land and water management, and urgent climate mitigation actions to keep warming below 2 degrees Celsius.
“The scale of action required to reverse current coral losses is significant,” added co-author Alice Webb from the University of Exeter. “To have meaningful effects on limiting water depth increases, any restoration will need to occur in tandem with effective land and water management, and rapid climate mitigation actions. Actions to keep warming below 2°C are critical.”
Perry stressed the importance of immediate action, concluding: “We are moving into a period where the two factors that control water depths above coral reefs — vertical reef growth rate and sea level rise rate — are starting to operate in increasingly divergent directions. Limiting climate warming is critical if we are to try to mitigate this and to avoid the worst impacts for coastlines and coastal ecosystems.”
Source: University of Exeter