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Understanding Global Risks to Coral Reefs

Understanding Global Risks to Coral Reefs

Project Lead: The Nature Conservancy
Support: Universidad Nacional Autónoma de México (UNAM)
Financial Support: Government of Canada
Location: Global


Coral reefs face a variety of severe threats, and reef managers and decision-makers need to understand their impact in order to properly allocate scarce resources and implement actions to safeguard their future. To better understand the relative importance of the risks reefs face, ORRAA partner The Nature Conservancy (TNC) conducted a holistic assessment of 16 physical and human related risks. This information can help decision-makers understand the risk landscape and take action to build resilience.


Coral reefs are the most biodiverse marine ecosystems – and are a first line of protection for coastal communities and infrastructure around the world. Healthy reefs can cut wave energy by up to 97 per cent, significantly reducing the flood damage caused by storms. With around eight per cent of the global population living less than 10 metres above sea level, floods could cost coastal cities as much as USD$1 trillion per year by 2050. Together, this presents a powerful case for the conservation of coral reefs.

However, reefs are being degraded by ocean warming, pollution and hurricanes, decreasing their capacity to provide this vital protection. Live coral cover declined from 40 per cent to 20 per cent in the Indo-Pacific and from 60 per cent to 10 per cent in the Caribbean in the last 40 years.


To inform the design of future risk models worldwide, TNC, in association with Universidad Nacional Autónoma de México (UNAM), completed a global analysis of the risks faced by coral reefs. TNC’s Reefs at Risk report compares 16 biological and physical risks based on the severity, frequency and extent of impact on reefs. It looks at natural disasters like cyclones, tsunamis and bleaching to anthropic events such as ship groundings, oil spills, and scuba diving. This highlights the importance of addressing non-frequent but catastrophic events as well as continuous threats to reefs. This analysis can help reef managers and other decision-makers better understand the reef risk landscape, and effectively allocate resources and implement policies and actions which maximise reef protection and conservation in the long-term.  

Scalability and Next Steps

The study findings can support potential future work to identify reef stressors, address risks, and drive investments towards the protection of critical ecosystems by public and private sector decision-makers