World Heritage coral reefs likely to disappear by 2100 unless CO2 emissions drastically reduce: UNESCO

The UNESCO’s World Heritage Centre on 23 June 2017 released the first global scientific assessment of climate change impacts on World Heritage coral reefs.

As per the assessment, soaring ocean temperatures in the past three years have subjected 21 of 29 World Heritage reefs to severe and/or repeated heat stress, and caused some of the worst bleaching ever observed at iconic sites like the Great Barrier Reef in Australia, Papahānaumokuākea in USA, the Lagoons of New Caledonia in France and Aldabra Atoll in Seychelles.

The assessment was developed with satellite data from the United States National Ocean and Atmospheric Administration’s (NOAA) Coral Reef Watch and received the support from the French Agency for Biodiversity (Agency Française pour la Biodiversité).

Key highlights of the assessment

• The analysis predicts that all 29 coral-containing World Heritage sites would cease to exist as functioning coral reef ecosystems by the end of this century under a business-as-usual emissions scenario.

• The 29 globally significant coral reefs on UNESCO’s World Heritage List are facing existential threats, and their loss would be devastating ecologically and economically.

• The social, cultural and economic value of coral reefs is estimated at USD 1 trillion. Recent projections indicate that climate-related loss of reef ecosystem services will total USD 500 billion per year or more by 2100, with the greatest impacts felt by people who rely on reefs for day-to-day subsistence.

• The last three years were the hottest on record, and they caused a global bleaching event that reached 72 per cent of World Heritage-listed reefs.

• The assessment looked at the frequency with which World Heritage reefs have been subjected to stress that exceeds best-case rates of recovery.

• It also examined future impacts to World Heritage reefs under two emissions scenarios. The results were sobering and concluded that delivering on the Paris Agreement target of “holding the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C” offers the only opportunity to prevent coral reef decline globally, and across all 29 reef-containing natural World Heritage sites.