Coral reefs

What it is

The Global Coral Reef Monitoring Network (GCRMN) report Status of Coral Reefs of the World: 2020 is the main quantitative global report on reef status. About 14 percent of the world’s hard coral was lost from coral reefs between 2009 and 2018 (GCRMN Status of Coral Reefs of the World: 2020). The report is available from GCRMN, the International Coral Reef Initiative (ICRI), and UNEP. For heat stress and bleaching, NOAA’s Coral Reef Watch provides 5 km satellite products, and NOAA’s Ocean Service explains how bleaching works.

Why it matters

The GCRMN report shows how reefs are doing worldwide, based on measurements. Coral restoration is a management practice; the status report tracks the condition of the reefs themselves.

How to read it

GCRMN combines in-water surveys of hard-coral and algae cover across reef regions. Coral Reef Watch uses satellites to track heat stress, which can come before bleaching. Long-term status trends and near-real-time heat stress are related but different, so it helps to look at both. Announcements of global bleaching events, such as NOAA’s, add useful context, while the GCRMN data remain the reference for reef status.

Sources

• GCRMN: Status of Coral Reefs of the World: 2020 (report page)
• GCRMN: Status 2020 full PDF
• DOI: GCRMN Status 2020
• GCRMN hub
• ICRI: GCRMN
• UNEP: Status of Coral Reefs of the World 2020
• NOAA Coral Reef Watch: 5 km product
• NOAA Ocean Service: Coral bleaching facts
• NOAA: Fourth global coral bleaching event (context)

Open source map →