Cell Reports Sustainability (Feb 2024)
New global area estimates for coral reefs from high-resolution mapping
Abstract
Summary: Coral reefs underpin the environmental, social, and economic fabrics of much of the world's tropical coast. Yet, the fine-scale distribution and composition of coral reefs have never been reported consistently across the planet. Here, we present new area estimates enabled by global geomorphic zone and benthic substrate maps at 5 m pixel resolution. We revise global coral reef estimates to 348,361 km2 of shallow coral reefs and 80,213 km2 (46,237–106,319 km2, 95% confidence interval) of coral habitat. The mapping used more than 1.5 million training samples supported by 480+ data contributions to deploy a coral reef classification of over 100 trillion pixels from the Sentinel-2 satellites and the Planet Dove CubeSat constellation. The publicly available maps are accessible via the Allen Coral Atlas and Google Earth Engine and are already being used by thousands of people to improve the conservation, management, and research of coral reef ecosystems. Science for society: Coral reefs possess a quarter of all marine life and contribute to the well-being and livelihoods of a billion people worldwide. Maps of ecosystems underpin many science and conservation activities, but until recently, there were no consistent high-resolution maps of the world’s coral reefs. In this paper, we describe new global coral reef maps from the Allen Coral Atlas, detailing the underlying methodology and our new understanding of the global distribution of coral reefs. The transparent and repeatable nature of our mapping framework allows the maps to be updated based on user feedback, and the ease of access has led to downstream applications such as coral bleaching monitoring and usage in scientific, management, and conservation activities. Hundreds of thousands of people have already accessed the maps, and they are already being used directly around the world for marine spatial planning, marine protected areas, environmental accounting and assessments, restoration, and education.
