The underestimation of projected effects of climate change on coral reefs

Abstract

Climate change poses unprecedented challenges to marine ecosystems, yet current assessments may substantially underestimate the magnitude and complexity of these impacts. This dissertation demonstrates three critical ways in which climate risks to marine ecosystems, particularly coral reefs, have been underestimated. Using global climate projections and comprehensive datasets of reef ecosystem and coral species distributions, this research examines limitations in current global assessment approaches. The first study investigates how spatial complementarity among multiple stressors affects projections of environmental suitability for coral reefs globally, revealing significantly reduced timelines of habitat suitability compared to single-stressor approaches. The second study examines how assessment metrics and scales influence our understanding of climate impacts, testing whether conventional ecosystem-level assessments systematically underestimate vulnerability compared to species-level analyses. The third study evaluates migration and adaptation strategies by assessing on a global context the extent to which some suitable habitats will remain available and accessible to marine species under future climate scenarios. Collectively, these findings demonstrate that habitat loss for coral reefs will occur more rapidly, extensively, and with fewer viable survival options than previously projected. This research highlights the urgent need for reevaluation of conservation priorities, enhanced monitoring systems capable of detecting species-level responses, and reduction of greenhouse gas emissions to preserve coral reef biodiversity and the essential ecosystem services they provide.