Coral reefs are fragile ecosystems that face human-induced threats from both local and global stressors.
Local threats can originate from within the ocean and immediate reef environment, adjacent coastal development, or even from seemingly unrelated land-use change that occurs far away from the coast but within a reef’s watershed. We’ve grouped these local stressors into 4 categories:
Global threats to coral reefs emanate from increasing concentrations of atmospheric CO2 (Hoegh-Guldberg et al., 2007; Kleypas, 1999). The unprecedented rate of CO2 increase in the atmosphere is matched by equally exceptional changes in the ocean (Doney, 2010). Average sea surface temperatures are warmer (+0.7 C), and the ocean is more acidic (-0.1 pH) than at any other time in the past 420,000 years (Hoegh-Guldberg & Bruno, 2010; Hoegh-Guldberg et al., 2007). These global stressors to coral reefs are categorized by all researchers as: