The ocean moderates anthropogenic atmospheric warming at the cost of profound alterations of its physics, chemistry, ecology, and ecosystem services. The Oceans 2015 Initiative has published a paper in Science evaluating and comparing the risks of impacts on marine and coastal ecosystems and the goods and services they provide under two potential carbon dioxide (CO2) emissions pathways over this century (see figure).
Four key messages are articulated. (1) The ocean strongly influences the climate system and provides important services to humans. (2) Impacts on key marine and coastal organisms, ecosystems, and services from anthropogenic CO2 emissions are already detectable across various latitudes, and several will face high risk of impacts well before 2100, even with stringent CO2 emissions scenarios. (3) Immediate and substantial reduction of CO2 emissions is required more than ever to prevent massive and effectively irreversible impacts on ocean ecosystems and their services. (4) As CO2 increases, the protection, adaptation and repair options for the ocean become fewer and less effective.
With such an analysis, the authors wish to address to the international climate negotiation process, the ocean providing further compelling arguments for rapid, rigorous and ambitious CO2 emissions reductions.