Biotic and human vulnerability to projected changes in ocean biogeochemistry over the 21st century.

Camilo Mora,Jeroen Ingels,Daniel O B Jones,David Billett,Qi Chen,Andrew J Gooday,Moriaki Yasuhara,Paolo Usseglio,Teresa Amaro,Henry A Ruhl,Amy R Baco,Eva Ramirez-Llodra,Laurent Bopp,Mark Collier,Audrey Rollo,Andrew R Thurber,Karl Norling,Lisa A Levin,Andrew K Sweetman,Les Watling,Tongwen Wu,Hideyuki Nakano,Paul R Halloran,Craig R Smith,Roberto Danovaro,Benjamin M Grupe,Chih‐Lin Wei ,Jerry Tjiputra ,Michael A Rex

doi:10.1371/journal.pbio.1001682

Abstract

Author SummaryClimate change caused by human activity could damage biological and social systems. Here we gathered climate, biological, and socioeconomic data to describe some of the events by which ocean biogeochemical changes triggered by ongoing greenhouse gas emissions could cascade through marine habitats and organisms, eventually influencing humans. Our results suggest that the entire world's ocean surface will be simultaneously impacted by varying intensities of ocean warming, acidification, oxygen depletion, or shortfalls in productivity. Only a very small fraction of the oceans, mostly in polar regions, will face the opposing effects of increases in oxygen or productivity, and almost nowhere will there be cooling or pH increase. The biological responses to such biogeochemical changes could be considerable since marine habitats and hotspots for several marine taxa will be simultaneously exposed to biogeochemical changes known to be deleterious. The social ramifications are also likely to be massive and challenging as some 470 to 870 million people – who can least afford dramatic changes to their livelihoods – live in areas where ocean goods and services could be compromised by substantial changes in ocean biogeochemistry. These results underline the need for urgent mitigation of greenhouse gas emissions if degradation of marine ecosystems and associated human hardship are to be prevented.

Highlights

As CO2 and other greenhouse gas emissions continue to rise, ocean biogeochemistry is being altered in ways that could potentially impact nature and mankind
Ocean warming and other climatic changes can trigger additional responses in connection to ocean circulation and stratification, which in turn reduce oxygen concentration [9,10] and primary productivity [11]
As noted below, multimodel averages were always more accurate than individual models, further justifying the assembly of biogeochemical projections based on all available Earth System Models. These data on ocean biogeochemical parameters represent an important component of our study, our main goals are to identify how their patterns of co-occurrence may pertain to marine biota and thereby social systems worldwide that rely on marine biodiversity goods and services

Summary

Introduction

As CO2 and other greenhouse gas emissions continue to rise, ocean biogeochemistry is being altered in ways that could potentially impact nature and mankind. By the year 2100, depending on the emission scenario, surface ocean temperature could increase by 2 to 3uC [9], pH decline by over 0.2 units [6,7], oxygen concentration decrease by 2% to 4% [9], and ocean productivity by 2% to 20% [11], from current values. The magnitude of these changes would be unprecedented in the Earth’s history during the last 20 million years [12,13]

Methods

Results

Conclusion