Ocean ecosystem responses to future global change scenarios: a way forward

Abstract

The overall aim of GLOBEC was ‘To advance our understanding of the structure and functioning of the global ocean ecosystem, its major subsystems, and its response to physical forcing so that a capability can be developed to forecast the responses of the marine ecosystem to global change’. GLOBEC specifi ed four objectives, and objective 3 was ‘To determine the impacts of global change on stock dynamics using coupled physical, biological, and chemical models linked to appropriate observation systems and to develop the capability to project future impacts’. During the GLOBEC era, earth observational networks were developed such as the Global Climate Observing System (GCOS), which includes the Global Ocean Observing System (GOOS). Although imperfect, this global observational network is providing an unprecedented view of climate change in the earth system, and has increased our understanding tremendously over the past several decades. An increasing number of independent observations of the atmosphere, land, cryosphere, and ocean are providing a consistent picture of a warming world. Such multiple lines of evidence, the physical consistency among them, and the consistency of fi ndings among multiple, independent analyses, form the basis for the iconic phrase of the observations chapter in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC-AR4, IPCC 2007a ) that the ‘warming of the climate system is unequivocal’. Moreover, the evidence is strong that, especially in recent decades, human activities have contributed to the global warming. The IPCC-AR4 additionally cautioned that further warming and changes in the global climate system will very likely emerge over the next century. The climate changes anticipated during the twenty-fi rst century have the potential to greatly affect marine ecosystems. A major challenge facing the scientifi c community is to develop modelling and data analysis approaches for determining how climate change will affect the structure and functioning of marine ecosystems. During the GLOBEC era, our understanding of ecosystem structure and dynamics has improved greatly (deYoung et al ., Chapter 5 ; Moloney et al. , Chapter 7 , both this volume), and new ecosystem modelling approaches have been developed and existing methods improved (see deYoung et al ., Chapter 5 , this volume). As we look forward, the next step is to use the knowledge gained from GLOBEC as a foundation, as we continue to develop data collection and modelling tools that can make suffi ciently confi dent projections of marine ecosystem responses to future global climate change. In this chapter, we summarize the available evidence for recent changes in climate effects in the oceans, and the status of our ability to project ecosystem responses to likely future global change.