30.09.2013 - Natural Sciences Sector

What the ocean can reveal about human influence on the climate

Human influence on the climate system is clear. This is evident in most regions of the globe, a new assessment by the Intergovernmental Panel on Climate Change (IPCC) concludes. Released on 27 September, the report provides a comprehensive assessment of the physical science basis of climate change and concludes that it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. The evidence for this has grown, thanks to more and better observations, an improved understanding of the climate system response and improved climate models.

The progress made in sustained monitoring and collection of ocean data has opened the way for researchers to gain a clearer view of the impacts of human activities on the climate as well as current and future trends. ‘Widespread warming is observed from the surface of the Earth throughout the troposphere and cooling is identified in the stratosphere’, observe the authors. This is consistent with the lower atmosphere (troposphere) trapping greenhouse gases, thereby preventing the heat from rising to the stratosphere. The report finds with high confidence that ocean warming dominates the increase in energy stored in the climate system, accounting for most of the energy accumulated between 1971 and 2010.

Monitoring and being able to predict the role played by the ocean is key to understanding – and preparing for – climate change’, said Wendy Watson-Wright, Executive Secretary of the Intergovernmental Oceanographic Commission and Assistant Director General of UNESCO. ‘The IOC-led Global Ocean Observing System (GOOS) has developed tremendously in the past 15 years, building on a longer history of oceanographic research. This makes us confident that more than 90% of the excess heat trapped in the Earth system by the greenhouse effect over the past 4 decades is stored in the ocean. In contrast, only 1% of that excess heat is stored in the atmosphere.’

Technically, GOOS is a global network of ships, buoys, subsurface floats, tide gauges and satellites that collect real time data on the physical state as well as the biogeochemical profile of the world's oceans. The data collected allows us to have a clearer picture of the impacts of human activities, providing for example heat maps that show us where and how impacts are occurring in near-real time, and to project their consequences. This data forms the basis of the research assessed by the IPCC to inform policy makers today.

GOOS is a platform for global collaboration that comprises a measuring subsystem, a data and information management subsystem, and a subsystem for tools and products such as rainfall measurements and forecasts, maps and forecasts of harmful algal blooms, assessments of the vulnerability of fish stocks and farms, and sea level monitoring.

This information is essential for effective coastal area management, but it is just as essential far from the coast, as the heat stored in the ocean drives changes in rainfall patterns. Understanding and monitoring such factors allows GOOS to provide forecasts of droughts or floods that can occur anywhere on the globe.
This is a global problem that concerns each of us,’ continued Ms Watson-Wright. ‘Looking forward, we need sustained ocean observations and continued research to understand vulnerabilities and to project impacts at the global and local level. This will provide policy makers everywhere, including in landlocked countries, with the information they need to plan ahead.’

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