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Earth observations vital for detecting climate change impacts
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The Nineteenth Session (SC-XIX) of the Global Climate Observing System (GCOS) Steering Committee was held at the headquarters of the European Centre for Medium-Range Weather Forecasts (ECMWF) in Reading, United Kingdom in September 2011.
SAEON’s Dr Juliet Hermes attended this first meeting as a steering committee member of GCOS.
Observations of the Earth’s climate system
The objective of GCOS is to provide observations of the Earth’s climate system necessary for monitoring the climate system; for detecting and attributing climate change; for assessing the impacts of climate variability and change; for supporting research toward improved understanding, modelling and prediction of climate; and for application to national economic development.
Many observing systems contribute to the GCOS network of global observing systems for climate. In most cases they also serve other functions, such as weather forecasting or air-quality monitoring. The contributing systems include the climate-observing components of the Intergovernmental Oceanographic Commission (IOC) Global Ocean Observing system, the Food and Agricultural Organization Global Terrestrial Observing System and the World Meteorological Organization (WMO) Global Observing System and Global Atmosphere Watch. A number of other research and operational systems also provide important contributions.
The observations themselves may be ground-based, or from airborne or satellite systems. GCOS is both supported by, and supports, the international scientific community, and the World Climate Research Program co-sponsors the expert panels set up by GCOS for the atmospheric, oceanic, and terrestrial domains.
Climate-observation component of GEOSS
The composite observing system designated as GCOS serves as the climate-observation component of the Global Earth Observation System of Systems (GEOSS). Along with the World Climate Research Programme, the GCOS underlies the proposed Global Framework for Climate Services (GFCS). A well-functioning GCOS is required for the success of this new framework.
The development of GCOS requires close cooperation between the research and operational components of the meteorological, hydrological and oceanographic services, terrestrial and ecosystem agencies, relevant institutions, and space agencies.
The Director-General of the European Centre for Medium-Range Weather Forecasts (ECMWF), Professor Alan Thorpe, welcomed steering committee members and other participants, including the Executive Secretary of the Intergovernmental Oceanographic Commission, Dr Wendy Watson-Wright, the Deputy Secretary-General of the World Meteorological Agency, Mr Jerry Lengoasa, and Mr Ashbindu Singh of the United Nations Environment Programme (UNEP). Professor Thorpe stressed that ECMWF could not make the weather forecasts that it does, day-in and day-out, for time scales from days to seasons ahead, without access to high quality observations of the atmosphere, ocean, and land.
Other key organisations present included GOOS (Global Ocean Observing System), GTOS (Global Terrestrial Observing System) and OOPC (Ocean Observing Panel for Climate).
Key discussions and questions
Some key discussions of interest to those involved in long-term observations included: - Information on the Global Observing Systems Information Centre which provides convenient, central, one-stop access to data and information identified by GCOS, GOOS and GTOS and their partner programmes, such as the Global Atmosphere Watch (GAW) and regional observing systems, such as the GOOS Regional Alliances (GRA) - WIGOS, WMO Integrated Global Observing Systems -- WIGOS is an all-encompassing approach to the improvement and evolution of WMO global observing systems. It will foster the orderly evolution of the present WMO global observing systems into an integrated, comprehensive and coordinated system.
Specific questions included: How do we link observations (eg ecosystem change and human exposure)?; What are the Essential Climate Variables (ECV) for required knowledge?, and How should GCOS organise to respond to these while sustaining current activities?
Global observation of the deep ocean
With regard to ocean climate observations, the OOPC Chair reviewed the state of ocean observing systems, highlighting that the continuity of Jason-3 altimetry is worrisome and that the in situ observing system has been stuck at 62 per cent for the last several years. He noted that the deep ocean constituted a large gap in the ocean observing system.
The objective of a Deep Ocean Observing Strategy (DOOS) Workshop in Paris in March/April 2011 was to develop a common statement of requirements and a first strategy for sustained global deep ocean observations for climate that would consider all essential climate variables, regions, and technologies and propose high priority and feasible actions for the next 5-10 years. It is hoped that a DOOS strategy can be established in the next two years and that it will be incorporated in GCOS. By Ocean Obs 2019 it is hoped that global sustained coverage of the deep ocean will be in sight.
Weather and climate variability
It was further suggested that weather and climate variability, rather than climate change, are going to be the main drivers for the next couple of decades. Thus, the historical range of variability is critical information for near-term adaptation/ resilience planning and action, and climate projections are not essential to this. People don’t understand just how variable our climate really is, and this means that it is difficult to derive useful trends for the near term. Shorter-term variability will often dominate trend estimates, even over multi-decadal periods. Hence, it may be smarter to think about adaptation in terms of variability. Historical data sets are the critical source of information needed for climate variability on regional scales.
Our present skill at seasonal prediction is demonstrated by the way forecasting systems capture the evolution of climate indices. The more one focuses on particular regions, the more likely it is that skill will become more evident if additional indices relevant to that region are introduced. Research is needed to enhance regional skill.
Pushing the limits of regional forecast skill
It was argued that the limits of regional forecast skill will be pushed forward only with continuing research and data availability. These thoughts led Dr Harrison to conclude that a robust set of adaptation activities is possible and appropriate, given only historical observations and impact analysis frameworks. Assessment of climate variability impacts and planning for adaptation actions fall usefully within this existing framework. The GCOS Programme, he suggested, might benefit from the creation of a new Panel with this focus.
The Global Climate Observing System (GCOS) is sponsored by the World Meteorological Organization (WMO), the Intergovernmental Oceanographic Commission (IOC) of the United Nations Educational, Scientific and Cultural Organization (UNESCO), the United Nations Environment Programme (UNEP), and the International Council for Science (ICSU).
The year 2012 is the 20th anniversary of the establishment of the Global Climate Observing System.
