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ENSEMBLES - ENSEMBLE based predictions of climate change and their impacts

Project website:

Summary information

Funding:FP6 - Integrated Project
Total cost:22790000
Ec contribution:15000000
Start date:2004-09-01
End date:2009-12-31
Duration:64 months
Coordinator:Paul Van Der Linden (
Organisation:Met Office, Hadley Center, Exeter - United Kingdom
Keywords:Climate Change, Climate Research, Global Climate Modelling, Regional Climate Modelling, Climate Observations, Climate and Weather Extreme Events, Physical Climate Processes, Climate Scenarios, Climate Projections, Climate Change and Policy, Climate Change Impacts, Energy, Agriculture, Insurance
Project name:ENSEMBLES - ENSEMBLE based predictions of climate change and their impacts
Project summary:Abstract
Prediction of both natural climate variability and human impact on climate is inherently probabilistic, due to uncertainties in forecast initial conditions, representation of key processes within models, and climatic forcing factors. Hence, reliable estimates of climatic risk can only be made through ensemble integrations of Earth - System Models in which these uncertainties are explicitly incorporated. For the first time ever, a common ensemble forecast system will be developed for use across a range of timescales (seasonal, decadal, and longer) and spatial scales (global, regional, and local). This model system will be used to construct integrated scenarios of future climate change, including both non-intervention and stabilisation scenarios. This will provide a basis for quantitative risk assessment of climate change and climate variability, with emphasis on changes in extremes, including changes in storminess and precipitation, and the severity and frequency of drought, and the effects of "surprises", such as the shutdown of the thermohaline circulation. Most importantly, the model system will be extensively validated. Hind casts made by the model system for the 20th century will be compared against quality-controlled, high-resolution gridded datasets for Europe. Probability forecasts made with the model system on the seasonal and decadal timescales will also be validated against existing data. The exploitation of the results will be maximised by linking the outputs of the ensemble prediction system to a wide range of applications. In turn, feedbacks from these impact areas back to the climate system will also be addressed. Thus ENSEMBLES will have a structuring effect on European research by bringing together an unprecedented spectrum of world-leading expertise. This expertise will be mobilised to maintain and extend European pre-eminence in the provision of policy-relevant information on climate and climate change and its interactions with society.

The overall goal of ENSEMBLES is to maintain and extend European pre-eminence in the provision of policy relevant information on climate and climate change and its interactions with society. ENSEMBLES will achieve this by:
- Developing an ensemble prediction system based on the principal state-of-the-art, high resolution, global and regional Earth System models developed in Europe, validated against quality controlled, high resolution gridded datasets for Europe, to produce for the first time, an objective probabilistic estimate of uncertainty in future climate at the seasonal to decadal and longer timescales;
- Quantifying and reducing the uncertainty in the representation of physical, chemical, biological and human-related feedbacks in the Earth System (including water resource, land use, and air quality issues, and carbon cycle feedbacks);
- Maximising the exploitation of the results by linking the outputs of the ensemble prediction system to a range of applications, including agriculture, health, food security, energy, water resources, insurance and weather risk management.

To meet the Project Goal the project is split into a number of scientific and technological objectives with a number of operational goals. The work in the project is conducted through 10 closely connected Research Themes (RTs), each of which has Major Milestones (MMs) which are the means of assessing progress towards the project objectives and operational goals.

ENSEMBLES will be a major step forward in climate and climate change science. Over the next five years the major progress in climate science is expected mainly to take place in six areas:
- The production of probabilistic predictions from seasonal to decadal and longer timescales through the use of ensembles
- The integration of additional processes in climate models to produce true Earth System models
- Higher resolution climate models to provide more regionally detailed climate predictions and better information on extreme events
- Reduction of uncertainty in climate predictions through increased understanding of climate processes and feedbacks and through evaluation and validation of models and techniques
- The increased application of climate predictions by a growing and increasingly diverse user community
- The increased availability of scientific knowledge within the scientific community and to stakeholders, policymakers and the public.

ENSEMBLES will make major scientific contributions in all these areas and, most importantly, will ensure that these six strands are all taken forward in an integrated and co-ordinated way. This will be possible because ENSEMBLES encases each of these elements within a planned and actively managed programme.

All of the major groups in Europe, who would individually be involved in the six elements, are participants in the project. In numerous ways ENSEMBLES will extend the state-of-the-art in the prediction of climate change and its impacts at seasonal to decadal and longer timescales. Foremost in this will be the development of the first global, high resolution, fully comprehensive, ensemble based, modelling system for the prediction of climate change and its impacts. This will confirm and maintain Europe’s position as the world leader in climate change prediction. The integrated system to be developed for this project will deal with issues related to:
- Natural variability of climate in the context of a changing chemical environment,
- Non-linearity in the response both at the global and regional scale,
- Quantitative estimates of uncertainty guided by observations, relevant to policy makers.
- This will require:

Inclusion of the non-linear feedbacks between climate and the impacts of climate change (e.g. water resource management, changes in land use, energy needs). This requires a more integrated approach to the assessment of the impacts of climate change than has hitherto been undertaken within a sophisticated, state-of-the-art earth system model;
- Quantifying uncertainty in individual components of the earth system and in the interaction between individual components, through the use of (i) different model constructions and (ii) ensemble-based “perturbed physics” versions of each model. The incorporation of “perturbed physics” techniques within the modelling framework allows for an exploration of uncertainties associated with the representation of individual processes (particularly relevant for those which cannot be resolved at the model grid-scale), and together with the multi-model approach will provide a much more complete estimate of uncertainty than has thus far been possible;
- Construction of an ensemble of earth system models to provide estimates of climate and other environmental change for the next 10 to 100 years. Model diversity is essential for providing a level of confidence to European predictions of climate change;
- Derivation of an objective method of deriving probability distributions using ensembles of models, weighted according to the ability of an individual model to represent key aspects of observed climate. Evaluation of model skill is an essential part of the process, which will involve the development of new methodologies for diagnosing key processes and phenomena in models and for confronting them with satellite and in situ observations;
- Using the probability distributions of the impacts of climate change from the integrated system (including water management, land use, air quality, carbon management and energy use) to determine the social and economic effects and provide a risk assessment for selected emissions scenarios (policies);
- Developing a comprehensive approach to the validation of climate change ensembles and the impacts assessments, which includes the exploitation of seasonal to decadal predictability studies, thereby providing for the first time a sound, quantitative measure of confidence in future scenarios.

Thus, ENSEMBLES will begin to move the state of the art in climate prediction from a small number of deterministic predictions with no quantitative assessment of relative confidence towards an end-to-end multimodel ensemble prediction system (quantitatively validated against recent past climates and against the ability to predict future climate at the seasonal to decadal timescales) which would be able to provide probabilistic estimates of future climate change and its impacts on key sectors, at the European and global scales.
Project outputs:Final project results and reports are available from the project website.