Models hone picture of climate impacts

[Dead_Parrot]

Will the warming planet be able to sustain coming generations? Few questions about the future matter more. But although modellers can forecast temperature changes and even precipitation, they struggle to say how climate change will affect the factors that make the planet habitable, such as food and water availability. Last week at the Potsdam Institute for Climate Impact Research (PIK) in Germany, researchers launched a fast-track programme to make their narratives of possible futures more coherent and useful to decision-makers.

Climate-impact models combine projections of change in physical climate with data on population, economic growth and other socio-economic variables. For various emissions scenarios, they forecast climate-driven changes in crop yields, vegetation zones, hydrology and human health (see ‘The browning of the planet’). But they often leave out important elements: for example, models of health impact often neglect the role of social factors in spreading disease; and models of water run-off may not account for changes in water loss from plants. Researchers have built dozens of models, but have never systematically compared their performance. As a result, say critics, the literature on climate impacts is as inconclusive as it is encyclopaedic.

“Impact research is lagging behind physical climate sciences,” says Pavel Kabat, director of the International Institute for Applied Systems Analysis in Laxenburg, Austria, which is to coordinate the fast-track programme jointly with the PIK. “Impact models have never been global, and their output is often sketchy. It is a matter of responsibility to society that we do better.”

The programme, dubbed the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), involves more than two dozen modelling groups from eight countries, and they have set themselves a tight deadline. At the kick-off meeting at the PIK, the researchers agreed to complete a comprehensive set of model experiments within six months. All the simulations will cover the globe at the same resolution, and will be based on the same set of climate data from state-of-the-art climate models, driven by the latest greenhouse-gas emission scenarios (R. H. Moss Nature 463, 747–756; 2010).

More: http://www.nature.com/news/models-hone-picture-of-climate-impacts-1.10020