More extreme weather events likely: Climate projections of unparalleled accuracy for the whole of Europe

Data from the EURO-CORDEX project have just been published and made available to scientists. This should lead to more precise studies of the impact of climate change in Europe on air quality, hydrology and extreme events, which are all areas that concern key sectors such as energy, health and agriculture.

EURO-CORDEX: more detailed forecasting of Europe's climate

The new simulations confirm the projections published last September[3] for the whole planet, while providing a far more accurate picture for Europe. They forecast an increase in temperatures in Europe of 1 °C to 5 °C by the end of the 21st century, with differences between one region and season to another. Southern Europe is likely to undergo far more rapid warming in summer than northern Europe, while warming in winter will probably be faster in eastern and northern Europe. Precipitation is likely to be heavier in northern Europe and lighter in the south. In practically every European country, the simulations predict that heavy precipitation will become more frequent, with such phenomena being shown much more clearly than previously thanks to the high resolution obtained.

Longer droughts and more frequent heatwaves are forecast. Predictions for France are more diverse, with a pronounced overall increase in precipitation in winter, together with more frequent droughts in summer, especially in southern France. High resolution simulations make it possible to show phenomena such as heavy precipitation in mountain areas.

Ten regional climate models

Launched in 2011 as part of the international CORDEX initiative, the EURO-CORDEX project has produced an ensemble of climate projections for Europe in the 21st century at very high spatial resolution. To do this, ten regional climate models were used, including two by the French community[4]. The projections were carried out according to three baseline scenarios selected from the four scenarios in the 5th IPCC report. These are three more or less optimistic pathways[5] for change in greenhouse gas concentrations from now until the end of the 21st century. Coordinated by a German team, EURO-CORDEX involves over twenty European research organizations, including CNRS, Météo-France, CEA, UVSQ and INERIS. French teams played an extremely active role in the initiative. They were able to use CEA and Météo-France's supercomputers, as well as being allotted time on the French National Supercomputing Facility GENCI.

Around a hundred simulations of Europe's climate in the 21st century

In all, around a hundred simulations were carried out for EURO-CORDEX. Approximately twenty of them are unique in that they reach a never previously achieved resolution of 12 km for projections for the whole of Europe. This degree of accuracy makes it possible to better show local phenomena such as heavy rainfall that are crucial to climate change. Better information is thus available for future studies into adaptation to climate change in Europe. It is now planned to study the impacts of climate change on air quality and on other key sectors of the economy such as energy and agriculture. CNRS, CEA, Météo-France, UVSQ and INERIS are currently participating in the analysis of the simulations, all of which were published on 1 December 2013.

The data has now been made available in particular to the scientific community and to climate services, with the aim of providing climate information to economic, industrial and political stakeholders. The simulations will also be supplied to the French national DRIAS portal, which collects data about predicted climate change in France.

[From global to local Global climate models are used to produce climate projections on the scale of continents, like those presented last September in the first volume of the 5th IPCC report. However, given the current power of supercomputers, their resolution remains limited to 200 km, which makes it impossible to describe phenomena taking place on the kilometer scale, such as torrential autumn rainfall, high wind episodes, and events taking place near coasts and higher ground. Using regional models makes it possible to increase resolution. Such models show specific regions of the world in more detail, by using global simulations especially to describe conditions at the edges of the regions. In this case, supercomputing power is primarily used to improve spatial resolution.]

Notes:

[1] The French laboratories concerned are the Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL, CNRS/CEA/UVSQ) and the Centre National de Recherches Météorologiques -- Groupe d'Etude de l'Atmosphère Météorologique (CNRM-GAME, Météo-France/CNRS), together with the Institut National de l'Environnement Industriel et des Risques (INERIS).

[2] The analyses appear in particular in three recently published articles: Vautard, R. et al., 2012: The simulation of European heat waves from an ensemble of regional climate models within the EURO-CORDEX project. Climate Dynamics, doi:10.1007/s00382-01-1714-z; Jacob, D. et al., 2013, EURO-CORDEX: New high-resolution climate change projections for European impact research, Regional Environmental change, doi:10.1007/s10113-013-0499-2; Colette, A. et al., 2013: European atmosphere in 2050, a regional air quality and climate perspective under CMIP5 scenarios. Atmos. Chem. and Phys., doi:10.5194/acpd-13-6455-2013

[3] Volume 1 'Climate Change 2013: the Physical Science Basis' of the IPCC Fifth Assessment Report was presented on 27 September 2013 following the adoption of the Summary for Policymakers.

[4] ARPEGE-Climat developed by CNRM-GAME and IPSL-CM5A-MR-WRF developed by the Institut Pierre-Simon Laplace (IPSL), which brings together several environmental science laboratories attached to CNRS, including LSCE.

[5] The three scenarios selected are RCP2.6, 4.5 and 8.5. RCP stands for 'Representative Concentration Pathways'. Scenario RCP8.5 is an extreme scenario with a major increase in greenhouse gases. The most optimistic scenario (RCP2.6) corresponds to virtuous behavior, with very low greenhouse gas emissions. RCP4.5 is an intermediate scenario.

[6] The international scientific community has taken action, especially through the World Climate Research Program (WCRP), to design and carry out a simulation exercise of past and future climate covering the entire planet: CMIP5.