How climate services keep the game balanced
We are so much used to have fresh water around, we just take it for granted. Our crops grow out of water and soil; our livestock feeds from water and forage; our cities and factories are built upon rivers and lakes; one-tenth of the energy we consume comes out of water stored in dams.
But taking fresh water for granted is a dangerous bet: being rainfall its main source, the slightest shift in climate conditions may ruin crops, livestock, energy supply and, ultimately, people’s life. With climate change into the game, no one is sure whether to raise or fold.
Stakes are high and betting against nature is not free of risk. Players around the table have been looking towards science for a hint on climate’s future movements. The challenge has been accepted and, in the last few years, climate scientists have shown it is possible to anticipate droughts, floods and fires months in advance.
A paper with participation of IMPREX partners found evidence that it is possible to improve current drought predictions by merging observations with forecasts. As published in 2017 by Marco Turco, a postdoctoral researcher at the Barcelona Supercomputing Center, droughts in Europe can be predicted 4 to 5 months in advance. This predictability is possible because such events are defined using the Standardized Precipitation Evapotranspiration Index (SPEI) which, apart from precipitation, takes temperature also into account over a predefined region. This is an important improvement, meaning it is viable to develop an early-warning system capable of anticipating droughts in areas where prediction still represents a challenge. The new method is highly relevant for European summers, characterized by high evapotranspiration potentials associated to high temperatures (1). In figure 1, a prediction of drought for August 2018, made in June, demonstrates a pretty good accuracy when compared to the actual occurrence in August.
Figure 1. Drought prediction for August 2018, made in June (left) shows a good performance when compared against the actual drought conditions observed during August (right).
Being able to predict droughts in advance can be useful for water reserve administration, agriculture and fire risk management. In a more recent publication in Nature Communications (2018), Turco uses a similar approach to predict the potential incidence of wildfires at seasonal time scales. Since some of the key drivers of fires are droughts and high temperatures, current seasonal climate predictions merge pretty well with climate fire models. Turco’s results, this time based on the analysis of the precipitation index (SPI), can anticipate the overall burned area of a region of interest one trimester in advance.
Anticipating a hazardous climate condition is by no means a way to prevent it from happening. However, suppose you own a farm and have to decide whether to buy forage to feed your livestock during the summer, or just rely on your own production. Wouldn’t you use some information about spring? If it is predicted to be dry, your lands might not produce enough and you can decide to order some forage today, at better prices. When you can not prevent, at least you can adapt.
Many European regions are or will be under water scarcity conditions due to climate change and agriculture is one of the most concerned sectors about it. Energy production from renewable sources, especially hydropower, and water management, are worried too. All three are highly relevant economic areas, strategic to the European Union. To foster adaptation measures, several initiatives have been put into action funded by the H2020 program.
These initiatives include IMPREX, a project focused on the management of hydrological extreme events, and others like MED-GOLD, for agriculture, or S2S4E, for renewable energy production and trading. The underlying science is strong, but these projects go much further: they seek to engage with the final users to tailor the services to each particular situation. For this to happen, an effort to move from national to sub-national, regional or even agricultural district scale has to be made. This level of detail would align more closely with the needs of the stakeholders.
Outputs from IMPREX, MED-GOLD and S2S4E suggest that operational forecasts of summer drought in Europe can be attempted, but users need to be well trained on how to best interpret and use these kind of tools and make them more relevant and usable, in a real context of decision making.
Under the common tag of Climate Services, the final objective of all these initiatives is to read the complex signs of nature and try not to lose the stack when facing climate change.
Additional information on the improvement of seasonal prediction of drought and other indices in Europe can be found in the deliverable 3.4 of IMPREX, lead by BSC project partners (Caron et al. 2018).
- Caron L.P., F.J. Doblas-Reyes, V. Guemas, R. Marcos, F. Massonet, N. Mishra, C. Prodhomme, M. Turco, C. Ardilouze, A. Ceglar, A. Toreti (2018) Hydro-meteorological indices for successively improving seasonal prediction systems for sectoral impact assessment, IMPREX D3.4.
- Turco, M., A. Ceglar, C. Prodhomme, A. Soret, A. Toreti, F.J. Doblas-Reyes (2017) Summer drought predictability over Europe: empirical versus dynamical forecasts. Environmental Research Letters 12, 084006, doi.org/10.1088/1748-9326/aa7859
- Turco, M., S. Jerez, F.J. Doblas-Reyes, A. AghaKouchak, M.C. Llasat, A. Provenzale (2018) Skilful forecasting of global fire activity using seasonal climate predictions. Nature Communications 9: 2718, doi: 10.1038/s41467-018-05250-0