Crop water demand

Assessment versions

Published (reviewed and quality assured)

• No published assessments

Rationale

Justification for indicator selection

Water is essential for plant growth and there is a relationship between plant biomass production and transpiration, with water-use efficiency (biomass production per unit of water transpired) being affected by crop species and management. The increasing atmospheric CO₂ concentration will lead to higher water-use efficiency through reductions in plant transpiration and increased photosynthesis. However, higher temperatures and lower relative humidity will lead to higher evaporative demands, which will reduce water-use efficiency. The resulting effect of climate change on water-use efficiency will therefore be the result of a combination of changes in climate and atmospheric CO₂ concentration, as well as changes in crop choice and management. The water demand by crops must be met through rainfall during the growing period, soil water storage or irrigation. In drought-prone areas, increasing demands for water by industrial and urban users intensify the competition for irrigation water, and managing this requires an integrated approach.

Scientific references

• IPCC, 2014a: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1132 pp.
• IPCC, 2014c: Europe. Kovats, R.S., R. Valentini, L.M. Bouwer, E. Georgopoulou, D. Jacob, E. Martin, M. Rounsevell, and J.-F. Soussana, 2014: Europe. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part B: Regional Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Barros, V.R., C.B. Field, D.J. Dokken, M.D. Mastrandrea, K.J. Mach, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1267-1326.

Indicator definition

• Trend in crop water deficit for grain maize during the growing period
• Projected change in the crop water deficit for grain maize during the growing period

Units

• Change in water deficit (m³/ha/a)

Policy context and targets

Context description

In April 2013, the European Commission (EC) presented the EU Adaptation Strategy Package. This package consists of the EU Strategy on adaptation to climate change (COM/2013/216 final) and a number of supporting documents. The overall aim of the EU Adaptation Strategy is to contribute to a more climate-resilient Europe.

One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which will be achieved by bridging the knowledge gap and further developing the European climate adaptation platform (Climate-ADAPT) as the ‘one-stop shop’ for adaptation information in Europe. Climate-ADAPT has been developed jointly by the EC and the EEA to share knowledge on (1) observed and projected climate change and its impacts on environmental and social systems and on human health, (2) relevant research, (3) EU, transnational, national and subnational adaptation strategies and plans, and (4) adaptation case studies.

Further objectives include Promoting adaptation in key vulnerable sectors through climate-proofing EU sector policies and Promoting action by Member States. Most EU Member States have already adopted national adaptation strategies and many have also prepared action plans on climate change adaptation. The EC also supports adaptation in cities through the Covenant of Mayors for Climate and Energy initiative.

In September 2016, the EC presented an indicative roadmap for the evaluation of the EU Adaptation Strategy by 2018.

In November 2013, the European Parliament and the European Council adopted the 7^th EU Environment Action Programme (7^th EAP) to 2020, ‘Living well, within the limits of our planet’. The 7^th EAP is intended to help guide EU action on environment and climate change up to and beyond 2020. It highlights that ‘Action to mitigate and adapt to climate change will increase the resilience of the Union’s economy and society, while stimulating innovation and protecting the Union’s natural resources.’ Consequently, several priority objectives of the 7^th EAP refer to climate change adaptation.

Targets

No targets have been specified.

Related policy documents

• 7th Environment Action Programme
  DECISION No 1386/2013/EU OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 20 November 2013 on a General Union Environment Action Programme to 2020 ‘Living well, within the limits of our planet’. In November 2013, the European Parliament and the European Council adopted the 7 th EU Environment Action Programme to 2020 ‘Living well, within the limits of our planet’. This programme is intended to help guide EU action on the environment and climate change up to and beyond 2020 based on the following vision: ‘In 2050, we live well, within the planet’s ecological limits. Our prosperity and healthy environment stem from an innovative, circular economy where nothing is wasted and where natural resources are managed sustainably, and biodiversity is protected, valued and restored in ways that enhance our society’s resilience. Our low-carbon growth has long been decoupled from resource use, setting the pace for a safe and sustainable global society.’
• Climate-ADAPT: Adaptation in EU policy sectors
  Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
• Climate-ADAPT: Country profiles
  Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
• DG CLIMA: Adaptation to climate change
  Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, or taking advantage of opportunities that may arise. It has been shown that well planned, early adaptation action saves money and lives in the future. This web portal provides information on all adaptation activities of the European Commission.
• EU Adaptation Strategy Package
  In April 2013, the European Commission adopted an EU strategy on adaptation to climate change, which has been welcomed by the EU Member States. The strategy aims to make Europe more climate-resilient. By taking a coherent approach and providing for improved coordination, it enhances the preparedness and capacity of all governance levels to respond to the impacts of climate change.
• EU Common Agricultural Policy (CAP) reform - basic regulations
  References to climate change particularly in Regulation 1307/2013 (direct payments for farmers), Regulation 1306/2013 (so-called horizontal issues such as funding and controls: Articles 12 and 93, Annex I) and Regulation 1305/2013 (rural development: Articles 5, 7, 15, 28, 34, 35, 53 and 55).

Methodology

Methodology for indicator calculation

The crop water deficit is the difference between the crop-specific water requirement (in this case grain maize) and available water through precipitation. The hindcast simulation is based on the Agri4Cast gridded meteorological dataset at 25 km resolution.

The projected changes in the crop water deficit for grain maize have been simulated using two different global climate models (HadGEM2 and MIROC). These delivered input data to the WOFOST (WOrld FOod STudies) crop model, which considers the effect of increases in the CO₂ concentrations on the water use efficiency of maize. The WOFOST model is maintained and further developed by Wageningen Environmental Research (Alterra) in co-operation with the Plant Production Systems Group of Wageningen University & Research and the Agri4Cast unit of the Joint Research Centre.

Methodology for gap filling

Not applicable

Methodology references

• Biavetti et al. (2014): European meteorological data: contribution to research, development, and policy support. Irene Biavetti, Sotiris Karetsos, Andrej Ceglar, Andrea Toreti and Panos Panagos: ’European meteorological data: contribution to research, development, and policy support’, Proc. SPIE 9229, Second International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2014), 922907 (August 12, 2014); doi:10.1117/12.2066286
• Documentation WOFOST. Wageningen University and Research, 2016.

Data specifications

EEA data references

• No datasets have been specified here.

External data references

• Agri4Cast Data

Data sources in latest figures

Uncertainties

Methodology uncertainty

Not applicable

Data sets uncertainty

Crop yield and crop requirements for irrigation are affected not only by climate change, but also by management and a range of socio-economic factors. The effects of climate change on these factors therefore have to be estimated indirectly using agrometeorological indicators and through statistical analyses of the interaction between climatic variables and factors such as crop yield (Caubel et al., 2015).

The projections of climate change impacts and adaptation in agriculture rely heavily on modelling, and it needs to be recognised that there is often a chain of uncertainty involved in the projections, which range from emissions scenarios, through climate modelling and downscaling, to assessments of impacts using an impact model The extent of all these uncertainties is rarely quantified, even though some studies have assessed uncertainties related to individual components. The crop modelling community has only recently started addressing uncertainties related to modelling impacts of climate change on crop yield and the effect of possible adaptation options. Recently, the effects of extreme climate events have also been included in impact assessments, but other effects such as those related to biotic hazards (e.g. pests and diseases) still need to be explored.

Rationale uncertainty

No uncertainty has been specified