Irrigation water requirement

Assessment versions

Published (reviewed and quality assured)

• Irrigation water requirement (CLIM 033) - Assessment published Nov 2012

Justification for indicator selection

Water is essential for plant growth and there is a relationship between plant biomass production and transpiration, with the water-use efficiency (biomass production per unit water transpired) being affected by crop species as well as management. Increasing atmospheric CO₂ concentration will lead to higher water use efficiency through reductions in plant transpiration and increased photosynthesis. Higher temperatures and lower relative humidity leads to higher evaporative demands, which reduces the water-use efficiency. The resulting effect of climate change on water-use efficiency is therefore a combination of changes in temperature 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, from soil water storage or by irrigation. In drought prone areas, increasing demands for water by industrial and urban users intensify the competition for water for irrigation in agriculture.

Scientific references:

• IPCC, 2007. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Parry, K. L.; Canziani, O. F.; Palutikof, J. P.; van der Linden, P. J. and Hanson, C. E. (eds.), Cambridge University Press, Cambridge, UK.

Indicator definition

• Rate of change of the meteorological water balance

• Projected change in water availability for irrigation in the Mediterranean region

Units

• m³/ha/yr
• %

Policy context and targets

Context description

Targets

No targets have been specified.

Related policy documents

• Climate-ADAPT: Mainstreaming adaptation in EU sector policies
  Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
• Climate-ADAPT: National adaptation strategies
  Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
• DG Climate Action: What is the EU doing about climate change?
  Activities of the EU regarding climate change (both mitigation and adaptation)
• White paper - Adapting to climate change: towards a European framework for action
  EU framework for adaptation to climate change, leading to a comprehensive EU adaptation strategy by 2013

Methodology

Methodology for indicator calculation

The indicator has been produced querying a database, internal to Joint Research Centre (JRC), containing meteo data at 25 kilometers grid level, interpolated from meteo station data. The interpolation is performed taking into account only arable land, potentially suitable for crop growth. The meteo data are provided to JRC in the frame of the MARSOP 3 contract, complying with Council Regulation (EC) No 78/2008 of 21 January 2008 on the measures to be undertaken by the Commission in 2008-2013 making use of the remote-sensing applications developed within the framework of the common agricultural policy, Official Journal of the European Union, L 25 of 30 January 2008, p. 1.

The relative change in water availability for irrigation was projected under the A1B emission scenario by the HIRHAM (DMI) regional climate model for 2071-2100 relative to 1961-1990, using the WAPAA model for water availability under policy and climate change scenarios.

Methodology for gap filling

Not applicable

Methodology references

No methodology references available.

Data specifications

EEA data references

• No datasets have been specified here.

External data references

• Regional Assessment of Climate Change in the Mediterranean
• Monitoring Agricultural ResourceS (MARS)

Data sources in latest figures

Uncertainties

Methodology uncertainty

Not applicable

Data sets uncertainty

Effects of climate change on the growing season and crop phenology can be monitored directly, partly through remote sensing (growing season) and partly through monitoring of specific phenological events such as flowering. There is no common monitoring network for crop phenology in Europe, and data on this therefore has to be based on various national recordings, often from agronomic experiments. Crop yield and crop requirements for irrigation are not only affected 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 between climatic variables and factors such as crop yield.

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 going from emission scenario, through climate modelling, downscaling and 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 effect of possible adaptation options, and so far only few studies have involved livestock systems. Future studies also need to better incorporate effects of extreme climate events as well as biotic hazards (e.g. pests and diseases).

Further information on uncertainties is provided in Section 1.7 of the EEA report on Climate change, impacts, and vulnerability in Europe 2012 (http://www.eea.europa.eu/publications/climate-impacts-and-vulnerability-2012/)

Rationale uncertainty

No uncertainty has been specified