Change in the mean potential need for irrigation in the years 2071-2100 compared to 1971-2000 (projection)

The map shows the change in the mean annual potential need for irrigation during the growing season (01 April-30 September) for the 30-year period 2071-2100 compared to the reference period 1971-2000 based on climate projection data. Positive values indicate an increase in the need for irrigation in the future, negative a decrease. Under irrigation requirements, the mean amount of irrigation (in mm) during the growing season (v) is defined, which is necessary to maintain a soil water content of at least 40 % of the more usable field capacity in the effective root space (nFCs). The available results are not to be understood as an average of cereals and minced crops, rather than fruit species. The irrigation of agricultural crops depends on a variety of influencing factors, such as regional climatic factors, groundwater conditions and soil characteristics. Thus, the amount of water that a soil can absorb and hold can depend on its water storage capacity and can vary significantly in small-scale areas. The basis for climate data is the assumption of the IPPC’s “further-how-as-to-date” scenario RCP8.5 from the Fifth Assessment Report (AR5). This is a scenario that describes a continuous increase in global greenhouse gas emissions, resulting in an additional radiative propulsion of 8.5 watts per m² compared to pre-industrial levels by the end of the 21st century. For scenario RCP8.5, a variety of climate projections are available, resulting from different combinations of global and regional climate models (or regionalisation methods). From a maximum available total ensemble of 37 climate projections, a reduced ensemble with 10 climate projections was created at the LBEG using a selection method of the DWD. The relevant climate model data (temperature and precipitation) were subjected to monthly BIAS adjustment (through linear scaling). For the identification term, the basic soil data is supplemented by relief data as well as data on land use. Shown are the mean value of the 30-year period considered, as well as the minimum and maximum value of the bandwidth.