Footprints of the German bioeconomy

What is the water footprint?

The water footprint for the consumption of biomass-based goods in Germany includes the water withdrawals from surface waters and groundwater (volume) used for irrigation in agriculture in Germany and abroad. Water use in the course of further processing of agricultural commodities is not included.

What is the significance of the water footprint for monitoring?

Globally, the irrigation of crops accounts for by far the largest share of water use. Since irrigation takes place especially where water availability is relatively low, agriculture often causes high water stress regionally. In order to identify potential negative impacts on the environment, monitoring must record the withdrawals of irrigation water caused by consumption in Germany, especially in regions with high water stress.

How is the water footprint calculated?

The calculation of the footprint of irrigation water withdrawals builds on the results of an integrated modelling approach:

  1. A material flow model (based on the multi-regional input/output database EXIOBASE) determines for 49 world regions (44 individual countries and 5 aggregated "rest" regions) the share of production of different crop classes grown directly or indirectly for consumption in Germany. It is assumed that this proportion applies equally to the water withdrawals for irrigation.
  2. A spatially explicit land-use model (LandSHIFT) simulates the global distribution of irrigated crop production for the same crop classes and calculates the necessary volumes of irrigation water withdrawals. Changing climatic conditions are taken into account. Water withdrawals are determined separately for three different water stress levels (low, medium, high) at the point of withdrawal.
  3. For all regions, crop and water stress classes, the corresponding water withdrawals are multiplied by the proportion calculated in the first step to calculate the individual contributions to the water footprint. In the following, the individual contributions are summed-up (e.g. total footprint or footprint in regions with high water stress).