Water Use

From Open Risk Manual

Definition

Water Use denotes environmental impact factors related to hydrological disturbance due to water abstraction (consumption and withdrawal). In the EEIO analytical context Water Use is one of the commonly considered Environmental Impact factors or stressors.

Formula

Calculation of the environmental multipliers by products follow the standard demand model of Leontief (1966), where environmental pressures per million euro Q are calculated via


Q = S  (I-A)^{-1}

where

  • the vector S denotes the environmental stressors (e.g., land, water, and material accounts) per unit output of each product-region combination;
  • the matrix A denotes the direct coefficients representing the global economic structure (I is an identity matrix of appropriate size).
  • Q is known as the multiplier matrix in I-O economics and denotes the effect in terms of environmental pressure that is generated for each unit of final demand. It corresponds to the “system process” in life cycle assessment (LCA)


where S is the environmental intensity matrix showing environmental pressure per unit output of intermediate producers (industry)

Calculation

  • Dataset for EXIOBASE: water use by 160 sectors for 43 countries[1] Its computation based on EXIOBASE environmental extensions is rather straightforward since the water account documents, among others, the total quantity of water consumed and withdrawn per {region; industry} in millions of cubic meters. As for GHG emissions, dividing by the total monetary production of the industry gives the cubic meters consumed and withdrawn per million euros.

Issues and Challenges

A subtlety however is that the water account distinguishes extractions of green water (coming from evapotranspiration of the vegetation), blue water (coming from water bodies) and grey water (post-industrial processes) for each {region; industry}. Considering that the impact factors concern the water abstracted from rivers and wetlands, only blue water is considered.


References

  1. Headline Environmental Indicators Revisited with the Global Multi-Regional Input-Output Database EXIOBASE, Z.Steinmann et al. 2017