Agriculture
Water pollution affects the economic productivity of
agriculture by destroying crops, reducing crop quality, and/
or diminishing yields. For instance, there is a long history
of agricultural collapses associated with the salinization
of the soil and water associated with irrigated agriculture.
Throughout history, societies have collapsed due to
decreased crop yields associated with increased salinity
(Postel 1999) (see case study of Pakistan below). It has
been estimated that land degradation of irrigated lands,
particularly from salinization, has resulted in the loss of US$
11 billion from decreased agricultural productivity worldwide
each year (Revenga et al. 2000, quoting Postel 1999).
In addition, as the quality of surface and groundwater is
degraded, farmers often must find new sources of water,
which are typically expensive and contentious, often leading
to significant political and military transboundary conflict
(see, for example, Cooley et al. 2009)