Water Footprints


Water Footprints: not the right tool for forests and water

Footprints are an important tool to quantify and communicate the effects of our lifestyles on the Earth’s finite resources, for instance the Carbon Footprint measures how our consumption patterns affect climate. Similar tools have been developed to measure our appropriation of fresh water.

Water Footprints are meant to promote sustainable water use by quantifying the amount of rain and surface water that is consumed in the production of an item as well as the volume of water polluted. Researchers in the CAR-ES network have studied the way in which water footprints can be used or misused for products from forests in the Nordic/Baltic countries and elsewhere where water is rarely in short supply.  Their findings have been published in an open access article in the journal Ambio (http://link.springer.com/article/10.1007/s13280-013-0380-z).

While water footprints are a commendable initiative, their misuse may lead to the wrong conclusions about the environmental impacts of wood products from forests in the Nordic and Baltic countries. Assuming that rain water is consumed by a growing tree is misleading, since trees in both managed and unmanaged forests “exhale” water vapour, thus rain is recycled rather than appropriated.

As a consequences of this work, the standard, ISO 14046:2014 ‘Environmental management — Water footprint — Principles, requirements and guidelines’ was changed to not include evapotranspiration for forest products.

For more information, contact Samuli Launianen (samuli.launiainen@luke.fi)

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