It is widely acknowledged that greenhouse gas emission-fueled climate change is having a profound and negative impact on fresh water systems around the world. Warmer weather causes more rapid evaporation of lakes and rivers, reduced snow and ice cover on open water systems, and melting glaciers.
What is less understood is that our collective abuse and displacement of fresh water is also a serious cause of climate change and global warming. If we are to successfully address climate change, it is time to include an analysis of how our abuse of water is an additional factor in the creation of global warming as well as solutions that protect water and watersheds.
There are two major factors. The first is the actual displacement of water from where it is sustaining a healthy ecosystem as well as healthy hydrologic cycles. Because humanity has polluted so much surface water on the planet, we are now mining the groundwater far faster than it can be replaced by nature. New Scientist reports of a "little-heralded crisis" all over Asia as a result of the exponential drilling of groundwater. Water is moved from where nature has put it in watershed and aquifers (where we can access it) to other place where it is used for flood irrigation and food production - where much of it lost to evaporation - or to supply the voracious thirst of mega cities, where it is usually dumped as waste into the ocean.
Water is also lost to ecosystems through global trade - water used in the in the production of crops or manufactured goods that are then exported (known as virtual trade in water). Over 20% of daily water used for human purpose is exported out of watersheds in this way. Water is also piped across long distances for industry leaving behind parched landscapes.
The second factor is the removal of the vegetation needed for a healthy hydrologic cycle. Urbanization, deforestation and wetland destruction greatly destroy water-retentive landscapes and lead to the loss of precipitation over the affected area.
Slovakian scientist Michal Kravcik and his colleagues explain that the living world influences the climate mainly by regulating the water cycle and the huge energy flows linked to it. Transpiring plants, especially forests, work as a kind of biotic pump, causing humid air to be sucked out of the ocean and transferred to dry land. If the vegetation is removed from the land, this natural system of biosphere regulation is interrupted. Soil erodes, reducing the content of organic material in the ground, thus reducing its ability to hold water. Dry soil from lost vegetation traps solar heat, sharply increasing the local temperature and causing a reduction in precipitation over the affected area. This process also destroys the natural sequestration of carbon in the soil, leading to carbon loss.
Of course, these two factors are deeply related. Just as removing vegetation from an ecosystem will dry up the soil, so too will removing water from an ecosystem mean reduced or non-existent vegetation.
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To Curb Climate Change, We Need to Protect Water
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To Curb Climate Change, We Need to Protect Water
An international rescue plan for fresh water
By Maude Barlow
On the Commons, January 19, 2010
Straight to the Source
