Rethinking Groundwater Supplies in Light of Climate Change: How Can Groundwater Be Sustainablly Managed While Preparing for Water Shortages, Increased Demand, and Resource Depletion?
Meyland, Sarah J., Forum on Public Policy: A Journal of the Oxford Round Table
Signals that a World Water Crisis is Developing
The Intergovernmental Panel on Climate Change (IPCC) has noted, in increasingly strong language, that the water sources (rivers, lakes, and bores/groundwater) humans have relied upon for millennia may disappear or be radically different in the future (Bates 2008; Gupta 2007; Lean 2007; Watson et al. 1997).
The predicted changes address where water is located, in what form water is stored (ice vs. liquid) and in what amount will water be available. The natural conditions related to these changes include:
$ shifts in precipitation patterns; some areas receiving more rain, others receiving less;
$ shifts in storm frequency (fewer) and intensity (more intense) (Chang 2008);
$ loss of ice stored as glaciers and as polar ice formations (Revkin 2008);
$ loss of inland river flow due to reductions in winter storms, spring snow melt and runoff; and
$ drop in groundwater levels due to reduced recharge (less rain over recharge areas) and increased pumpage from aquifers (Bates 2008; Rogers 2008).
Although public and regulatory attention is slowly exerting pressure to make public water supply systems more efficient, meaning they waste less water, and more conservation minded, are these efforts missing the bigger picture of overall freshwater availability, now and in the future? According to Peter Rogers, P.E., of Harvard University (2008), "the world's demand for freshwater is currently overtaking its ready supply in many places and this situation shows no sign of abating."
Reminder of World Water Resources
It is worth remembering how the earth's water is distributed across the planet. Of all the water on earth, 97 per cent is held as saline water, primary in the earth's oceans, and is unfit for use by most terrestrial plants and animals, including humans. Only 3 per cent of the earth's water is freshwater and of this, 2 per cent is stored as ice in continental glaciers and the polar ice caps. Thus, only 1 per cent of the earth's total water is readily usable by humans. Most of the 1 per cent is stored as groundwater. Surface water (streams, rivers and lakes) makes up only about 0.02 per cent of all water (USGS Water Basics).
Climate Change Is Already Affecting Freshwater Resources
Some of the most important glaciers around the world are in retreat. For example, glaciers in the Himalayas, the Tibet-Qinghai Plateau, Alaska and Canada, Greenland, South America and Switzerland are melting faster than most climate models predicted.
"Yao Tandong, one of China's leading glaciologist, believes that at currents rates, two thirds of the Tibet-Qinghai Plateau glaciers could disappear by 2060" (Brown 2008 4). The Greenland glaciers are melting so rapidly that they are triggering localized earthquakes as the crust adjusts to the loss of billions of tons of ice that is "breaking off and sliding into the sea." (Brown, P. 2007).
According to Chris Rapley, leading expert for the British Antarctic Survey, "the ice is moving faster both in Greenland and Antarctica than the glaciologist had believed would happen" (Brown 2008 4). Recently, "the Markham Ice Shelf, a sheet of ice that had been attached to Ellesmere Island in the Canadian Arctic for 4,500 years, broke loose and disintegrated over a few days in August , scientists reported," in September (New York Times 2008).
The loss of major continental ice formations is important for many reasons. One reason important to humans is that the melting water drains a significant amount of fresh water to the oceans. Excessive melting represents a disruption of the normal snow and melt cycles that have historically provided water to some of the world's major river and groundwater systems. "The glaciers in the Himalayas and on the Tibet-Qinghai Plateau feed all the major rivers of Asia, including the Indus, Ganges, Mekong, Yangtze, and the Yellow Rivers. …