World on edge of water crisis

The world is on the edge of a global water crisis as a result of depleting underground supplies caused by a combination of climate change and a rapidly increasing demand for water.

The worsening problem was highlighted at the International Astronautical Congress (IAC) in Toronto, Canada, where scientists and specialists considered how space remote sensing satellites could help.

Bob Sandford, EPCOR Chair of the United Nations’ Water for Life Decade in Canada, expressed his “grave concerns” that the world is heading for a “global water emergency”.

An expert on water scarcity and conservation issues, he said an expanding world population, increasing agricultural production and rapid industrial growth all demanded more water.

“This is happening at a time when our water supply is becoming less reliable due to climate warming-induced changes and the rate and manner in which water moves through the hydrological cycle,” he said.

“Disappearing Arctic sea ice and changes in the timing, duration and extent of snowfall in the northern hemisphere also appear to be altering the behaviour of the jet stream, causing destabilisation of historic weather patterns.

“Flooding events are damaging critical infrastructures while at the same time – and sometimes in the same region – persistent drought threatens agricultural productivity,” he added.

Addressing some of the world’s leading space experts and space policy-makers, Sandford described satellite-based technology as “our best bet” for understanding the link between the oceans, water, weather and climate.

“From space we can see and forecast changes in weather patterns, track and predict the precipitation, forecast water availability, monitor soil moisture levels and ground water depletion, and also identify contamination pathways,” he said.

“Satellite observations are also for the first time permitting us to anticipate seasonal weather and long term trends.”

But he called upon the space community to do more in communicating the benefits of information gathered from space to both the general public and those responsible for setting policies for using satellites to gather information.

Jim Crocker, of Lockheed Martin Space Systems, said fresh water was not just about lakes and reservoirs.

“It is increasingly about underground aquifers and our ability to accurately predict rainfall and track fresh water supplies routinely and over long periods of time,” he stated.

Dr James Famiglietti, a senior water scientist at the Jet Propulsion Laboratory in California, said satellites now had the capability to track freshwater availability on both land and underground.

“About a third of the world’s water use comes from ground water and over half of the water that we use for irrigation is from under ground – water is a central element of climate change,” he stated.

“Ground water is the strategic reserve in times of drought. In California, where we are in the midst of an epic drought, we are currently getting about 75% of our water from below ground.

“A sustainable ground water reserve is the key to water security across the world but in many areas it is un-managed and poorly monitored relative to surface water in rivers and reservoirs.”

Since 2002 the twin Gravity Recovery and Climate Experiment (GRACE) satellites have been making highly sensitive measurements of Earth’s gravity field

Variations in the gravity field can be caused by several factors, including the amount of water stored underground in soil and rocks.

The GRACE satellite measures tiny variations in the gravity field caused by movement of water around the globe and in this way helps provide a global picture at groundwater stocks and depletion.

Massive losses of groundwater from the aquifer underlying California’s agriculturally important Central Valley since the 1980s have been confirmed by GRACE.

In the decade up to 2012 the draw-down was equivalent to the entire water storage volume of Lake Mead, the nation’s largest surface reservoir.

The extraction of groundwater has caused wells to run dry and produced detectable regional uplift or rebound of the land due to water displacement,” Dr Famiglietti explained.

“The drought situation in California is absolutely abysmal,” he said. “There is no end in sight – more towns each day are running out of water and more and more farmers are throwing in the towel.”

He said data from satellite remote sensing satellites indicated similar patterns of ground water depletion being replicated all over the world.

“During wet periods you get a some recovery but then in droughts we get huge declines. We’re clearly using more water than is being replenished. It is the definition of unsustainable,” he stated.

Dr Famiglietti urged those involved in satellite remote sensing with access to imagery and data to take more responsibility in communicating it.

“Satellites have a huge role to play and are a major contributor in our understanding the global water crisis,” he said.

“But it has to go beyond just scientific study or papers in journals. We have to communicate the science to the general public, to decision-makers and to research managers.”

Richard Lawford, a senior scientist at Maryland’s Morgan State University and member of the  International Institute for Sustainable Development, described the agriculture and food sectors as the major source of demand for water.

“Food production is a big driver for water and irrigation for agriculture consumes around 71% of the water used by humans,” he said.

“As populations grow the demand for food increases and often the population pressure is coming in areas where water is already in short supply.

“It is projected that by 2030 the global demand for water is going to increase by 53% over what it was in 2010.

“And some of the largest increases are going to come in those areas where people are already under stress because of the lack of access to water.”

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