Peak water might be a more serious problem — and perhaps happening sooner — than peak oil. NASA satellites provide more evidence of the danger. But as the comment at the end notes, profitable but unsustainable agriculture is the underlying cause of the problem — and ending it will be the eventual result (but hardly a solution).
As SOP on the FM site, here is a general explanation plus an abstract of the article.
- “NASA Satellites Unlock Secret to Northern India’s Vanishing Water“, NASA, 12 August 2009
- “Satellite data show Indian water stocks shrinking“, Quirin Schiermeier, Nature, 20 August 2009
- Conclusions — about shockwaves
- For More Information
(1) “NASA Satellites Unlock Secret to Northern India’s Vanishing Water“, NASA, 12 August 2009 — Excerpt:
Beneath northern India’s irrigated fields of wheat, rice, and barley — beneath its densely populated cities of Jaiphur and New Delhi, the groundwater has been disappearing. Halfway around the world, hydrologists, including Matt Rodell of NASA, have been hunting for it.
Where is northern India’s underground water supply going? According to Rodell and colleagues, it is being pumped and consumed by human activities — principally to irrigate cropland — faster than the aquifers can be replenished by natural processes. They based their conclusions — published in the August 20 issue of Nature — on observations from NASA’s Gravity Recovery and Climate Experiment (GRACE).
“If measures are not taken to ensure sustainable groundwater usage, consequences for the 114 million residents of the region may include a collapse of agricultural output and severe shortages of potable water,” said Rodell, who is based at NASA’s Goddard Space Flight Center in Greenbelt, Md.
… Changes in underground water masses affect gravity enough to provide a signal, such that changes in gravity can be translated into a measurement of an equivalent change in water.
“Water below the surface can hide from the naked eye, but not from GRACE,” said Rodell. The twin satellites of GRACE can sense tiny changes in Earth’s gravity field and associated mass distribution, including water masses stored above or below Earth’s surface. As the satellites orbit 300 miles above Earth’s surface, their positions change — relative to each other — in response to variations in the pull of gravity. The satellites fly roughly 137 miles apart, and microwave ranging systems measure every microscopic change in the distance between the two.
With previous research in the United States having proven the accuracy of GRACE in detecting groundwater, Rodell and colleagues Isabella Velicogna, of NASA’s Jet Propulsion Laboratory and the University of California-Irvine, and James Famiglietti, of UC-Irvine, were looking for a region where they could apply the new technique. “Using GRACE satellite observations, we can observe and monitor water changes in critical areas of the world, from one month to the next, without leaving our desks,” said Velicogna. “These satellites provide a window to underground water storage changes.”
The northern Indian states of Rajasthan, Punjab and Haryana have all of the ingredients for groundwater depletion: staggering population growth, rapid economic development and water-hungry farms, which account for about 95% of groundwater use in the region.
Data provided by India’s Ministry of Water Resources suggested groundwater use was exceeding natural replenishment, but the regional rate of depletion was unknown. Rodell and colleagues had their case study. The team analyzed six years of monthly GRACE gravity data for northern India to produce a time series of water storage changes beneath the region’s land surface. They found that groundwater levels have been declining by an average of one meter every 3 years (one foot per year). More than 109 cubic km (26 cubic miles) of groundwater disappeared between 2002 and 2008 — double the capacity of India’s largest surface water reservoir, the Upper Wainganga, and triple that of Lake Mead, the largest man-made reservoir in the United States.
“We don’t know the absolute volume of water in the Northern Indian aquifers, but GRACE provides strong evidence that current rates of water extraction are not sustainable,” said Rodell. “The region has become dependent on irrigation to maximize agricultural productivity, so we could be looking at more than a water crisis.”
… “At its core, this dilemma is an age-old cycle of human need and activity — particularly the need for irrigation to produce food,” said Bridget Scanlon, a hydrologist at the Jackson School of Geosciences at the University of Texas in Austin. “That cycle is now overwhelming fresh water reserves all over the world. Even one region’s water problem has implications beyond its borders.”
“For the first time, we can observe water use on land with no additional ground-based data collection,” Famiglietti said. “This is critical because in many developing countries, where hydrological data are both sparse and hard to access, space-based methods provide perhaps the only opportunity to assess changes in fresh water availability across large regions.”
(2) “Satellite data show Indian water stocks shrinking“, Quirin Schiermeier, Nature, 20 August 2009 — “Groundwater depletion raises spectre of shortages.”
Unsustainable water use in India is threatening agricultural production and raising the spectre of a major water crisis. Matthew Rodell of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and colleagues used data from the Gravity Recovery and Climate Experiment (GRACE) satellites — operated by NASA and the German Aerospace Center (DLR) — to determine how groundwater levels are changing in the Indian states of Rajasthan, Punjab and Haryana, which includes the national capital of New Delhi.
Comment by Arvind Kumar:
I think that the main reason for the fast depletion water stock in north India, particularly in Haryana and Punjab is the success of Green Revolution. Green Revolution introduced the Paddy (Rice) crop in this region. Rice crop requires a lot of water and thus, ideally not suited for Haryana and Punjab – definitely not at the level that was demanded by the green revolution. The success of green revolution in India was due to use of ground water.
If we want to reduce the depletion of water stock in north India, the most important step would be to change the agricultural habits of the farmers in Haryana and Punjab, and introduce alternative crops which do not rely so heavily on water as rice does.
This is the story of water shortages in many countries, from northern India to southern California. Water intensive crops grown in dry areas, exhausting the underground water reserves. The after-effects will be painful.
(3) Conclusions — about shockwaves
The precautionary principle is usually applied in an irrational manner to individual threats, such as climate change. There are many high impact – low probability threats, which I call “shockwaves”. Also, the US and world have many vital if more mundane needs that deserve funding. Since resources are finite, we must access their relative importance — which few of these special interest groups around each shockwave bother to do. I discuss this in greater length at this post; here is my suggestion:
Commission a group to collect as many shockwave scenarios as possible, with a brief analysis of each. Fortunately there are thousands of interest groups willing to pitch in and help! Then apply a common analytical framework to rate them on both dimensions: probability and impact. The results would prove quite interesting, and allow more rational public policy discussion about which to act upon.
(4) For more information
To read other articles about these things, see the FM reference page on the right side menu bar. Of esp interest are Science & Nature – my articles.
FM posts about shockwaves and other geo-science related issues
- We are so vulnerable to so many things. What is the best response?, 30 December 2008
- About our certain doom from the Yellowstone supervolcano, 11 January 2008
- My nomination for a top priority shockwave, 19 January 2009
- A serious threat to us – a top priority shockwave – a hidden danger …, 20 January 2009
- What about all the hype, the extreme warnings, about swine flu?, 3 September 2009
Categories: Science & Nature