Is the World Reaching
“Peak Water”?
Gulbenkian Foundation, Lisbon, Portugal
Dr. Peter H. Gleick
Pacific Institute
2010
“Peak water: Conceptual and practical limits to
freshwater withdrawal and use”
Peter H. Gleick and Meena Palaniappan
Proceedings of the National Academy of Sciences
(PNAS)
June 22, 2010 vol. 107 no. 25 pp. 11155-11162
doi: 10.1073/pnas.1004812107
Global
Population
Global CO2
Concentration
U.S. Oil
Production
Atlantic Cod
1950-2008
Market
Penetration of
Telephones in US
Ecosystem
carrying capacities
Cumulative Dam
Capacity in US
Renewable or Non-Renewable?
• Non-renewable resources are “stock” limited.
• Renewable resources are “flow” limited.
• Water uniquely exhibits characteristics of
both: overall renewable but with some fixed,
isolated non-renewable stocks.
Peak Renewable Water
Total Renewable Supply
But, how much can we
actually use??
How much should we
actually use?
Total Colorado River Flow at the Delta
Gleick and Palaniappan 2010
Peak “Non-Renewable” Water
Such as fossil groundwater
(Central Valley, Ogallala, Libya,
North China Plains, central
India…)
Peak “Ecological” Water
Value Provided by Water
Value of Ecological
Services Provided
by Water
?
Amount of Water Appropriated by Humans
Value of Human
Services Provided
by Water
Overall Economic and Ecological Value
Peak “Ecological” Water
Amount of Water Appropriated by Humans
Peak Water and Water Quality
• Approaching peak renewable water leads to
accelerating decline in water quality (e.g.,
limited dilution flows) and limits to growth.
• Approaching peak non-renewable water leads
to accelerating decline in water quality (e.g.,
salinization of groundwater) and declining
productivity.
• Approaching peak “ecological” water leads to
ecosystem decline.
So, What Does Peak Water Mean?
• We’ll never “run out” of water overall. It is
(mostly) renewable.
• Where water is “non-renewable” we will run
into stock constraints.
• We will run up against “flow” limits that are a
combination of natural and economic
constraints.
• We are increasingly hitting (or exceeding)
peak “ecological” water limits.
Total U.S. Water Use and GDP
Peak Water?
Dr. Peter H. Gleick
[email protected]
Pacific Institute, Oakland,
California
www.pacinst.org
www.worldwater.org