Peak water – will it happen?
Lester R. Brown, a United States environmental analyst and founder of Worldwatch Institute has recently written an article published in The Guardian proposing that ‘peak water’ is the major threat to our future, more so than peak oil.
So what does this concept actually mean? We know that peak oil is the point at which global production of oil will reach its maximum rate, after which production will gradually decline. Dr. Peter Gleick, president and co-founder of the Pacific Institute for Studies in Development, Environment, and Security, defines three forms of peak water as:
- peak renewable water – the peak limit of renewable systems including both surface water and groundwater systems fed by rainfall and river flow
- peak non-renewable water – the peak limit of non-renewable groundwater systems such as fossil aquifers containing ‘paleowater’
- peak ecological water- the peak limit of water where abstraction from hydrological systems is causing more ecological harm than producing economic benefit
Dr Gleick cites the Colorado River, the Nile River, the Yellow River as systems where peak renewable water has been reached. That is, the total amount of water abstracted from these rivers is greater than the flows generated by rainfall and groundwater expression, resulting in a decrease in availability. The increase in abstraction rates of non-renewable aquifers significantly greater than natural recharge is also thought to have resulted in peak non-renewable limits being surpassed in groundwater systems across the US, Northern China, India, and large areas of the Middle East. Lester Brown warns that groundwater wells are drying up and groundwater tables are falling so fast in these countries that global food supplies are seriously threatened. This is a significant concern given that China, India and the US are the world’s big three grain producers.
A groundwater survey released in Beijing in 2001 indicated that the water table under the North China Plain, an area that produces half of the country’s wheat and a third of its corn, was falling fast. While in the state of Colorado in the US, cities and towns buying irrigation water rights from farmers resulted in the drying up of an estimated 400,000 acres of wheat-producing farmland statewide between 2000 and 2005.
American Journalist Alexander Bell has also investigated the concept of ‘peak water’, suggesting that the failure to resolve our water problems will result in the movement of great waves of people, from country to country, searching for resources and a life away from the social instability and poverty that is expected to accompany water scarcity.
But what does this mean for Australia and is the concept of ‘peak water’ applicable here?
According to Dr Gleick, Australia is a good example of where peak water constraints are occurring due to physical limitations on how much water we can use. In an effort to manage our existing surface water and groundwater resources and reduce our reliance on them, a number of strategies have been developed and implemented. Desalination plants purifying seawater by reverse osmosis were first built in Perth in 2006 to provide an alternative freshwater supply and have since been constructed and are in operation in Queensland, NSW and Victoria, with additional plants currently being built in Western Australia and South Australia.
Regional water trading schemes have been also been established in recognition of the need to avoid surpassing peak water limits in our water systems. The Australian water market is a composite of many separate water market segments, each defined by water system and administrative boundaries, and of varying size, activity, and connectivity with each other. The most well known of which is the water trading system established for the Murray-Darling Basin. The Murray-Darling system has been long identified as having reached its peak ecological water limit due to its significant decline in ecological health, particularly in the downstream area of the catchment. In 2009 the Australian Government introduced water charges and water market rules under the Water Act 2007 to regulate water trading across the Murray-Darling Basin, with the first foray into temporary water trading by the Government occurring in January of this year.
More locally, water entitlements transactions in Western Australia are granted by the Department of Water under the Rights in Water and Irrigation Act 1914 and water transactions can occur at any time, subject to approval by the Department. Both surface water (comprising four irrigation cooperatives) and groundwater allocations are traded, with most trade occurring in the south-western irrigation districts managed by the Harvey Water Irrigation Cooperative (all surface water) and in horticultural areas to the north of Perth (mostly groundwater).
The development and implementation of these strategies is expected to steer us away from reaching peak water in Australia’s rivers and aquifers, which is becoming more and more critical as we obtain meteorological data such as that showing 2013 as the hottest year on record, 2010 as the driest year on record in the south west of Western Australia, and Sydney currently experiencing its driest summer for more than 70 years. In addition, population growth such as the additional 20 million people envisaged by Richard Weller and Julian Bolletter in their 2013 book Made in Australia will need to be watered somehow. But are we doing enough to secure our water resources into the future and not just for current demand? How close are our surface and ground water systems to reaching their peak limits?
The recent and exciting Nature article reporting on the newly discovered freshwater reserves beneath our oceans – an estimated half a million cubic kilometers of low-salinity water buried beneath the seabed on continental shelves off Australia, China, North America and South Africa – could be used to accommodate a growing population and reduce pressure on our rivers and aquifers to avoid reaching peak water. This potential new resource could give also regions suffering limited access to freshwater more options for combating the impact of droughts and alleviating the impact of water scarcity in the future.
In general, it seems the answer to the question of whether peak water will happen (or even has already happened) varies from region to region, in response to a number of social, economic and environmental factors. There is clearly a need to plan for it, especially where populations are dependent on non-renewable water supplies and systems that retain good ecological health.
It may seem obvious, but while we can produce food without oil, we cannot produce it without water.