Saturday, September 20, 2008
Running Dry/The answer is in irrigation
The world has a water shortage, not a food shortage
MOST people may drink only two litres of water a day, but they consume about 3,000 if the water that goes into their food is taken into account. The rich gulp down far more, since they tend to eat more meat, which takes far more water to produce than grains. So as the world’s population grows and incomes rise, farmers will—if they use today’s methods—need a great deal more water to keep everyone fed: 2,000 more cubic kilometres a year by 2030, according to the International Water Management Institute (IWMI), a research centre, or over a quarter more than they use today. Yet in many farming regions, water is scarce and likely to get scarcer as global warming worsens. The world is facing not so much a food crisis as a water crisis, argues Colin Chartres, IWMI’s director-general.
The solution, Mr Chartres and others contend, is more efficient use of water or, as the sloganeers put it, “more crop per drop”. Some 1.2 billion people, about a fifth of the world’s population, live in places that are short of water (see map). Farming accounts for roughly 70% of human water consumption. So when water starts to run out, as is happening in northern China, southern Spain and the western United States, among other places, farming tends to offer the best potential for thrift. But governments, whether to win votes or to protect the poor, rarely charge farmers a market price for water. So they are usually more wasteful than other consumers—even though the value they create from the water is often less than households or industry would be willing to pay for it.
The pressing need is to make water go further. Antoine Frérot, the head of the water division of Veolia Environnement, a French firm, promotes recycling, whereby city wastewater is treated until it can be used in industry or agriculture. This costs about a third less than desalination, and cuts pollution. He expects his recycling business to quadruple in the next decade. Yet as Mr Frérot himself concedes, there are many even cheaper ways to save water. As much as 70% of water used by farmers never gets to crops, perhaps lost through leaky irrigation channels or by draining into rivers or groundwater. Investment in drip irrigation, or simply repairing the worst leaks, could bring huge savings.
Farmers in poor countries can usually afford such things only if they are growing cash crops, says David Molden of IWMI. Even basic kit such as small rainwater tanks can be lacking. Ethiopia, for example, has only 38 cubic metres of storage capacity per inhabitant, compared to almost 5,000 in Australia. Yet modest water storage can hugely improve yields in rain-fed agriculture, by smoothing over short dry spells. Likewise, pumping water into natural aquifers for seasonal storage tends to be much cheaper than building a big dam, and prevents the great waste of water through evaporation.
I believe that irrigation holds the solution to a great part of the global water crisis. In many parts of the world sprinkler irrigation is still the most used method of irrigation because it is the most available and least expensive. This method however is very wasteful, and using it in places where pervasive drought is common is not cost effective. In order for us as a species to mitigate the crisis we will surely face regarding water if present behavior persists we will have to change how we do things. Regarding the irrigation of crops it will be how they are irrigated, when they are irrigated based on changing weather patterns, and also in focusing on areas looking towards less water intensive crops in drier areas.
It is unfortunate that the very places where the most water intensive crops are grown such as cotton, rice, and corn (India, China, Africa, and the Southwest US ) are experiencing the most pervasive droughts and desertification now. As population increases towards 9 billion and resources become scarcer, farmers will most certainly have to devise ways of conserving water to get optimal growth and yield from a limited resource.
Through shifting the emphasis on crop varieties grown in these areas if possible and by changing irrigation methods from sprinkler to drip irrigation, trillions of gallons of water could be saved. Also in places where weather patterns are changing and are seeing more rain, rain catchement systems will be invaluable in helping to catch excess rain and use it for irrigation purposes.
This is where satellites that predict such patterns can also certainly be of great help in pinpointing what areas will need such changes as the effects of climate change are also felt more in these areas as well. We must begin now to work on a global plan for water conservation that takes climate change into account, but also seeks globally to shore up outdated water systems and infrastructure.
This is not something that requires any new inventions to be made that will take years to get to market. All it will take is an effort on the part of government and undividuals to see how their actions are affecting the planet and adjust them accordingly. That will not be an easy task granted, but the consequences of not doing so regardless of the types of crops planted will be detrimental to the continued sustainability of the human species.
This as well encompasses other efforts that include a global climate treaty that places caps on Co2 emissions (which causes drought and water evaporation as well as glacier melt) with an emphasis on looking at the population issue which is also an important component of resource depletion, and enforcing caps on water usage in areas where overusage is not necessary. And of course, not allowing private enterprises to buy up water rights simply to exploit water as a commodity.
The global water crisis is the most important environmental issue we will face in this century. We can no longer take this precious resource for granted. We are running dry. It is time to take action to conserve what we have left through effective irrigation practices, infrastructure, and more informed personal choices.
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