Limited availability of fresh water is often overlooked as a cause of food scarcity and environmental decline, according to Colin Chartres. Governments should be ramping up efforts to make sure we have enough to grow crops as well as enough to drink, he argues.
Essentially, every calorie of food requires a litre of water to produce it
This year, the world and, in particular, developing countries and the poor have been hit by both food and energy crises.
As a consequence, prices for many staple foods have risen by up to 100%.
When we examine the causes of the food crisis, there are many contributing factors: a growing population, changes in trade patterns, urbanisation, dietary habits, biofuel production, climate change and regional droughts.
Thus, we have a classic increase in prices as a result of high demand and low supply. However, few commentators specifically mention the declining availability of water that is needed to grow irrigated and rain-fed crops.
According to some, the often mooted solution to the food crisis lies in plant breeding that produces the ultimate high yielding, low water-consuming crops.
While this solution is important, it will fail unless attention is paid to where the water for all the food, fibre and energy crops is going to come from.
The causes of water scarcity are essentially identical to those of the food crisis.
There are serious and extremely worrying factors that indicate water supplies are close to exhaustion in some countries.
Human needs for water have to be balanced against nature's needs
Population growth over the next four decades will see the number of people in the world increase from 6.5 billion up to 9.0 billion.
Essentially, every calorie of food requires a litre of water to produce it.
So on average, we require between 2,000 and 3,000 litres of water per person to sustain our daily food requirements.
We will have 2.5 billion extra mouths to feed by 2050, so finding the extra water each year will not be an easy task, given that it is more than double what is currently used in irrigation.
We also have to bear in mind that the availability of new fertile land in humid areas for rain-fed farming is extremely limited.
Recent studies, as part of the Comprehensive Assessment of Water Management in Agriculture, have indicated that we will not be able to produce all the food, feed and fibre required in 2050 unless we improve the way we manage water.
Invest and survive
A few years ago, the International Water Management Institute (IWMI) demonstrated that many countries are facing severe water scarcity, either as a result of a lack of available freshwater, or as a consequence of a lack of investment in infrastructure such as dams and reservoirs.
Current estimates indicate that we will not have enough water to feed ourselves in 40 years time
What makes matters worse is that this scarcity predominantly affects developing countries where the majority of the world's 840 million undernourished people live.
However, there are potential solutions. These include more water storage, improved management of irrigation systems and increasing water productivity in irrigated and rain-fed farming systems.
All of these will require investment in knowledge, infrastructure and human capacity.
Better water storage has to be considered. Ethiopia, which is typical of many sub-Saharan African countries, has a storage capacity of 38 cubic metres per person.
In contrast, Australia has almost 5,000 cubic metres per person, an amount that in the face of current climate change impacts may be inadequate.
Whilst there will be a need for new large and medium-sized dams to deal with this critical lack of storage in Africa, other simpler solutions will also be part of the equation.
Governments should make sure water infrastructure is up to standard
These include the construction of small reservoirs, sustainable use of groundwater systems including artificial groundwater recharge, and rainwater harvesting for smallholder vegetable gardens.
Improved year-round access to water will help farmers maintain their own food security using simple supplementary irrigation techniques.
The redesign of both the physical and institutional arrangements of some large and often dysfunctional irrigation schemes will also bring the required productivity increases.
Safe, risk-free re-use of wastewater from growing cities will also be needed.
Of course, these actions need to be paralleled by development of drought-tolerant crops, and the provision of infrastructure and facilities to get fresh food to markets.
Since the formulation of the UN Millennium Development Goals (MDGs), much of the water agenda has been focused around the provision of drinking water and sanitation.
This puts demand on the same resources as agricultural water; and as we urbanise and improve living standards, increasing competition for drinking water from domestic and other urban users will put agriculture under further pressure.
While improving drinking water and sanitation is vital with respect to health and living standards, we cannot afford to neglect the provision and improved productivity of water for agriculture.
Many communities are still struggling to gain enough clean water
Current estimates indicate that we will not have enough water to feed ourselves in 40 years time, by when the current food crisis may turn into a perpetual crisis.
Just as in other areas of agricultural research and development, investment in the provision and better management of water resources has declined steadily since the Green Revolution.
My water science colleagues and I are raising a warning flag that significant investment in both research and development and water infrastructure development is needed if dire consequences are to be avoided.
Dr Colin Chartres is director-general of the Sri Lanka-based International Water Management Institute (IWMI), a not-for-profit research organisation focusing on the sustainable management of water resources for food, livelihoods and the environment
To read the summary of "Water for Food, Water for Life", visit http://www.iwmi.cgiar.org/Assessment
The Green Room is a series of opinion articles on environmental topics running weekly on the BBC News website
Do you agree with Colin Chartres? Is the availability of water likely to constrain increases in food production? Are governments doing enough to safeguard the supply and encourage economy? How should we prioritise drinking water, sanitation and the needs of agriculture?
The article made no mention of the great inefficiency of growing and slaughtering animals for protein; their feed, over their lifespans, requires a great deal of water. Vegetable protein requires much less, perhaps one-tenth, (or even less) water. Vegetarians have a point or two.
Nicholas Bodley, Waltham, Mass., USA
The planet will survive but it may have to wipe a great many of us out to do it. In order to keep our numbers healthy, Mother Earth will weed out the sick and overly numerous in whatever ways she can - natural disasters, diseases and wars among the top methods. I agree with a previous comment made, I don't think the leaders of the world will act fast enough and many of us will die - but in the end our numbers will be healthier and the planet will eventually recover.
R. Eagleton, Austin, Texas USA
We must start to use water more efficiently and prevent water-waste in the home. Spain is already having problems producing enough veg from its limited water supply.
The one thing that we seem to ignore is the fact that all of the farm animals we raise use up water. Lots of it. According to a University of California study, raising 1 lb of vegetables uses 25 gallons of water, 1 lb of beef uses 5214 gallons of water. Furthermore, it is very often farm effluent that is polluting our streams and contaminating our groundwater. For me, the solution to our water crisis is simple - consume a vegetarian or vegan diet.
Richard Howard, Chiang Mai, Thailand
It is absolutely clear that population control underpins all efforts of the human race to survive - so why will no one discuss it? We need to control ourselves or nature will do it for us causing untold misery in the process.
Australia's food crisis is here now: rising population, depleted aquifers, dysfunctional dams, cropland degradation and rising oil costs.
There's insufficient available water to support irrigated industrial agriculture now and this will significantly worsen. For Western Australia, a wheat growing region of global importance, the sudden 15% reduction in rainfall in the late 1970's equated to a 60% increase in evaporation from croplands and dams. Now our Murray-Darling Basin is dead this country has lost 40% of its fresh fruit and vegetables - all irrigated crops.
Organic farming can sequester 70% of Australian annual CO2 emissions, build stronger soil, supply nutritious food, and use 40% of the oil currently used to grow industrial food. It's transition time folks!
Jerry Coleby-Williams, Brisbane, Australia
Simple solution: Pay people to NOT reproduce! If every couple had only one child (or even better, no children at all, if that was their wish) this seemingly inevitable human population crisis would never be arise. Not everyone wants to be a parent. Most men do not dream of becoming fathers and increasing numbers of single women feel the same. Were the world's current population to be halved tomorrow, think of how much better off all of us would be.
Monica, Seattle, USA
This "Water crisis" is very much unlike the "Climate Crisis". Water availability and its management are concepts that are well understood. There is no need for politicians to put faith in dubious computer models to understand these issues. They will not need to put their faith in yet to be perfected technologies nor risk taking unilateral action without any guarantee that other governments will follow suit. Governments will see a payback on investment in water infrastructure and be making a popular and tangible contribution to the well-being of their people in addition to helping solve a "world" problem. For these reasons there is a good chance that that appropriate measures will be taken.
G Gaskell, Michigan USA
One important - and very obvious fact - was omitted... the critical need to get global warming under control that will otherwise drastically change rain patterns and expand deserts. This includes the urgent need to stop the destruction of forests which not only act as natural generators and reservoirs of most of the World's water, but hold immense amounts of carbon that are released as they are razed and burnt. Combine this with the also very obvious issue of limiting population growth and, just perhaps, humanity has a chance at preserving some level of quality of life. Otherwise, I see a very bleak and difficult future. Continued destruction of our remaining intact ecosystems, such as forests, is nothing less than humanity's signature on a suicide note.
JF Chalmers, Toronto, Canada
I would agree with both John Yaya and Gordon Stanger: there is an enormous wastage of water. This contributes to economic water scarcity. The number of countries that will face 'real' physical water scarcity will remain very small. These also happen to be oil and gas rich countries which have money to spend on desalination.
The biggest improvement that can be made, however, is by restoring the water retention capacity of soils, through biochar. This is so because of all economic sectors, agriculture uses up most water, by far. Putting biochar into soils can slash the amount of water needed to irrigate crops dramatically.
Many other water/soil management techniques exist, but the question is whether they can be implemented fast enough and on a wide enough scale.
Laurens Rademakers, Brussels, Belgium
What about going into the asteroid field and finding a cubic mile of fresh water (mixed with rock and such, of course). That would satisfy earthly needs for awhile. Remember, the gravitational gradient is down. Towing it into earth orbit would not be too difficult. To get it to earth, either shuttles could be used (very inefficient) or you could hook it up to a miles high vertical cable, in small chunks, attached to the ground, and let gravity do the rest.
Steve MacDonald, Ottawa, Canada
When will anyone or any government finally address the Catholic church about its views on contraceptives? All of our earth crises now are compounded tremendously by our ever increasing population growth. We cannot find a way to have more people living better, more people simply means bigger problems for the forseeable future. We need to slow down growth in order to begin to get a handle on our current situation.
R. Fuentes, Decatur, GA USA
"Population growth over the next four decades will see the number of people in the world increase from 6.5 billion up to 9.0 billion" - this statement, or something similar, is often repeated as if this is something we have to accept. If we do, then all the technical fixes in the world are not going to save us - the world can not support 9 billion people - and will not. Ultimately if we do nothing about it - and it looks as if we will not - then we will suffer the same fate as all plague species - massive population collapse due to lack of resources.
I dont really agree with that.For myself the water is something that we can not make sure that is gonna be finished one day,its impossible to control its amount of water.I mean,to control the environmental polluiton,yes,that`s what intelligent human being should do! I agree during the population growth would damage completely those future lives if we do not educate ourselves following education to the others to come.Be attention to the potential solutions,please.
wellington bastos junior, Joinville Brazil
'Unless these problems are robustly dealt with, there is no hope, and the poor will starve.
Gordon Stanger, (currently) Jaipur, Rajasthan, India'
The poor are already starving (even the not quite so poor now), yet there is still not the political will to address the problem. Polititians still waltz around in government properties, exclusive golf clubs, private estates & hotels all with free flowing fountains and lush gardens, whilst their people die on the back steps of those 'haunts of the elite' from lack of the basic necesities of life.
This tells you all you need to know about the polititians and the economic policies of the world.
Since most of the problems in the world today are caused by bickering polititians, the people of the world need to ask themselves sincerely 'Do we still need polititians and their flawed economics-based politics, being paid for from the pocket of big business, yet still taxing the populous into destitution - until there are no more people able to afford the consumer culture that big business depends on?'
Free Earth is the only way out.
There is enough scientific proof. I don't know why governments, businesses and some individuals keep burying their heads in the sand.
According to some books, here are listed the main reason for past societal collapses. There's a lot to do, but we need to act NOW. What are the governements waiting for? what are we waiting for?
Deforestation and habitat destruction
Soil problems (erosion, salinization, and soil fertility losses) Water management problems Overhunting Overfishing Effects of introduced species on native species Population growth Increased per-capita impact of people
Human-caused climate change
Buildup of toxins in the environment
Full human utilization of the Earth's photosynthetic capacity
The world is in deep doh-dof indeed.
Have less children (means available contraceptives / sexual health education / curbing some social and religious beliefs....)
Consume less / lobby our shops, brands and governments to become sustainable
Become less dependent on oil (see Transition Towns initiative)
Read Collapse by Jared Diamond.
Nathalie Tafelmacher, London, GB
The future major life threatening crisis the world will face will be the water availability crisis .Oil supplies may run out but there will always be alternatives to take its place but for a lack of water there is no alternative .One must remember the amount of water on Earth today is the same amount that we had during the age of the dinosaurs it is just found in different physical forms and in different locations .Unfortunately ,these different locations are not where it is needed most . The word USABLE is the key word here .Many areas of the world have water but it is not USABLE .. salt water and contaminated cannot be used to grow crops support livestock .Potable water must be available humans to live in the areas that they now inhabit If water is not available then they must move or die. Will this stem the next major migration of the human race .I have see countless countries on my travels allow their precious water reserves to slip away almost within !
the blink of an eye . Uncontrolled deforestation , wasteful agricultural practices coupled with explosive relentless urban development has diminished the USABLE water supplies of many countries If you cannot move to a new water supply like our ancestors did when available water ran out then you will did .Until humans LEARN to treat water as the most precious ingredient needed to maintain life on planet Earth then we will forever be held hostage by its availability.Presently, wars are being fought in the oil rich areas of the world to keep its supply flowing ,if the world's future " oil" becomes water where will the next wars be fought ? NOTHING lives without USABLE water... will it become worth dying for more so than oil ?
skip nieman, ottawa canada
Unless, as a species, we acknowledge that over population is the root cause of ALL survival problems on planet Earth we are doomed. Its not necessary for billions to die a horrible death if we would just act to constrain the relentless population rise.
Bruno Wallenburg, Sunbury, Ohio USA
Certainly he is.India is using ground water, from deep bore wells, for all it's agricultural irrigation.Insufficient rains falls there to replenish it so starvation will result if no action.China's river are so polluted that one understands they cannot be treated to make water drinkable, or usable on crops! Thus there is a large market for those specialist companies in water management
Alastair Clarke, Leamington Spa UK
"Matter is neither created nor destroyed" so goes the scientific saying.
Yes, food production and life of the more than 9 billion people in 40 years to come will depend greatly on investment in water harvesting and storgae facilities. Planet Earth has a stock of over 1,384,120,000 cubic kilometers of water involved in the hydrological cycle. The nine (9)billion people by the year 2048 will need about 45,000 cubic kilometers at 5,000 cubic meters storage capacity per person of the 225,000 cubic kilometers of the surface freshwater that can be replenished through the hydrological cycle. Yes, there is need to worry in the absence of investment in water harvesting and storage facilities.
Faustino L. Orach-Meza, Entebbe, Uganda
Yes, water for food is critical, but in most developing countries there is still chronic wastage of water, hopelessly dysfunctional water resources management, blatant and pervasive corruption, out-of-control population growth, and lack of political will (plenty of PC platitudes, but minimal and ineffective investment). Unless these problems are robustly dealt with, there is no hope, and the poor will starve.
Gordon Stanger, (currently) Jaipur, Rajasthan, India
The BBC ignored the real storage solution to water which is to increase the amount of carbon in soils. Soils with more carbon percolate more water to groundwater recharge as well as holding more water in the soil zone longer. Both pasture management and the addition of biochar, charred agricultural waste, to the soil are ways to effectively increase soil carbon. As a final bonus soils with more carbon have higher yields in both crops and biomass.
John Yaya, Chico, CA.
yes we need to manage water supply better .but Colin Chartres and co have to realize that every coutry must also have a sustainable population ,its not rocket science . We cannot keep populating ad infinitum and they should have the guts to say so
I don't expect the ineffectual governments of the world to do anything meaningful about this. So, the world is in deep doo-doo.
Jared Markham, Norwood, NY USA