Rising populations and growing demand is making the world a thirsty planet, says David Molden. In this week's Green Room, he says the solution lies in people reducing the size of their "water footprints".
Today, one-third of the world's population has to contend with water scarcity, and there are ominous signs that this proportion could quickly increase.
Each of us can make a difference if we first consider the water implications of our lifestyles and the water footprint we are leaving behind
Up to twice as much water will be required to provide enough food to eliminate hunger and feed the additional 2.5 billion people that will soon join our ranks.
The demands will be particularly overwhelming as a wealthier, urbanised population demands a richer diet of more meat, fish, and milk.
The water required for a meat-eating diet is twice as much needed for a 2,000-litre-a-day vegetarian diet.
Cities and industries will also demand more water. Ironically, even new endeavours pursued in the cause of environmental preservation, such as producing biofuels, will place even more pressure on dwindling water supplies.
Clearly, we are heading toward a tipping point that could soon bring us to a day of reckoning when we will have literally made one too many trips to the planetary well.
Given the current rate of development, we will not be able to provide water for producers to grow enough food and sustain a healthy environment.
The only solution is to learn how to live with less water by making much better use of what we have.
Better water management is good for farmers, good for the environment and good for all of us. We already know many of the ingredients to make this happen; the big question is why isn't it happening?
The good news is that it does happen.
People are reaching for tools - new and old - to produce more food with less water.
Rice farmers in the region are now also saving water by a practice known as 'wet and dry' irrigation
They are adopting more precise irrigation practices, such as drip and sprinkle irrigation.
For example, many farmers in Nepal and India now regularly use low-cost drip irrigation to grow vegetables.
In sub-Saharan Africa, just a little water - combined with improved crop varieties, fertiliser and soil management - can go a long way.
Farmers can double the yield per hectare they currently harvest, and double the amount of food produced per unit of water.
Over the last two decades in Asia, sales of pumps that allow farmers to more reliably and precisely apply water to their crops, have skyrocketed.
Rice farmers in the region are now also saving water by a practice known as "wet and dry" irrigation, rather than following the traditional practice of keeping rice fields constantly flooded.
Also, many farming communities are getting organised into associations for more effective irrigation management.
But the bad news is that change isn't happening fast enough.
For example, there are still far too many ill-maintained and poorly operated irrigation systems across Asia that use two times more water than is really needed.
In sub-Saharan Africa, the problem is not water being wasted, but the simple yet devastating issue of access.
Despite water being available in nature, many farmers routinely lack enough water to produce food to feed their families.
Why is it that some areas use water so carelessly?
One problem lies with public policies that fail to connect the interests of different user groups.
The industrialised world is quick to point its finger at agricultural producers, blaming them for water woes, but it is our food habits that drive the problem
For example, farmers may see little self-interest in being more conservative with water if the benefits flow to cities and not to them.
Although, broadly speaking, water is a precious commodity, for many users its costs are negligible, so there is no incentive to conserve.
Many countries do not invest enough in water to enable poor rural communities to grow more food.
In the US and Australia, annual per capita water storage is more than 4,000 cubic metres. Yet in much of sub-Saharan Africa it is less than 100 cubic metres; poor countries simply cannot afford investments in large hydraulic infrastructure.
Nonetheless, the International Water Management Institute (IWMI) and other research organisations have identified new and more affordable opportunities for low-cost water investment.
For example, resource-poor farmers can afford low-cost drip irrigation kits, whereas conventional irrigation, which costs more than $4,000 per hectare, is well beyond their means.
Unfortunately, while we think we know the answers, reality is more complex.
We have dramatically altered natural water systems in the quest for more water control.
Unwittingly, we have created salinity problems, dried up rivers and have caused groundwater tables to decline.
Institutions that govern water have not adapted to address these issues. Added to this is the fact that we don't fully understand what new water problems will result from climate change.
While we desperately need to know more about water resources, basic data and knowledge are hard to get because of a lack of investment.
The industrialised world is quick to point its finger at agricultural producers, blaming them for water woes, but it is our food habits that drive the problem.
When 50% of food is wasted after it leaves farmers' fields, it leads to an equivalent water waste of 50% because wasted food is also wasted water.
Action is urgently required on several fronts: we must continue to encourage the many local actions that are having a positive impact now; we must establish policies that create incentives for farming communities to invest in better water management; and we must invest in the infrastructure and the knowledge systems needed to manage complex water systems for the benefit of all.
Each of us can make a difference if we first consider the water implications of our lifestyles and the "water footprint" we are leaving behind.
Dr David Molden is deputy director of research for the International Water Management Institute (IWMI)
The Green Room is a series of opinion articles on environmental topics running weekly on the BBC News website
Do you agree with Dr Molden? Is the world becoming an increasingly thirsty place? Is urgent action needed to help people use the precious resource more efficiently? Or will technologies like desalination plants ensure that there is enough water to go round?
While what Dr Molden said is true and has to be taken care of, it is the industrialized nations which are wasting the maximum amount of fresh water via golf resorts, etc. Food is necessary. Golf resorts are not. While we have to adopt ways to minimize water wastage during farming, I think wasting a scarce and valuable resource like water for golf,etc when water levels in earth may reach critical levels and more than one third of the world's population is suffering from its scarcity...is exactly not a good idea and needs to be addressed.
D Datta, USA/India
Over population is unfortunately the root of most resource scarcity problems. Lifestyle choices and technology can help but any improvements there will quickly be overtaken by the increasing population.
The earth is right sized for 3 to 4 billion people not 7 or 8 billion.
Michael, Philadelphia, PA, USA
Not sure I fully agree with just the numbers scenario. There are development inadequacies that compound the problem (both in numbers and resource depletion). Quite frankly - the west needs to revisit how it uses resources more than the armies of rags in poorer countries whose lives are short and brutish - with more and more population controlling factors such as HIV/AIDs. There is nothing taboo about discussing population - but it becomes a taboo if it only is biased towards poor rural peasants in Africa, Asia and Latin America and in complete isolation from other issues as well - and in complete isolation from the west's influence as well. It reminds me of the HIV - African promiscuity debate. It goes nowhere if it is not properly approached in a holistic view!
asma_756, New York
You've got to be kidding me....first off, this planet does not have a water shortage, we have an idea shortage. While I will agree that de-salination is a costly venture, it is no more expensive than setting up any other type of large volume refinery. The main problem that is that water programs are continuing to be placed into coorporate hands. Water is a utility, an essential service, it is owned by all. Water should never be in the hands of a company who's main concern is the bottom line.
Its the same old story,there's too many of us!The religeous and freemarket fundamentalists hate facing up to the truth.Oh and before the the usual dimwits line up and tell me to volunteer to be euthanased first,the point is that we should breed a little slower because people actually die naturally.
steve johnson., whitwick Leics.
The problem needs addressing on two fronts. 1 - We need to use our resources more efficiently. 2 - We need to reduce the number of people in the world. Over-population is the fundamental problem that is causing our environmental woes.
Jim G, Birmingham, England
As I see it, Monty Hall of the old US TV show "Let's Make a Deal" is offering us our choice of two curtains: behind curtain one, we can either limit populations ourselves (as odious as that may be); or, behind curtain two, we can experience global famine and resource wars (which is surely worse). There are no other curtains: imaginary deities cannot save us, nor can technology, nor can conservation, in the face of another 2.5 billion souls on this planet.
China recognized this reality and has taken harsh but prudent measures to limit the size of its population. We in the rest of the world must do the same.
James Edward Heath, Richmond, Virginia, USA
Make a start now. Go online to your water supplier's website and order water saving devices for your toilet cysterns at home (and at work). They are free, save water and are simple to install. It's a small and easy first step. "Be the change you want to see in the world" - Mahatma Gandhi
Chris, England and Wales, UK
I find the comments on population growth yet another example of worldwide issues being someone elses problem. Everyone wants to slow population growth, but no one would accept being denied their right to have children. Everyone wants to slow population growth, but no one would accept being denied access to medicines and treatments that prolong their life. Take some responsibility for your own actions and stop expecting everyone else to solve these problems!
Water access is a good example of how well-intentioned (or more precisely, self righteous) activists have done enormous harm. A properly functioning private market has consistently demonstrated itself suited both for providing water and conservation. Alas with a rallying cry of "Water must be free!" companies are chased out of South America and the poor are left to the mercy of corrupt municipalities in league with black market suppliers.
Jude Kirkham, Vancouver Canada
With all the shortages around the worls and the impact on food, surely the best way forward is to control the population, or is every human being afraid to put forward this common sense idea.
Paul Reeves, Birmingham, England
An interesting piece of article. I totally agree with Dr Molden. We need to conserve water as much as possible. And let's not play a blame game where developed and developing countries blame each other but rather work for effective solutions for this crisis.
Karan Bhambri, Delhi, India
we now have: * soil amendment that reduce water consumption by 25%. They slowly dissolve and become fertilizer. * enhanced waters that increase water bio avaiability, mitosis and reduced pathogens, more.. * together with improved soil nutrition food quality (Brix test method) increases * crop yield also increases, demonstrated * technology also exists to reverse and prevent scale build up in farm irrigation equipment to minimize pumping costs, descaling.. Consultant health scientist
John Butters, Redondo Beach, CA USA
I am partially agree with the solutions suggested by Dr.Molden as I believe these are all secondary solutions, the main issue is the population of the planet and we must hit the problem at the source. At present, we are 6.1 billion people and planning to stabilize ourselves at the score of 8.5 billion. I do not understand why population is not being focused? Yes, I am not against to the thought, that the water must be efficiently utilized.
Sanjay Singh Thakur, Indore,India
water scarcity is only a symptom of the single biggest problem the world faces, over-population. even if we had enough water to satisfy food production the environmental cost of shipping that food around the world would only cause yet more problems. personally i don't think we're too far off the production of soylent-green, ...at least as an animal feed.
david murphy, galway
I do not want to share the world resources with another 2.5 billion. Stop the population increase and there is more to go around. So when the world's breeders stop breeding I will decrease my consumption in recognition of their sacrifice. In the meantime, it is eat, drink and be merry, because tomorrow there will be a lot more people at the party.
Andy , Wales Sometimes
Is urgent action needed? Of course. We are on a finite planet with finite resources. Desalination will only be feasible if we have access to, and an abundance of, non renewable energy sources from geopolitical secure areas. Away from the anthropocentric popular worldview, we are a species in population overshoot. We have been living beyond our natural means since 1980. From an ecological standpoint, the sad, but true fact, is, WE NEED TO DIE OFF! We are outcompeting all other lifeforms for space and resources-not to mention changing ecosystems and displacing, or terminating species, through global warming. By our success we have precipitated a recent species extinction rate 100 times greater than the background extinction rate. It is time to move over and make some room. Harsh, but true. And yes, I am willing to rejoin the carbon cycle when called.
Mr. Ronald Brown, Phuket, Thailand
I agree wholeheartedly, and want to promote desalination plants for states in the US where water can be pumped to areas that are drying out. We have an increase in global warming increasing this problem and failed education in how to recycle water and use it effectively. These are areas I hope we are able to correct through programs and policies in the near future.
Deena, Stamford/Connecticut, USA
It is not only water that is wasted in this world. We waste every exploitable resource until it is gone. The human race is now completely unsustainable.
maunu, Portland, Oregon USA
An even better (but not mentioned) solution would be reducing population growth! The world can't support another 2.5 billion people without a devastating impact on the environment.
Suzanne, Melbourne, Australia
Yes I agree with Dr Molden. To use Water efficiently must be a major priority in this century. Better and cheaper technologies for desalination should also receive more attention in our Technology and Engineering Research agendas.
Alexandra Abreu, Oeiras- PORTUGAL
Like so many problems which are caused by too many people unless we address this basic situation we will only delay problems. We can help with water saving and better methods of using it but the seeds of conflict are already sown in the fight for water. Just look through how many countries some important rivers flow through.
stewart smith, St Dizant du Gua SW France