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.
Thirsty world
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.
Continued at ... http://news.bbc.co.uk/2/hi/science/nature/7564140.stm
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.
Thirsty world
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.
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.
Continued at ... http://news.bbc.co.uk/2/hi/science/nature/7564140.stm