Monday, June 13, 2011

Food Security - How Will We Grow Enough Food?

log-y scale of the world population curve. Jus...Image via Wikipediaby J. Mark Dangerfield, PhD

Around the middle of 2011 the world population clocks tell us that there will be 7 billion people on earth; that is 7,000,000,000 chemical engines requiring a minimum of 2,000 calories a day in food to stave off hunger.

The calorific value to our digestive systems of rice and wheat, the staple starches for most of us, is around 340 per 100g. If we only ate cereals to supply our daily calorific needs the gents would get through 290 kg and the ladies 214 kg in a year.

So we need 1.76 million every day if we were all vegetarians. Of course many of us enjoy meat. The efficiency of the energy transfer from plant to livestock to us means we need roughly three times the plant calories to provide animal protein.

Round off some numbers and ratios for the meat eaters and each and every day the agricultural land must produce the equivalent of 3 million metric tons of usable grain; over a billion tons every year.

Suppose that 7 billion was the peak and the population was stable for a while. Maintaining food production would get harder each year because nutrient depletion, soil degradation, desertification and shortages of irrigation water are spreading across much of our productive land. Demographers suggest global population growth will slow but not until the total number has reached somewhere between 9 and 12 billion souls. Then the numbers may drop back over time to perhaps 6 billion by the end of the millennium.

The challenge for this generation is the planning to get through this population hump without starving.

Imagine the squabbles we will have if food supplies run out. Our history is one of war and conquest whose proximate cause might be the desires of egotistic empire builders but ultimately is about land, natural resources and growing enough food.

It would also be sensible to get through the hump without stripping the land of its ability to support life.

This challenge is real. Finding enough food is a daily truth to many in the developing world but food production requires solutions from everyone, even those of us who are well fed.

So what can be done?

One solution is to continue to throw technology at the problem. For some time now farmers have used artificial fertilizers, genetics and irrigation methods developed by scientists to prevent yield declines. These agronomic efforts have produced spectacular results in the short term, notably the green revolution of the 1970's.

In recent times more hi-tech has been added to the mix. Today we can see crops grown on laser levelled fields with irrigation managed by computer to synchronise with plant water demand and fertilizers applied with precision from hoppers triggered by onboard GPS systems linked to yield maps. This is the ultimate high input system and it can work extremely well where the soil is suited to the precise management of nutrient input and offtake. The Dutch have been especially good at perfecting these systems.

This intensive approach to farming sits well with us. We are very fond of the technology fix that decreases the direct human effort and increases both the amount and reliability of returns even though initial investment is prohibitive for subsistence systems.

Hi-tech agribusiness also sits well in our economies. It generates profitable product and uses many suppliers and service providers to spread the economic returns through the market.

Given all these benefits option one looks attractive and we must implement it, especially where the soils, climate and management capacity are suitable.

But technology is not a universal solution.

Most agriculture is low input relying on nature to deliver production mostly unaided. It will be hard to supply technology solutions to agricultural land managed with little or no external input because the farmers that rely on the natural regeneration of soil have no alternative. They lack the resources to do it any other way. Yet these lands must also produce consistently to support the growing human population.

The solution on these lands is to assist nature achieve natural regeneration and efficient nutrient recycling. This means helping soil regenerate the natural fertility.

Maintaining production in low input farming has been the holy grail of agricultural development work for many decades. Under the guise of 'sustainable land management' organisations from the FAO and the World Bank to local organic co-operatives have searched for ways to achieve sustainability.

What has been missed in many of the grander schemes is the simplicity of the sustainable solution. All it requires are practices that retain carbon in the soil.

So how will we grow enough food?

We will need to apply technology where we can. The science will help and we cannot be too picky on issues such as genetic modification.

However, smart application of technology is essential. It cannot work everywhere and it is unwise to create vast tracts of monoculture crops even if they are managed with computers. Nature has a nasty habit of replacing similarity with diversity. And in this case for diversity read pests and disease.

The big solution though will be to both put carbon back into the soil where it has been depleted and also enhance soil carbon levels wherever we can.

Soil maintained for optimum carbon levels retains and exchanges nutrients efficiently, has good structure that supports plants and allows roots to develop, and retains moisture but also drains. In short, soil carbon promotes plant growth.

The initial solution to growing enough food on low-input lands is to use the carbon markets to reward farmers who store carbon in soil. Paying farmers to farm carbon will help to reduce greenhouse gas emissions and even sequesters some CO2 from the atmosphere into the soil. Emitters of greenhouses gases can buy the greenhouse credit created by the low-input farmers.

In the end though a greenhouse benefit is not the real value of the investment; the real return is growing enough food.

J. Mark Dangerfield, PhD is a scientist, consultant and educator with a different take on our environmental challenges. Read more of his work at or grab a copy of his book 'Awkward news for Greenies and everyone else' at

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