The world's population grows by some 83 million people each year - more than the population of Germany. Even if population growth slows, it is expected that there will be nine billion people on the planet by the year 2050 and ten billion at some point this century.

In order to satisfy their requirements, about 2,400 kilocalories per head would be necessary. Agricultural production, as a result, would have to be doubled or even tripled in the next 40 years.

Given the limited resources of the earth, the question arises as to whether this is even possible. In essence, it is, says Harald von Witzke, professor of agricultural sciences at the Humboldt University of Berlin. But there is one major requirement.

The enormous growth in agricultural production of past decades, Witzke says, is a result in an increase in productivity of the land. Only 20 percent was down to an expansion in the amount of land set aside for agricultural use.

"In the future we need to have to ensure that there is even greater productivity if we are to succeed in satisfying the rapidly growing demands of people for food. Land area is increasingly becoming a limiting factor for the increase in food production."

Best land already in use

In fact, some 40 percent of the surface area of the world's land is used for agricultural production. On 16 million square kilometers of that land, grain is grown. Some 30 million square kilometer - an area the size of South America -  is used as pasture land. These are the best pieces of land, and they are already being used.

In many parts of the world, there are no significant reserves of land to be set aside for food production - with the developing world being the exception.

According to the United Nations' Food and Agriculture Organization (FAO), only a little more than a third of land that could, in theory, be used is currently being farmed. The conversion of tropical rain forests and peat lands, however, is ruled out for climate protection reasons.

Water, a limiting factor

The increase in productivity itself will be influenced and slowed by various factors. First there are water and energy costs. Globally, agriculture consumes huge quantities of water. It is predictable, according to FAO deputy general director Alexander Müller, that water shortages will become a central theme in the coming years. "We have examined the global distribution of water scarcity and established that, in the areas with high population increase, the water shortages will be at their greatest," said Müller.

"That means that, of all places, it is those countries where it is absolutely vital that more food is produced, the basic prerequisites are lacking."

Efficiency is one of the approaches mentioned in a study by an international research team led by Jonathan Foley from the University of Minnesota.

In the future, irrigation and fertilizer should only be used where worthwhile. Plants that need lots of water, for example, should not be grown in dry areas. As for fertilizer use, studies have shown that half of the fertilizer seeps away instead of actually being taken up and used by the plants. It is a process of waste that has also led to the proportion of phosphates and nitrates in the environment to increase – something that results in water pollution. It is a vicious circle that needs to be broken.

New breeds, new lifestyles

To increase current productivity, better crop varieties and growing methods are needed. That way, according to the Minnesota study, global food production can be increased by about 60 percent.

Better varieties on the one hand mean cereals and vegetables with particularly high yields that can thrive even under harsh environmental conditions. On the other hand, staple foods could also be enriched with micronutrients in the future.

This could be achieved through the appropriate breeding or genetic technology.

World food security would be easier to ensure if more people ate less meat and other animal products, because animals need to be fed. Production of animal feed competes just as much with the growth of food for people as the growth of plants for biofuels.

However, the idea that animal products would become less popular appears to be illusory. In fact the opposite trend is apparent, with the consumption of animal products set to rise.

Reserving land for the basics

Scientists have urged that land be set aside for the growth of basic foodstuffs in future. In Latin America, Africa and Eastern Europe, especially, there is good enough land for the yield to be increased substantially. Production of animal feed and biofuels would take place elsewhere.

The production of more meat, eggs and milk products, if it were not possible to produce some of these artificially in the future, would also have an impact on the climate. Currently, 30 percent of greenhouse gas emissions are attributable to agriculture. The effects of CO2 and methane in the atmosphere will affect most those parts of the world where population is growing fastest.

Experts have called for targeted agricultural research and policy, with a specific focus on farming in the developing world.

Currently, 30 percent of greenhouse gas emissions can be put down to agriculture. The effects of more carbon dioxide and methane in the atmosphere will, in fact hit those parts of the world hardest where the increase in population is greatest.

Developing world need most attention

It is the inhabitants of developing countries who will suffer under increasing frequencies of drought, flooding, and other natural disasters. That, according to Alexander Müller, from FAO, is something that will create substantial new problems when it comes to feeding the world.

"Every debate about global hunger needs to address the issue of areas of high demand that can be found in developing countries, and that can be found in urban areas and in countries that are only partly economically developed that also have a corresponding potential for market demand," said Müller.

In other words, almost all of these countries are net importers of food, although they usually do not have enough money to buy food on the world markets.

The need to concentrate on the developing world is also stressed by the Berlin scientist von Witzke.

"The worst thing about all of this is that these countries only have very rudimentary agricultural research systems in place and so it is very difficult for farmers in these countries to adapt to climate change," said von Witzke.

More agricultural research

Experts have called for targeted agricultural research and policy, with a specific focus on farming in the developing world.

As a proportion of development aid, agriculture received 18 to 19 percent in 1980, compared with only 3.5 percent in 2007. There is a lack of advice on better farming methods, training, affordable credit, good seeds and information on opportunities for farmers to sell what they grow.

As a result, almost half of the total harvest in developing countries is lost because food is not properly harvested, transported and stored and there are not enough opportunities to add value by further processing. 

Then there are also many conflicts. If countries cannot fulfill their potential because they are torn by civil war or due to bad governance, there is little that can be done to improve agriculture and resultant yields.

How many people can the earth support? That there is a recipe for world food security is something experts agree does not exist. While the planet should be able to feed ten billion people in theory, with the growth of population highest where food security is most precarious, this may not happen in practice.

Author: Sabine Kinkartz / rc
Editor: Sarah Steffen