One of the remarkable achievements of the 20th century was the near tripling of the world grain harvest between 1950 and 1996, an achievement that not only fed people throughout the world but allowed their numbers to grow.

Environmental trends now threaten that achievement, making it much harder for farmers to feed the Earth's increasing population. A frightening gap between consumption and production has developed.

Falling grain stocks and rising grain prices may signal a new era in the world food economy, one dominated not by surpluses but by scarcity. If stocks fall farther, as is likely, dropping far lower than at any time in modern history, the world will move into uncharted territory.

China, the most populous nation, so far has been able to feed its people by drawing on its grain stocks. These stocks are nearly depleted, and the country is starting to look abroad. China may soon need to import up to 50 million tons of grain a year. Such demand could overload world grain markets — creating major problems for the United States, which controls nearly half the world's grain exports, as well as for the rest of the world.

This potential era of food scarcity forces us to answer two questions: How did this happen and what can we do?

Production Falling Short

Farmers have long had to cope with the cumulative effects of soil erosion, the loss of cropland to non-farm uses and the encroachment of deserts on cropland. But now they also are facing two dangerous new trends: falling water tables and rising temperatures. These converging conditions have taken a toll on food production.

World grain production did not increase at all during the seven years following 1996. Instead it fell behind the growth in consumption, generating progressively larger shortfalls. The harvest shortfalls of 89 million tons in 2002 and 94 million tons in 2003 are the largest on record. Four consecutive shortfalls have dropped world grain reserves to their lowest level in 30 years.

In early 2004, wheat and corn prices climbed to seven-year highs.

Early estimates put the 2004 crop, boosted by near-ideal weather and stronger grain prices, at 1,962 million tons. If this estimate holds, the world won't have to draw on its grain stocks for the first time in five years. But even this exceptional harvest won't rebuild grain stocks. They'll remain at a dangerously low level in the event of a shortfall in 2005.

Historically, when world food supplies tightened, rising prices prompted farmers to apply more fertilizer, drill more irrigation wells and clear more land. But today many of these actions are no longer options. Applying more fertilizer to crops today in the United States, Western Europe, Japan or China has little effect on production. Similarly, drilling more irrigation wells may just accelerate aquifer depletion.

Elsewhere, once-vast frontiers of agricultural settlement have disappeared. The age-old approach of clearing more land to boost production is now limited to a few countries such as Brazil, and even there it carries a heavy price — the irreversible loss of biological diversity. Farmers no doubt will seek to increase production in response to the probability of much higher prices, but they're not likely to be as successful this time.

The Threat of Price Hikes

Low levels of grain stocks could easily force prices to spike. When stocks were this low during 1972 through 1974, wheat and rice prices more than doubled. The world wheat price climbed from $1.90 a bushel in 1972 to $4.89 a bushel in 1974. Bread prices climbed everywhere. So too did the prices of meat, milk, eggs and other grain-based livestock products.

Exporting countries like the United States restricted exports to keep domestic food prices under control, and food aid requests were denied. In hungry countries like Ethiopia and Bangladesh, hundreds of thousands of people starved to death.

A poor Soviet grain harvest in 1972 triggered this earlier decline in grain stocks. The Soviets, anticipating their need for large quantities of imported wheat, managed to corner the world wheat market before other countries learned of the extent of their crop shortfall. Coupled with short world harvests in the following two years, this led to tight grain supplies and high prices for three years.

In 1972, world carryover stocks of grain — the amount in the bin when the new harvest begins — had dropped to 56 days of consumption, well below the 70 days that is widely seen as the minimum needed to ensure food security. Carryover stocks in 2004 were at just 63 days of consumption.

Anytime stocks are below 70 days of consumption, one poor harvest can drop them into the danger zone where grain markets become highly volatile and prices climb.

The big question today is, Can the world's farmers boost the grain harvest by enough to close the gap between consumption and production, cover this year's population growth and rebuild stocks? Unless stocks are rebuilt, the world faces another year of living close to the edge.

Food Demand Growing

While the increase in production has been losing momentum, the increase in demand has continued. World population growth has slowed from 2 percent in 1970 to 1.2 percent in 2004. Still, about 76 million people are added each year, putting relentless pressure on the Earth's land and water resources.

And the United Nations projects that by 2050 the world will add nearly 3 billion people to the current population of 6.4 billion. The vast majority of that population growth will be in countries where water tables are already falling and irrigation water supplies are shrinking as aquifers are depleted.

During this half-century, as in the last one, population growth will drive the growth in the demand for food. But given the record or near-record economic growth in countries such as China and India, each with more than a billion people, we cannot ignore the effect of rising affl uence on the world demand for food.

Several billion people want to move up the food chain, diversifying their diet by consuming more grain-fed livestock products. Growth in the demand for livestock products translates into additional demand not only for grain but also for soybeans, because soybean meal has become an invalu-able protein supplement in feed rations.

While the use of soybean meal reduces the amount of grain used to produce ani-mal products, it has boosted the world demand for soy-beans from 17 million tons in 1950 to 190 million tons in 2003, an 11-fold increase. Future expansion of soybean area is projected to occur primarily in Brazil, which is considered the world's largest remaining agricultural frontier. The soybean is consuming the cropland of the Western Hemisphere.

Water Tables Declining

Seventy percent of world water use is for irrigation, 20 percent for industry, and 10 percent for residential purposes. While many observers now recognize that the world is facing water shortages, few have connected the dots to see that a future of water shortages means a future of food shortages.

As world food consumption has nearly tripled, so too has the use of water for irrigation. As a result, the world is incurring a vast water deficit, but because it takes the form of aquifer overpumping and falling water tables, it is nearly invisible.

The world water deficit is recent in historical terms. Only within the last 50 years, with the advent of powerful diesel and electric pumps, has the world had the pumping capacity to deplete aquifers. The worldwide availability of these pumps and the drilling of millions of wells, mostly for irrigation, have pushed water withdrawals beyond what rainfall can naturally
replenish.

As a result, water tables are falling in countries that contain more than half of the world's people, including China, India and the United States, which together account for nearly half of the world grain harvest.

Groundwater levels are declining throughout the northern half of China. Under the North China Plain, they are dropping three to 10 feet per year. In India, water tables are falling in most states, including the Punjab, the country's breadbasket. In the United States, water levels are falling throughout the southern Great Plains, shrinking the region's irrigated area by 24 percent over the last 20 years.

With aquifers that are not rechargeable, such as the vast Ogallala aquifer under the Great Plains in the United States or the deeper of the two aquifers under the North China Plain, depletion means the end of irrigated agriculture.

Overpumping creates a false sense of security because though it enables us to satisfy growing food needs today, it almost guarantees a decline in food production tomorrow when the aquifer is depleted.

Many countries that rely on surface water for irrigation are also losing water. The reservoirs behind the large dams that were built several decades ago are slowly filling with silt as their watersheds are deforested.

This situation, now affecting thousands of reservoirs around the world, is a lose-lose state of affairs since the eroded soil that ends up in a reservoir reduces both the productivity of the land upstream and that of the land that can no longer be irrigated.

Temperatures Rising

As concern about climate change has intensified, scientists have begun to focus on the precise relationship between temperature and crop yields. Crop ecologists at the International Rice Research Institute in the Philippines and at the U.S. Department of Agriculture recently have evolved a rule of thumb that with each 1 degree Celsius rise in temperature above the optimum during the growing season, the yields of wheat, rice and corn drop by 10 percent.

Crops are most vulnerable to higher temperatures during the fertilization period. A research project in the Philippines looking specifically at the effect of rising temperature on rice determined that at 93 degrees Fahrenheit virtually every one of the tiny flowers on the plant's spikelets turned into a kernel, yielding a bumper crop. As the temperature rose, however, fertilization diminished until at 104 degrees Fahrenheit almost no kernels formed, resulting in a near-total crop failure. Wheat and corn are similarly vulnerable.

During the last three decades, the Earth's average temperature has climbed by 0.6 degrees Celsius. The four warmest years on record have come during the last six years. In 2002, record-high temperatures and drought shrank grain harvests in both India and the United States. In 2003, a record-breaking August heat wave in Europe claimed 35,000 lives in eight countries and withered grain harvests in virtually every country from France through the Ukraine.

The Intergovernmental Panel on Climate Change projects that during this century, with a business-as-usual scenario, the Earth's average temperature will rise by 1.4 to 5 degrees Celsius (2 to 10 degrees Fahrenheit). If the accelerating rise during the last few decades is any guide, the actual increase may be closer to the top of the range than the bottom.

These projected rises are for the Earth's average temperature, but the increase will not be evenly distributed. Temperature is expected to rise much more over land than over the oceans, more in the higher latitudes than in the equatorial regions, and more in the interior of continents than in the coastal regions.

This suggests that increases far in excess of the projected average are likely for the North American breadbasket — the region defined by the Great Plains of the United States and Canada and the U.S. corn belt. Today's farmers confront the prospect of temperatures higher than those faced by any other generation since agriculture began.

As the Earth warms, agriculture could expand northward in both Canada and Russia. But these are not necessarily regions of fertile soils. There is a world of difference, for instance, between the glaciated soils north of the Great Lakes and the deep, fertile corn belt soils that lie south of them. And extending agriculture into the uninhabited regions of the north would require an enormous investment in infrastructure.

China's Harvest Shrinking

Perhaps the most dramatic development in the world food economy has been the precipitous fall in China's grain production since it peaked in 1998. After an impressive climb from 90 million tons in 1950 to 392 million tons in 1998, China's grain harvest has fallen in four of the fi ve crop years since then, dropping to 322 million tons in 2003. For perspective, this decline of 70 million tons easily exceeds the entire grain harvest of Canada.

Behind this harvest decline is a decline in the amount of land devoted to grain production, a reduction from 90 million hectares (222 million acres) in 1998 to 76 million hectares (188 million acres) in 2003.

Five distinct trends are contributing to this reduction. They are 1. the loss of irrigation water, 2. the expansion of deserts (largely from over-plowing and over-grazing), 3. the conversion of cropland to non-farm uses, 4. the shift of grainland to higher value fruits and vegetables, and 5., in some of the more prosperous regions, the loss of rural labor needed for multiple cropping.

Irrigation water shortages have reduced grain harvests in smaller countries, such as Saudi Arabia, but China is the first large food producer where water shortages have contributed to an actual decline in production.

China desperately wants to reverse the decline in its grain production. In February 2004, Beijing announced an emergency supplemental appropriation to the year's agricultural budget, expanding it by 20 percent ($3 bil-lion) to encourage farmers to grow more grain. Unfortunately for China, none of the five trends that are shrinking the grainland area is easily
reversed.

China so far has covered the fall in its grain harvest by drawing down its once massive stocks of grain. With these now largely depleted, and with domestic wheat and rice prices up 20 percent or more, China is starting to turn abroad for grain.

The Foreign Policy Challenge

The big test of the international community's capacity to manage scarcity may come when China turns to the world market for 40 million or 50 million tons of grain per year — a demand that could quickly overwhelm the system. When this happens, China will have to come to the United States, which controls nearly half the world's grain exports.

This will pose a fascinating geopolitical situation: 1.3 billion Chinese consumers, who have a $120 billion trade surplus with the United States — enough to buy the entire U.S. grain harvest twice — will be competing with Americans for U.S. grain, thus driving up food prices. In such a situation 30 years ago, the United States would simply have restricted exports, but today the country has a stake in a politically stable China. The Chinese economy is not only the engine powering the Asian economy; it is also the only large economy in the world that has maintained a full head of steam in recent years.

Within the next few years, the United States may be loading two or three ships a day with grain for China. This long line of ships stretching across the Pacific may link the two economies more closely than ever. Managing this flow of grain to satisfy the needs of both countries may become one of the major foreign policy challenges of this new century.

The risk is that China's entry into the world market will drive up grain prices so high that many developing countries will not be able to import enough grain. What began with the neglect of environmental trends harming food production could end with political instability on a scale that disrupts global economic progress.

What Can We Do?

Falling grain stocks combined with rising grain prices may mean the end of global food surpluses and the beginning of an economy of food scarcity.

These changes signal the need or a much broader effort to secure our food supplies, one that involves ministries of energy, of health and family planning, and of water and natural resources working in concert with ministries of agriculture to achieve an acceptable balance between food and people.

Stabilizing population means making sure that women everywhere have access to family planning services and education. It also means a worldwide effort to eradicate the poverty that leads to high infant mortality and large families. Such an effort begins with at least an elementary school education for girls everywhere. Together, these initiatives can accelerate the shift to smaller families and a stable world population.

Food security now depends on raising water productivity in all sectors, in agriculture of course but also in industry and in homes. Today we need a global full-court press to raise water productivity similar to that launched a half-century ago to raise land productivity as the frontiers of agricultural settlement disappeared. We have the technologies, like drip and low-pressure sprinkler irrigation, but all too often not the policies nor the economic incentives to raise water productivity in all sectors worldwide.

A world facing food scarcity can no longer afford heavy soil losses from erosion. Reducing soil erosion means a worldwide effort to reduce overplowing and overgrazing and to adopt soil conservation practices such as terracing and minimum tillage. Nor can our modern civilization afford to continue converting cropland to non-farm uses as though cropland were an endless resource. The mounting competition between cars and crops for land calls for a reexamination of existing transportation strategies. Among other things, cropland scarcity may force developing countries to stop build-ing auto-centered transport systems and instead use extensive high-tech light-rail networks augmented by bicycles.

And finally, climate stabilization may be essential to securing future food supplies. If it becomes apparent that rising temperatures are shrinking harvests and raising food prices, we will suddenly have a powerful new lobby of consumers pushing for a cut in carbon emissions. This will require a restructuring of the world energy economy, shifting from fossil fuels to renewable kinds of energy. It is perhaps a measure of the complexity of our time that decisions made in ministries of energy affecting climate may have a greater effect on food security than those made in ministries of agriculture.

These four steps — stabilizing population, raising water productivity, protecting cropland and stabilizing climate — constitute a challenging agenda. It is time to redefine security. The threat now is not so much military as it is environmental, not so much invading armies as it is encroaching deserts, falling water tables and rising temperatures.

Lester R. Brown, author of Plan B: Rescuing a Planet Under Stress and a Civilization in Trouble, is founder and president of the Earth Policy Institute, www.earth-policy.org [1].

This article originally appeared in the January/February 2005 issue of World Ark magazine, a publication of Heifer International [2]. Copyright © 2005 Heifer International. Used with permission.