Riots have broken out in more than a dozen countries as prices of food staples have doubled and reserves declined to their lowest levels in a generation. The world food crisis is at the top of the agenda at the Group of Eight summit meeting in Japan this week.

Is Thomas Robert Malthus right after all, that human numbers have finally overwhelmed our ability to produce food, leading inevitably to mass starvation? In 1798, Malthus wrote An Essay on the Principle of Population, where he famously asserted that "population does invariably increase where there are the means of subsistence." As a consequence, some portion of mankind must forever be starving; and, further, efforts to aid the hungry will only lead to more misery, as those initially spared from famine bear too many children to feed with existing food supplies.

In subsequent editions Malthus softened his dismal conclusions and argued that "preventative checks" could avert overpopulation by reducing birth rates. Preventative checks included later marriage and abstinence, along with indulgence in "unnatural passions" and "irregular connections," by which Malthus meant prostitution, abortion, masturbation, and homosexuality.

Modern disciples of Malthus have stressed the dismal checks on population, e.g., war, pestilence, and famine. The most famous neo-Malthusian was Stanford University biologist Paul Ehrlich, author of The Population Bomb (1968), in which he declared that it was inevitable that hundreds of millions would die in the 1970s. Why inevitable? Because, as Ehrlich explained, "To ecologists who study animals, food and population often seem like sides of the same coin. If too many animals are devouring it, the food supply declines; too little food, the supply of animals declines... Homo sapiens is no exception to that rule, and at the moment it seems likely that food will be our limiting resource." Or more simply stated, the goal of all animals is to turn food into offspring.

In 2003, Duke University consultant Russell Hopfenberg restated this claim in an article called "Human Carrying Capacity Is Determined by Food Availability," published in the journal Population and Environment. Hopfenberg wrote, "[T]he problem of human population growth can be feasibly addressed only if it is recognized that increases in the population of the human species, like increases in the population of all other species, is a function of increases in food availability."

Ehrlich was wrong. A global famine did not occur in the 1970s, 1980s, or the 1990s. Instead, food became cheaper and more abundant than ever before, even as the world's population doubled. But what about now?

The price of staples like corn, wheat, and rice are escalating, indicating that demand is outstripping supplies. Why? Because of political and economic institutional failures, not overpopulation. First, let's deal with the claim that human population, like the populations of all other animals, expands as food supplies increase. On a global level that certainly looks plausible. As the amount of food increased over the last century, world population rose from 1.5 billion in 1900 to 6.6 billion today. Case closed?

Not so fast. Consider that countries with the highest food security are also the same countries with below replacement total fertility rates. If the availability of food was the chief determinant of birth rates, then one would expect Iowa farmers would spawn more kids than any group on the planet. Instead, it is countries in which food insecurity is greatest that have the highest total fertility rates. As an empirical fact, as people become wealthier and better fed, they tend to bear fewer children. Well-fed human beings can evidently override the genetic programming that drives other animals to turn more food into more offspring.

How much food is there right now? Enough to feed 10 billion vegetarians. One oft-heard argument is that increased Chinese prosperity is driving up meat consumption, which is diverting grain into livestock production. It takes about eight pounds of grain to produce one pound of beef, and 2.5 pounds of grain to produce a pound of chicken. It is true that Chinese meat consumption is soaring, but China has produced nearly all of the extra grain it needs to grow its burgeoning numbers of livestock. In fact, China remains a net exporter of grains. Chinese corn yields an average of 82 bushels per acre compared 150 bushels per acre in the United States. In other words, Chinese yields could nearly double using already existing technologies. In addition, crop biotech leader Monsanto predicts that corn yields will double to 300 bushels per acre by 2030.

So what is driving up global food prices? Joachim von Braun, Director General of the International Food Policy Research Institute (IFPRI), points to high oil prices which have "made agricultural production more expensive by raising the cost of mechanical cultivation, inputs like fertilizers and pesticides, and transportation of inputs and outputs."

In addition, biofuel mandates in the United States and Europe are diverting food into fuel and boosting the price of feedstock crops like corn. So, on the demand side, higher corn prices cause food consumers to shift to rice and wheat. On the supply side, higher corn prices cause farmers to reduce rice and wheat production in favor of corn. These shifts in demand and supply have tended to boost the price of rice and wheat and other crops. IFPRI estimates that increased biofuel demand accounts for 30 percent of the increase in weighted average grain prices.

In response to higher food prices, several major food-producing countries have instituted export bans on various agricultural commodities. Export controls shrink the size of the market and reduce domestic prices to farmers. Of course, reduced prices signal farmers to produce less. For example, China has banned rice and maize exports, and India has banned exports of rice and pulses. Argentina has raised export taxes on soybeans, maize, wheat, and beef, and Ethiopia and Tanzania have banned exports of major cereals. In addition, Benin, China, Malaysia, and Senegal have imposed price controls on some staples. Price controls are especially damaging because they strongly discourage farmers from increasing their production. IFPRI estimates that "the elimination of export bans will stabilize grain price fluctuations, reduce price levels by as much as 30 percent, and enhance the efficiency of agricultural production." Clearly eliminating subsidies for biofuel production in developed countries and export controls in developing countries would go a long way towards easing the world food crisis.

A longer-term problem is that decades of rising food security have led to cutbacks in both public and private agricultural research focused on boosting yields. Since 1980, rich donor countries have cut their support for agricultural research and development for poor countries from $6 billion to $2.8 billion. Other bad policies have contributed substantially to the current food crisis. For example, most governments in sub-Saharan Africa have underinvested in farm-to-market roads and in agricultural research, while also imposing high import taxes on fertilizer and modern high-yielding seed, price controls, and bans on genetically enhanced crops. Making the heroic assumption that if sub-Saharan governments "fulfill their commitments," IFPRI estimates that spending an additional $14 billion per year could boost African agricultural production by 7.5 percent annually through 2015.

Finally, the world food crisis could have the highly beneficial effect of jumpstarting the Doha round of World Trade Organization negotiations. High food prices could serve as the impetus for eliminating damaging food market distortions such as rich country farm subsidies and poor country protective tariffs.

The current world food crisis is not the long predicted signal of Malthusian overpopulation. Instead, it is the result of political Malthusianism, that is, a series of government policy failures that are preventing farmers from growing the food demanded by the world's hungry billions.

Ronald Bailey is reason's science correspondent. His book Liberation Biology: The Scientific and Moral Case for the Biotech Revolution is now available from Prometheus Books.