In the early spring this year, US farmers were on their way to planting some 96m acres in corn, the most in 75 years. A warm early spring got the crop off to a great start. Analysts were predicting the largest corn harvest on record.

The United States is the leading producer and exporter of corn, the world’s feedgrain. At home, corn accounts for four-fifths of the US grain harvest. Internationally, the US corn crop exceeds China’s rice and wheat harvests combined. Among the big three grains – corn, wheat, and rice – corn is now the leader, with production well above that of wheat and nearly double that of rice.

The corn plant is as sensitive as it is productive. Thirsty and fast-growing, it is vulnerable to both extreme heat and drought. At elevated temperatures, the corn plant, which is normally so productive, goes into thermal shock.

As spring turned into summer, the thermometer began to rise across the corn belt. In St Louis, Missouri, in the southern corn belt, the temperature in late June and early July climbed to 100F or higher 10 days in a row. For the past several weeks, the corn belt has been blanketed with dehydrating heat.

Weekly drought maps published by the University of Nebraska show the drought-stricken area spreading across more and more of the country until, by mid-July, it engulfed virtually the entire corn belt. Soil moisture readings in the corn belt are now among the lowest ever recorded.

While temperature, rainfall, and drought serve as indirect indicators of crop growing conditions, each week the US Department of Agriculture releases a report on the actual state of the corn crop. This year the early reports were promising. On 21 May, 77% of the US corn crop was rated as good to excellent. The following week the share of the crop in this category dropped to 72%. Over the next eight weeks, it dropped to 26%, one of the lowest ratings on record. The other 74% is rated very poor to fair. And the crop is still deteriorating.

Over a span of weeks, we have seen how the more extreme weather events that come with climate change can affect food security. Since the beginning of June, corn prices have increased by nearly one half, reaching an all-time high on 19 July.

Although the world was hoping for a good US harvest to replenish dangerously low grain stocks, this is no longer on the cards. World carryover stocks of grain will fall further at the end of this crop year, making the food situation even more precarious. Food prices, already elevated, will follow the price of corn upward, quite possibly to record highs.

Not only is the current food situation deteriorating, but so is the global food system itself. We saw early signs of the unraveling in 2008 following an abrupt doubling of world grain prices. As world food prices climbed, exporting countries began restricting grain exports to keep their domestic food prices down. In response, governments of importing countries panicked. Some of them turned to buying or leasing land in other countries on which to produce food for themselves.

Welcome to the new geopolitics of food scarcity. As food supplies tighten, we are moving into a new food era, one in which it is every country for itself.

The world is in serious trouble on the food front. But there is little evidence that political leaders have yet grasped the magnitude of what is happening. The progress in reducing hunger in recent decades has been reversed. Unless we move quickly to adopt new population, energy, and water policies, the goal of eradicating hunger will remain just that.

Time is running out. The world may be much closer to an unmanageable food shortage – replete with soaring food prices, spreading food unrest, and ultimately political instability– than most people realise.

• Lester R. Brown is the president of the Earth Policy Institute and author of Full Planet, Empty Plates: The New Geopolitics of Food Scarcity, due to be published in October

America’s drought threatens a recurrence of the 2008 global food crisis, when soaring prices set off riots and unrest to parts of Africa, the Middle East, and Latin America, food experts warn.

Corn prices reached an all-time high on Friday, as the drought expanded across America, trading at $8.24 a bushel on the Chicago exchange. Soybeans were also trading at record levels.

The US department of agriculture meanwhile predicted there would be less corn coming onto global markets over the next year, because of a sharp drop in US exports.

America is the world’s largest producer of corn, dominating the market. Corn is also connected to many food items – as feed for dairy cows or for hogs and beef cattle, as a component in processed food – expanding the impact of those price rises.

That means the effects of the drought will travel far beyond the mid-western states baking under triple-digit temperatures, said Robert Thompson, a food security expert at the Chicago Council of Global Affairs.

“What happens to the US supply has an immense impact around the world. If the price of corn rises high enough, it also pulls up the price of wheat,” he said.

He went on: “I think we are in for a very serious situation worldwide.”

Some analysts are predicting a repetition of the 2008 protests that swept across Africa and the Middle East, including countries like Egypt, because of food prices.

In 2008, the food shock was due to rising prices for rice and wheat. This time, it’s because of corn and soybean, and there were no signs of shortfall in rice or wheat production.

But the full effects of the American drought will likely take several months to emerge. Its severity will be determined by a number of additional risk factors.

Global grain stocks have reached a new low, with the US and other countries running down their reserves. “There are no reserves of these foods in the US anymore,” said Sophia Murphy, a fellow at the Institute for Agriculture and Trade Policy.

That means there is no room for manoeuvre for countries forced to import grains.

Thompson also warned that countries could make matters worse by stockpiling – putting further pressure on prices. That was the pattern during the 2008 food crisis when Russia, Ukraine, India and Argentina all cut off grain exports.

It was unclear as well whether America’s demand for ethanol would further limit the amount of corn on the world market. About 40% of America’s corn is used for ethanol – which helps drive up the price of corn, analysts say. But there were some reports that American ethanol plants were in shutdown across the mid-west, because high corn prices made production uneconomic.

“What’s difficult is that we see a drought happen today but people really are going to be feeling that six months from now, possibly a year from now,” said Marie Brill, a policy analyst at ActionAid.

But she said it was already clear the reduced supply and high prices of corn and soybean were set to cause serious hardship – especially among poor people in poor countries which depend on imported grain.

Countries that are net importers of corn be hit the hardest including South Korea, Japan, Peru, Guatemala, El Salvador and Columbia. Much of East Africa will be badly affected, she said.

Even those African countries that produce their own corn will suffer because they are locked into the higher global prices, she said. West Africa is already in food crisis. “If supply is as awful as the US government is predicting we’re going to see another round of high prices and another increase in hunger,” Murphy said.

Freak weather in some of the world’s vital food producing regions is ravaging crops and threatening another global food crisis like the price shocks that unleashed social and political unrest in 2008 and 2010.

As the US suffers the worst drought in more than 50 years, analysts are warning that rising food prices could hit the world’s poorest countries, leading to shortages and social upheaval.

The situation has sparked comparisons to 2008 when high food prices sparked a wave of riots in 30 countries across the world, from Haiti to Bangladesh.

Researchers say rising food prices also helped trigger the Arab Spring in 2011.

Nick Higgins, commodity analyst at Rabobank, said: “Food riots are a real risk at this point. Wheat prices aren’t up at the level they got to in 2008 but they are still very high and that will have an effect on those who are least able to pay higher prices for food.”

In America’s agricultural heartland, searing heat and sparse rainfall have left farmers helpless as their corn and soy bean crops wither in dry fields. Earlier this month, the US department of agriculture (USDA) slashed forecasts for the corn crop by 12%.

US agricultural secretary Tom Vilsack said: “I get on my knees every day, and I’m saying an extra prayer right now. If I had a rain prayer or a rain dance I could do, I would do it.”

As it is, current weather forecasts suggest the drought will continue and experts fear the USDA may have to cut its targets again in August.

Dan Basse, president of AgResources in Chicago, said the government’s prediction would prove too optimistic if the drought continues. “We’ve been traipsing through the fields of southern Illinois, and it is worse than the government says.”

The US is crucial to global food markets as the world’s largest exporter of corn, soy beans and wheat, so the impact of the drought will be felt across the globe.

Corn prices have already shot up 40% since June to hit all-time highs, soy bean prices have jumped 30% to record levels, and wheat has surged 50%.
It is not just the US. Unseasonal weather, thought to be caused by climate change, is affecting farmers across the world.

South America has been hit by a drought, which could damage the soy bean harvest, while UK wheat has been damaged by the rain.

Flash flooding in Russia could also affect the wheat harvest. Traders are particularly concerned about the latter as Russia might limit exports if it is worried about wheat supplies at home, causing further price spikes.
Shortages have been compounded by huge orders for corn and soy beans to make biofuels, in order to meet quotas in the US and Europe.

The US agriculture secretary said last week the situation was not bad enough to warrant a reduction in government mandates for biofuels, driving the price of corn even higher. Traders say China also buys and stores grain strategically, putting more pressure on limited supplies.

Consumers will soon feel the effects of these spikes. A high price of wheat leads directly to higher prices in the shops, as it is the main ingredient for bread and other staples.

The link is less direct with other crops. Corn and soy beans are used to feed livestock, so rising prices will ultimately cause the price of meat to rise. In the short-term, however, they will have the reverse effect. As the cost of feed rises, farmers kill cattle at lighter weights to avoid having to feed them. That will briefly flood the market with meat, causing prices to fall, but subsequent shortages will causes prices to rise sharply.

Higgins at Rabobank said meat will then remain expensive for a long time. “It is very hard to rebuild cattle herds and these inflationary effects will be long and lingering.”

Rising food prices have a disproportionate effect on the poorest people in the world.

Ruth Kelly, Oxfam’s food policy adviser says people in the Western world spend around 15% of their income on food, but that rises to around 75% in developing countries, so any change in food prices has a dramatic impact on household budgets.

Kelly says problems will be compounded by the previous two food price spikes in 2008 and 2011:

“People are already in debt from previous spikes and suffering the consequences. When the first food crisis hit people were forced to sell off their assets, their cattle and jewellery, and take on debt to make ends meet. After multiple crises, people run out of savings and that can be quite disastrous.

“People can find it much harder to cope when you have multiple shocks like this, without time to recover between them, rather than just a single shock.”

Economists fear food price inflation will exacerbate the global economic crisis, as it limits the ability of emerging markets to provide any kind of stimulus to drive a recovery. Karen Ward, senior economist at HSBC, said: “What the world economy really needs right now is a break. Any inflationary pressure, particularly that stops the emerging world loosening policy and providing the boost to the global economy, would be a problem.”