The world is just one poor grain harvest away from chaos, warns renowned environmentalist and agricultural economist Lester Brown.

That’s the bad news.

The even worse news is that a lot of the world’s farmland is already looking very dusty, and heavy rains threaten crops elsewhere.

What’s more, grain reserves are down, largely thanks to last year’s heat wave in Russia, floods in Pakistan and the recent cyclones in Australia.

“There’s no assurance that we’re going to have a really good global grain harvest this year,” says Brown, on the phone from his Washington-based Earth Policy Institute. “If we don’t, we won’t be able to dig our way out of the hole we’re in. Food prices will rise to previously unimaginable levels and food riots will multiply, political unrest will spread and governments will fall.

“We haven’t gone over the edge, but we’re much closer than most people think.”

Certainly, there’s widespread agreement that soaring food costs in Tunisia and Egypt contributed to the uprisings in those countries.

Meanwhile, food prices — and demand — are soaring around the world.

The United Nation’s Food and Agriculture Organization (FAO) reports that its global food price index is at a record high, above even the crisis levels of 2008. That’s when there were food riots in dozens of countries — including Egypt, the world’s largest importer of grain.

Just this week, the World Bank reported that prices had hit “dangerous levels,” sinking 44 million more people into the dire poverty already experienced by nearly a billion. And, as Brown points out, every year there are “80 million more people (born) that the world’s farmers have to feed, good weather or bad.”

As if all this wasn’t ominous enough, there’s increasing evidence that investment bankers are speculating on food, sending prices even higher.

It’s a recipe for revolution, all over the world.

Rumblings, the UN said this week, are already being felt in Mozambique, Uganda, Mali, Niger and Somalia in Africa, Kyrgyzstan and Tajikistan in Asia and Bolivia, Honduras, Guatemala, and Haiti in Latin America.

The Bloomberg business news service reported that “governments from Beijing to Belgrade are raising imports, limiting exports or releasing supply from stockpiles to curb inflation.”

Hunger, hoarding and profiteering have brought violent upheaval before, as France’s Marie “Let them eat cake” Antoinette painfully discovered.

In the mid-19th century, when blight hit the potato crops that fed much of Europe, starving peasants rioted in the streets. The so-called “Springtime of the Peoples” was a continent-wide revolution which ultimately brought about the overhaul of Europe’s long-entrenched class system.

This year, we saw Tunisia’s Jasmine Revolution, sparked in part by food prices and high unemployment. That, in turn, precipitated the uprising in Egypt, where, as the World Food Program reports, some 17 million — more than one-fifth of the 80.5-million population — can barely feed themselves.

It’s not going to get any better now that Russia has cancelled its grain exports there.

“As we entered 2010 the global larder was pretty good, but it was a crappy year, largely thanks to Russia’s drought,” says Guelph University food security expert Evan Fraser, co-author of Empires of Food. “Now we face the question of what the 2011 harvest will be, and certainly there are some preliminary, medium-range weather forecasts that suggest that China could be considerably down, Australia could be down and even Canada could be down.

“That could mean a very rocky road for the food system. All this could cause significant hardship for the most poor, and political volatility in areas that aren’t the most poor but are politically restless.”

And that includes China, the world’s largest wheat producer, now facing its worst drought in six decades.

“I think China is the place to watch,” says Fraser. “It’s stockpiling food. I think it’s watching Tunisia and Egypt’s food-related unrest cascading into major political protest.”

On the other hand, China could simply call its huge loans to the U.S. — in the form of grain.

“For American consumers, this could be a nightmare scenario,” cautions Brown. “We have never had a food security crisis in this country.

“There would be a lot of political pressure to restrict exports to China in order to keep our food prices down. But China is our banker. The bottom line is there are limits to what you can say to your banker.”

Especially a banker with 1.4 billion people boasting rapidly rising incomes, and thus in a position to send prices sky-high.

“The critical thing relating to food riots is that, as people perceive merchants, politicos, warehouse owners as profiteering from the situation, it’s moral outrage that is particularly explosive,” says Fraser. “Which means that it’s more complicated than just hunger equals collapse and poverty equals suffering. Rising food prices and a sense of moral outrage at profiteering, that’s what equal collapse.”

But good crop or not, we were already heading down the road to disaster, insists Brown.

In his just published World on the Edge: How to Prevent Environmental and Economic Collapse, he sounds the alarm: on the diversion of grain into ethanol to fuel cars, the growing taste for grain-fed meat in developing countries, the over-pumping of the world’s fossil aquifers to irrigate crops, spreading soil erosion, the burgeoning population and, of course, climate change and extreme weather.

“The rule of thumb that crop ecologists use in assessing the effect of rising temperature is that, for each one degree Celsius rise in temperature, we can expect a 10 per cent decline in grain yields — and we saw that borne out quite dramatically last year in Russia,” says Brown.

“But what if that heat wave had hit Chicago? The U.S. would have lost at least 40 per cent of its 400 million ton harvest. Canada would have been affected as well.

“We would have seen grain prices literally going off the top of charts. We would have seen many grain-exporting countries restricting exports in order to keep their food prices down. In all probability we would have seen oil-exporting countries that import grain trying to barter oil for grain to ensure they got what they needed. And then the rest of the world would have scrambled for whatever is left.”

“Yes, I am worried about it,” says Fraser. “I think the critical thing for us in the next year will be what the rains are like over the next three or four months. This will have a huge impact on global harvests.”

Not to mention global stability.

“The bottom line is, we need to redefine security,” says Brown. “We have inherited a definition of security from the last century, one dominated by two world wars and the Cold war. So, when you mention national security in this country, and I think it’s largely true in Canada as well, people think in military terms.

“But if you were to sit down today and start listing the principal threats to our future security — and indeed to civilization itself — it would be climate change, it would be population growth, it would be soil erosion, and it would be rising food prices, growing political instability, and the number of failing states in the world. And then, maybe, military security. But all these other threats are much more real and imminent.

“We’ve got some basic rethinking to do.”