OK, it's not real economics, just pseudo-economic punditry.

Mr Sachs writes that the world faces a growing triple threat--rising food prices, conversion of food into fuel, and global warming--which will hit those living in the least developed nations hardest.

It isn't particularly difficult to see where he's coming from. Wheat prices have been navigating unknown territory recently, due in part to high food demand but also to reduced wheat acreage in response to high prices, and high subsidies, for fuel crops.

It seems that it's been a bad year for Australian wheat growers as well.

The Australian Bureau of Agriculture and Research Economics (ABARE) today released its latest crop forecast as drought grips much of southern Australia.

"Winter grain production in 2007/08 is forecast to total 25.6 million tonnes," the forecast said.

"Even though this amount is well above last year's drought affected crop, it will be around 27 per cent below the five year average."

The forecast for Australia's largest crop - wheat - has dropped seven million tonnes on June estimates, to 15.5 million tonnes.

And last year . . .

The price of wheat surged to a 10-year high on the Chicago Board of Trade on Wednesday, rising the maximum amount permitted by the exchange, as a worsening drought in Australia increased the chances that its wheat crop would be reduced by more than half.

Based on the average estimates of five analysts surveyed by Bloomberg, Australia, one of the world's largest exporters of wheat, might produce just 10.5 million tons of the grain this year, 58 percent less than last year.

It looks to me like weather may be a major issue for wheat production. Seems like that should have been mentioned, doesn't it?

The kicker, the real fly in the ointment in all this, is global climate change. Global warming turns a manageable and perhaps even desireable state of affairs into a potential catastrophe. It does this in two ways. First, changing weather patterns are likely to do some unpleasant things to world food markets. Supplies and prices may become quite volatile, as climate shifts mean that crops boom or fail unpredictably, leading to possible localized or widespread shortages and making investment decisions very difficult.

Crops already "boom or fail unpredictably". That's why we have invented such things as futures contracts, and why there is a booming speculative market in them rain or shine. Since the dawn of agriculture this has been an issue.

And secondly, it seems likely that climate change will have uneven effects across the globe, and that negative effects may be concentrated in some of the earth's poorest areas. Warming might well lead to increased Canadian grain yields but swamped crops in south-east Asia, meaning that the gains to higher food prices accrue almost entirely to wealthy nations in temperate zones, who need the help the least.

This is double Dutch gobbledy-gook. If world food production rises or remains constant in spite of climate change then prices won't be greatly affected. However, non-food uses of food creates extra demand, and raises prices. It isn't that diminished food production in poor countries isn't a concern, it's that prices aren't much effected.

Of course, those uneven effects also reduce the odds of the international community arriving at a substantive, binding solution for cutting carbon emissions; when those most responsible for warming also stand to lose the least, the prospect for moral hazard rears its ugly head. We would probably be wise to focus our efforts and investments on climate change, even if there is considerably uncertainty over the scope of its potential effects. Humanity has a great deal of experience handling and responding to price increases and demand shifts, but this will be our first time facing dramatic temperature increases over the course of mere centuries, or decades.

What a non sequitur. The magician's hands became completely detached from his wrists to do that trick. Do we have experience with "extended, intertemporal collective action problems directed against small probability events, with unclear periodic feedback", any reason at all to assume that it would be wise to launch into this great experiment with our hands tied and eyes covered? Where do they get these pundits?