One of the marvels of our time is watching how politicians deal with science questions — or maybe that should more accurately be phrased as "science-ized" questions.

The most obvious example is human-induced climate change, a domain in which there is general scientific agreement that change is happening, but where the question of what to do about it doesn't easily present itself as a "political science." I argue this from the context of a recent trip to Cuba where I gave a talk to the Fundacion Antonio Nunez Jimenez de la Naturaleza y el Hombre (FANJ), a Cuban environmental non-governmental organization (NGO).

I had never been to Cuba before, and so as I was coming from the airport I was much struck by a billboard that proclaimed — in my rough translation — that turning food into energy was stupid.

I wasn't sure where that sentiment came from until I came across what one might term Fidel Castro's late-life conversion, a series of speeches he recently has given on climate change and food production. In them he says unequivocally that, "transforming food into fuel is a monstrosity." And he goes on to argue that the efforts by U.S. President George W. Bush to create more ethanol — both in the U.S. and in places like Brazil — are driving the world down the path of food shortages.

Particularly worrisome for him is the conversion of crops like corn and soya into ethanol. The creation of biofuel from them would save the United States, Europe and the industrialized countries, "more than $140 billion [U.S.] each year, without having to worry about the consequences for the climate and hunger," writes Castro.

And he is not alone in these worries.

A recent, much-discussed paper in the journal Science calculated that instead of 20 per cent savings in carbon emissions coming from ethanol, the changeover would encourage poor farmers to convert forests and grasslands to ethanol production. And by the paper's authors' measures, that would double greenhouse emissions over 30 years and increase greenhouse gases for 167 years. If corn was changed to switchgrass, which is even better for producing ethanol, emissions would go up by 50 per cent.

On top of this argument has been the volley of recent media stories tying increases in grain prices, hunger and food riots to the drive to make more ethanol.

What's the science-based policy option which moves us away from using fossil fuels but still allows us to feed the hungry masses?

Nobody is sure, but a letter to Science following up on the corn/ethanol original analysis suggested that what Americans, and likely Canadians, should do to mitigate global warming is to become vegetarians. Since cattle require 13 kilograms of grain and 30 kilograms of forage to produce a kilogram of meat, and similarly high numbers go into the production of other meats, switching over to a lacto-ovo-vegetarian diet "requires animal feed, but about half as much as a meat-heavy American diet," said the letter. So by swearing off meat, one could devote present farmland to growing biofuel crops without hurting anyone.

This need to radically change lifestyles was on my mind after I spoke to FANJ. I noted to the group following my formal presentation — it had nothing to do with climate change — that I had a question. I said I had seen the billboards and read Castro's speeches and thought there was much truth to what he said about the self-interest of the developed world, but I wondered why he didn't also say that if Cuba wanted to deal with global warming it would have to think not as poor people but as revolutionaries.

Specifically, Cuba would have to break with its historical agricultural past.

It should take all those fields devoted to producing tobacco and use them to grow ethanol, I suggested to the audience. Cuba does, after all, have the second-largest area of planted tobacco fields of any country in the world. And why didn't it take some of those fields it used to grown sugar cane to make rum — nobody's definition of a food — and use it to produce ethanol?

Yes, there might be land-use changes, but those scenarios don't involve turning food into ethanol. They turn, well, poison and drugs into ethanol.

The answers I got from audience members were interesting. One woman said she thought that was a good idea and worthy of thought. But another put up her hand and remarked that while what I said might be true, you also had to remember how it was that Cuba earned its foreign exchange. Cuban cigars and Cuban rum were big sellers — indeed, they are almost brand names that define Cuba to the world.

I listened and wished Castro was there, so I could tell him: I understand everyone's attachment to the products that have historically defined Cuban-ness, but you also have to understand that if mankind is going to deal with climate change and energy worries, we all must change.

Cuba, for example, is going to have to redefine itself into being something other than the home of cigars and rum. Cuba is going to have to stop complaining about the rich countries' duplicities and reconfigure what has been the source of its own richness. Cuba is going to have to think Revolucion o Muerte when it comes to dealing with climate change.

I can't say that is the political wisdom of science, but it is as politically wise as this gringo science writer gets.