Why is India’s future brighter than China’s, especially in a warming world? Because India has more good agricultural land per person. That will get more and more important as the temperature goes up.

I first encountered the concept of Real Population Density (note the “Real”) when I was interviewing people in the Netherlands last year about how the country would fare as the temperature rose. My initial focus was on sea-level rise, because 20 per cent of the country is already below sea level. But the Dutch are confident that they have the sea-level problem under control.

The Dutch sea-level experts were also confident that the Netherlands would not face any problem with food when the temperature rises. The country is, after all, the second or third biggest agricultural exporter in the world. But it still feels like a very crowded country, so I looked up a few agricultural experts, and they explained the concept of Real Population Density to me.

“It would take a country three or four times the size of the Netherlands to support our present diet,” said Dr Huib Silvis of the Agricultural Economics Research Institute at Wageningen University. “We import huge amounts of soybean and other animal feed, which we could not produce ourselves. If we had to be self-sufficient, we would not be eating meat.” The Real Population Density of the Netherlands —how many people there are per square kilometre of farmland — is 2,205. That’s higher than Bangladesh, and it means that the Netherlands, to be self-sufficient in food, would have to feed 22 people from each hectare of land. So how can the country be the second- or third-biggest agricultural exporter in the world? Because that’s the cash value of its exports, which are mostly high value-added products. You get a lot more for a tonne of cut flowers than you do for a tonne of potatoes — but you can’t eat cut flowers, and the Dutch could barely feed themselves from their own resources.

New lottery

Global warming makes matters much worse, because it hits food production very hard. The rule of thumb is that the world loses about ten per cent of its food production for every rise of one degree Celsius in average global temperature.

So the amount of food that is for sale on the international market drops drastically, because some of the big food-exporting countries are not producing enough food to export it any more. As the food gets scarce, the price goes up. Countries that cannot feed themselves either pay huge amounts to buy the limited amount of food that is still available on the international market, or else go hungry. Which brings us back to India and China.

Almost half the total land area of India is good arable land, whereas only 15 per cent of China is. So although China looks bigger on the map, India has a significantly lower Real Population Density: 753 people per sq km of farmland compared to 943 for China. Add in the fact that China is currently losing about 1 per cent of its arable land per year to buildings, roads and parking lots, and the numbers for China start looking seriously bad.

At the other end of the spectrum, look at the big industrialized states in Europe. Italy and Germany are in the 700s, but Spain, France, Sweden and Poland are all in the 300s. The lucky ones still have room to grow; the others don’t.

And the uncontested winners in this new lottery? The United States of America has only 179 people per sq km of good agricultural land. Russia has 117. Canada is 78, and Australia is 43. Australia, in other words, has more than half a hectare of good land per person. This is deeply unfair, given which countries are actually responsible for the global warming. To them that hath, shall it be given. But then, you already knew that the universe isn’t fair.