Drawing the short straw in food security
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' when I was interviewing people in the Netherlands last year about how the country would fare as the temperature rose. The Dutch were confident that they have the sea level problem under control.
The sea-level experts were also confident that the Netherlands would not face any problems with food when the temperature rises. But I looked up a few agricultural experts, and they explained 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. 'If we had to be self-sufficient, we would not be eating meat.'
The real population density of the Netherlands -the number of people per square kilometre of farmland -is 2,205. That is higher than Bangladesh (1,946).
The Netherlands is the second- or third-biggest agricultural exporter in the world, but that is in terms of the cash value of its exports, which are mostly high value-added products such as cut flowers. The Dutch could barely feed themselves from their own resources even now.
Global warming makes matters much worse, because it hits food production very hard. The rule of thumb is that the world loses about 10 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 market drops drastically, because some of the big food exporters are not producing enough to export it. As the food gets scarce, the price goes up.
Countries that can't feed themselves either pay huge amounts to buy the limited amount of food, or else they 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. In fact, China is currently losing about one per cent of its arable land per year to buildings, roads and car parks.
At the other end of the spectrum, look at the big industrialised states in Europe. Italy and Germany are in the 700s, but Spain, France, Sweden and Poland are all in the 300s. So are Brazil, South Africa and Turkey, the most promising of the rapidly developing countries.
And the uncontested winners in this new lottery? The US has only 179 people per sq km of good agricultural land. Argentina has 144, Russia has 117, Canada, 78, and Australia just 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. But then, you already knew that the universe isn't fair.
Gwynne Dyer's latest book, Climate Wars, is distributed in most of the world by Oneworld