The latest report of the UN population division of March 11, 2009 shows that the world's population is 6.8 billion, and is expected to exceed 9 billion by 2050.

When I was born in 1930, there were only 2 billion people on Earth. What has happened to cause this staggering increase, and for how long can it continue?

Back in 1972, the Club of Rome pointed out that there are indeed limits to growth, as exemplified by the finite limits to our reserves of fossil fuels. But we failed to realise that we are living under a glass ceiling that traps our carbon emissions and causes the Earth to warm up. It is an ill bird that fowls its own nest, but that is exactly what we are doing to our environment. We always used to think that the future was boundless; the sky's the limit. But it is slowly beginning to dawn on us that the phrase has acquired a sinister new meaning; today, the sky is the limit.

It is human activities, whether it be the farts of our domestic cattle and sheep, or the burning of our forests, or the emissions of our power stations, or the exhausts of our cars, or the production of cement, or the cremation of our bodies at the end of our days, that are all are contributing to global warming. What can we do about it?

Unfortunately, natural selection has ensured that we are well-endowed with selfish genes. We will always put self before family, family before community, community before country. Hence efforts to get international agreement on controlling global carbon emissions will always be bedevilled by the "after you" syndrome. With the Copenhagen Climate Change Conference set for December, can we expect any breakthroughs in this potential stalemate?