What a fine pickle for humanity. On one side is the very powerful argument of global warming and its potential effects on climate, and the call for steps to stop either the process, or plan for the necessary adjustments and, the major polluters arguing that technology will see us through. On the other side, forget Kyoto and Bali accords, the mega consumption economies of the northern hemisphere are pulling out all stops to find and extract more oil and gas, the raw materials that will keep adding greenhouse gases to the overburdened atmosphere.

Even in little T&T, as the Government makes noises at every seminar, workshop and summit about the seriousness of the problem, it encourages further exploration, and we are told by those on high to unplug our cell phone chargers as our contribution in the fight to halt climate change while we prepare to spew 200,000 tonnes of carbon dioxide from a single aluminium smelter each year for the next thirty years.

But look at what is happening with the ’developed’ and ’developing’ economies of the more populous countries; no more than talk about plans to stabilise or reduce emissions at some yet-to-be scientifically agreed levels.

And the Arctic? Now that global warming has thawed out much of the frozen Arctic wastes we have the scramble for continental shelves, slopes and rises of seabed adjoining the countries that border the Arctic - Russia, Canada, the US, Norway and Sweden, and Denmark (Greenland).

The respected US Geological Survey announces the probability of about three years’ world use of oil and gas on the seabed adjacent to these countries. Bush frees up exploration on the outer continental shelf. And the BBC points out the irony of human-caused melting of the Arctic ice sheet from excessive consumption of fossil fuels now making it technologically more feasible to exploit these resources year-round in ice-free seas to maintain economic growth and fuel further global warming, possibly over a tipping point.

And what about the current oil sand mining in Canada and proposed oil shale mining in the US? The consumption economies demand energy from fossil fuels, in the absence of alternatives.

We have from time to time been reminded of the ’tragedy of the commons’, a conflict in public resource exploitation between individual benefit and group benefit. The idea goes back over two millennia, modelled after use of common pasture. Villagers pasture their animals, say, sheep, in a pasture of finite size in a village. A few villagers each have a few sheep that they pasture on the village green. It works. Every villager now wants to pasture sheep on the same common green. The result? Over-cropping and starving sheep, and village life is irretrievably damaged.

Our global commons includes the entire biosphere and each country has its ’ecological footprint’, a sort of measure of spatial demands of the country on the varied productive ecosystems in hectares of land or water required to satisfy the needs of the country and consume the wastes produced, expressed as global hectares per capita.

Given the available productive systems and the current human population the per capita ecological footprint of humanity is somewhat less than two global hectares. It should not surprise anybody that there are many countries that have smaller-than-average footprints, and that several, for example the G8 countries, have larger-than-average footprints, most being in the order of five or six global hectares per capita.

The US has a footprint of about 10 global hectares per capita. What does this mean? If every country had the consumption levels of the US the world would need about five or six planets to sustain humanity, assuming of course that population growth ceases. And this is the tragedy of the global commons, this is why whatever is said, annually millions of tonnes of greenhouse gases enter the atmosphere.

Here the individuals that are exploiting the commons are the 200-odd countries, and the commons is the biosphere, that thin shell of land, water and atmosphere enveloping the lifeless bulk of the planet that is the home for all living organisms, including ourselves.

I rather doubt that any educated citizen, as well as the Al Gores of the world, will not accept in the solitude of their minds that there is a finite limit to what this planet can carry - a function of basic population dynamics and biology.

The pasture is already over-grazed as we see the continued deforestation and world fisheries depletion. And the politicians and economists see solutions in further extraction of fossil fuels, industrialisation, sustainable development, economic development in the Third World and of course the eternal promise of technological innovation. The former are more concerned with self-serving policies that keep the barbarians at the gate, while many of the latter are narcotised with the miasma of sustainable development.

And the ’rapture ready’ crowd seems to think that our species is immune from biological law.