Not surprisingly, Tong's call for a moratorium has been supported by 11 other Pacific island nations worried about rising sea levels. But he's also winning support from such influential figures as the Nobel Prize-winning scientist Peter Doherty and the British economist Lord Nicholas Stern. For such an international moratorium to be effective, we'd have to be part of it. At present, we have 52 proposals to build new coals mines or expand existing ones. But isn't it too much to ask us to leave all that black gold in the ground? Mining and exporting coal is an important way this economy makes its living. The developing countries – including China and India – have a lot more developing to do, meaning they'll need a lot more energy, much of which will be coal. What's so bad about them trying to get rich like us? And why shouldn't it be we who supply that coal? We need more jobs, and think of all the jobs building more big mines would create.

So what's it to be? Conscience or self-interest? Well, how about both? The Australia Institute think-tank has begun campaigning hard for a moratorium, and a forthcoming paper by its chief economist, Richard Denniss, argues that economic and political considerations actually say we should be joining the moratorium. Why? In a nutshell, because coal's days are numbered. The rapidly falling price of renewable energy such as wind and solar, combined with the growing resolve of China, the US and others to reduce their emissions, put a dark cloud over the future of coal. So what's it to be? Conscience or self-interest? Well, how about both? Coal mines are intended to have lives of 50 to 90 years. Will coal prices be high enough in 30 or 40 years to make continued production profitable? If not, investors in new coal mines won't get their money back, but will be lumbered with "stranded assets" – assets that no longer earn much of a return.

Denniss says it's now widely accepted by international agencies that meeting the goal of limiting global warming to 2 degrees requires keeping most fossil fuels unburnt and in the ground. All this helps explain why the world's big banks, including our own, have become markedly less enthusiastic about financing new coal mines. That – plus the present flat state of the world coal market. According to the BP company's energy outlook, global coal consumption grew by just 0.4 per cent last year, well below its 10-year average growth rate of 2.9 per cent. Within that, China's consumption grew by just 0.1 per cent. And Professor Ross Garnaut, of the University of Melbourne, is predicting a significant decline in China's demand for coal for the foreseeable future. Were we to build all our proposed new mines, we'd double our annual exports. According to Denniss, just proceeding with the five biggest projects in Queensland's Galilee Basin would increase the world's seaborne coal trade by 18 per cent.

What do you reckon that would do to world coal prices at a time when coal demand is weak? See the point? In such circumstances, preventing further coal development – including by governments declining to subsidise new mine railways and ports – wouldn't just reduce future greenhouse gas emissions. By avoiding causing further decline in coal prices, it would also benefit the owners of existing mines, the banks that have lent to them and those who work for them, as well as the owners of present and future renewable energy projects. Not to mention the governments dependent on revenue from price-based mining royalties and company tax collections. On its face, by causing coal prices to be higher than otherwise, it would harm the users of coal and coal-fired electricity. But when you remember that, without something like a carbon tax, the price of coal fails to include the cost to the community of the environmental damage that coal-burning does (including the dead and ill health caused by the particulate air pollution from power stations), that's not anything to feel bad about. But what about all the jobs that building new mines would have created? They're temporary and often exaggerated by the projects' proponents. Once they're built, open-cut coal mines employ surprisingly few workers.