Illustration: Glen Le Lievre. "There is little doubt that the combustion of coal to produce electricity has made the greatest contribution to increasing carbon concentrations in the atmosphere," he says. But the most economically efficient way to deal with climate change is to tax all carbon emissions by means of a carbon tax or an equivalent emissions trading scheme. "Banning new coal mines would reflect an arbitrary approach to reducing emissions. On what basis should various fuels be permitted or banned? Why is coal to be singled out but other fuel with significant emissions such as oil and gas are not?" So his first objection to a moratorium is that it seeks to reduce climate change in a way that doesn't minimise the resulting loss of efficiency in the allocation of resources.

His second objection is more practical: it wouldn't work, anyway. He says that, according to the International Energy Agency's latest World Energy Outlook, global demand for electricity will increase by 70 per cent between 2013 and 2040. The agency's middle projection, based on the commitments to counter climate change that countries took to in the run up to the Paris conference, sees coal's share of global power generation still at 30 per cent in 2040 (compared with 41 per cent in 2013), meaning growth of nearly 25 per cent in absolute terms. Stanford says that "while the Australia coal industry is a very efficient it does not dominate the global market and could not be said to possess any significant market power". Australia's coal reserves amount to less than 9 per cent of global reserves. As a producer of steaming (thermal) coal, we rank a distant sixth behind China, the US, India, Indonesia and South Africa, not far ahead of Russia and Kazakhstan. These other countries are unlikely to agree to a global moratorium on new mines so, were Australia to impose a moratorium on itself, the investment in new mines displaced from Australia would merely take place in other countries. Malcolm Turnbull has used the same argument.

Illustration: Glen Le Lievre. Sorry, but I'm not convinced. It's true that a global carbon price would be a more economically efficient solution than an arbitrary moratorium on new coal mines. But with the problem worsening as each year passes, we don't have the luxury of waiting until a "first-best" solution can be agreed upon. In an emergency, second-best solutions are better than inaction. As for the practicalities of a unilateral Australian moratorium, the facts are more complex than Stanford implies. The International Energy Agency's figure of a 70 per cent increase in global demand for electricity is an assumption, not an estimate. All 25-year projections are just projections, and likely to be wrong, often because they're overtaken by events. The agency's projections don't take sufficient account of the fall in China's coal consumption over the past 18 months.

Projections that don't allow for further technological advances and price falls in renewables and energy storage, nor for countries to step up their efforts to reduce warming, over the next 25 years, are particularly unreliable. Stanford's figures for global coal reserves and even global coal consumption aren't relevant. That's because not all coal is the same. Some is high quality – in terms of its ability to generate more electricity – some is low. Some can be extracted quite cheaply, some would be very expensive. Coal is a low value commodity that's expensive to transport over long distances. This means a high proportion of coal deposits and domestic coal consumption is irrelevant in assessing Australia's market power and the likely effects of a unilateral moratorium. What determines the world price is seaborne exports of thermal coal. A Reserve Bank analysis shows Indonesia's low-quality coal has 41 per cent of world exports, while we come second with 18 per cent. Australia is a high quality, low-cost producer, which makes us a more powerful market player than the raw figures suggest.

World prices of steaming coal have fallen a long way since their peak in 2011, in response to a huge increase in supply (mainly by Indonesia and Australia) and flat world demand. If our 52 proposals to build new coal mines or expand existing ones went ahead, this would eventually double our exports. Do you really think that would have no effect on the world price? If it caused the world price to be lower than otherwise, this would hurt our existing coal mines, their lenders and their employees. It would also hurt existing and prospective renewable energy projects. And it would cause the price to be even less reflective of the high social costs caused by carbon emissions, the adverse effect on miners' health and air pollution around coal-fired power stations (the latter a big part of China's reasons for turning against coal). With the world coal price relatively low, it's not at all clear other, higher-cost producers would happily step in to take our place. If they could, why aren't they doing it already?