Along with 60 other Australians, mostly more eminent than me, I’ve signed an open letter to world leaders calling for a moratorium on new coal mines and coal mine expansions. The letter focuses particularly on Adani’s proposed Carmichael mine in Queensland but this is part of a global movement to stop new coal mines everywhere in the world.

The underlying reasoning isn’t spelt out but ought to be clear enough. If we are to stabilize greenhouse gas concentrations at 450 ppm or below, as the world’s leaders have already agreed we should, it is necessary for carbon dioxide emissions to peak soon, and decline to zero over the next 30 years or so. Given that burning coal creates major health hazards in addition to C02 emissions, coal burning needs to eliminated even more rapidly. That means first, that no new coal mine can expect to work for an operating life of more than 30 years, and second that any new coal mine must be offset be additional closures of existing coal mines. Once these factors are taken into account, it’s essentially impossible for new coal mines to make economic sense within the constraints imposed by a limited carbon budget. Certainly, that’s the case for Carmichael, which is a massive boondoggle keeping alive only in the hope of extracting some form of government assistance or compensation.