In 1992, in response to the threat of global warming, the governments of the world agreed to "stabilise greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous human interference with the climate system".

Recently, the G8 nations agreed to an objective of limiting global warming to only two degrees above pre-industrial temperatures. The best estimate of what is needed to have a 50:50 chance of avoiding two degrees of global warming is to stabilise greenhouse gas concentrations in the atmosphere below 450 parts per million of carbon dioxide and other long-lived greenhouse gases.

To do that, global emissions must peak before 2015 and fall by 50 per cent to 85 per cent by 2050.

How can global emission reductions be distributed between different countries? A fair way of distributing a limited resource among a group of people is to give everyone an equal share. Children understand that this is a fair approach, even if politicians don't.

All governments in the world agreed in 1992 to the underlying principle that "developed countries should take the lead in combating climate change". Per person emissions of greenhouse gases in developed countries are four times higher than in developing countries. Australia has the highest emissions of carbon dioxide per person in the world, six times higher than the average for developing countries and even higher than the US.