If further proof were needed that, despite their pious words, our political leaders do not take climate change seriously, the recent population debate provides it.

The argument over whether we should aim for 36 million people by the middle of the century is conducted as if the world in 2050 were going to be a richer version of what we have now. This is the grand delusion of the climate change debate.

None of our political or business leaders is listening to what the scientists are saying. More surprisingly, nor are our leading demographers, economists and Treasury officials. All have joined the debate but seem oblivious to the sort of world the growing population is expected to inhabit.

In truth, Australians in 2050 will be living in a nation transformed by a changing climate, with widespread doubt over whether we will make it to the end of the century in a land that is recognisably Australian.

Over the next decades hundreds of thousands of Australians will try to escape those parts of the continent that have become too unpleasant or dangerous to live in and migrate to those that have better water supplies, fewer days of extreme heat and adequate protection from floods, fires and rising seas.