The government is only interested in improving the economy and driving commercial interests.

Any real addressing of climate change is given tokenism and they are dragging their heels. The rich will get richer while the conditions in Australia will get worse.

Humans are the drivers of climate change, and their livestock, and increasing the population just puts more pressure on the ecology and produces more greenhouse gases.

Why depend on high migrant intake for economic health when water is such an issue and we are such heavy producers of co2 per head?

But then, just how much less co2 would each migrant have produced if left in a homeland?

What is the use of little Australia ruining its self cutting emissions when we make such a small percentage of what the world produces - unless the technology for a lower footprint that we can discover becomes a saleable commodity to those who do more damage than we do?

This suggestion falls into the "robbing Peter to pay Paul" category. It will do nothing to address what is a GLOBAL problem.

All it does is help make Australia look good by forcing the emission source (the people) to stay offshore.

The critical factor in reducing population growth is equality between the sexes. Once women are treated equally to men, family sizes reduce within a generation.

This will truly deal with this issue in a productice, posistve and global way.

Dr Birrell gets my vote. We must be as vigilant with the movement of people across borders as we are with animals, plants and money. Open borders lead to creating additional problems for humanity and the environment irrespective of the commodity.

Birrell has been flogging this one eyed dead horse for more than 20 years.

The problem is that our trusted representatives at Kyoto etc have not bothered to ensure that a migrants carbon quota comes to the new country when the migrant arrives.

And, of course, Birrell's argument only holds a scrap of credibility as long as the debate relies on national average emissions.

As if the average Chinese migrant to Australia was a rice farmer from Guizhou. The reality is that it is only the richest urban cohort that can muster the capital to migrate and these folk have a lifestyle (and emissions footprint) that is rapidly matching our own.

So here we are with an entirely self-inflicted problem where thousands of Kiwis and Brits can come here but leave their carbon quota behind to make life easier for the source country.

Meanwhile, our own representatives, keen to display their new hair shirt and self flagellating whips, tighten the screws and stress levels on millions of otherwise enduring marriages and nearly as many otherwise viable small businesses.

Some prominent social scientists would not be happy unless everyone but them moved back into the caves and lived a simple stone-age lifestyle.

I have been saying for two decades that Australia does not have enough water to support immigration. Our country has very little habitable land and water is a scarce resource.

Now communities along the Murray River are on the verge of a water crisis. Adelaide’s water supply is not assured.

In Sydney they are planning a desalination plant and in Canberra they want to treat sewerage and turn it into drinking water.

Brisbane is parched and Perth has its own water problems. About the only city not to be acutely short of water seems to be Darwin.

Anyone who believes that population growth is the key to our continued success needs to take a course in biology. Water is the essential element and we don’t have enough of it to support our current population let alone more immigrants.