Attenborough: endless growth 'lunacy' One of the world's leading naturalists Sir David Attenborough has cautioned Australia against pursuing further population growth, labelling an unlimited expansion a kind of madness. Speaking before touring Australia next month, Sir David questioned why the country still found itself actively debating whether it needed to grow its population. Why would you want to do that? I don't understand that. The notion that you could continue to expand and increase and grow in an infinite way on a planet which is finite, is a kind of lunacy. You can see how mad that is by the expression that you can't believe that you can grow infinitely in a finite place - unless of course you're an economist," he said. Advice: Sir David Attenborough. According to the Bureau of Statistics, Australia's population is estimated to grow to between 30.9 million and 42.5 million people by 2056. The first Sustainable Australia report released this month said the nation's population was growing at 1.7 per cent, one of the fastest rates in the developed world, but still well behind the more than 4 per cent growth rates of many African nations. The report lists environmental degradation as one of the greatest challenges facing development of regional parts of the country. In 2009, former prime minister Kevin Rudd sparked a national debate about population growth when he stated his belief in a "Big Australia." Since that time, the government's stance on population growth has cooled significantly, with his successor Julia Gillard rejecting that notion and calling for sustainable growth. In 2011, federal Environment Minister Tony Burke released a population strategy that was criticised for not setting a target, instead focusing on a more nuanced approach to growth in regions that were crying out for skilled workers. Sir David said his June tour was to discuss highlights of his six decades of nature filmmaking, not to speak out on environmental issues. However, he felt his global audience did place responsibilities on him. I'm not on a proselytising tour. On occasions I speak on these issues where it's appropriate and where the subject has come up," he said. Sir David said while he did not believe bureaucrats and governments should meddle in a family's right to have children, had China not introduced its controversial one-child policy in 1979, the consequences for the planet would have been catastrophic. "One thing you can say is that in those places where women are in charge of their bodies, where they have the vote, where they are allowed to dictate what they do and what they want, whether it's proper medical facilities for birth control, the birth rate falls," he said.