''The 21st century is a critical period for people and the planet. Our population growth is pushing our planet to the limit and there are limits to growth on a planet with finite resources,'' Sir John Sulston said in the St David Lecture Theatre last night.
The 550-seat theatre was three-quarters full for the Royal Society of New Zealand 2013 Rutherford Memorial Lecture.
With the human population forecast to pass 10 billion this century, there were some ''difficult ethical, legal, social and scientific'' decisions to be made, the chairman of the Royal Society of London's people and the planet international working group said.
''It is not feasible for all of Earth's present inhabitants to consume material resources at the current rate of most developed countries.
"If we do nothing, the discrepancy will increase. Our descendants ought to have opportunities at least as great as those we ourselves enjoy. But if we continue in our current style, they will not.''
The effects of population and consumption should be considered together, he said.
''They should not be split up. If we don't talk about this properly, we won't make progress.
"We have more people and we have more consumption, with the accompanying emissions that are leading to climate change.''
Humans had a responsibility to nurture Earth and its resources, Sir John said.
''We are the most powerful species on Earth. We can grow our capability in a way no other species can. So, we have a responsibility for what we are doing. At the moment, it's a failure of stewardship.''
Sir John was jointly awarded the Nobel Prize for Physiology or Medicine in 2002, with Sydney Brenner and Bob Horvitz, for their work on the nematode (worm) Caenorhabditis elegans.
