This article from seven news
Population growth must be slashed to protect human health and wellbeing, a Harvard University health professor says.
Dr Aaron Bernstein, who also works as a pediatrician, says population growth and climate change are the two biggest threats to the future of life on earth.
Speaking at the National Press Club in Canberra on Tuesday, he said the discovery of new medicines often depends on healthy ecosystems, which continue to be destroyed.
Dr Bernstein gave the example of a recently extinct species of gastric-breeding frogs, that were unique to Australia.
The chemicals used to gestate spawn internally could have led to a cure for peptic ulcer disease, affecting more than a million Australians and 25 million Americans.
"With loss of individual species we foreclose upon the discovery of new medicines," he said, noting that one third of the world's species were forecast to be extinct by 2050.
Dr Bernstein said three-quarters of emerging diseases, including respiratory ailments, were the result of damaged ecological systems.
"Ecological barriers that once kept these infections at bay have been broken, opening the door to their passage of the human population, he said.
Over the past 50 years one fifth of the earth's topsoil and agricultural land has eroded, along with 90 per cent of marine fisheries and a third of forests, he said.
Over the same period the population has tripled to 6.5 billion people.
Dr Bernstein said to protect ecosystems, as the global population soars towards nine billion, policy makers need to cut carbon and population growth.
"We must do everything possible to further limit the growth of the human population," he said.
Dr Bernstein didn't suggest how to achieve this, saying it is up to policy makers in each country.
But he said the local debate on population, forecast by Treasury to reach 36 million by 2050, needs "careful consideration" by government.
On the issue of climate change, he suggested a carbon price be set to "drastically alter people's consumption habit".
Dr Bernstein also weighed into the genetically modified (GM) food debate, saying it should be part of the global solution to climate change.
He says he has no health reservations about the food source, that billions of people in poorer countries will depend on in the coming years.
And he said it's crucial GM crops, including drought resistant varieties, are freely available."Genetic resources cannot be held as high profit enterprises when they are critical to the health and nutritional status of people in the developing world," he said.