Nobody expects halting population growth alone to stop global warming but ignoring it altogether will ensure failure, a leading environmental scientist says in a report released on Monday.

Continuing population growth in Australia, combined with climate change, will make us vulnerable to food, water and energy scarcity in the future, lead author Ian Lowe warns.

The single act today of choosing not to have a child could spread the avoided emissions over many decades.

In a rich country like Australia, having one less child could save more than 20 times as much greenhouse gases as living without a car, or about 70 times as much as switching to a meat-free diet, he said.

The COVID-19 pandemic has put the brakes on migration, but employers are urging a return to pre-pandemic levels to help fix worker shortages.

But if immigration is high enough to cause population growth, it also increases a country's emissions.

"Some people argue that it makes no difference globally," Professor Lowe said.

"This is untrue; the average migrant to Australia increases their carbon footprint fourfold by adopting Australian lifestyles."

While Australians have recently reduced their per capita emissions a little, the nation's total emissions from energy use have risen 49 per cent since 1990 due entirely to population growth of 8.3 million people, he says.

Commissioned by environmental advocacy group Sustainable Population Australia, the report says affluent countries such as Australia should not be promoting population growth

"The link between population and climate change is often overlooked or misunderstood," SPA president Jenny Goldie said.

Prof Lowe says measures to curb population growth should not be "taboo".

He said voluntary family planning services were severely underfunded and under-promoted in poorer high-fertility countries, leaving many women without the means to avoid pregnancies they don't want.

Family planning programs could help development, the environment and climate adaptation.

The most recent figures from the Australian Bureau of Statistics show the nation's population was just over 25.7 million at June 30, 2021.

Australian Associated Press