The world's wealthiest people must urgently reduce their consumption to save the Earth from a "vortex of economic, socio-political and environmental ills", a major report by Britain's leading scientific academy concludes.
The Royal Society panel of 23 eminent academics from around the world in the fields of economics, population studies and conservation science, calls for a radical "rebalancing" of global consumption to go hand-in-hand with attempts to curb further rapid rises in population.
It concludes that tackling global inequality is central to solving the problem of too many people exploiting dwindling natural resources.
The global population, which has reached seven billion, is growing at about 80 million a year. Developing countries will need to build the equivalent of a city of a million people every five days for the next 40 years because of urban migration.
The increased demands this will place on the Earth's limited resources means that people living in rich countries will need to consume fewer natural resources so that poorer nations can consume more, the scientists say.
"Human impact on the Earth raises serious concerns, and in the richest parts of the world per capita, material consumption is far above the level that can be sustained for everyone in a population of seven billion or more," the report says.
"This is in stark contrast to the world's 1.3 billion poorest people, who need to consume more in order to be raised out of extreme poverty," it says.
It recommends a "decoupling" of economic activity from the natural resources of the global environment so that economic growth and human wellbeing are no longer linked with the increased utilisation of the finite goods and services provided by nature.
Expanding the availability of contraceptives to the poorest people in the world will not on its own solve some of the most difficult problems associated with an increase in human numbers and a depleted natural environment, the report concludes.
Sir John Sulston, the chairman of the working group, said that separating the twin problems of overpopulation and over-consumption had in the past polarised the debate over the effects of rising numbers of people inhabiting the planet.
"The world now has a very clear choice. We can choose to address the twin issues of population and consumption... to rebalance the use of resources to a more egalitarian pattern of consumption," Sir John said.
"Or we choose to do nothing and to drift into a downward vortex of economic, socio-political and environmental ills, leading to a more unequal and inhospitable future," he said.
"Improving the wellbeing of individuals so that humanity flourishes rather than survives requires moving from current economic measures to fully valuing natural capital," the report says.
The report is unequivocal about the pressing need to slow down and stabilise the population of those countries where numbers are expected to rise rapidly in the coming century.