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The UK's Royal Society is launching a major study into human population growth and how it may affect social and economic development in coming decades.

The world's population has risen from two billion in 1930 to 6.8 billion now, with nine billion projected by 2050.

The society acknowledges it is delving into a hugely controversial area, but says a comprehensive and scientific review of the evidence is needed.

It is led by Nobel laureate Sir John Sulston of Human Genome Project fame.

"This is a topic that has gone to and fro in the last few decades, and appears to be moving back up the political agenda now," he told ´óÏó´«Ã½ News.

"So it seems a good moment for the Royal Society to launch a study that looks objectively at the scientific basis for changes in population, for the different regional and cultural factors that may affect that, and at the effects that population changes will have on our future in term of sustainable development."

The burgeoning human population is acknowledged as one of the underlying causes of environmental issues such as climate change, deforestation, depletion of water resources and loss of biodiversity.

The working group includes experts on the environment, agriculture, economics, law and theology drawn from a mix of rich and poor countries including the UK, China, Brazil and the US.

In the 1970s, with disastrous food shortages routine in regions of Asia and Africa, the world's apparently dwindling capacity to feed its rapidly growing population was an issue high on the political agenda.

New crops developed during the Green Revolution and other advances in agriculture, combined with economic progress, seemed to allay these fears in subsequent decades.

In addition, some people in developing countries argued that western nations raised the issue as a means of distracting attention from the rising and unsustainable consumption in the west.

Recently, however, population has started to re-emerge as an issue of discussion among people working on environment and development issues.

High-profile champions such as Sir David Attenborough have spoken of its importance and the threats it may pose.

However, some economists and policymakers consider population growth a good thing, as it produces a swelling workforce capable of producing more goods and continued economic growth.

Jonathon Porritt, founder and director of the UK think tank Forum for the Future and a member of the Royal Society's working group, suggested the review could shed some objective light on the issues under dispute.

"What it can do is shed some light on the different interpretations that people draw from the underlying trends," he said.

"Why do some people say it doesn't matter and is all welcome, while others such as me say it is likely to have a greater impact on the future of humanity than some of the other issues we are talking a lot about?"

Policymakers needed such objective studies, he said, in order to make effective choices - for example, deciding whether and how to support family planning policies in the developing world.

The Royal Society's study is launched on World Population Day, and is expected to conclude in early 2012.