The sixth billionth inhabitant of the Earth has arrived.

While the United Nations has welcomed the baby into the world, born shortly after midnight on October 12 in Sarajevo, the future of 240,000 others born everyday is far from certain.

Most of these children are born to parents in the developing world, parents with little formal education or knowledge of health care.

The pregnancies will probably have been unwanted, and the mothers may have already seen other children die in their early years.

If these mothers do survive giving birth, they are likely to fall pregnant again since they have little modern support in family planning. And so the cycle continues.

Under pressure

Since 1927, in less than a lifetime, population has tripled.

Global birth rates are slowing - down to just 1.4% in the industrialised north and 1.7% in developing countries.

But the number of actual births continues to rise, largely because of the near one billion fertile people aged 15 to 24-years-old.

Earlier this year, governments and development experts met at the United Nations in New York to discuss these issues.

At that conference, the United Nations' Population Fund (UNFPA) predicted that if we introduce the correct policies now, population will stabilise at 7.9 billion people by 2050.

But if we leave both growth and associated consumption unchecked, it warned, it will lead to catastrophe - even more deaths from famine, energy crises and civil breakdown in some regions as the fight begins for scarce resources such as water and arable land.

Amy Coen, head of the US-based Population Action International, said that everyone would be the loser.

"When women have too many children which they cannot care for, the ripple effects are both local and global," said Ms Coen.

"Children are not cared for, they are not healthy, women die in childbirth, the economy of the family is much worse because the mother and the father cannot support the children.

"They don't have proper housing, they don't have proper education and so the economy suffers."

While one of the challenges of the 20th Century has been to combat mortality by improving public health, the challenge of the 21st Century will be to find a way to curb fertility.

Cairo summit

Five years ago the United Nations held a groundbreaking conference to tackle the ripple effect of population growth on the world.

The Cairo conference agreed a radical effort to stabilise population by providing universal health care and basic education throughout the world by 2015.

This programme includes reproductive education and empowering women with the means of choosing how to plan a family.

For instance, women who are able to space the period between pregnancies live longer and have fewer children who tend to be healthier.

The ripple effect on the local, national and ultimately the global economy is beneficial.

"Kenya is one example of a success story," said Ms Coen. "Its total fertility (birth rate) has dropped by nearly one child per woman in five years - that's an amazing achievement.

"The number of women using contraception has risen from 33% to 39%.

"We are very hopeful that women who want to use contraception will be able to."

Brazil has seen a major programme to improve reproductive education while Uganda, another country experiencing worrying population growth, is undergoing a similar scheme to try and tackle the appalling threat of HIV/Aids.

Political fears

While campaigners believe that there has been success in implementing the Cairo programme, there is growing pressure on international donor countries to pay their share.

Individual programme countries meet two-thirds of the annual $17bn costs.

UNFPA predicts that its current $2bn shortfall will lead to 97 million fewer people receiving family planning in 2000, resulting in 42 million more unintended pregnancies, 17 million more abortions - and 99,000 more maternal deaths.

The USA has been heavily criticised for cutting UNFPA funding, although Senators brought a bill before Congress to restore the contributions.

The Vatican has also been accused of using its UN membership to try and block contraception-based initiatives and legally agreed programmes, a move which led some campaigners to call for it to be thrown out of the body.

The UNFPA says that, besides resources, the key areas which must be addresed are:

• Adolescent reproductive health. The number of people now aged 15 to 24 is the largest it has ever been. Their attitude to family planning will be crucial
• Refugee populations and access to emergency contraception
• Abortion
• Civil society: What role non-governmental organisations should play in devising family planning policies

Consumption

However, many population experts say that one critical part of the issue is being overlooked.

While population growth in the developing world makes stark reading, the populations of the industrialised north cause the most damage to the planet.

And as increasing numbers of people in the developing world shift into urban areas to seek similar consumer lifestyles, the pressure on the world's finite resources intensifies.

Dr Norman Myers, fellow of Green College at Oxford University, said that the industrialised world must examine its own consumption as part of the population-resources equation.

"In the UK we have a population growth rate of 0.2%, we produce 120,000 more people every year," said Dr Myers.

"Bangladesh has a growth rate 10 times higher but because of the way we use our resources, we produce 50 times more emissions than Bangladesh.

"We are causing two and half times more damage to the environment."

Dr Myers said that while people speak of grain shortages in the developing world, America's annual consumption of 800kgs per person - feed for cattle in a meat-based diet - is far more concerning as the developing world seeks to follow suit.

If every person in China ate an extra chicken, said Dr Myers, the grain needed to rear the birds would be equivalent to the entire grain exports of Canada.

He called for nations such as the UK to implement population policies alongside tax incentives to change consumption and fuel use.

"There is a great deal that we can do," said Dr Myers. "Some people say that you cannot shift consumption patterns. But 60 million Americans have given up smoking. That's a social earthquake.

"Whether the political will is there to act in other areas, we will have to wait and see.

"It would not take much to get through the bottleneck."