The debate around population growth and its risks has raged for over two centuries. Economist Thomas Malthus was the first to predict that rapid population growth during the Industrial Revolution would bring starvation and death to his native England due to dwindling food resources.
History proved him wrong, but Malthus' argument is still very much alive now that the world population has surpassed the 7 billion mark and is expected to grow to 9 or 10 billion by 2050, according to United Nations projections.
With climate change finally sinking in as a reality in people's minds, experts are concerned living conditions will become unsustainable if the world population continues to grow at the current pace.
So what is the right way to go about this? Many say we need to bring the numbers down - halt, or at least slow, population growth.
A new documentary by Oscar-winning director Jessica Yu adopts a different perspective.
In bustling Beijing, there is 29-year-old Bao who is desperately looking for a wife. China's one child policy has prevented nearly half a billion births since it was introduced, the government says, resulting in a deficit of 30 million women.
"It's not a normal situation," Bao says in the film. "China has a lot of leftover men. I'm one of them."
Bao and millions of other young Chinese men are dealing with the consequences of a policy aimed at reducing population growth to protect the nation's economic development. But in a culture where it's still preferable to have a male child, the policy has had - perhaps unwanted - repercussions.
Bao is under pressure to get married from his conservative family who lives in rural China. Due to the one child policy, aging parents rely on their children's family to provide for them once they are too old to work. Their only child is a sort of investment in their own future and an unmarried son means their own livelihood is at risk.
However, modern life has caused a shift in many Chinese women's priorities. Contrary to their male counterparts, they no longer want to get married at a young age, they want to focus on their careers and postpone childbirth.
As China struggles with this population imbalance, other countries are struggling with explosive growth - like Uganda, where Yu followed Gladys, a Ugandan journalist who reports on lost and abandoned children.
In the east African nation's capital Kampala, hundreds of children are abandoned by their mothers who can't afford to take care of them.
Gladys works with social workers and local authorities to rescue the children and raise awareness about family planning and maternal health care among women, in a country where girls are often married off at a very young age and the lack of access to health services contribute to high fertility rates.
"Since 1960, a staggering 4 billion people have been added to the world population," Swedish health expert Hans Rosling is shown in the documentary as saying. "You don't need to control population numbers - this is a myth."
Rosling argued that the only way of curbing population growth is to improve child survival. "We could stop at 9 billion if we do the right things," he said.
Uganda’s socioeconomic context suggests that extending family planning services so that women are able to plan their pregnancies and provide for their children would help. Fewer newborns would lead to more children surviving, and those children would then live in better conditions, in less poverty and with greater opportunities.
However, there are often moral obstacles to family planning and contraception. Yu follows Denise, a Canadian pro-life activist, on a trip to the U.N. where she tries to garner support for her anti-abortion and anti-contraception views.
Eighty percent of families globally have an average of a little over 2 children and, according to Rosling, this is the trend in countries that have reached a certain degree of prosperity.
This means that population growth would automatically stop, or slow down, as living conditions improve and nations progress economically.
However, more developed, richer societies consume, and pollute, a lot more than developing ones, eating away at the planet’s resources, Rosling argued.
In other words, less populous nations consume much more than the more populous.
Yu’s film by no means provides an answer to the population issue, but it looks at its various underlying causes that suggest different solutions, while challenging misconceptions.
Lifting people out of poverty, granting mothers and families access to health care, and investing in sustainable development in both developed and developing countries is the most comprehensive response to population growth and its challenges.
“The problems of the world aren’t on the shoulders of people having ‘too many kids,’ Yu said in a recent interview. “Everyone has a role in this — whether it’s a smaller, wealthier family that consumes a lot or a larger family that has more kids than can easily be handled by the parents.”