We’ve Successfully Populated Earth, Now What?

Words by: Natasha Bloomfield

The most logical response to this question is, quite simply, to overpopulate it. Human overpopulation of Earth has fascinated our race for a remarkable length of time. In the 2nd century AD, when the human population was only 190 million, writer Tertullian stated that ‘Our numbers are burdensome to the world, which can hardly support us.’

Our Earth is, in fact, estimated to be able to hold a maximum capacity of 10 billion, an amount the United Nations estimates we will reach by 2100.

Human overpopulation occurs when the number of people exceeds the carrying capacity of the occupied region, especially in relation to relevant resources such as water, food, and space. It can also occur when the population cannot be maintained due to the rapid depletion of non-renewable resources and the environment can no longer support the population.

From a historical perspective, medical and agricultural revolutions have coincided with population explosions. Most notably this occurred during the tool-making, agricultural and industrial revolutions.

Most countries have no direct policy for limiting birth rates, yet they have fallen due to increased education and access to birth control and contraception. Only China has imposed legal restrictions on having more than one child by implementing a family planning policy in 2007, although the policy is complex with a number of exceptions. This is in stark contrast to Niger, where the average fertility rate is the highest in the world, with 6.89 children per woman.

Many environmental problems such as rising levels of atmospheric carbon dioxide, global warming, and pollution are aggravated by population expansion. Other problems include increased demand for resources such as fresh water and food, starvation and malnutrition, consumption of natural resources faster than the rate of regeneration, and a deterioration of living conditions.

However, some believe that waste and over-consumption, especially by wealthy nations, is putting more strain on the environment than overpopulation. But with the world’s richest 500 million people producing half the world’s carbon dioxide emissions, that’s not really a comforting thought.

So, say the Earth actually does make it to a holding capacity of 10 billion, what happens to us and the planet? Many experts believe that the major limiting factor for the Earth’s capacity to hold population growth is whether the Earth has enough energy to support that population level.

It is estimated that by the time Earth’s population reaches this level we will be consuming more than 140 billion metric tons of minerals, ores, fossil fuels and plant materials per year. It is forecast that there will be limited availability to freshwater and food, there will be a severe loss of biodiversity, and there will be disastrous ecosystem decline. Given this reality, we’d be unlikely to survive with a capacity that much exceeds 10 billion.

Once the human population reaches 10 billion it is expected to eventually stabilise and then decline, due to fertility rates falling to the level needed to replace the human population but not expand it, at approximately 2.1 children per woman. Given the abhorrent living conditions expected, this may be a blessing in disguise.

There have been a number of solutions suggested to prevent the population reaching this level before it happens naturally. Some propaganda states that the only way to control the human population is by supporting abortion and establishing a global one-child policy, yet such reports are dismissive of the influence of education, religion and societal traditions.

My personal favourite is intergalactic space travel and colonisation of either the Moon or Mars. But as much as I like this idea, with any luck I won’t have to even consider the issue for at least another 85 years.