Science Saturday - Are There Too Many Humans?

As a matter of fact ...

The world's population is expected to reach 12.3 billion by 2100. It's currently at 7.2 billion. That's an astonishing 5.1 billion increase in the next 86 years. This recent and somewhat shocking report by the United Nations goes against previous world population estimates of 10 billion people by 2100.

So should we be worried? Well, Earth does only have a finite amount of resources and so therefore has a limit to human population; but where is the limit? And if we surpass that, do we risk mass famines that may lead to conflicts over the scraps of resources left?

Overcrowding at a swimming pool in China; the world's most populous country

It's not a nice prospect to dwell on. However, some scientists think there is nothing to be alarmed about as we may make a U-Turn before that and reverse the current growth trend. 

UN findings show that the fertility rate across most countries has been steadily falling since the 1950's and is rapidly approaching the optimum rate of 2.1 children per woman; the rate at which children replace their parents and make up for any loss of young life. If that happens, that world population should stabilize somewhere between 9 - 10 billion; an amount that pushes the upper limit of what Earth can support. 

Our future still seems unclear at this point but our past is set in stone. To understand how we're growing, you need to understand how we've grown and this chart shows it best:

Graph from Scott Manning, compiled from various studies and U.N reports

On the right you can see the different studies used to create this graph. Starting with an estimated 5 million people in 10,000 BC, you can see it took almost 12,000 years for Earth's population to reach the 1 billion mark in 1804.

Then, the agricultural and industrial revolutions happened. This catapulted the Earth's population into overdrive and it took just 123 years for it to double to 2 billion in 1927.

Fast forward to 2014, only 87 years on, and we're at 7.2 billion. That's a crazy rate of growth. So will we reach 10 billion by 2100? Probably. Will exceeding that spell doom for the human race? Possibly. Will the trends reverse and the population stabilize? Who knows!

The figures from Asia, the fastest growing continent, suggest things are slowing down but just as nobody foresaw the industrial or agricultural revolutions, so too are we somewhat blind to what lies around the corner for our species. 

I think that population stabilizing is just one answer to our problems. We apply these limits and boundaries on our growth within the context of our current capabilities. In this technological age, it would be foolish to think we have reached our peak when it comes to maximising the food and energy this planet has. 

I'm quietly confident that there will be an environmentally friendly and game changing breakthrough within this century that will set our fears aside. Perhaps I'm just a naive optimist, but history speaks for itself. 12.3 Billion people in 2100 might seem too close for comfort, but a lot can happen in 86 years.