New Study Projects World Population of 11B by 2100

vinces99 (2792707) writes Using modern statistical tools, a new study led by the University of Washington and the United Nations finds that world population is likely to keep growing throughout the 21st century. The number of people on Earth is likely to reach 11 billion by 2100, the study concludes, about 2 billion higher than widely cited previous estimates. The paper published online Sept. 18 in the journal Science includes the most up-to-date numbers for future world population, and describes a new method for creating such estimates. "The consensus over the past 20 years or so was that world population, which is currently around 7 billion, would go up to 9 billion and level off or probably decline," said corresponding author Adrian Raftery, a UW professor of statistics and of sociology. ... The paper explains the most recent United Nations population data released in July. This is the first U.N. population report to use modern statistics, known as Bayesian statistics, that combines all available information to generate better predictions.

Most of the anticipated growth is in Africa, where population is projected to quadruple from around 1 billion today to 4 billion by the end of the century. The main reason is that birth rates in sub-Saharan Africa have not been going down as fast as had been expected. There is an 80 percent chance that the population in Africa at the end of the century will be between 3.5 billion and 5.1 billion people.

Comments

Not a problem...

[mi]

Vast areas of Earth remain unpopulated. In no particular order:

• American Midwest
• Most of Canada
• Australia's Outback
• Siberia
• Sahara and other hot deserts
• Antarctica — a whopping continent

Sure, some of the above would require some work to make comfortable, but it can be done even with today's technology — by 2100 even an individual (or a family) would convert surroundings to their tastes. And it would certainly be easier, than moving an appreciable quantity of people off-Earth...

Re:Not a problem...

[rogoshen1]

they're unpopulated for a reason. the logistics behind supporting any reasonable habitat for a dense population aren't so workable. namely water. mostly water. Which, according to the UN and a few other NGO's, will be sort of a big deal during this time frame.

Re:Not a problem...

[Xest]

That assumes that all those environments are pointless wastes of space, unfortunately that premise isn't true- those areas of land serve important purpose for example the sands of the Sahara blow across the Atlantic and fertilise the likes of the Amazon rainforest.

A lot of people say "Why don't we geo-engineer the Sahara to make it tropical forest again!" but it becomes almost a zero-sum game, as you grow forests in Africa you decrease the fertilisation of the Amazon and so growth is stunted there in turn.

We can only move into these territories (or even keep expanding in existing ones) if we can find a way to do so without impacting the underlying ecosystem, otherwise we find ourselves with a whole lot of people and not enough resources and you know what that generally means? war - winning side gets the resources.

So it's not just about making an area habitable, or comfortable, it's about doing so in a manner that doesn't have a knock on effect elsewhere - by regrowing Africa into a tropical jungle paradise you'd be slowly pushing ever more of South America into a poor inhospitable desert. Similarly if you start inhabiting Siberia and Antarctica with more human activity resulting in greater melting of these regions you'll simply be flooding coastal regions elsewhere and making them uninhabitable.

Long story short, you cannot make massive changes to large areas of land without there being an impact elsewhere. You can see this on many scales, whether it's the farmers that cleared the forests on the hills of South West England to give themselves more land for crops leading to widespread devastating flooding due to lack of trees to slow water down in the hills, or whether it's something much larger scale as with the Africa/Amazon connection above. For every sizeable environmental change we make there is an impact elsewhere.

For what it's worth, I suspect the place we could most likely inhabit on land with the least impact elsewhere is in parts of the sea but even this would require a lot of care so as to restrict ocean pollution from waste which may damage fish stocks and decrease food. Failing that it's to space we go I guess.

Which isn't to say that there aren't some areas of the planet we can inhabit with little impact elsewhere meaning there is some scope for population growth, but those areas are becoming ever less common and the effects of inhabiting them elsewhere are often subtle making it difficult to know when you have and haven't found a reasonable spot to settle more people. Thus fundamentally it's not simply a case of saying "Hey look that place isn't inhabited, let's inhabit it!" because in doing so you're causing destruction of environments elsewhere where people were inhabiting and now you have to find room for them too.

Of course, I suspect none of it will matter- the rich will live where they desire to live and any knock on impact on anyone else? well they can go fuck themselves, because humans are an inherently selfish species.

Africa

[superdave80]

Most of the anticipated growth is in Africa, where population is projected to quadruple from around 1 billion today to 4 billion by the end of the century.

You mean, the continent that can barely feed itself and is the source of deadly plagues (Ebola, etc.) is somehow going to support four times it's current population? I'd like to see how that is feasible...

Assuming we find a hydrocarbon energy substitute

[gestalt_n_pepper]

One that's as cheap, energy dense and as easy to handle at room temperature as oil, coal, natural gas and so on.

If we *don't* do this, then I'm fairly sure that after we hit 11 billion by 2100, we'll be lucky to hit 50 million by 2200. Fewer, if we try and solve our resource problems by throwing nukes at one another, which sounds likely.

Like all species, we simply consume resources until the population crashes. What we've been so far with technology is "lucky." There's always been another *cheap* and *easy* resource to exploit. Short of a breakthrough in battery technology and thorium reactors (or fusion) that's not going to happen again.

Don't look at me

[JudgeFurious]

I'll be long gone and I've made sure that I created no annoying descendants too. I've done my part for population control. It's partially how a rationalize my 16MPG Mustang GT, hour long hot showers, and keeping my thermostat at 60 degrees all summer long. I'm bad but I've made sure that I'm the last of my line. Now get off my lawn!