15 Billion People by 2100? Don't believe it. (UPDATED)

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Contrary to reports by journalists and population alarmists, the UN isn’t releasing a new population forecast this week, and there is virtually no possibility that global population will ever reach 15 Billion.

UPDATE, OCTOBER 26: As this article predicted two days ago, the UN Population Fund report did not include a new population forecast. It merely repeated the projections released six months ago by the Population Division.

That didn’t stop the London Daily Telegraph from headlining its article on the UNFP report, “World population could double, warns UN.” The Telegraph article was republished in several Postmedia papers in Canada, including the Ottawa Citizen and the Vancouver Sun, under the headline “World population hits seven billion and could double within 100 years.”

The media never lets accuracy get in the way of publishing scary population numbers…


by Ian Angus

The world’s population will soon pass 7 Billion, and the United Nations Population Fund will mark that milestone this week by releasing its annual State of World Population report.

On October 22 the UK Guardian claimed that the report will contain a statistical bombshell. It headlined:

Population of world ‘could grow to 15bn by 2100’
Nearly 7 billion people now inhabit planet but projections that number will double this century have shocked academics

The headline in the Daily Mail, Britain’s largest circulation daily, was even more sensationalist:

World population will more than double to 15 billion by 2100, says UN

The Guardian story tells us:

“The United Nations will warn this week that the world’s population could more than double to 15 billion by the end of this century, putting a catastrophic strain on the planet’s resources unless urgent action is taken to curb growth rates….

“That figure is likely to shock many experts as it is far higher than many current estimates. A previous UN estimate had expected the world to have more than 10 billion people by 2100; currently, there are nearly 7 billion.”

The Guardian‘s editors repeated the claim in an editorial on October 23. “Without radical action, the UN now predicts the world’s population doubling again before the end of this century.”

Population Matters – the brand-name recently adopted by the arch-populationists of Optimum Population Trust – quickly posted the Guardian October 22 article on its website.

Populationists around the world have jumped on the wagon: less than 48 hours after the Guardian article first appeared, a Google search for “15 Billion by 2100” found “about 10,900” results.

But the Guardian article isn’t true. The UN isn’t releasing a new population forecast this week, experts aren’t shocked, and there is virtually no possibility that global population will ever reach 15 Billion.

For starters, the United Nations Population Fund doesn’t compile population statistics or produce population forecasts. Any statistics it publishes come from a separate UN agency, the Population Division of the Department of Economic and Social affairs. The Population Division’s report, World Population Prospects, 2010 Revision, was published six months ago – another isn’t due until 2013.

In this year’s report, the Population Division says that if current population trends continue, the world’s population will be 9.3 Billion in 2050, and 10.1 Billion in 2100. Their projections stop there, but if the trends they describe continue, world population growth will stop early in the 2100s.

So where does 15 Billion in 2100 come from?

The 10.1 Billion figure, called the Mid-Range projection, is based on a careful, country-by-country analysis, combining the latest statistics with the Division’s considered assumptions about long-term trends. The UN has been making these calculations since 1950, and its projections have consistently been off by less than 4%.

But to show that the results aren’t certain, the Population Division also produces two other projections by simply assuming that each adult woman will have 0.5 more or fewer children than the detailed Mid-Range projection. The choice of 0.5 seems to be entirely arbitrary: I’ve been unable to find any explanation of why the UN uses it it instead of a larger or smaller number.

This year, that calculation produced projections for 2100 that range from a low of 6 Billion to a high of more than 15 Billion, as shown in this graph. (click image for a larger version.)

(The highest line assumes that fertility doesn’t change at all from now on, taking us to 27 Billion in 2100. Not even the most extreme populationists quote that number.)

It’s important to understand that the 6 Billion to 15 Billion range is not comparable to the “margin of error” figure often reported in statistical studies. No probability whatsover is attached to it – it is just the result of a very crude calculation using an arbitrary adjustment.

In fact, the chance that population will reach 15 Billion this century is very close to zero. For that to happen, global fertility rates would have to be 20 to 25 percent higher than the UN’s best estimates, every single year for the next 90 years. Countries where birth rates have been falling for years would have to experience nine unprecedented decades of baby boom. Global birth rates, which have been declining for half a century, would have to reverse direction immediately, and stay high until the next century.

As noted above, previous UN Mid-Range projections have been accurate within 4%. Reaching 15 Billion in 2100 would be 50% off the mark. That’s extremely unlikely, to say the least.

The Guardian report is sloppy journalism, by reporters and editors who likely aren’t familiar with population projections.

But Optimum Population Trust claims to be a source of population expertise. For them to highlight the Guardian‘s grossly inaccurate article qualifies as either ignorance or deliberate misrepresentation. Either way, their judgement obviously can’t be trusted.

Unfortunately, as Mark Twain said, a lie can travel round the world while the truth is still lacing up its boots. Eventually the truth will win, but I expect we’ll see the “15 Billion by 2100” lie quite a lot for a while.


  • “if activists are diverted into population reduction schemes instead of confronting the real causes.”

    This is clearly the real issue for you. If you believe in “One solution – revolution”, then anything else is a diversion. The unfortunate consequence of this position is that you end up expending your energy attacking all other progressive or philanthropic activities as diversions when they don’t fit neatly into your class struggle model.

    You might more progress if you took on board more modern ‘big tent’ or ‘rainbow coalition’ models of progressive politics while of course retaining your own position.

    • Once again, Simon Ross of Optimum Population Trust falsely attributes the sectarian slogan “One Solution – Revolution” to Climate & Capitalism. He has said that before, so I’ll simply repeat my previous reply:

      Simon Ross caricatures our approach as “one solution, revolution,” a slogan chanted by some sectarian leftist groups in the 60s. In reality, ecosocialists will and do support any movement or reform that reduces, limits, or delays the devastating effects of capitalism. We will work with anyone, socialist or not, who seriously wants to to fight for such measures.

      What we won’t do:

      ++blame poor women for environmental problems;

      ++tell people in the South that they have to change their behaviour in order to save the world from problems caused by the rich and powerful in the North;

      ++promote birth control as a means to achieve populationist goals, rather than as a fundamental human right;

      ++tell anyone that using birth control is an effective way to fight climate change;

      ++try to turn rich countries into gated communities by locking out immigrants.

      Those are policies of privilege, policies that shift the responsibility for change from rich to poor, policies that divert attention away from the real environmental criminals. And they are the policies of Optimum Population Trust, which Simon Ross heads.

      No socialist can support them — not because we are sectarian, but because they are directly opposed to our fundamental goal of social justice.

      If Simon Ross cared to check, he’d find ecosocialists in the Occupy movement, in the protests against Canada’s tar sands and the Keystone Pipeline, in demonstrations against fracking, and many more “big tent” actions in which people who share our political views are a minority. We support such campaigns precisely because they have the potential to bring together people with a wide range of views in united efforts to reduce, limit or delay environmental destruction.

      In contrast, populationism divides us and cuts us off from our most important allies. It promotes division instead of unity, privilege instead of justice, complacency instead of change.

      As my co-author Simon Butler wrote recently, “Population theories assume other people are the problem. Genuine social change relies on people power — those who fight for social change must hold that other people are the solution. In the end, the two views are at odds with one another.”

  • For the head of Optimum Population Trust to say “don’t get fixated on the numbers” is truly bizarre. OPT’s entire raison d’etre is an obsession with human numbers as the primary cause of all social and enivironmental ills.

    And then he treats us to the ever-popular populationist cliche about population reduction making all other problems easier to solve.

    Actually, every problem of development, the environment and sustainability will be harder to solve if activists are diverted into population reduction schemes instead of confronting the real causes.

  • Some DWEM once said that “Philosophers have interpreted the world in various ways, the point however is to change it”.

    In other words, don’t get fixated on the numbers: think about ways of reducing human population numbers. Every problem of development, the environment and sustainability would be easier to solve if there are fewer people.

  • This wiki article is worth reading: http://www.powerbase.info/index.php/Optimum_Population_Trust – not an organization that I would trust.

    It seems to me that the usual cranks and deniers and free market fans like the idea of ‘overpopulation’ because it distracts attention from the massive consumption by the 1% which is the real problem.

    George Monbiot has thankfully stopped talking nonsense about energy and is making sense again: http://www.guardian.co.uk/environment/georgemonbiot/2011/oct/27/population-consumption-threat-to-planet

  • Hi Ian,

    Great response. I also read your excellent piece over at Grist. Sadly, far too many otherwise sensible people shut down their reasoning abilities when it comes to ‘overpopulation’!

    I thought this series of videos also explains it quite well:

    * Overpopulation Is A Myth. http://overpopulationisamyth.com/category/categories/pop101

    P.S. Typo in article – I think you’re missing a ‘not’: “For them to [NOT] highlight the Guardian‘s grossly inaccurate article qualifies as either ignorance or deliberate misrepresentation.”

  • Thanks. I eventually found the figure here:

    The text below explains these scenarios:

    “If fertility were to remain constant in each country at the level it had in 2005-2010, the world population could reach nearly 27 billion by 2100. A future fertility that remains just half a child above that projected in the medium variant would result in a population of 15.8 billion in 2100 (high variant), but if fertility remains just half a child below that of the medium variant, the world population in 2100 could be 6.2 billion, the same size it had at the start of the 21st century.”

    If this, then that. These are projections, not predictions.

    The article in The Guardian is amazingly wrong. But the thing that bothered me the most is how the article states that experts were shocked and then presents the opinions from populationist and anti-abortion groups… The article is pure propaganda and more worthy of the Daily Mail than of The Guardian.

  • I’d like to consult the assumptions of the graph but the link you provided only gives a press release and I’ve been unable to find the report on-line.

    From what you report, I guess that this is another example of the common mistake made by journalists of confusing projections with predictions. What we see in these graphs are projections, whereby one can insert numbers in a more-or-less arbitrary way into a model and see the results. So, I can have a model to project population growth and run several simulations with different fertility rates, for instance, obtaining a number of scenarios. This is useful to answer the question “What will happen if this and that happens?”.

    A different question is “what will happen in the future?”. To answer that question, we make predictions. We can make predictions based on numbers that we somehow expect to confirm in the future or we can take some projections made with the model and attribute probabilities to each scenario.

    The problem is when journalists see graphs showing projections, somehow choose a scenario and then write pieces saying “this will happen”, which is a distortion of the scientific work.

    Regarding population growth, we can make projections but I don’t think we can make predictions. The margin of error in each variable is so huge and so dependent on political decisions that we cannot anticipate that any prediction on the number of people we will have on the planet in 2100 will be as credible as a number that Population Matters decides to throw in the air out of nowhere.

  • We can only guess what the global population will be in 2100. However, If Eric Kaufmann in “SHALL THE RELIGIOUS INHERIT THE EARTH?” is correct the religious fundamentalists will be in the majority. This is because the more secular population rarely have more than 2 or 3 children, whilst the fundamentalists may have 6 or 8.

    Be furtive and populate, that’s what the Torah, Bible and Koran emphasise, but the writers of these ancient books wrote at a time when the world population was only a few millions, and life was short and brutal.

    Now more and more people live to 70 or 80 and beyond, adding not only to the total population, but also increasing unsustainable consumption. When will the fundamentalists learn that the earth resources are limited and already well beyond sustainability.

    Already an estimated one billion people go hungry. Do people really believe that God will provide?

  • Simon Ross of Optimum Population Trust (Population Matters) is being ingenuous. In fact they are quite selective about what they post on their website.

    Example. The Guardian is currently publishing a series of articles on population under the heading “Crowded Planet.” That series has included “Why population hysteria is more damaging than it seems” which OPT did not repost, and “Population of world ‘could grow to 15bn by 2100′” which they did.

    Now he has taken the time to object to my criticism of them for selecting one particular article — but he carefully does not say that OPT disagrees with it.

    That’s a particularly significant omission, because OPT’s chair is quoted in the article in a way that seems to endorse the reporter’s claims.

  • Unlike your blog, we report on media coverage of population on our website in some quantity and without comment. Reporting any particular article does not mean that we endorse or specifically highlight it. Putting it another way, reporting an article does not mean that we are ignorant of any weaknesses it might have or seeking to promote the article. We are aware of and quote the UNDESA projection. We may respond to the UNFPA report once we have seen it.