When it comes to the party that is planet Earth, we might need to plan for a few extra guests, according to scientists. A new statistical projection concludes that the world population is unlikely to level off during the 21st century, leaving the planet to deal with as many as 13 billion human inhabitants—4 billion of those in Africa—by 2100. The analysis, formulated by U.N. and University of Washington (UW), Seattle, researchers, is the first of its kind to use modern statistical methods rather than expert opinions to estimate future birth rates, one of the determining factors in population forecasts.
“The U.N. in the past has been criticized for not doing complete statistics on their data and now they’ve done it exactly right,” says demography researcher John Bongaarts, vice president of the Population Council in New York City, who was not involved in the new work.
Through the early 2000s, most researchers thought that the world population—which today hovers around 7 billion—would reach 9 billion by midcentury and then stop growing. But the projection assumed that birth rates in Africa—the highest in the world—would steadily drop as access to contraceptives and women’s education improved. Instead, birth rates in most African countries have remained stagnant or declined only slightly. This can be explained partially by smaller jumps in contraception and education than predicted, though most scientists don’t fully know why the rates have stalled so much.
Africa’s situation is only part of what’s led to the new numbers. Every few years in recent history, the United Nations has recalculated its population projections after consulting with individual demography and statistics experts who provide best-guess estimates of future fertility (birth rates) and mortality (death rates). But not all experts agree on the trends these numbers will take. And the United Nations couldn’t run advanced statistics on the forecasts, because there were no quantifiable levels of uncertainty associated with the projections.
“Experts are pretty good at knowing where things generally stand with these rates,” says statistician Adrian Raftery of UW, a senior author on the new paper. “But what they don’t seem to be good at is integrating the newest data into future estimates in the right way.”
Rather than rely on expert opinions for the newest population projections, the United Nations teamed up with Raftery and his colleagues, who developed statistical equations—based on historical and real-time data—that describe how the fertility rate is changing over time in different places around the world. This let them crunch the numbers in a new way, and—in addition to calculating a single estimate—determine the statistical probability of different events, such as the population leveling off.
“The combination of a new method that’s not based on assumption but is based directly on data, and also the new data on Africa, have combined to make quite a big change to the overall population projections,” Raftery says.
To wit, there’s a 95% chance the world population will be between 9 billion and 13.2 billion by the year 2100, the team concludes online today in Science. Much of that growth, it found, will likely take place in Africa, whose population is estimated to rise from 1 billion to 4 billion by the end of the century. And, unlike projections from last decade, the new graphs show a steady increase through 2100 rather than a midcentury leveling off.
The new numbers will be used in models created by economists, environmentalists, and governments who use population estimates to predict pollution and global warming levels; prepare for epidemics; determine road, school, and other infrastructure requirements; and forecast worldwide economic trends. All of these plans need to be altered if the population is going to grow an extra few billion. “There’s a need to put population back on the world agenda as a major issue,” Raftery says. Determining what’s caused Africa’s birth rates to stagnate could be a step toward dealing with this skyrocketing population, he says.
But there’s no guarantee that the world’s population is going to continue to rise at its current rate, points out economist and population researcher David Lam of the University of Michigan, Ann Arbor. “We’re still talking about much slower population growth than we just came through,” he says. “The world population doubled between 1960 and 1999 and we’re never going to do that again. The population is leveling off and it’s going to eventually level off under any of these scenarios, whether that’s before 2100 or after.”
And of course, the numbers are just projections, Bongaarts says. “It could very well be that we could have epidemics, or wars, or unrest that creates massive mortality. But to be honest, it would require something of a huge magnitude to alter this trajectory.”
Plantagenet on Fri, 16th Jan 2015 6:04 am
Almost all the new population growth will be in Africa and other underdeveloped areas
Rodster on Fri, 16th Jan 2015 6:49 am
Of course population growth won’t level off. Population growth is the catalyst which fuels the infinite growth economic Ponzi scheme.
meld on Fri, 16th Jan 2015 6:51 am
Well if Scientists say it then it must be true. What with science being the infallible truth and all…
Science is your god
Scientists are your preachers
Scientific Knowledge is your bible
Rodster on Fri, 16th Jan 2015 6:51 am
No matter where those extra inhabitants wind up it will put further strains on an already stressed planet.
Plantagenet on Fri, 16th Jan 2015 7:16 am
What source of information do you prefer over science? Ignorance? Fantasy? Holy writ?
Davy on Fri, 16th Jan 2015 7:20 am
Article said – “And of course, the numbers are just projections, Bongaarts says. It could very well be that we could have epidemics, or wars, or unrest that creates massive mortality. But to be honest, it would require something of a huge magnitude to alter this trajectory.” It is amazing that these academic studies devote so much time to the statistical and the exponential in their calculations based on BAU growth. The very last sentence mentioned the typical Hollywood style apocalyptic mortality conditions.
The above from the article there is no mention of limits of growth to the foundational requirements of modern population growth. Pop growth require systematic complexity with social fabric and financial system stability. It requires growing energy, food, and water. These are the basics folks that are now at limits of growth and with diminishing returns to efforts. Put simple we are out of time and money to support more population. What could be more in your face than that?
These cats are supposed to be experts. This is the problem I have with specialists in general. We know not all specialists are this way but they seem to be concentrated at the highest levels of the mainstream academics and research. This is especially true of the Universities, NGO’s, think-tanks, and UN organizations. The very levels that have the greatest influence. If we can’t get these folks who are the very top to admit we are at limits with conditions for increased mortality then we have little hope of mitigation and adjustment strategies that will reduced population through unpalatable policies.
Nature will have to run its course with mortality adjustments for global ecosystem balance. TPTB top will react reactively trying to solve all the problems that will develop from high mortality ahead. IMA systematic problems that will likely bring global BAU down. We just can’t grow much more than 500MIL in my opinion. There is too much happening right now in all facets of the foundational requirements of modern population growth.
There is little we can do to forecast the exact time and amount of further population growth but I see the beginning of a bottleneck in the vicinity. I see us now in a bumpy descent because of systematic disequilibrium in the important financial system that drives production and distribution. I see depletion of oils economic value driving the energy descent. This is uncharted waters so we just don’t know when these two disruptive conditions will bifurcate the system into a break to a lower level of complexity and economic activity.
Food, energy, and water are BAU dominant today. Population can’t grow much more without growth in these foundational variables. Without these variables the systematic side will be further destabilized. This is a perfect storm of problems and predicaments just now becoming apparent to those with a multidimensional and multidiscipline approach. It is the combinations of multiple predicaments that point to this apparent limits to population growth “NOW”.
Makati1 on Fri, 16th Jan 2015 7:36 am
500 million is about 6 years … so? 2020? That is my max timeline for BAU to remain in suspended animation.
Ralph on Fri, 16th Jan 2015 7:52 am
We have seen the future for Africa. It is Rwanda. It is Boko Haram. It is Ethiopia. It is Sudan. Too many people, not enough resources.
The ROW will close their eyes and walk away.
Dave on Fri, 16th Jan 2015 9:00 am
Almost without exception, every time a study of this issue is undertaken the problem comes down to one word… Africa! WTF, can’t the world get it’s act together and fix this problem.
Plantagenet on Fri, 16th Jan 2015 9:17 am
The days of the world “fixing” Africa are long gone.
It’s up to Africans now
Davy on Fri, 16th Jan 2015 9:25 am
Dave there can be no solutions with the predicament in Africa of exploding population growth. They are in a “catch 22” because the conditions required to stop that population growth will stop growth. No growth no fix because problems are not solved without growth. Descent will solve Africa’s problems but by any imagined scenario that will be ugly.
Beery on Fri, 16th Jan 2015 9:36 am
“What source of information do you prefer over science? Ignorance? Fantasy? Holy writ?”
That’s it – we’re all doomed. Plantagenet said something I agree with. The End Times are here. The Age of Ragnarok is at hand.
GregT on Fri, 16th Jan 2015 9:49 am
We have seen the future for America. It is Detroit. It is Chicago. It is California. It is interracial conflict and civil unrest. Too many people, not enough resources.
The ROW has enough of our own problems, that we won’t be able to simply close our eyes and walk away from.
Rodster on Fri, 16th Jan 2015 10:32 am
“We have seen the future for America. It is Detroit. It is Chicago. It is California. It is interracial conflict and civil unrest. Too many people, not enough resources.”
That’s actually the future of this planet when it’s finally over for industrial civilization.
Dredd on Fri, 16th Jan 2015 10:33 am
Correct, population will not level off.
It will suffer abrupt decline.
Apneaman on Fri, 16th Jan 2015 10:37 am
Overshoot is self correcting. In about 6 months or so we should see the first big domino fall; São Paulo, Brazil.
Planetary dashboard shows “Great Acceleration” in human activity since 1950
“Human activity, predominantly the global economic system, is now the prime driver of change in the Earth System (the sum of our planet’s interacting physical, chemical, biological and human processes), according to a set of 24 global indicators, or “planetary dashboard”, published in the journal Anthropocene Review (16 January 2015). ”
http://www.igbp.net/news/pressreleases/pressreleases/planetarydashboardshowsgreataccelerationinhumanactivitysince1950.5.950c2fa1495db7081eb42.html
viewcrafters on Fri, 16th Jan 2015 11:39 am
No one asked for an economist’s opinion.
viewcrafters
Apneaman on Fri, 16th Jan 2015 11:57 am
Math is not an opinion.
Rodster on Fri, 16th Jan 2015 12:23 pm
“Math is not an opinion.”
Correct !
1+1 will always equal 2. Our govts and central banks will have us believe that 1+1=112. 😛
Apneaman on Fri, 16th Jan 2015 12:43 pm
All Africans could disappear off the face of the earth tomorrow, but that will not change the fact that the wealthy 20% use 80% of resources. Nor will it bring back the low hanging fruit we have squandered. All this “concern” about Africa makes a great pretext for imperial powers to continue to send in their advance scouts (NGO’s) to create the conditions to further strip mine the continent. White mans burden 21st century style. Do it for the children for pity’s sake. Tell yourself.
GregT on Fri, 16th Jan 2015 1:25 pm
Rodster,
Exactly my point.
We in the REST OF THE WORLD have enough of our own problems, that we won’t be able to simply close our eyes and walk away from.
Just getting a little tired of Americans constantly point fingers at everyone else, without a clue that they will be in just as much trouble as everyone else. Those living in the cities probably even worse.
Perk Earl on Fri, 16th Jan 2015 1:39 pm
The idea of 4 billion in Africa is the stuff of dystopian futuristic sci-fi movies. The misery index would be off the charts. Since they are apparently unable to control their reproductive prowess, we can only hope that limits to growth holds their total population to a max. of 2.5 billion.
Craig Ruchman on Fri, 16th Jan 2015 3:41 pm
If the population numbers are true, this could be the opportunity of a lifetime. As oil gets harder and harder to get, we will need more of it. The data seems to imply that we would need an astonishing 150mbd by then, which is impossible given the peak oil predicament. This makes me bullish on solar even if 2014 was tempered by low oil prices.
Craig Ruchman on Fri, 16th Jan 2015 3:41 pm
If the population numbers are true, this could be the opportunity of a lifetime. As oil gets harder and harder to get, we will need more of it. The data seems to imply that we would need an astonishing 150mbd by then, which is impossible given the peak oil predicament. This makes me bullish on solar even if 2014 was tempered by low oil prices.
GregT on Fri, 16th Jan 2015 4:32 pm
Craig,
Oil prices were not low in 2014, and a liquid fuels crisis will be anything but an opportunity, no matter how many solar panels we have.
Go Speed Racer. on Fri, 16th Jan 2015 4:51 pm
Grind them up for pet food.
Go Speed Racer. on Fri, 16th Jan 2015 4:52 pm
Give all of them guns. They will sboot each other.
Speculawyer on Fri, 16th Jan 2015 5:54 pm
Yeah, this is something that really worries me. So many demographers have been saying that population would soon level off. But I have not been convinced by these projections.
The natural instinct for sex combined with many ancient superstitions (AKA religions) creates a dangerous incentive for every growing populations.
MSN Fanboy on Fri, 16th Jan 2015 6:05 pm
LOL Go Speed Racer, it funny because it true LOL
I wonder if it will be so funny when it begins affecting the west, how about some more Islamic migration Go Speed Racer?
GregT on Fri, 16th Jan 2015 7:10 pm
Our population is in mass overshoot. The laws of nature trump the human being’s desire for sex and his ‘superstitions’, including the greatest superstition of all. The one where the human being believes that his science and technologies make him exceptional, and therefore above the laws of nature.
HARM on Fri, 16th Jan 2015 7:34 pm
“We have seen the future for America. It is Detroit. It is Chicago. It is California.”
While I agree that the world is in total population overshoot, that’s a mighty suspiciously “blue” list of cities you have there. Why not “Houston” or “Dallas” or “Las vegas”? Are those cheery-red cities developing oh-so sustainably?
Makati1 on Fri, 16th Jan 2015 7:58 pm
GregT, Americans don’t have mirrors that correctly show them as they are, so they have to blame everything on another country or countries. That is a result of their indoctrination since WW2.
Africa has been plundered for centuries. From slaves to oil. And it is still going on by the same Western countries.
Apneaman on Fri, 16th Jan 2015 9:10 pm
Living the American Dream is a Nightmare
“In Plato’s little-recognized prediction of the Age of Television, slaves chained to their couches watch reflections of events, while philosophers struggle up to the sunlight to see what’s really going on.”
http://www.dailyimpact.net/2015/01/12/living-the-american-dream-is-a-nightmare/
Go Speed Racer. on Fri, 16th Jan 2015 9:56 pm
Dump bagful of birth control pills into their water wells.
GregT on Fri, 16th Jan 2015 10:08 pm
Sorry Harm,
Missed that one. In Canada we don’t think in terms of red and blue, and myself personally I see through all of the two sided BS anyways. Neither side is any more worthy than the other. They are one and the same.
dubya on Fri, 16th Jan 2015 11:31 pm
Suggestion:
We export large numbers of Africans to work in the cotton & sugar cane fields of the Americas. This will greatly reduce or eliminate the necessity of using fossil fuels for agriculture. Of course we would not be able to pay them, but they should at least be grateful that we are giving them a chance at life. We could sell them like hockey players – Those that performed well would be worth a lot, and those that weren’t so good; well, they would get selected out.
I think I have a winner here.
dubya on Fri, 16th Jan 2015 11:38 pm
Oh, one other thing. What, exactly, are these 13 billion people going to be made of?
Imagine all the food we have grown as humans in the last 10,000 years – the wheat buried in Tutankhamen’s tomb, the Irish potatoes, the pre-Columbian corn, the Easter island chickens.
We have to produce all that in the next 50 years. That’s what happens when you double things.
Which means producing record amounts of organic nitrogen – already at least 50% of us are built from industrial Haber-Bosch nitrogen.
Half of the other animals are gone already to make way for us. When our population doubles again where are all those animals going to live? I guess it does not matter if they are not economically useful to us.
Davy on Sat, 17th Jan 2015 7:38 am
Mak, just like glass houses the rest of the global world is well adjusted to the same insane BAU world so they have few reasons to throw stones. It is those who prositalize about the decouple of the rest of the world to this reality who are throwing stones at glass houses and mirrors. The US may be bad in regards to the unreality of BAU. Yet, Mak, give me a break on the global situation being much better. Your comment is more agenda.
Makati1 on Sat, 17th Jan 2015 7:50 am
But, Davy, I like to throw stones. And my ‘agenda’ is no worse than yours. You think you know how the rest of the world lives because you experienced some of it once upon a time or see it in the MSM ‘news’ sources. Or how it may suffer when the SHTF. Well, I think you are way off base, but I do not expect to change your mind. It appears to be set on a “bumpy path” that will end in some 3rd world level eventually.
I see it as a series of cliffs, not ‘bumps’, any one of which could end civilization or even the human species in the next few years. I hope I am wrong but, I don’t see any evidence to make a difference.
As I said before, don’t read my comments if it bothers you…lol.