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“It took until about 1800 or 1825 to put the first billion people on the planet. We added the most recent billion in 12 or 13 years. We anticipate two billion more by 2050.”
That’s Joel Cohen, head of the Laboratory of Populations at Rockefeller University in New York. He spoke February 20th at the annual meeting of the American Association for the Advancement of Science in Washington, D.C. So how many people can the Earth hold?
“In the last half century, people have estimated human-carrying capacities for the Earth that have ranged from less than one billion to more than a trillion. They can’t all be right. In fact, those numbers are political numbers, not scientific numbers. Because the question how many people can the earth support is an incomplete question, and doesn’t take account of with what technologies, at what average level of well-being, with what distribution of income, with what political and economic institutions.”
—Steve Mirsky
[The above text is an exact transcript of this podcast.]
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46 Comments
Add CommentWell, thank you for that Spock-ian precision. We all hope you didn't strain your Scientifically American brain too much coming up with that level of detail.
Reply | Report Abuse | Link to thisI've asked before elsewhere and never gotten an answer to this related question: how many people have lived on earth in total, since the beginning?
Reply | Report Abuse | Link to thisFirst of all, this is under 60-second science, a podcast dedicated to telling science stories in under a minute. Before you go judging other people, perhas check what you are reading from..
Reply | Report Abuse | Link to thisI don't see how this is possible. There are not many records when you go far back in time. And at what point do you draw the line as far as human goes? Keeping records? Certainly there were plenty of cavemen that aren't getting counted.
Reply | Report Abuse | Link to thisI would also like people to consider not only the space/capacity for humans, but for the rest of nature itself. We will have more ROOM for humans if we cut down all the trees, but will have profound effects on how we live and communicate.
Reply | Report Abuse | Link to thisBottom line is, we should be living as efficiently as possible. This means using solar, recycling, and reducing waste/land consumption.
@Promytius Since the world began, about 2200BC, there have been exactly 9,283,666,223 people in it, not counting Adam and Eve, who weren't born but created.
Reply | Report Abuse | Link to thisIF resources were adequately shared and intelligently managed, there IS enough for ALL.
Reply | Report Abuse | Link to thisAAHHH,THE PIED PIPER, OR WAS THAT THE PIE-EYED PIPER.
Reply | Report Abuse | Link to thisIf it's not science, the time factor is irrelevant.
Reply | Report Abuse | Link to thisTime for a cull me thinks..
Reply | Report Abuse | Link to thisSemiahmoo - no, that's 9,283,736,322.
Reply | Report Abuse | Link to thisNo, now it's 9,283,794,252.
No, ... oh, well, keep counting...
Growing in numbers at this rate, it is little surprise that the Caucasians I see in my travels are showing signs of severe inbreeding. This is the same kind of overpopulation inbreeding that was observed in ancient Egypt that prompted someone to write the Adam and Eve myth of the common ancestor. Population genetics forecasts that take into account that the number of children a couple has is also an aspect of their genetic makeup, these forecasts forecast inbred populations, and inbred devolution.
Reply | Report Abuse | Link to thisDevolution, not famine, is the really frightening permanent consequence of human overpopulation.
Pogroms are looking like a necessary idea to me also. The targets should be those who have the most children and their children.
Reply | Report Abuse | Link to thisThe scope would have to be global or the effort would be pointless.
While the military might exists to undertake the project, we must do so.
Or the race will continue to devolve.
mmm... are you serious?
Reply | Report Abuse | Link to thisI got a vasectomy, 15 minutes of pain for a lifetime of worry free sex and the knowledge that I m not contributing to the environmental crisis (having kids are the worst thing you can do for the environment).
Reply | Report Abuse | Link to thisThe question is profound because we are using some non renewable resources that will run out. In addition the planets ability to reliably produce food is becoming unstable. I think that we are past the healthy limit now, and future growth of population will be at the expense of well being and longevity. In fact we could see vast populations dying from malnutrition and unsanitary conditions as a result of flooding and drought. What I would like to know, is what can we rationally do about it?
Reply | Report Abuse | Link to thisDoug Norton
Whitby Ontario Canada
That's a very valid question.
Reply | Report Abuse | Link to thisIMHO energy availability will make a serious dent in food production. The Green Revolution that we learned about in school was 100% based on fossil fuels. Same thing with large scale food production in the developed countries.
@Semiahmoo It has actually been 9,283,666,224 I think you forgot Jesus who technically should be counted twice since he rose again.
Reply | Report Abuse | Link to thisSheesh, you so smart, mon. I tell you, 28,445,899,456.
Reply | Report Abuse | Link to thisDat be it. One more, mon, kabloooie.
It is well a known fact that the current resource levels (e.g., food) in the world is enough to support the current population. However, it is the inefficiencies in distribution channels that is causing starvation in many countries, creating an illusion that there are not enough resources to support even the current population. Let's solve today's population crises before jumping ahead to the future.
Reply | Report Abuse | Link to this-PTS
www.parttimescholar.com
Very good point. Briefly, current agricultural production levels are highly dependent on fossil fuels, to fertilize the soil as well as mechanize production, and, in many cases, fossil water aquifers to artificially irrigate the land. Both are non-replenishable resources that are rapidly being depleted as they are being consumed by the increasing population for other purposes.
Reply | Report Abuse | Link to thisIn another 10 years the global population will have tripled since 1950. We've not even been tested with normal 100 year weather variations, much less any more general instabilities affecting agriculture resulting from any global warming.
Not to mention that the oceanic fish populations, provided much of the global population's protean, are being depleted by mechanically optimized over fishing.
There are a very large number of factors contributing to the determination of the Earth's human population carrying capacity. It depends on how long the population must be sustained. One thing is certain: if half the population dies, it will be the largest human catastrophe ever. The remainder might not survive the consequences. This is quite an experiment we've got going on here...
I
Reply | Report Abuse | Link to thisI think it is important to note that the UN's numbers suggest that population will top off at around 2019, and that population will begin to dwindle away, so much so that Russia right now is paying their citizens to have children! The reason for the drop off is because when third world nations become first world nations they drop in reproduction. There are many reasons for this, but the most obvious reason is the fact that standard of living is a drastic change; examples are the US or the UK
Reply | Report Abuse | Link to thisI think it is important to note that the UN's numbers suggest that population will top off at around 2019, and that population will begin to dwindle away, so much so that Russia right now is paying their citizens to have children! The reason for the drop off is because when third world nations become first world nations they drop in reproduction. There are many reasons for this, but the most obvious reason is the fact that standard of living is a drastic change; examples are the US or the UK
Reply | Report Abuse | Link to this
Reply | Report Abuse | Link to thisI think it is important to note that the UN's numbers suggest that population will top off at around 2019, and that population will begin to dwindle away, so much so that Russia right now is paying their citizens to have children! The reason for the drop off is because when third world nations become first world nations they drop in reproduction. There are many reasons for this, but the most obvious reason is the fact that standard of living is a drastic change; examples are the US or the UK - with a reproductive rate of 1.2 children for every 2 parents.
Reply | Report Abuse | Link to this@Monki, Do we see you and your loved ones volunteering for the first round of the cull. The root problem with our society is that others think they have a right to force their will on others.
Reply | Report Abuse | Link to thisWhile it is true that we currently can produce enough food to feed our present population, much of that food production depends on farming methods that deplete the topsoil. In addition the production of chemical fertilizers requires resources that are increasingly in shorter supply. Don't be led astray by the statistics of the present situation as though it where static. It is dynamic and therefore when you look at trends we are already on the titanic. What course that ship takes is up to us. If we steer the present course, there is an iceberg waiting for us.
Reply | Report Abuse | Link to thisDoug Norton
Whitby Ontario Canada
I don't know about the U.N.'s numbers, but the U.S. Census Bureau's International database indicates that by 2050 the global population will exceed 9 billion (as indicated in the opening paragraph of this article), up from about 2.5G in 1950 and about 2G more than the current 6.9G.
Reply | Report Abuse | Link to thishttp://www.census.gov/ipc/www/idb/worldpopgraph.php
One cannot reliably extrapolate recent trends over future decades, presuming there will be no fundamental changes in determining factors. Neither the Census Bureau nor the U.N. have been collecting worldwide data long enough or accurately enough to have a proven track record for their forecasting methods - their models could not have been formally validated.
Click on the Joel Cohen's name. Then go to his extensive publications list. At least two of the most recent papers can be downloaded and read.
Reply | Report Abuse | Link to thisThe Census Bureau estimates that the 1.75G people alive in 1910 increased by less than 50% to 2.5G in 1950. During the next 50 years the population increased by 238%. In the past 11 years its increased by about 12%.
Reply | Report Abuse | Link to thisSince around 1900 people living in rural areas around the world have been migrating to urban areas. Most of the world's population now lives in urban centers. One quarter of the human population live within 50 miles of a seashore.
Almost all of these fundamental changes have occurred as a result of increased agricultural production due primarily to mechanization. When the fuel and water become sufficiently depleted that urbanized populations can no long afford to buy the products of highly optimized agriculture, critical sociopolitical factors contributing to population will become unpredictable.
Will sea levels be rising? What other destabilizing conditions will arise?
No matter how expert the forecasters and whatever their credentials, if conditions continue to change in unprecedented and/or unpredictable ways any and all forecasts will be useless. I predict that recent trends cannot continue.
Am I serious? Yes. Keep in mind mankind did not evolve to be the invasive species that we are. Genetic defenses to overpopulation inbreeding are all but gone in man except for aboriginal peoples that remain in small groups and consciously fight inbreeding. I have also personally witnessed inbreeding from overpopulation in rabbits, and google searches show it has been noted to occur in "Walden deer" and coyotes. The science presumption has been that there is a bottleneck in the population or small original population which is false. To make the inbred prediction it is simply a matter of correcting population genetics models to account for the inheiritance of the genes selecting the number of children a couple has.
Reply | Report Abuse | Link to this@Monik Time for a cull me thinks..
Reply | Report Abuse | Link to thisAfter you:)
To an old fellow like me, the present generation in affluent countries is incredibly wasteful. The homes my adult children own have more than four times the floor space of the home I was raised in & that is a minor example. Many things however are much cleaner & more efficient than in the ‘good old days’. I am all for minimising pollution but do not kid yourselves that the western world was a cleaner place pre 1930s. It was not. If you think that, you have never gone to a rural school by a dirt road. Drinking water from a rainwater tank with a resident & sometimes dead population of frogs. Early morning wood smoke. Poor diet contributing to young children with perpetually snotty noses. Many things I miss but many more that I do not. The earth’s capacity is finite but with proper care we have not reached it yet. Last week I flew for over five hours coast to coast across continental Australia. For the vast majority of the time no habitation could be seen. The same situation applies when you fly over many parts of the world. This is even more obvious when you drive across these vast distances. People who live in cities do not realise how large the earth is. This is one of the reasons so many people who live in cities believe in AGW. Cut pollution sure but do not waste resources on non solutions for non problems. problems.
Reply | Report Abuse | Link to thisThere is no point cutting pollution when population is not cut. Pollution is a paper tiger. Think of the resources a single person uses over their lifetime and realize how much pollution all those things generate to produce and dispose of. Only a small percentage of that can be done away with compared with doing away with the individual.
Reply | Report Abuse | Link to thisStill lots of open space? So what? Please don't fill it with inbreds. We have seen you once we have seen you 100 million times.
Realize that the population genetics model I just spoke of forecasts the doom of the human species - our stagnation in an inbred devolvement. It is an improvement on Darwin's theory of evolution and better explains and predicts reality then Darwin. Dare to win "Darwin" because his theory is an incomplete loser.
The Census Bureau site has a number of estimates, including summary upper and lower bounds, for years prior to 1950 - 'actuals' thereafter. Some selections:
Reply | Report Abuse | Link to thisWorld Population (upper bounds - millions)
10000 BC . . . . . 10
_1000 BC . . . . . 50
_0001 AD . . . . 400
_1000 AD . . . . 345
_1500 AD . . . . 540
_1900 AD. . . 1,762
_1950 . . . . . 2,557
Current . . . . 6,899
source: http://www.census.gov/ipc/www/worldhis.html
As you can see, the carrying capacity of the Earth was pretty low until 1900.
BTW, I think that, if anyone should ever perform such an analysis, population totals would also strongly correlate to all measures of human produced GHG emissions, global warming, etc.
Reply | Report Abuse | Link to thisWhile global warming may be attributed to human GHG emissions, population is likely a controlling factor: if the human population had never exceeded 1 billion, for example, I doubt that global warming would be an emerging problem.
I remember hearing (from some authoritative source) about 40-50 years ago that if the human race kept on reproducing at the current rate by the year 2700 (or maybe the 27th century) there would be so many people on the Earth that each person would have only one square foot of available space. I can't help but wonder how much that prediction has changed since then.
Reply | Report Abuse | Link to thisall must be considered given the form of the question. the most important parts are as various as they are variable. Importantly, we do know history to a great degree and with that come to some similar degree of predictions.
Reply | Report Abuse | Link to thisA related question that I've pondered since I read Leonard Read's essay "I, Pencil" (http://www.econlib.org/library/Essays/rdPncl1.html): What's the MINIMUM number of people that could exist on earth and still maintain a standard of living at or near what the average American now experiences??
Reply | Report Abuse | Link to thisI guess that vasectomy of yours produces "worry-free sex" in a world without HIV or drug-resistant STDs? Not quite so simple, is it?
Reply | Report Abuse | Link to this"Well, thank you for that Spock-ian precision. We all hope you didn't strain your Scientifically American brain too much coming up with that level of detail."
Reply | Report Abuse | Link to thisIt seems to have been too much strain for your brain to notice that this was in the section "60-Second Science". Thanks for the entertainment of your most unSpock-ian derision.
Just wanted to let you guys know I landed here thru a link from a Facebook page I follow. It seemed an interesting question to me, and even more to know I would get an answer in 60 seconds. Add to that that it was "Scientific American" who I was going to get the answer from.
Reply | Report Abuse | Link to thisAnd then... pure relativism, no chance of a straight answer.
So... I think in less than 60 seconds I could get a voice recorder and answer "I have no idea how many people can the earth hold", upload it and walla! I have a scientific podcast? I totally understand @ Ensoh.
I also understand some questions don't have straight answers, specially scientific ones.
So, my point is: Don't blame not so scientifically wise people like me (just a regular guy) to think this podcast is some type of joke because most of the time we just want a straight, honest answer.
Do you science guys get our point? Are shall I invite you to some tolerance and empathy blogs/podcasts?
I'm sorry, but until people start facing facts about primitive stuff like how the world was created, we are going no where as a race. Whats a dinosaur fossil then? A specially shaped rock?
Reply | Report Abuse | Link to thisLike electriclady281 said, "IF resources were adequately shared and intelligently managed, there IS enough for ALL." Earth can be sustained if we make a valiant effort to preserve it. So far we are getting better but it needs to be done faster. I live in Canada, there is plenty of room for people around here, if we just spread out a little, areas like China and India won't get so polluted and compact. If we focus on spreading wealth among the poorest of the world and spreading the human population, we can change the world. You may think when seeing cities like Shanghai, China, that the entire world is just pact with people and the population is out of control. Truth is, the population is out of control for our own hands but not for the earth. We need to find more efficient ways to deal with pollution and conservation everywhere in the world. But all that comes with a price. It costs money to build recycling plants and clean energy facilities. That's why it can be so rare in some areas. If these countries had stronger leaders, and more cash, then just maybe, we can fix the pollution and consumption as a whole. But don't blame just the less fortunate countries, because they don't only produce waste or consume goods. Countries with higher power like the U.S. create the most waste per person than any other country in the world. But, they don't have the highest population.
Bottom like is, population is a worry, but, it's not our greatest concern anymore, the world is capable, with our technologies and effort, to sustain 6,840,507,000 people, but we simply cannot as a race right now. Our focuses right now are on war and money, even though money is of great importance for changing the world, but it can be done at a cheaper price if people work together. The human race still has some evolving to do and until then, we need to make a valiant effort to forget war and focus on the problems that affect the entire world, not just specific countries. As weird as it sounds, the overall population isn't a great problem, our level of intelligence is.
The world did not begin in 2200bc lmfao. The earth is over 4 billion years old. That's proven by science, where's your proof?
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