When I was a child in the 1960s, this news story was predicted to happen by the turn of the last century. Population growth has slowed considerably in its rate during my lifetime.
Further increase in population from this already large base is predicted for what is predicted to be the rest of my lifetime, but it is now foreseeable that the world will eventually reach a peak population,
"The world's population will grow to 9 billion over the next 50 years -- and only by raising the living standards of the poorest can we check population growth. This is the paradoxical answer that Hans Rosling unveils at TED@Cannes using colorful new data display technology (you'll see)."
Phillip Longman spoke at the Long Now Foundation about the coming depopulation problem. Developed countries have fewer children (near or below replacement rates) and increased life expectancies. So much of the world population growth is from fewer deaths, not more births. This trend will pose new economic challenges for health care and social security because a shrinking workforce will be supporting a growing elderly population.
If families in developed countries continue to have just one child, few children will have brothers, sisters, aunts, or uncles! In Phillip Longman's talk, he says that some developed countries like France and Australia already have subsidies and programs encouraging couples to have more children.
Though there's also a plus side. I assume that world consumption of resources will go down, since one person not born in a developed country is equivalent to probably 2+ not born in a developing country.
> and in all probability that birth will take place in China or India
While they are the most population-dense areas and are growing faster than other places in the world, I'm pretty sure it's more likely that the 7 billionth person won't be born in India or China.
While they are the most population-dense areas and are growing faster than other places in the world, I'm pretty sure it's more likely that the 7 billionth person won't be born in India or China.
Therefore the odds of it being India or China is ~ (17.4+27.6)/142 ~ 31%.
Fact: Considering that No country has a birth rate larger than 3x India and only China has a population larger than India, India has the maximum # births/year in the world.
Which countries are currently birthing more people/day?
If none, then it could be said that China or India are more likely than any other particular country.
Is the birth rate of China and India combined more than that of the rest of the world? If so, then it's more likely that it will occur there than anywhere else.
Burger, you're saying something different than the OP (and hence, different than what tghw was criticizing). In "all probability" the location won't be China or India, as those two countries alone don't represent a substantial majority of births.
So your point that those two have the highest birth rate isn't responsive to tghw's point that those two alone don't represent the majority of new births. So if we had to bet on "one country", a person would pick one of those two. But when we're betting "India/China or somewhere else?" the smart money is on "somewhere else".
"Is the birth rate of China and India combined more than that of the rest of the world? If so, then it's more likely that it will occur there than anywhere else."
I'm asking two questions. The second, quoted here, is saying the same thing as the OP.
Presumably, the author meant that the two most likely nations to birth the 7 billionth human are China and India. I doubt the intended comparison was between the set {x ∈ nations : x = China or x = India} and its complement {x ∈ nations : x != China and x != India}.
I realize I'm being a little pedantic, but the original phrasing does read as the probability of it being in India or China is greater than the rest of the world combined.
Small nitpick, I know it's not meant for a "serious" application, but this seems to have a significant digit problem. The number of people to have ever lived can't possibly be known to that kind of accuracy.
Sorry, that sort of thing just bugs me for some reason ;)
It is estimated that approximately 106 billion have lived on Earth between 8000 BC and 2002. (The population before 8000 BC is thought to have been too small to count on a scale of billions.)
At what level of theory? Is the planet still a solid ball with 99.9% of its mass unused in its depths? Are humans still 50-100 kg masses of biological metabolism, and not, say, programs being simulated on small computers? Not trying to be pretentious, but I think the question needs to be more specific.
Here's two soft limits.
The solar power incident on the earth is on the order of 10^17 watts -- harnessing more than this means creating structures much larger than the earth, at which point it's not really "the same planet" (most of the surface area would have to be non-planet). Humans metabolize on the order of 10^2 watts, just like desktop computers. So, 10^17/10^2 = 10^15 humans, one quadrillion,
Suppose instead the earth uses an energy source much more powerful than its surface solar power (e.g. fusion power). Then one limit is how much heat can be produced without temperature reaching impossible levels. Basically, heat rejection is by thermal radiation into space (no conduction); the power goes as T^4 [1]. Right now we're rejecting on the order of 10^17 W (same as the solar input -- it's balanced), at about 300 Kelvin. So without changing the surface environment drastically, we can't really go above 10^17 W. But if we're willing to do drastic terraforming -- living in underground air-conditioned chambers with Herculean heat pumps everywhere, leading to an uninhabited surface hotter than molten iron (the Great Radiator), you could push the limit above that. At a surface temperature of 3000 Kelvin (~2700 C), that's 10 times what it is now, so the thermal radiation would be 10^4 times = 10,000 times larger. We could reject 10^21 W, enough to power 10^19 humans. (Which would comprise 0.01% of the earth's entire mass! Bit like Hong Kong really.)
Sustainable and the meaning of "deal with" are indeed loaded concepts. Some people would say 1 billon or less, others at least 15 billon at first world standards of living.
You'd have to work out the maximum theoretical food production without phosphorus fertilizers or petrochemical insecticides, and without using aquifers or artificial irrigation. Basically roll back the green revolution. The world was bumping up against food production limits when the green revolution happened in the 60s. But the green revolution is totally unsustainable. The sustainable population is probably somewhere around a pre-1960 number.
Organic (CNHO) chemicals aren't in the slightest dependent on petroleum, it is only a passing quirk of the early 21st-century economy that oil and natural gas byproducts are the most common chemical feedstocks. CNHO atoms are everywhere on earth, and they're not going anywhere (mass doesn't leave the earth, for the most part). Basic organic chemistry building-blocks, e.g. ethylene, are not much more difficult to obtain from biological matter (e.g. ethanol) than from oil/gas. Organic chemistry -- insecticides, plastics, pharma, what have you -- isn't going anywhere, and this is all a silly misunderstanding from confused Malthusians.
...aquifers...
...artificial irrigation...
There's no theoretical limit to artificial irrigation (well there is, but it's ludicrous). In refutation: nuclear or solar powered ocean desalination plants, with aqueducts, large pipes, or underground canals piping freshwater inland -- thousands of miles if need be. Elementary, existing technology, and I think not too far from economic feasibility even today. Desalination is already economic (if not directly competitive with natural freshwater sources, when they are available) -- lots of it in the Middle East, Southeast Asia. Aqueducts are ancient technology.
...phosphorus fertilizers...
Nothing stopping us from recycling phosphorus -- it's not like we're flinging it off the earth into space. The whole earth is a closed cycle for chemicals -- water, CNOH, trace minerals, all of them sustainable. Since the issue is framed as "maximum theoretical", well, in the limit we can ion-exchange phosphorus out of the seas -- the ultimate repository for "used" phosphorus. (Although in the nearer term there's more simple resolutions, like preventing runoff waste, recovery from sewers/rivers, mining new types of phosphorus minerals, etc.)
But the green revolution is totally unsustainable.
Ignorance is totally unsustainable. Please conserve.
Irrigation always builds up salt in the soil. Areas of California are falling out of production for this reason, after a good 100 year run. Irrigation is what turned much of the middle east into desert.
The rest of your points I guess boil down to needing infinite cheap energy. Anything's possible with massive amounts of free power, I suppose. I wouldn't bet on it.
Large areas of China, Egypt, ect have been under continuous irrigation for thousands of years and they can still grow just fine. If California is having issues with irrigation over what 100 years then it's a separate issue.
They probably do have issues due to the amount of rainfall vs. irrigation and their crop rotation etc. But, it's not really an issue with irrigation just their approach to irrigation. Desalination also gives you the option to have much lower salinity than river water which should allow areas like California to cope with this issue.
The tipping point was around 1915 when the world had slightly less than 2 billion people, with the introduction of the Haber-Bosch process. After that the population growth is virtually dependent upon artificial nitrogen fixing fertilizers.
Naturally-produced fertilizers can provide approximately 200 kg. of nitrogen per hectare annually; this allows for the production of between 200 and 250 kg. of plant proteins. This places a theoretical limit on the number of people that each hectare of land could sustain. Under ideal conditions this would amount to around 15 people per hectare; in practice, the historical limit has been about 5 people per hectare.
In this paper he shows - dramatically - that there is a hard limit to the number of people that can be supported by natural nitrogen fixation. The population could have continued to grow through more drastic conversion of land to agriculture and better use of natural mechanisms, but at the end of the day, as he puts it:
"... at least two billion people are alive because the proteins in their bodies are built with nitrogen that came from a factory using [the Haber-Bosch] process."
Why does the answer have to forgo everything that facilitates optimal modern high-tech food production?
Gladwell's "Outliers" spent a lot of time on farming technologies thru the ages (and subsequent impact on cultural success). Japanese rice farming amounts to a sustainable long-term high-tech process making heavy use of artificial irrigation and any other suitable tech, maximizing production with limited space and growing seasons.
For starters, one could compute an outer limit of calories per square meter and match that to basic caloric needs per person: given an average solar energy concentration there is no way (unless you want to turn geothermal & fossil fuel) to produce more food (whatever manifestation) in caloric terms than sunlight provides. From there the answer requires providing assorted limiters, reducing the potential caloric output to more realistic levels based on viable technologies.
Computing from a different angle:
149M sq km total land, 15M sq km farmland, 7000M people
Dividing current farmland by population and rounding the result up a bit, each person gets a plot 47x47m for 603 sq ft for living and the rest for farmland. Assuming half the land is rank (unusable) wilderness, that roughs out to an optimistic carrying capacity of 33000M people.
If history is any indicator, there have been events that wiped out most or all of a species. Even in our times, nature has swayed at her discretion; look at the earthquakes and tsunamis and the destruction to human life and property.
For some reason, when I think of human growing population, I always think back to the Star Trek "The Mark of Gideon", which featured a world where overpopulation is a real problem.
I am sure that is not realistic but I worry that the world could one day become like that.
http://www.google.com/publicdata/explore?ds=d5bncppjof8f9_&#...
Further increase in population from this already large base is predicted for what is predicted to be the rest of my lifetime, but it is now foreseeable that the world will eventually reach a peak population,
http://esa.un.org/unpd/wpp/Other-Information/Press_Release_W...
and then decline in population over time, as is already happening in many developed countries.