How Many People Can Fit in Kellogg Arena in Michigan
How many people can Earth support?
"The power of population is so superior to the power of the Earth to produce subsistence for man, that premature death must in some shape or other visit the homo race."
The late-18th century philosopher Thomas Malthus wrote these ominous words in an essay on what he saw every bit the dire time to come of humanity. Humans' unquenchable urge to reproduce, Malthus argued, would ultimately lead us to overpopulate the planet, eat upwards all its resources and die in a mass dearth.
Only what is the maximum "power of the Earth to produce subsistence," and when will our numbers push the planet to its limit? More importantly, was Malthus' vision of the future correct?
Related: What would happen to Earth if humans went extinct?
Earth'southward capacity
Many scientists think World has a maximum carrying capacity of nine billion to 10 billion people.
I such scientist, the eminent Harvard Academy sociobiologist Edward O. Wilson, bases his guess on calculations of the Globe's available resources. As Wilson pointed out in his volume "The Time to come of Life" (Knopf, 2002), "The constraints of the biosphere are fixed."
Bated from the limited availability of freshwater, in that location are indeed constraints on the amount of food that Earth can produce, just as Malthus argued more than than 200 years ago. Even in the example of maximum efficiency, in which all the grains grown are dedicated to feeding humans (instead of livestock, which is an inefficient way to convert plant energy into food energy), there'due south all the same a limit to how far the available quantities can stretch. "If anybody agreed to get vegetarian, leaving little or nothing for livestock, the present ane.4 billion hectares of abundant state (three.5 billion acres) would support about 10 billion people," Wilson wrote.
The three.5 billion acres would produce approximately ii billion tons of grains annually, he explained. That's plenty to feed 10 billion vegetarians, just would merely feed 2.v billion U.S. omnivores, because so much vegetation is defended to livestock and poultry in the U.s.a..
Then 10 billion people is the uppermost population limit where food is concerned. Because information technology's extremely unlikely that everyone will hold to stop eating meat, Wilson thinks the maximum carrying chapters of the Globe based on food resource will most likely fall short of x billion.
According to population biologist Joel Cohen of Columbia Academy, other environmental factors that limit the World's carrying capacity are the nitrogen cycle, bachelor quantities of phosphorus, and atmospheric carbon concentrations, but there is a great amount of uncertainty in the impact of all of these factors. "In truth, no one knows when or at what level peak population will be reached," Cohen told Life's Little Mysteries.
Related: When volition Earth run out of nutrient?
Slowing growth
Fortunately, we may be spared from entering the terminate-times stage of overpopulation and starvation envisioned by Malthus. According to the United nations Population Partitioning, the human population volition hitting vii billion on or around October. 31, and, if its projections are correct, we're en route to a population of 9 billion past 2050, and ten billion past 2100. Even so, somewhere on the route between those milestones, scientists recollect we'll make a U-plough.
Un estimates of global population trends show that families are getting smaller. "Empirical information from 230 countries since 1950 shows that the slap-up majority have fertility declines," said Gerhard Heilig, primary of population estimates and projections department at the UN.
Globally, the fertility rate is falling to the "replacement level" — two.1 children per adult female, the rate at which children supercede their parents (and make up for those who die young). If the global fertility rate does indeed reach replacement level past the terminate of the century, then the human population will stabilize between ix billion and 10 billion. As far every bit Globe's capacity is concerned, nosotros'll have gone virtually as far as we can go, simply no farther.
This story was provided by Life'due south Little Mysteries , a sis site to Live Science.
Natalie Wolchover was a staff author for Live Science from 2010 to 2012. She hold a bachelor'southward degree in physics from Tufts University and has studied physics at the University of California, Berkeley. Follow Natalie on Google+.
Source: https://www.livescience.com/16493-people-planet-earth-support.html
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