I ask because of the following thought experiment–if you take the population of the US (304 MM) and fit them all into one area that has the population density of Chicago (12,000 people per square mile), we’d only fill up half of Florida leaving the other 49 states vacant.
So if you extrapolate this to the world…the entire population of the world could fit into less than 600,000 sq miles or roughly the great plains states running from texas to north dakota. surely with so much empty space on earth, things can’t be so bad?
Even if we all lived underground and had an “infinite” power source to desalinize ocean water, there is only so much arable land. We’ve yet to develop photosynthesis or any other way to power ourselves outside of proteins, carbohydrates, and fats. One day we might have Star Trek’s replicator to make those out of their constituent atoms (or even smaller pieces?), but for now we rely on other organisms abilities to fashion those building blocks out of inorganic matter and solar power.
It might be possible to engineer some edible organism that is able to grow out of inorganic matter and any heat source, but as far as I know, they don’t exist yet.
We actually need not worry about running out of farmland. Worldwide, the human race cultivates roughly the same amount of land now that we did in 1951. The yield from that land has doubled thanks to genetic engineering of crops and improvements in irrigation, fertilizers, and pesticides. (Discussion here, slightly out of date.)
The world is not overcrowded, but a lot of sections of it are.
The USA alone has enough land to grow enough food to feed the world. Of course there are a million things in the way preventing us from doing this.
Look at China, 90+ percent of the population lives in one third of the area by the coast.
Look at the USA, we here of water shortages in San Antonio and Atlanta among other cities.
Yet people keep moving there in record numbers. Los Angeles is capable of supporting about four million people in the whole area. But thanks to the Colorado River, it can support much more (currently more than 14 million.) Phoenix wouldn’t be able able to support 100,000 without the Colordao River, and Las Vegas would still be a tiny little town. But both cities are growing rapidly. Indeed Phoenix is the 5th largest US city now.
But look at places like Detroit, Buffalo, Cleveland are all next to HUGE amounts of fresh water, yet they are losing population. Outside of Chicago and Toronto, the Great Lake Cities are all in decline.
The answer to questions like these pretty much boils down to distribution of goods. Food is commonly used as a weapon by governments against their own people. Think Sudan and Ethiopia of the 80s.
There are lots of resources the problem is distribution. There are plenty of areas in the world that are too crowded, places in China, India, the Nile River Valley, on the flip side there are lots of places around the Great Lakes of North America that are very underpopulated.
Affordable petroleum is probably the biggest bottleneck to human population today. If the entire world had the same level of economic development as North America and western Europe and all seven billion of us were competing for petroleum to power our cars and fertilize our farms, the price of petroleum and everything dependent upon it would skyrocket. The semi-good news is that population growth is leveling off and no one expects to see a world with twenty, thirty, or fifty billion people fighting for what’s left of the planet. The bad news is it’s now believed that the level of consumption we already have is unsustainable, at least with current technology.
When discussing how many people can fit per square inch, we need to remember that humans are only one part of an ecosystem. We need the trees and plants and birds and bugs and animals to stick around to fill their spot in the food chain (amongst other nice, treehuggy reasons).
Cite for topsoil losses? Organic fertilizers are just as effective as petroleum based ones, btw, they are just less efficient to make.
As for topsoil, the “loss” of topsoil is true in some places, but topsoil is easily renewable, and proper agricultural methods can stop topsoil loss. New topsoil forms all the time; tall plants comb dust out of the air. If we really wanted to, we could use hydroponic systems in trouble areas and give the land time to recover.
The effects of climate change aren’t necessarily harmful, either. Plants grow better with increased CO2 concentrations, and warmer temperatures mean longer growing seasons in the temperate zones, and better growth ability in the lower latitudes (north and south). Of course, there are some concerns about desertificaton, but even the highly unlikely scenarios don’t predict much of that.
The other issue people talk about is that of energy shortages. If/when we “run out” of petroleum, there is almost no question that we will have alternative fuel technologies available. We already have many of them, such as nuclear power, hydrogen, biofuels, wind farms, solar, etc. Increasing the inefficiency of petroleum will make these other forms more attractive as well as having the effect of speeding development on increasing the efficiency of the other forms of energy production.
Or not. It depends entirely on which study you wish to believe. The best data series over the largest area says that the loss is immeasurable.
Of course we have enough petroleum to last, at current usage rates, at least 400 years, and population is predicted to decline within 50 years. So it’s not really a problem.
And even if we have a lack of petroleum based fertiliser that does not equate to any lack whatsoever of fertilizer. Exactly the same fertilisers can be manufactured from coal or biomass if we desire.
Which are likely either neutral or positive in terms of food production and include increased rainfall, longer growing seasons and increased harvests.
Yes, this factor has been largely ignored. Certainly as the world grows warmer, some areas will no longer be able to grow the same crops, or the productivity may even decline. But other areas which are now too cool, may well flourish.
One of my biology professors once opined that the world has the carrying capacity to support about 100 billion people. After that, not enough sunlight falls on the Earth to support more. However, he stressed that that figure assumes the use of currently existing agricultural technology. I seriously doubt that overpopulation will be our species’ downfall. I suspect that we will succumb to a biological pathogen or global conflict before we reach that point.
However, the problem with this is that the “Green Revolution” has resulted in the depletion and pollution of potable and irrigable water resources. While we are far from using all arable land–in fact, due to higher crop densities a fair portion of cropland in Europe and the United States has been converted to commercial and residential use–water, and goodly quantities of it are required to sustain agriculture and industry, not just for irrigation itself but to also carry away waste products, work as a solvent and medium, et cetera. An increase in the production density of agriculture, far from making the situation better in the long term, has actually worsened it by increasing the rate of resource consumption.
For instance, in North America the Ogallala Aquifer that provides irrigation for roughly 30% of the nation’s agriculture, is comprised of fossil water from the last ice age and is being replenished at a rate of only a fraction of a percent of what is being withdrawn, requiring deeper wells and more pumping. Worse yet, as the water table is depleted the structure of the aquifer will subside, leaving it with reduced capacity, and pollutants and minerals in the water will become more concentrated, making it less useful for irrigation. The Ogallala Aquifer is projected to be substantially depleted in the next 30-50 years, leaving the American “breadbasket” to be effectively the dry prairie/desert it was prior to intensive agriculture and irrigation. Similarly, aboveground rivers and reservoirs from which extensive irrigation systems have drawn have become depleted and polluted. This can be seen in the Indus River Valley and irrigation systems it supports, the Mexico City Aquifer, the Nile Delta region, the Aral Sea (deliberately and tragically depleted by the Soviet Union) and other major inland water sources for irrigation and aquaculture.
Someone will no doubt come along and suggest that we can just desalinate sea water (by some magical low cost, low energy process unknown to man) and pump it back uphill to wherever it is needed, or migrate agriculture to regions that have sustainable water supplies. A cursory look at the amount of energy required to transport water gives lie to the former plan; while the Sun has energy to fritter away on supporting the filtering and delivery of fresh water via the hydrological cycle, the increase of energy demand to perform this task via extant technology is prohibitive. Moving agriculture is somewhat more feasible (and has and will continue to be necessary), but ultimately we’re going to have to learn to consume less water more efficiently, and perhaps curtail our need or convert to agricultural products that do not stress non-renewable fresh water supplies.
I doubt that petroleum is really the limiting factor for two reasons; one, reserves, while diminishing, are still substantial and still being discovered, and two, it is feasible (albeit not with the technology and infrastructure we currently have) to convert to other energy storage mediums for transportation. On the other hand, the reserves of fresh water are what they are, and the difficulty of redistributing and refining additional water is opprobrious.
I don’t know by what method (other than the famous PDOOMA method common to academic discussions) your prof came up with his or her 100 billion figure, but that is larger than the most optimistic estimate I’ve ever seen by a factor of two. Most credible high end estimates have the maximum carrying capacity to be between 10-20 billion, and at the low end of a maximum sustainable population to be around 1 billion.
No, it’s just an idiotic urban myth cooked up by Paul Ehrlich and his followers. It’s not that there isn’t enough food, it’s that there aren’t methods for there to be enough food for anyone. As for resource depletion it’s the fault of many environmentalists for blocking the way in getting resources such as the draconian restrictions on nuclear power plants, ban on drilling in ANWR and elsewhere. If nuclear power had been implemented since the 1970s who knows, we might have energy independence by now in the US.