CATASTROPHIC GLOBAL COOLING AND A POPULATION CRASH
When growth curves become asymptotic in living systems they invariably crash at some point. They must crash because growth that increases exponentially for very long is untenable. Stock market and population curves are good examples. When growth curves such as these crash they fall rapidly, ultimately by 50 to 90 percent, the median being about 2/3. Afterwards the recovery takes quite a while.
The human population growth curve is now "stratospheric" and can crash at any time. One of the main reasons allowing such growth has been a long sustained warm period in the Earth's climate. This provided the necessary climatic stability for civilizations to develop and create and organize farming to support large populations. With the advent of mechanized farming and longer life spans coupled with a stable warm climate, human population is now soaring out of sight. In just the last 60 years human population has tripled and is now over 7.3 billion.
What could possibly make the human population crash by 2/3? A combination of chemical, biological and nuclear wars happening close together might do it, especially if some really nasty highly infectious airborne pathogen were developed that didn't kill people too fast at first and had a long infectious period before symptoms showed up but the likelihood of this happening is unpredictable. A natural pandemic is also a possibility but probably wouldn't kill off 2/3 of the world. Even the nastiest one on record, the Black Plague, killed off only 1/3 to 1/2 of Europe. Very interestingly, episodes of pandemic black plague have historically coincided with periods of global cooling.
A large asteroid or comet hitting the Earth would definitely do it very quickly but that's a pretty remote possibility. A decades long decrease in solar energy output is another possibility and this seems somewhat of a likelihood at this point. Another possibility would be dust blown into the solar system by a galactic cosmic event that would decrease the solar energy reaching the Earth but this is a remote and unpredictable possibility. Yet another remote possibility could be a gamma ray burst aimed at our planet. That would fry our atmosphere and bathe the world in deadly radiation. The inevitable Yellowstone caldera eruption could crash the human population as well. This will happen within 100,000 years. There is a .1% chance of this happening in the next 100 years and a 5% chance of it happening within 5000 years. There is pretty much a 100% chance that the next ice age will start within 5000 years.
The advent of extracting oil by novel means, i.e. "fracking" (cracking the earth deep underground using high pressure, water and chemicals) which is probably causing the dramatic increase in earthquake activity in the middle of the US, could perhaps end up weakening the crust overlaying the Yellowstone caldera. The high pressure injection of waste water from fracking deep underground below water tables appears to be the cause of the huge increase in small quakes in the region. Many seismologists worry that this increases the likelihood of a very big quake in the region. This then could also increase the chance of the Yellowstone caldera erupting sooner and causing catastrophic global cooling and food production loss for at least 2 or 3 years resulting in billions of people starving to death.
Nevertheless the most likely thing that will crash the human population and which is inevitable will be the next ice age (perhaps with a premature eruption of the Yellowstone caldera helping to cause it). Onsets of ice ages can occur quite rapidly (within a generation) and are devastating. A 10-20 degree or more decrease in global mean temperature will surely wipe out most food production and as a result it's quite possible that 4 or 5 billion people would starve to death. By studying past ice ages and the warm periods between them it is pretty clear that the warm period in the Earth's climate that we currently enjoy should have ended already. What has quite possibly been keeping it going are human activities producing extra "greenhouse" gases.
What this means is that efforts to decrease human greenhouse gas emissions could horribly backfire by helping a bit to accelerate the onset of the next ice age! The scientific and political elite that are currently promoting the global warming hysteria and are actively trying to reduce these greenhouse emissions could easily end up being scapegoats when the inevitable catastrophic global cooling begins and people start starving.
Since the most likely event to cause the human population to crash is inevitable catastrophic global cooling, maybe efforts to forestall the onset of the next ice age could be made. I'm pretty sure, though, that nothing we do can stop it. Perhaps to prevent a potential shut-down of the Atlantic gulf current, vast amounts of salt could be stockpiled on Greenland and distributed in the North Atlantic Ocean as needed. Supposedly it is sinking water in the North Atlantic made heavier by its salt content that keeps the gulf current going. If the gulf current shuts down, Europe and the entire northern hemisphere will get much colder which could be a main trigger for the onset of the next ice age. Some of the global warming elite warn that increased temperatures, resulting in larger and larger amounts of the Greenland ice sheet melting into the North Atlantic and reducing its salt content could shut down the gulf current.
If this is the case the global warming elite would only be partially correct in their assessment of what needs to be done. All of their promoted efforts to reduce greenhouse gases are falling on the developed West while China and India get a free pass and continue to exponentially increase their greenhouse gas emissions, thereby negating efforts to reduce greenhouse gases. China and India would have to reduce their emissions as well if the global warming elites' theories are correct and they refuse to do that. However, this gulf current shut-down scenario is just speculation at this point.
The transition from our current warm age to the next ice age will be accompanied by a period of weather chaos with increasingly wild swings in weather patterns and temperatures until it settles into the ice age mode. The current global warming could be a manifestation of this effect.
Meanwhile, global warming hysteria gets all the headlines and focus and is being used to herd people into government managed and controlled economic systems (which will be an economic disaster) and promotes unproven speculative theory which can't even be sufficiently applied by their own speculative calculations while the inevitable catastrophic global cooling sure to occur (quite possibly in our lifetimes) and preparations to deal with it are almost completely ignored.
Another solution exists for this dilemma. The answer lies in the underlying mathematical dynamic that controls everything. The human population is asymptotic because the base used to measure it is the Earth. If we extend the base to include the entire solar system then the human population is no longer asymptotic and is small and just beginning. Therefore an obvious solution is evident: We must explore, utilize and colonize our vast solar system as fast as possible before it is too late and civilization is destroyed requiring us to start all over again a hundred thousand years from now after scratching through yet another ice age waiting for the next warm period to occur.
12,000 year chart of Baffin Island temperatures: HERE
As can be seen from the shape of the Baffin Island temperature curve, there has been a recent uptick in Baffin Island temperatures. Before that uptick, temperatures were plummeting toward the previous ice age's levels and were on par with the temperature during the ending of that ice age. This could be evidence that the global warming phase we are in is preventing the onset of the next ice age. Thus if the global warming alarmists are correct that human-caused greenhouse gases are causing this temperature uptick then their hysteria could well be misplaced as it then would appear that humans have (unbeknownst to themselves) been actually forestalling the next ice age! The effects from a little bit of warming won't be nearly as bad as the effects from a new ice age. Something to think about before we rush into some panicky greenhouse gas reduction scheme.