Weighty title. :-)
I recently read the netbook
Sustainable Energy: Without the Hot Air, and found it quite thought provoking.
In particular, showing energy production and consumption in terms of kWh/d/person I find refreshing. Finally, somebody telling you something comprehensible.
The most interesting thing to me, however, was the insight (not horribly profound, just I hadn't had it before) that really all of life is an energy game.
Microbes burn energy to get to nutrients, which gives them energy.
Plants consume energy from the sun and use it to grow.
Wild carnivores use energy to catch prey, which gives them energy.
Some odd edge cases occur, as well.
If wild carnivores consume too much prey, then their source of energy is depleted. They need to either (a) find another source of energy, use another strategy, or (b) die.
Thinking of energy availability in terms of kWh/day/person is fun: if you have twice the people, the available energy per person goes down by half. If you have half the people, the available energy per person doubles.
This is the same as the wild carnivore. If there's lots of prey, the available energy per individual is high. Their life is good, so they breed. At some point, their prey is diminished or their numbers get too high. Either way, their available energy per person is too low, and they die off.
Humans are an interesting case. First, we discovered tribes/cooking/intelligence/agriculture/whatever that made us successful. All of the advantages conferred by these advances are in terms of increased available energy per individual. Life was good.
Life was so good that in many cases, human have outstripped their available energy. Forests are felled (all the energy in the wood is gone), mines are mined out, cropland is occupied, oil reserves are consumed, power grids can't keep up, whatever.
Really, this is very similar to the wolves that eat all the rabbits and then don't have any rabbits left. The only difference is that humans are creative enough that when one energy source runs dry, they move on to another one. And we're getting more and more creative all the time.
The trick, however, is that in all cases in nature, when life is good (which it still is for people), the population grows (which we're doing) until the energy is consumed (which it will be). Then, there's the big die-off.
We haven't reached that yet.
Environmentalists have been predicting doom for a long time. Leave aside the fact that environmentalists often have bizarre views on the world that don't quite match reality. The essential truth is that they're right. If we keep consuming energy, and keep increasing our population, we will eventually die out. It's nature, it's inevitable.
We need to do one of a few things to avoid this fate:
(1) come up with more sources of energy.
(2) consume less per individual
(3) stop growing / decrease our population
(1) is what we're mostly doing now. Some of the sources of energy are nonrenewable (like most sources of energy, just like the rabbits for the wolves), and will eventually be depleted. Some sources are renewable, but will still be consumed if our population keeps increasing. In the end, as long as we remain on this planet, this option can't work on its own.
There are other issues here as well. Consumption of energy costs more than just the energy itself. Pollution is a well known one, but the scarier one is global warming.
We may be seeing some global warming now, based on carbon emissions. This is largely irrelevant, I say, in view of the real risk.
Say we avoid this, somehow reduce carbon emissions, and everybody's life is good again. In the best case scenario, we find an essentially limitless source of free, nonpolluting energy. Say we perfect cold fusion.
All of the energy consumed from this clean limitless source would do something, but ultimately end up as heat energy. All of this heat energy would be generated where people are consuming the energy (say on the surface of the earth). If we manage to have an unbounded population and energy consumption, we're essentially piping the heat of a sun onto the earth. This is going to really screw up our living conditions.
So, short of leaving the planet (which is an option, at some point, although seeming increasingly unlikely with the current space climate), this is a dead end.
(2) is more interesting. Say we could get everybody (through a miracle) to cut their personal energy consumption down to 1/100th of what it is now. Note that this involves eating less, having fewer hobbies, heating and cooling less, probably moving less (you'd need to eat more). Eliminating all personal hobbies and entertainment.
Now, this is going to be a very difficult thing to do. It's basically like saying to the wolves: now eat fewer rabbits, please, and sleep more. It goes against our profound animal nature. As individuals, we want to grow, to succeed, to have more leisure time, to consume more energy.
This goes against our hard wiring. When energy is plentiful, we want to consume it. We strive consume available free energy.
Maybe you could do it. Probably the easiest way is to eliminate all culture and degenerate to a primitive society without modern conveniences. Cook everything you eat. Walk to get places.
This buys us time. Basically, if there's more energy to go around, then (nature says) the population will increase until we consume it again.
Which brings us to (3). This is by far the easiest solution, but it's the one nobody ever talks about. Sterilize 1/2 of the population at random, and the problem goes away in one generation, probably without much social upheaval. Oh, but this goes against our natural rights as creatures that live upon the earth! Can you imagine the riots? You can't even enforce parenting classes for new parents, let alone question their inalienable right to breed and reproduce.
No wonder, this is the fundamental force of nature as well. We're hard wired to increase our population when things get better, when energy is freely available. Going against this hard wiring will obviously ruffle some feathers.
So, we can't keep using more energy. We aren't likely to force people to change their lifestyles. We'd be shot politically if we proposed decreasing the population.
We have two more choices: (A) go into space, and hopefully (randomly) find another inhabitable planet, or (B) give up and prepare for the worst.
These are pragmatic options.
(A) is a nice dream, and I'm all in favor of it. I'm furious when the space program languishes - it may be our one real chance to do something here. Unfortunately, as an individual, there's not much you can do about it.
(B) is more interesting. Survivalists have been saying this for years: a plague, or a war, or something will bring down society, and they'll have to survive. Maybe this is true. Eventually, we're going to run out of energy, and they'll have been proven right. Will it happen in our lifetime? Maybe, maybe not.
What can you do about it? The real question here is what kind of society do you want to have after the crash? Do you want it to be a regression to primitive times, but with guns and Mad-Max style gang warfare? Do you want to lose our culture, our knowledge, the legacy of the human race?
It's unlikely that things will go quietly. It's a depopulation, obviously, and the depopulated will be unhappy about it. They'll fight. Lots of things will be destroyed. Society will likely collapse.
How do we protect the human legacy through these end times? How will the smaller human population that survives the wars have access to our legacy?
This is probably one of the most important problems of our day. By all means, try to stave off the end, by approximating solutions (1) (2) and (3).
But work on (A), and fund the space program.
And work on (B) too. Come up with ways of encapsulating knowledge, and spreading it far and wide, in ways that will survive the apolcalypse. Make sure that anybody sifting through the dust and rubble finds LOTS to rebuild with. Build enclaves and such that won't be destroyed somehow.
This we can do something about as individuals. Come up with robust ways of storing knowledge. Come up with easy ways of learning everything we know today.
The beauty of this strategy is that it works no matter what's the cause of the fall. If there's a plague or a bad war, or the goverment just screws up really bad, or terrorists get their act together and kill everybody. Disaster recovery makes pragmatic sense. It's a way cheaper than prevention (there are too many possible avenues of attack, but only one consequence).
Just some random thoughts.
