Open Thread, September 1-15, 2012

OpenThreadGuy

If it's worth saying, but not worth its own post, even in Discussion, it goes here.

I have a Great Filter related thought which doesn't address your question directly but, hey, it's the Open Thread.

My thesis here is that the presence of abundant fossil energy on earth is the primary thing that has enabled our technological civilization, and abundant fossil energy may be far less common than intelligent life.

On top of all the other qualities of Earth which allowed it to host its profusion of life, I'll point out a few more facts related specifically to fossil energy, which I haven't seen in any discussions of Fermi's Paradox or the Great Filter.

Life on Earth happens to be carbon-based, and carbon-based life, when heated in an anoxic environment, turns into oil, gas and coal.
Earth is roughly 2/3 covered in oceans (this figure has varied over geologic time), a fact with significant consequences to deposition of dead algae, erosion, and sedimentation.
Earth possesses a mass, size, and age such that the temperature a few kilometers below the surface may be hundreds of degrees C, while the surface temperature remains "Goldilocks."
Earth has a conveniently oxidizing atmosphere in which hydrocarbons burn easily, but not so oxidizing that it prevents stable carbon-based life. Quite a narrow window, really.
Life has existed on Earth for billions of years, and thus algae and other life forms have been dying in oceans and swamps and accumulating subsurface hydrocarbon source material, for billions of years.

Put all this together and realize that the formation of oil, gas, and coal happens only in rare and specific circumstances even on Earth. We seem to have a lot of these resources today, but it took billions of years for them to accumulate in the quantities we now find.

If any one of the above facts were not true, we would not have fossil energy - coal, oil, gas, plastics, lubricants - we would not have an industrial revolution, and we would not have a technological civilization.

Many of the facts on the above list have to be true simply to enable fire, as in, wood fire, imagine what human history would look like if the oxygen content of Earth's atmosphere was too low to sustain wood fire?

Anyways, maybe people have discussed this before, but I wasn't able to Google anything up.

Frankly, I'm wondering if the whole idea of exponential growth is just short cultural time horizons applied to the implications of fossil fuels for energy production, which touched off the Industrial Revolution. The Hubbert Peak holds, although coming out the other side of it resembles a gradual stepping-downward with its own local spikes and valleys (much as there are spikes and valleys in growth and use now, despite a steady upward trend). Fossil fuels still supply over three quarters of the world's energy demand; there hasn't been a nuclear renaissance ... (read more)

7JoshuaZ14y

The limiting oxygen concentration for most woods is between 14% and 18%. The Earth oxygen concentration is a little over 20% so it does look close. But this is slightly misleading: All that oxygen showed up because carbon based life was releasing it from water and carbon dioxide in photosynthesis. Oxygen using life only showed up after there were dangerously high levels of oxygen. And if the oxygen levels get very high then the photosynthesizers will start to get poisoned and the percentage will go down. So it isn't really likely to have an atmosphere with so much oxygen that it is a problem for carbon life. But yes, certainly an equilibrium with less oxygen is plausible in which case fire would be close to impossible even if the percentage dropped by only a small amount.

20evand14y

The oxidizing atmosphere is not due to chance. It was created by early life that exhaled oxygen, and killed off its neighbors that couldn't handle it. Hence, I don't think the goldilocks oxygen levels speak much to great filter questions. Early in civilization, we used wood and charcoal as energy sources. Blacksmithing and cast iron were originally done with wood charcoal. Cast iron is a very important tool in our history of machine tools and hence the industrial revolution. It's possible that we could have carried on without coal, instead using large-scale forestry management or other biomass as our energy source. In the early 1700s there were already environmental concerns about deforestation. They were more related to continued supply of wood for charcoal and hunting grounds than "ecological" concerns, but there were still laws and regulations enacted to deal with the problem. How many people do we need to support a high-tech civilization? I suspect fewer than we tried it with. It's quite possible that biofuel sources would have produced a high tech civilization, just slower and with fewer people. Also, note that biofuels can produce all the lubricants and plastics you need just fine. The Fischer-Tropsch process has been implemented on a large scale before. I think that given all this, you could get the modern metal lathe and the steam engine without fossil fuels. We already harnessed basic water and wind power without fossil fuels. I suspect with modern machine tools you get to electricity and large-scale water and wind power generation, even without fossil fuels. Again, more slowly, and possibly without so many people, but I think you can get there.

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Open Thread, September 1-15, 2012

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Open Thread, September 1-15, 2012

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