Sustainability, astrobiology illuminate future of life in universe, civilization on Earth

November 6, 2014
This is a schematic of two classes of trajectories in SWEIT solution space. Red line shows a trajectory representing population collapse whereby development of energy harvesting technologies allows for rapid population growth which then drives increases in planetary forcing. As planetary support systems change state the SWEIT population is unable to maintain its own internal systems and collapses. Blue line shows a trajectory representing sustainability in which population levels and energy use approach levels that do not push planetary systems into unfavorable states. Credit: Michael Osadciw/University of Rochester

Human-caused climate change, ocean acidification and species extinctions may eventually threaten the collapse of civilization, according to some scientists, while other people argue that for political or economic reasons we should allow industrial development to continue without restrictions.

In a new paper, two astrophysicists argue that these questions may soon be resolvable scientifically, thanks to new data about the Earth and about other planets in our galaxy, and by combining the earth-based science of with the space-oriented field of astrobiology.

"We have no idea how long a technological civilization like our own can last," says University of Rochester astrophysicist Adam Frank. "Is it 200 years, 500 years or 50,000 years? Answering this question is at the root of all our concerns about the sustainability of human society."

"Are we the first and only technologically-intensive civilization in the entire history of the universe?" asks Frank. "If not, shouldn't we stand to learn something from the past successes and failures of these other species?"

In their paper, which appears in the journal Anthropocene, Frank and co-author Woodruff Sullivan call for creation of a new research program to answer questions about humanity's future in the broadest astronomical context. The authors explain: "The point is to see that our current situation may, in some sense, be natural or at least a natural and generic consequence of certain evolutionary pathways."

This is a plot of human population, total energy consumption and atmospheric CO2 concentration from 10,000 BCE to today. Note the coupled increase in all 3 quantities over the last century. Credit: Michael Osadciw/University of Rochester

To frame these questions, Frank and Sullivan begin with the famous Drake equation, a straightforward formula used to estimate the number of intelligent societies in the universe. In their treatment of the equation, the authors concentrate on the average lifetime of a Species with Energy-Intensive Technology (SWEIT). Frank and Sullivan calculate that even if the chances of forming such a "high tech" species are 1 in a 1,000 trillion, there will still have been 1,000 occurrences of a history like own on planets across the "local" region of the Cosmos.

"That's enough to start thinking about statistics," says Frank, "like what is the average lifetime of a species that starts harvesting energy efficiently and uses it to develop high technology."

Employing , the authors map out a strategy for modeling the trajectories of various SWEITs through their evolution. The authors show how the developmental paths should be strongly tied to interactions between the species and its host planet. As the species' population grows and its energy harvesting intensifies, for example, the composition of the planet and its atmosphere may become altered for long timescales.

Frank and Sullivan show how habitability studies of exoplanets hold important lessons for sustaining the civilization we have developed on Earth. This "astrobiological perspective" casts sustainability as a place-specific subset of habitability, or a planet's ability to support life. While sustainability is concerned with a particular form of life on a particular planet, astrobiology asks the bigger question: what about any form of life, on any planet, at any time?

We don't yet know how these other life forms compare to the ones we are familiar with here on Earth. But for the purposes of modeling average lifetimes, Frank explains, it doesn't matter.

"If they use energy to produce work, they're generating entropy. There's no way around that, whether their human-looking Star Trek creatures with antenna on their foreheads, or they're nothing more than single-cell organisms with collective mega-intelligence. And that entropy will almost certainly have strong feedback effects on their planet's habitability, as we are already beginning to see here on Earth."

"Maybe everybody runs into this bottleneck," says Frank, adding that this could be a universal feature of life and . "If that's true, the question becomes whether we can learn anything by modeling the range of evolutionary pathways. Some paths will lead to collapse and others will lead to sustainability. Can we, perhaps, gain some insight into which decisions lead to which kind of path?"

As Frank and Sullivan show, studying past extinction events and using theoretical tools to model the future evolutionary trajectory of humankind—and of still unknown but plausible alien civilizations—could inform decisions that would lead to a sustainable future.

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9 comments

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gkam
1 / 5 (2) Nov 06, 2014
We can survive without an economy and without politics, but not without a complete and nourishing environment to clean our water, make our oxygen, and provide us with food.
eachus
5 / 5 (1) Nov 06, 2014
We can NOT survive without an economy and without politics, but not without [a complete and nourishing] environment to clean our water, make our oxygen, and provide us with food.

There. Fixed it. Living without an economy would mean that there are no resource limits. Economy deals with the allocation of scarce resources. There was a time (at least 3000 years ago, probably closer to ten--at the end of the Younger Dryas era) when humanity could expand exponentially without any effective resource limits. Same goes for politics. One person doesn't need politics, but whether the number at which politics becomes important may be as low as two people, or as high as a thousand. In any case well below sustainable population levels.

Finally, limiting the concern to one planet is silly. One solar system might make more sense. Space elevators will happen, which reduce the marginal cost of (inner system) space transport by 10,000% or more. Men will inhabit the solar system soon.
gkam
1 / 5 (2) Nov 06, 2014
If a decision is forced upon us, there is no other choice. Kill the environment, you kill us.
Modernmystic
1 / 5 (1) Nov 06, 2014
If a decision is forced upon us, there is no other choice. Kill the environment, you kill us.


I think you should do some reading on molecular manufacturing, nanotechnology, and throw in some of the thinking and current technology that we'd use to colonize Mars.

We, in our present condition, need something to purify air, water, maintain temperature, and assemble sunlight (or energy) into carbohydrates (something we can now do artificially).

We can do all those things today without "the environment". So let's be clear, we don't NEED the environment to live (especially long term)...we VALUE the environment at differing levels depending on our worldviews. Because those worldviews may disagree doesn't change biology or physics though.

Now if the environment collapsed so would our population, but the fate/survival of humanity as a species is absolutely no longer tied to the biosphere of the planet. It wouldn't be fun, but it would be survival.
gkam
1.7 / 5 (3) Nov 06, 2014
Look up Spaceship Two.

You are in fantasy if you think we can artificially care for ourselves in any number at all.
Modernmystic
2 / 5 (1) Nov 06, 2014
Look up Spaceship Two.

You are in fantasy if you think we can artificially care for ourselves in any number at all.


I appreciate your opinion, not the manner in which you expressed it though. I think we can be respectful can't we?

The facts however state otherwise. Current nuclear submarines can stay submerged for 90 days limited only by the amount of food they can carry. We can now artificially create carbohydrates without plants. This technology will only get better. Even if we aren't able to indefinitely separate ourselves from the biosphere (for the sake of argument) at this moment; the time when we can is not far off at all....that's not fantasy it's reality.
gkam
2.3 / 5 (3) Nov 06, 2014
As one with a maintenance background, I think you may be unaware of how many people are behind every one under water. I understand self-sufficiency and as soon as the pumps start breaking down, seals leak, or things break, you are dead without a complete set of facilities to fix it all. All that needs more people and more resources, and bigger problems.

When those subs sail, there is a massive wave of entropy in their wake.
xstos
not rated yet Nov 09, 2014
We must mimic nature. If nature can operate in a closed loop with only the energy of the sun, our technologies must emulate that same principle. The earlier the better.
gkam
1 / 5 (2) Nov 09, 2014
xstos, that is what alternative energy does. Anaerobic digestion is just an extension of the rumen and stomach of the cow. We continue the process and contain the methane, instead of letting it pollute the atmosphere.

It also stabilizes the nutrients in the aqueous effluent, making them amenable to field application. The cellulosic substrates still in the effluent hold the beneficial bacteria for soil re-innoculation.

A seven thousand-head dairy, typical for California, can power itself, provide all its own hot water and electricity, stop polluting the air and water, and generate electrical power for a thousand households.

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