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It's not that hard to imagine scenarios over the next few decades in which we find ways to use resources far more efficiently (e.g., improved battery technology

by cs702 5y ago

It's not that hard to imagine scenarios over the next few decades in which we find ways to use resources far more efficiently (e.g., improved battery technology, improved factory-made meats/foods), find ways to extract far greater resources from space (e.g., improved solar technology, asteroid mining), and/or find ways to expand the resources available to us (e.g., establishing colonies on Mars, or in space).

esailija 5y ago
Improving efficiency doesn't address the problem at all. If you only improve efficiency then consumption grows to negate any gains.
- feanaro 5y ago
  Improving efficiency means we can at least potentially retain current levels of consumption. Not that this is a particularly good idea but it shows why it is relevant.
  - actually_a_dog 5y ago
    Except the entire problem is that current levels of consumption are unsustainable.
    - feanaro 5y ago
      They are unsustainable at current efficiency levels. If things got more efficient, they wouldn't necessarily be unsustainable.
      - actually_a_dog 5y ago
        No.... the amount of energy consumption is unsustainable at any efficiency level. But, what I think you're saying is that if we can increase efficiency by X%, then we can still sustain current economic output, yes? Well, considering we're 70% over the sustainable level, that means we'd need to get 58% more efficient, with no increase in consumption, in less than 20 years. How likely do you think that is?
        Ygg2 5y ago
        Citation needed. Our current energy needs could be harvested from the sun exclusively. Cover sahara in solar collection and you satisfying energy requirements of all of humanity, several times over.
actually_a_dog 5y ago
Extracting resources from space, and expanding to Mars or space colonies are likely non-starters due to simple physics. No matter how you do it, it takes around 100 MJ/kg to get something into orbit, which translates into about 28kWh of electricity per kg, to offer a more relatable comparison [0]. It costs roughly the same amount to land the equivalent amount of mass on Earth without making an impact crater. One single, average human weighs somewhere around 65kg. So, not counting the mass of the fuel and vehicle necessary to do so, evacuating one human costs the energy equivalent of around 1820kWh of electricity. The average American household uses just over 10000kWh per year [1], just for comparison. Now, let's get to the bad news. Remember the weight of the vehicle and fuel that we just conveniently forgot about? Let's not forget about it anymore. Falcon 9 weighs around 550,000 kg [2]. So, just to put it in orbit, empty, costs the equivalent of over 1.5x10^6 kWh of electricity, or, roughly the yearly consumption of 1500 years worth of the average American household's energy consumption. That energy has to come from somewhere. Tell me, how is space going to save us again? On the other end, in less than 20 years, we need to not only offset the trend of 50% increase in global energy consumption, but also cut back an additional 50% from where we are today. In other words, in 20 years, in order to simply break even in terms of sustainability, we need to become 3x more efficient than we ever have over any 20 year period, if we want to maintain current levels of economic growth. And you don't find that hard to imagine? Edit: Alternatively, do you see us supporting 2 billion more people on this planet in 2050 with lower levels of economic growth than we've had the past few decades? See https://en.wikipedia.org/wiki/Projections_of_population_growth#2050 https://en.wikipedia.org/wiki/Projections_of_population_grow... for population growth estimates. --- [0]: https://space.stackexchange.com/questions/4330/how-much-energy-is-required-to-put-1-kg-in-leo https://space.stackexchange.com/questions/4330/how-much-ener... [1]: https://www.eia.gov/tools/faqs/faq.php?id=97&t=3 https://www.eia.gov/tools/faqs/faq.php?id=97&t=3 [2]: https://www.spacex.com/vehicles/falcon-9/ https://www.spacex.com/vehicles/falcon-9/
- alasdair_ 5y ago
  I don't think "space" is a short term solution in the slightest. It's more an eventual, partial solution. Wouldn't the general idea be to put things like solar cells into space, to increase the amount of harvestable energy we can use, not humans? Very long-term projects like space elevators, mass drivers etc. can help reduce the amount of energy (from Earth) that is required to efficiently launch something.

by cs702 5y ago

esailija 5y ago

Improving efficiency doesn't address the problem at all. If you only improve efficiency then consumption grows to negate any gains.

feanaro 5y ago
Improving efficiency means we can at least potentially retain current levels of consumption. Not that this is a particularly good idea but it shows why it is relevant.
- actually_a_dog 5y ago
  Except the entire problem is that current levels of consumption are unsustainable.
  - feanaro 5y ago
    They are unsustainable at current efficiency levels. If things got more efficient, they wouldn't necessarily be unsustainable.
    - actually_a_dog 5y ago
      No.... the amount of energy consumption is unsustainable at any efficiency level. But, what I think you're saying is that if we can increase efficiency by X%, then we can still sustain current economic output, yes? Well, considering we're 70% over the sustainable level, that means we'd need to get 58% more efficient, with no increase in consumption, in less than 20 years. How likely do you think that is?
      - Ygg2 5y ago
        Citation needed. Our current energy needs could be harvested from the sun exclusively. Cover sahara in solar collection and you satisfying energy requirements of all of humanity, several times over.

actually_a_dog 5y ago

Extracting resources from space, and expanding to Mars or space colonies are likely non-starters due to simple physics. No matter how you do it, it takes around 100 MJ/kg to get something into orbit, which translates into about 28kWh of electricity per kg, to offer a more relatable comparison [0]. It costs roughly the same amount to land the equivalent amount of mass on Earth without making an impact crater. One single, average human weighs somewhere around 65kg. So, not counting the mass of the fuel and vehicle necessary to do so, evacuating one human costs the energy equivalent of around 1820kWh of electricity. The average American household uses just over 10000kWh per year [1], just for comparison. Now, let's get to the bad news. Remember the weight of the vehicle and fuel that we just conveniently forgot about? Let's not forget about it anymore. Falcon 9 weighs around 550,000 kg [2]. So, just to put it in orbit, empty, costs the equivalent of over 1.5x10^6 kWh of electricity, or, roughly the yearly consumption of 1500 years worth of the average American household's energy consumption. That energy has to come from somewhere. Tell me, how is space going to save us again? On the other end, in less than 20 years, we need to not only offset the trend of 50% increase in global energy consumption, but also cut back an additional 50% from where we are today. In other words, in 20 years, in order to simply break even in terms of sustainability, we need to become 3x more efficient than we ever have over any 20 year period, if we want to maintain current levels of economic growth. And you don't find that hard to imagine? Edit: Alternatively, do you see us supporting 2 billion more people on this planet in 2050 with lower levels of economic growth than we've had the past few decades? See https://en.wikipedia.org/wiki/Projections_of_population_growth#2050 https://en.wikipedia.org/wiki/Projections_of_population_grow... for population growth estimates. --- [0]: https://space.stackexchange.com/questions/4330/how-much-energy-is-required-to-put-1-kg-in-leo https://space.stackexchange.com/questions/4330/how-much-ener... [1]: https://www.eia.gov/tools/faqs/faq.php?id=97&t=3 https://www.eia.gov/tools/faqs/faq.php?id=97&t=3 [2]: https://www.spacex.com/vehicles/falcon-9/ https://www.spacex.com/vehicles/falcon-9/

alasdair_ 5y ago
I don't think "space" is a short term solution in the slightest. It's more an eventual, partial solution. Wouldn't the general idea be to put things like solar cells into space, to increase the amount of harvestable energy we can use, not humans? Very long-term projects like space elevators, mass drivers etc. can help reduce the amount of energy (from Earth) that is required to efficiently launch something.