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At some point waste heat itself will warm the planet enough to matter. With exponential growth one can get there pretty quickly. A few hundred years. At some po

At some point waste heat itself will warm the planet enough to matter. With exponential growth one can get there pretty quickly. A few hundred years. At some point we should add a heat tax to compliment the carbon tax (that we should already have in place).

mrob 8y ago
True, but very low priority compared to getting CO2 under control. From "Sustainable Energy – without the hot air" by David MacKay, pages 170 to 171: "the average solar power absorbed by atmosphere, land, and oceans is 238 W/m^2; doubling the atmospheric CO2 concentration would effectively increase the net heating by 4 W/m^2. This 1.7% increase in heating is believed to be bad news for climate. Variations in solar power during the 11-year solar cycle have a range of 0.25 W/m^2. So now let’s assume that in 100 years or so, the world population is 10 billion, and everyone is living at a European standard of living, using 125 kWh per day derived from fossil sources, from nuclear power, or from mined geothermal power. The area of the earth per person would be 51 000 m^2. Dividing the power per person by the area per person, we find that the extra power contributed by human energy use would be 0.1 W/m^2. That’s one fortieth of the 4 W/m^2 that we’re currently fretting about, and a little smaller than the 0.25 W/m^2 effect of solar variations. So yes, under these assumptions, human power production would /just/ show up as a contributor to global climate change." http://www.withouthotair.com/c24/page_170.shtml http://www.withouthotair.com/c24/page_170.shtml
- njarboe 8y ago
  It seems to me the assumption that energy consumption per person has peaked at the current European level and not increase in 100 years wildly false. Compelling new uses for energy will be found and other cultures are less likely, I think, to restrict personal energy consumption as much as Europe does currently.
  - mrob 8y ago
    That might be true, but remember that MacKay's numbers assume 100% non-renewable energy. In reality, solar panel prices are dropping fast, and they'll likely make up a substantial portion of the energy supply. Solar energy captured with photovoltaic panels is solar energy that's not heating the earth directly, so the waste heat problem is much smaller. The same is true for all renewable sources, e.g. winds and tides heat the earth uselessly if we don't capture them.
    - njarboe 8y ago
      I agree. Keep power production on Earth to like 50% solar (wind, sunlight, tidal, etc) and there will be no problem with this heat issue. Bezos has specifically stated that he hopes to put industrial production off earth to avoid the industrial heat production problem in the far future.

mrob 8y ago

True, but very low priority compared to getting CO2 under control. From "Sustainable Energy – without the hot air" by David MacKay, pages 170 to 171: "the average solar power absorbed by atmosphere, land, and oceans is 238 W/m^2; doubling the atmospheric CO2 concentration would effectively increase the net heating by 4 W/m^2. This 1.7% increase in heating is believed to be bad news for climate. Variations in solar power during the 11-year solar cycle have a range of 0.25 W/m^2. So now let’s assume that in 100 years or so, the world population is 10 billion, and everyone is living at a European standard of living, using 125 kWh per day derived from fossil sources, from nuclear power, or from mined geothermal power. The area of the earth per person would be 51 000 m^2. Dividing the power per person by the area per person, we find that the extra power contributed by human energy use would be 0.1 W/m^2. That’s one fortieth of the 4 W/m^2 that we’re currently fretting about, and a little smaller than the 0.25 W/m^2 effect of solar variations. So yes, under these assumptions, human power production would /just/ show up as a contributor to global climate change." http://www.withouthotair.com/c24/page_170.shtml http://www.withouthotair.com/c24/page_170.shtml

njarboe 8y ago
It seems to me the assumption that energy consumption per person has peaked at the current European level and not increase in 100 years wildly false. Compelling new uses for energy will be found and other cultures are less likely, I think, to restrict personal energy consumption as much as Europe does currently.
- mrob 8y ago
  That might be true, but remember that MacKay's numbers assume 100% non-renewable energy. In reality, solar panel prices are dropping fast, and they'll likely make up a substantial portion of the energy supply. Solar energy captured with photovoltaic panels is solar energy that's not heating the earth directly, so the waste heat problem is much smaller. The same is true for all renewable sources, e.g. winds and tides heat the earth uselessly if we don't capture them.
  - njarboe 8y ago
    I agree. Keep power production on Earth to like 50% solar (wind, sunlight, tidal, etc) and there will be no problem with this heat issue. Bezos has specifically stated that he hopes to put industrial production off earth to avoid the industrial heat production problem in the far future.