We might regret pushing out the earth’s orbit when the present interglacial period ends. (Also, careful: to push the earth’s orbit further out you don’t want to be pushing the earth further out directly; that will just make a more elongated orbit. You need to push mostly along the earth’s direction of travel.)
Make a little Dyson swarm (maybe somewhere further in than the orbit of Mercury) to reduce how much of the sun’s output reaches us in a form that can get through our atmosphere.
Apply genetic engineering to our crops, our food animals, and (at least for people in hotter regions) ourselves, to cope happily with higher temperatures. (And gradually move in away from the coasts, and learn to be less worried by hurricanes.)
Painting roofs and roads and things white (an obvious extension of the bright-white-litter idea) has actually been not-so-crazily suggested. I don’t know how it compares as a solution with turning them all into solar panels in order to reduce the amount of CO2 we need to make for energy generation.
Construct lots of gigantic heatsinks, attached to the earth but stretching up above the atmosphere.
Construct lots of gigantic heatsinks, attached to the earth but stretching up above the atmosphere.
Wouldn’t the heatsinks need to have very high temperature conductivity? Do we have suitable materials today? Are we talking about mountain-masses of superconductors?
| Wouldn’t the heatsinks need to have very high temperature conductivity?
I don’t think so. If you were to build /very tall/ tubes arching up into the upper atmosphere and cycle water through them (warm water up, cooling, and them travelling back down the other side of the arch), you could easily make them out of insulated concrete and still have to worry about freezing rather than lack of cooling. Of course, the problem then becomes what material can build this sort of structure, balancing height with throughput to prevent freezing.
But over long time periods, I think that you would also have to worry about the heat sinks evaporating the upper levels of the atmosphere.
If you transfer the heat to the atmosphere, it won’t leave the Earth+atmosphere system, so the net effect will be zero. To actually cool the earth, you’d need to heat the atmosphere enough to make parts of it escape Earth’s gravity. Aside from problematic effects on weather, this would be really hard because the upper atmosphere is very thin and so has low heat capacity and low heat conductance.
I was thinking about direct-radiation heatsinks: the inner part made of super-heat-conductive material that transports heat from ground level to a huge radiator fan in outer space, insulated by an outer layer on the way up (otherwise you lose all the heat to the atmosphere). But it would have to be both superconducting and very, very large.
Also, the cooling effect would be localized at the bottom end, so what would you stick it into? A volcano?
If you transfer the heat to the atmosphere, it won’t leave the Earth+atmosphere system, so the net effect will be zero. To actually cool the earth, you’d need to heat the atmosphere enough to make parts of it escape Earth’s gravity.
Depends how high you send the heat, I would’ve thought...? If you ferry the heat above the current effective emission-to-space height (the mesosphere should suffice), you warm that high-up air and raise the effective emission-to-space height. Assuming a fixed lapse rate, a cooler surface temperature follows.
I’m a mad scientist, not a real one. I can’t make a complex model that predicts the effects of heating up the mesosphere by a degree in terms of changes in both outgoing heat radiation, reflection and absorption of sunlight, etc. I can only make a very simple model of radiating directly into space from a really, really, really big mad space radiator.
Fair enough, haha. I figured there was a non-trivial chance you were right and I was wrong, because it’s been years since I studied this stuff systematically and my memory of it isn’t great.
Allow me to draw your attention to the first word in the title of the thing we’re commenting on.
Yes, I think they would need to conduct well. I don’t think they’d need to be superconductors. I have made no attempt to do the calculations that would be needed to figure out what would actually be needed.
But are you thinking about direct radiation at the upper end, or evaporating water into outer space with Earth-escape velocity, or something else? See also my other comment.
I was thinking direct radiation, and assuming that either (1) they go deep as well as high, cooling down the magma or something, or (2) we plug them into some kind of huge mesh of highly-heat-conductive stuff all over the earth, or most likely (3) we just let the wind do its job: if some region is being cooled relative to the surrounding region, you’ll get winds blowing that will equalize the temperature somewhat.
We might regret pushing out the earth’s orbit when the present interglacial period ends. (Also, careful: to push the earth’s orbit further out you don’t want to be pushing the earth further out directly; that will just make a more elongated orbit. You need to push mostly along the earth’s direction of travel.)
Make a little Dyson swarm (maybe somewhere further in than the orbit of Mercury) to reduce how much of the sun’s output reaches us in a form that can get through our atmosphere.
Apply genetic engineering to our crops, our food animals, and (at least for people in hotter regions) ourselves, to cope happily with higher temperatures. (And gradually move in away from the coasts, and learn to be less worried by hurricanes.)
Painting roofs and roads and things white (an obvious extension of the bright-white-litter idea) has actually been not-so-crazily suggested. I don’t know how it compares as a solution with turning them all into solar panels in order to reduce the amount of CO2 we need to make for energy generation.
Construct lots of gigantic heatsinks, attached to the earth but stretching up above the atmosphere.
Wouldn’t the heatsinks need to have very high temperature conductivity? Do we have suitable materials today? Are we talking about mountain-masses of superconductors?
| Wouldn’t the heatsinks need to have very high temperature conductivity?
I don’t think so. If you were to build /very tall/ tubes arching up into the upper atmosphere and cycle water through them (warm water up, cooling, and them travelling back down the other side of the arch), you could easily make them out of insulated concrete and still have to worry about freezing rather than lack of cooling. Of course, the problem then becomes what material can build this sort of structure, balancing height with throughput to prevent freezing.
But over long time periods, I think that you would also have to worry about the heat sinks evaporating the upper levels of the atmosphere.
If you transfer the heat to the atmosphere, it won’t leave the Earth+atmosphere system, so the net effect will be zero. To actually cool the earth, you’d need to heat the atmosphere enough to make parts of it escape Earth’s gravity. Aside from problematic effects on weather, this would be really hard because the upper atmosphere is very thin and so has low heat capacity and low heat conductance.
I was thinking about direct-radiation heatsinks: the inner part made of super-heat-conductive material that transports heat from ground level to a huge radiator fan in outer space, insulated by an outer layer on the way up (otherwise you lose all the heat to the atmosphere). But it would have to be both superconducting and very, very large.
Also, the cooling effect would be localized at the bottom end, so what would you stick it into? A volcano?
Depends how high you send the heat, I would’ve thought...? If you ferry the heat above the current effective emission-to-space height (the mesosphere should suffice), you warm that high-up air and raise the effective emission-to-space height. Assuming a fixed lapse rate, a cooler surface temperature follows.
I’m a mad scientist, not a real one. I can’t make a complex model that predicts the effects of heating up the mesosphere by a degree in terms of changes in both outgoing heat radiation, reflection and absorption of sunlight, etc. I can only make a very simple model of radiating directly into space from a really, really, really big mad space radiator.
So you may well be right; I don’t know.
Fair enough, haha. I figured there was a non-trivial chance you were right and I was wrong, because it’s been years since I studied this stuff systematically and my memory of it isn’t great.
Allow me to draw your attention to the first word in the title of the thing we’re commenting on.
Yes, I think they would need to conduct well. I don’t think they’d need to be superconductors. I have made no attempt to do the calculations that would be needed to figure out what would actually be needed.
But are you thinking about direct radiation at the upper end, or evaporating water into outer space with Earth-escape velocity, or something else? See also my other comment.
I was thinking direct radiation, and assuming that either (1) they go deep as well as high, cooling down the magma or something, or (2) we plug them into some kind of huge mesh of highly-heat-conductive stuff all over the earth, or most likely (3) we just let the wind do its job: if some region is being cooled relative to the surrounding region, you’ll get winds blowing that will equalize the temperature somewhat.
But, once again: crazy ideas.