Cooling a Planet?

[Jester85]

Say you (humanity) are at war with a cold-blooded reptilian species that requires a hot, swampy, primordial environment.

Say you are fighting over a planet they've already conquered, and you can't drive them off by brute force and turn to another strategy....make the planet useless to them so they just abandon it.

Would there a way to somehow basically artificially induce an ice age, or turn the planet into a cold/arid environment? Ideally without completely destroying it (if humans could still get around in oxygen masks/bodysuits, that would still work for what I'm looking for).

 

[Harpo]

Nuke the largest supervolcano.

 

[Venusian Broon]

Nuke the largest supervolcano.

Wouldn't work in the medium term - you'd get a 'nuclear winter' for a few years, but after the clouds of ash and dust disappear all the greenhouse gases being emitted by the volcano would pump the temperature up for a long time.

So to cool a planet, really you either want to reduce the amount of greenhouse gases, so that more heat gets radiated back into the cosmos or you want to make it as white as possible to reflect more sunlight back, increasing the albedo, so that the light doesn't get there in the first place....

A method I've seen suggested is to flood the atmosphere with sulphate particles. It whitens the sky and actually makes it brighter therefore reflecting back a larger proportion of the sun's light away from the planet. Apparently it also has the added benefit of being more beneficial to plants so they would grow more strongly and therefore absorb more carbon from the atmosphere.

See this: Geoengineering Could Turn Skies White

Do that for long enough and get the ice poles of the planet (if it has any) to expand, helping you increase the albedo of the planet and you could get a runaway ice age.

 

[psikeyhackr]

Developing an airborne disease fatal to reptiles that has no effect on humans would be easier.

 

[Plucky Novice]

A different approach might be to shield the planet from the sun. You could create a dust cloud in space orbiting the planet. Maybe push some asteroids into place and pulverize them. Or blow up a moon?

 

[Cathbad]

Make lots of ice!

 

[CTRandall]

Various greenhouse gas capture methods are theoretically possible, though it would take considerable time (decades at a minimum) to really cool things down. All of the above suggestions would obviously wreak havoc with all other life on the planet, as well, not just the alien reptiles.

 

[Onyx]

A different approach might be to shield the planet from the sun. You could create a dust cloud in space orbiting the planet. Maybe push some asteroids into place and pulverize them. Or blow up a moon?

Blow up something nearby and the rain of meteors will likely destroy everything for thousands of years and heat the whole planet up. See SevenEves.

A more controllable approach would be to orbit a soleta, which is a thin veil that blocks some sunlight. I would not be surprised if we put some in our orbit in the next 40 years.

 

[BAYLOR]

Blow up something nearby and the rain of meteors will likely destroy everything for thousands of years and heat the whole planet up. See SevenEves.

A more controllable approach would be to orbit a soleta, which is a thin veil that blocks some sunlight. I would not be surprised if we put some in our orbit in the next 40 years.

Interesting Idea and probably feasible.

 

[Jay Greenstein]

Seems to me that since the lizards came from elsewhere, and won the battle, they're not all that numerous on that world as yet. So killing off all life on the planet, just because you're pissed, seems a bit extreme—especially when there is at least one world full of lizards who just might be miffed, and who are better at war. The result of mass deaths a planet full of the creatures who just kicked your ass are seeking revenge, while you just lost the moral high ground—and possibly the reader's support.

There's a story there, but not the one you wanted, I think.

Always look at the real-world consequences of what's done.

 

[K.S. Crooks]

Create a giant space shield and place it in orbit to block sunlight and have it always be night/ total eclipse. The farther the planet is from the sun the smaller the shield can be or the farther the shield is from the planet. Keep will still need to be very large.

 

[Onyx]

Create a giant space shield and place it in orbit to block sunlight and have it always be night/ total eclipse. The farther the planet is from the sun the smaller the shield can be or the farther the shield is from the planet. Keep will still need to be very large.

That's what a soleta is. But moving it further from the planet would mean it would need to be larger, not smaller. The Earth just barely eclipses the moon because they are far apart. If the moon was closer it would easily fit in the earth's shadow.

 

[Plucky Novice]

Blow up something nearby and the rain of meteors will likely destroy everything for thousands of years and heat the whole planet up. See SevenEves.

A more controllable approach would be to orbit a soleta, which is a thin veil that blocks some sunlight. I would not be surprised if we put some in our orbit in the next 40 years.

More scientifically accurate I'm sure but not half as much fun!

 

[zmunkz]

Blow up something nearby and the rain of meteors will likely destroy everything for thousands of years and heat the whole planet up.

If you blew up a moon in orbit, the parts would continue to orbit, for the most part. You may end up with a mini asteroid belt around the planet which could be a decent shield. Some parts would fall and some would be ejected from orbit, sure, but it’s not like the moon would rain down from the sky in pieces.

 

[BAYLOR]

If you blew up a moon in orbit, the parts would continue to orbit, for the most part. You may end up with a mini asteroid belt around the planet which could be a decent shield. Some parts would fall and some would be ejected from orbit, sure, but it’s not like the moon would rain down from the sky in pieces.

The moon fragments raining done on the planet would likely render the Earth surface completely lifeless.

 

[Onyx]

If you blew up a moon in orbit, the parts would continue to orbit, for the most part. You may end up with a mini asteroid belt around the planet which could be a decent shield. Some parts would fall and some would be ejected from orbit, sure, but it’s not like the moon would rain down from the sky in pieces.

If a small percentage of the moon rained down, the sky would be on fire for hundreds or thousands of years. There is no way to blow something up and expect the ejecta to stay in its old orbit.

 

[Venusian Broon]

The moon fragments raining done on the planet would likely render the Earth surface completely lifeless.

I'm not sure many of the fragments would actually hit the planet. Although it really does depend on the magnitude of the explosion and how the energy is transmitted into kinetic energy. Which means you could actually tailor it so that most of the moon would just break up and remain in orbit - making the shield that zmunkz states.

 

[BAYLOR]

I'm not sure many of the fragments would actually hit the planet. Although it really does depend on the magnitude of the explosion and how the energy is transmitted into kinetic energy. Which means you could actually tailor it so that most of the moon would just break up and remain in orbit - making the shield that zmunkz states.

But the moon, even at only 1/6 the size of the earth, would produce alot fragments and many of which might end up being too large to burn up in the atmosphere.

 

[-K2-]

Fragments from a moon raining down would likely be inconsequential considering the gravitational shifts from the loss of that moon. Our own moon causes surprising changes. That said, it might be worth investigating if such a loss could timed correctly shift the planet's orbit about its star enough to cause a temperature change... Then again, if the planet's ecology is based upon its current conditions, you might be looking at wiping it out too with a climate change.

K2

 

[psikeyhackr]

But the moon, even at only 1/6 the size of the earth, would produce alot fragments and many of which might end up being too large to burn up in the atmosphere.

Any explosion or impact powerful enough to break up the Moon would send down lots of fragments as big as what wiped out the dinosaurs. If you buy that theory. LOL