I am a vengeful scientist who crash-landed on your Earth. While I was repairing my space ship, I had to obtain nourishment by consuming organic matter, and visited a local nutrition warehouse your people call "Arby's."

I have decided that the species responsible for this perversion must perish.

Fortunately, I had a spare Axial-Tilt-Tweaker-9000 aboard my vessel. I understand that your Earth has a delicate climate that can be easily affected by tilting the planet. While I have no doubt that the device will be soon discovered and disabled by your species' caste of handsome action heroes, it should be able to alter the axial tilt of Earth by several degrees over the course of some years or decades but will stop well short of turning the Earth on its side.

How much change to the Earth's tilt, between its rotational axis and its solar orbit, would be enough to cause unimaginable disaster and suffering on this planet, and should the axial tilt be increased or decreased?

Edited to add: This would take many years to affect the planet.

  • 3
    $\begingroup$ I dunno. I do have a vivid imagination... $\endgroup$
    – nzaman
    Jul 5, 2018 at 17:13
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    $\begingroup$ @nzaman In that case I encourage you to apply to become a vengeful space scientist, so that you can put your imagination to use. $\endgroup$
    – SPavel
    Jul 5, 2018 at 17:16
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    $\begingroup$ What did you eat at Arby's that caused such planetary offense? Mercifully you didn't eat at Taco Bell or you might have dematerialized the entire planet. $\endgroup$
    – smci
    Jul 5, 2018 at 19:43
  • $\begingroup$ @smci: That's assuming he would survive the food poisoning to begin with. $\endgroup$ Jul 7, 2018 at 6:43

6 Answers 6


The first thing I'd be worried about is how fast the change in axial tilt would happen.

If it happens in minutes or seconds, then people get thrown into walls at high velocities. The walls won't survive.

If it happens over the course of a day, there would be major tectonic stresses suddenly redistributed. Earthquakes, volcanoes, dogs and cats living together... Mass hysteria!

Even if it happened over the course of several months, there is still a huge mismatch in rotational energy, where the core is spinning in a different direction from the crust, causing huge stresses.

But, if it happens over the course of a day, it still allows for an interesting story. Some buildings might slip from their foundations, as the forces of inertia suddenly make gravity seem that "down" has shifted by a couple of degrees for several hours, but most buildings and technology would survive.

Astronomers are pissed off. Besides all of their telescopes pointing in the wrong direction, their favorite observatories that used to sit on some of the tallest and most remote mountains are sitting in active volcanic calderas.

People also can't get satellite TV unless they reposition their dishes.

And, somewhat more significant to the future: Jet airplanes would be grounded. Not because of any property of axial tilt, but because of volcanic ash and how destructive it is to jet engines.

The first climate effect would be the same, whether you increased or decreased axial tilt:

Volcanic winter.

Volcanic ash is pretty reflective, and doesn't hold heat very well; quite the opposite to atmospheric CO2, which doesn't reflect light but holds heat very well.

Global temperatures drop quickly. Some microclimates may warm up -- i.e., decreased turbulence would keep tropical air from mixing with air in cooler regions as much, but overall the average temperature drops quickly and significantly. (See Little Ice Age for an example of just a few more volcanoes than usual being active over a long period of time.)

Ash doesn't stay in the air for long. Tectonic stress doesn't stay high for long when the stress is actively being relieved. This volcanic winter should only last for a decade or so.

It's likely to be followed by a volcanic summer. Ash on the ground gets wet, gets dark, and traps heat on the surface. Humans will have probably used much more fuel to warm their homes and try to plant more crops, releasing more CO2, which will now start trapping that heat.

But, the next effect depends more on which direction you tilted the axis. Is the tilt now 13 degrees or 33 degrees?

If the tilt were only 13 degrees, then seasons as we know it would greatly diminish. Areas at the equator would get much warmer. Areas near the poles would get much colder. There would be much less circulation between these regions. The tropics (which would be a much more narrow band around the equator) would see more rain, while the rest of the world would see much less. Much ecological diversity would be lost, and humans would have to struggle to adapt.

If the tilt were increased, then seasons would get far more pronounced. Deserts would get rain. Rainforests would dry up. Much ecological diversity would be lost, and humans would have to struggle to adapt.

Note that this answer is based on an earlier version of the question, where the change of axial tilt was limited to 10 degrees, and there were no limits on how fast the change would occur.

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    $\begingroup$ "people get thrown into walls at high velocities. The walls won't survive." I like your way of thinking. $\endgroup$ Jul 5, 2018 at 17:55
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    $\begingroup$ Great answer, but it's the elaboration of the last two paragraphs that I would be interested in. Exactly how do the weaker/stronger seasons affect the Earth? $\endgroup$
    – SPavel
    Jul 5, 2018 at 18:16
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    $\begingroup$ Is there any specific location that you're looking at? Hypothesizing about specific effects on climate throughout the entire world is beyond anyone's abilities. With less tilt, the deserts of the southwest United States would get even dryer, without the monsoon flow in late summer or the late fall/winter rains from the elongated jet stream. With more tilt, much much more rain as the Sierra Nevada mountains would no longer be blocking the flow, but Canada would become a new Siberia, and all of Canada would go 6 months at a time with almost no sunlight, and almost no night the other 6 months. $\endgroup$
    – Ghedipunk
    Jul 5, 2018 at 18:27
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    $\begingroup$ In short, every region would have to be looked at individually. There are no blanket statements for the entire world that would fit in an answer. $\endgroup$
    – Ghedipunk
    Jul 5, 2018 at 18:27
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    $\begingroup$ "dogs and cats living together... Mass hysteria!" I'd give you an extra thumb up only for being a fan^^ $\endgroup$ Jul 5, 2018 at 18:47

You can really cause a lot of destruction with that machine, but you know what? If you just kill everybody in the span of a week, then there will be no people suffering on Earth forever after.

If you want to maximize disaster and suffering, you want to torture rathen than to kill. So flip the planet around, 180 degrees. Seasons will be preserved. Some organic life might have to readjust to an unexpected extended summer or winter but they will be able to deal with it.

However, until the Sun becomes a red giant and swallows the Earth - which should take a few billion years - you will see people strugling with the change of direction.

Initially everybody is going to be pretty mad at GPS failing miserably. That will be a good one, but it should be fixed quickly.

Flat earthers will be pulling their hairs when Polaris is no longer the central star, but then again, who cares about them?

The best part will be people who are too proud of whatever plot of land they have been born on. They will not accept that the South is the new North (and vice-versa). There are enough of them to keep the debate of what is South and what is North going on, and heated at that, forever.

It will take centuries to clear up the nomenclature mess. There will be gnashing of teeth over NAFTA becoming SAFTA, and the whole north americans vs south americans thing, with America being in South America now. That oughta drive a lot of people crazy.

The ensuing debate between those who wish to rename the hemispheres and those who don't will confuse anyone working with geolocation, and also those who work in the fields of history, especially dealing with pre-change texts. And since being pedant is basic human nature, this talk will dominate conversations on social media and create yet another schism factor between people.

But if you really don't care and just want to kill rather than stun, decreasing tilt by a degree and a half will cause an ice age. It may take a few years to kick in, though.

If you don't want to be economic, increase tilt to 90 degrees. If you time it right you melt the South pole and cause a flood that would put the biblibal account of Noah to shame.

  • $\begingroup$ Definitely interested in the ice age bit. How long is "a few years"? $\endgroup$
    – SPavel
    Jul 5, 2018 at 18:20
  • $\begingroup$ @SPavel I believe that, unfortunately, there would be only one way to find out, and we don't have the technology to test. $\endgroup$ Jul 5, 2018 at 18:23
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    $\begingroup$ I'm starting to think we should not be helping this guy. I kinda like the Earth the way it is. $\endgroup$
    – Brian C
    Jul 5, 2018 at 20:10
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    $\begingroup$ North and South would not change, from conventional definitions, assuming you are rotating the entire Earth (including its core and magnetic poles). Only the stars and the seasons would flip around, and while that would cause some chaos (particularly around Christmas time), people would quickly adapt. GPS and satellites would also be affected, assuming they did not rotate with the planet. $\endgroup$
    – Miral
    Jul 6, 2018 at 3:04
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    $\begingroup$ Fixing GPS is simply a matter of uploading the new ephemeris data to every device. Ephemeris is a regular part of the data stream that GPS satellites send, so it's just a matter of updating those. I don't know how often, but GPS automatically updates these using ground stations at known positions. So really, fixing GPS is just a matter of waiting for a short while. In the meantime, global wind patterns rearranging themselves would cause major storms in which you can't use your car anyways because you run the risk of being impaled by a road sign. So really, the GPS is a non-issue. Weather isn't $\endgroup$ Jul 6, 2018 at 8:38

Point the South Pole at the sun. For the next month or two there would be no sunlight in the northern hemisphere. All plants would die. (Plus it would be really cold.)

Three months after the initial shift, the Earth will have traveled 1/4 of the way around the sun. Both hemispheres would have daylight half of the day.

A month later and the South Pole is getting shorter and shorter days.

6 months after the initial tilt-change, the southern hemisphere would be in complete darkness. The month before and after that would be dark and cold too. During that time, all plant life in the southern hemisphere would die.

Sounds pretty catastrophic to me. "Handsome action heroes: the South Pole is pointing at the sun! We only have a short time to move everybody to the southern hemisphere, and 6 months to fix the axial tilt and save the planet!"

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    $\begingroup$ As specified in the question, the handsome action heroes will surely disable the device before it can tilt the Earth more than a few degrees. $\endgroup$
    – SPavel
    Jul 5, 2018 at 19:02
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    $\begingroup$ @SPavel Oh. Shoot. Thanks for clarifying. $\endgroup$ Jul 5, 2018 at 20:53
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    $\begingroup$ "move everybody to the southern hemisphere" - excellent. Instead of shipping a couple extra-thick winter jackets to everyone, we'll cook them alive. I think that's even worse than polar winter. Really the only place to go is the new equator. $\endgroup$ Jul 6, 2018 at 8:42
  • $\begingroup$ I dunno. Seems like this jumps to a certain change and doesn't consider whether smaller changes would be effective enough — should at least interpolate conditions between this and 0 change. $\endgroup$ Jul 6, 2018 at 23:25
  • $\begingroup$ You cannot keep a (former) pole pointing it at the Sun always without also changing the planet's axial rotation period from one turn in 24 hours to one per a year, assuming you keep the axis unchanged. But since the device can change only this vector but not own rotation of the Earth (the OP did not have that handy rotation rate control upgrade that was just released in beta only a few Galactic days ago), you can only put the planet's rotation "on the side", so it's axis in in the plane of ecliptic. This will melt the (former) poles, as they will have a constant sunlight for months on end. $\endgroup$ Jul 7, 2018 at 6:41

Nope. It would be quite annoying, but well short of "unimaginable disaster".

Decrease the tilt from 23 degrees to 13 degrees, and seasonality is decreased in the temperate zones and polar regions -- summers would be cooler and winters would be warmer. In time this would have a large impact on things like the boreal forest and forces changes to some crops in some areas, but the entire tropics and sub-tropics would be basically unaffected. Impact: definitely. Disaster: Maybe in some areas, and probably rather slow motion. Unimagiable disaster: No.

Increase the tilt to 33 degrees and seasonality is increased. Again, the tropics would be little affected while higher latitudes would be affected most. The Arctic Circle would come down to 56 degrees north latitude, so all of Scandinavia would be north of the Arctic Circle as would be Russia right down to Moscow. High latitudes would have long, brutal winters and long, probably hot summers. Impact: definitely. Disaster: definitely at high latitudes and pretty quickly. Unimaginable disaster: Still no. Quite imaginable.

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    $\begingroup$ Sounds like increasing the tilt will stick it more to the people in your 'America' who appear to be responsible for Arby's, than would decreasing it. $\endgroup$
    – SPavel
    Jul 5, 2018 at 18:18

I have honestly no idea how much more or less tilt the planet could handle, but i know that our climate is a complicated system of interactions between air and sea currents, mountain ranges, energy input and loss, the distribution of ice covered areas, etc. pp.
If you tilt the axis of earth in either direction, changes and chain reactions can be expected. But if this is enough to get to a scale of "unimaginable disaster"... i don't think so. It definitly won't trigger something like in "The Day after Tomorrow".

  • $\begingroup$ Agreed. Surely altering the Earth's tilt will change a lot of things here on Earth, but life's change, after all. We are all living through a Great Extinction, where species are disappearing at a much faster rate than the last one (the one which killed off dinosaurs)... and well, the world won't end tomorrow. $\endgroup$
    – Rekesoft
    Jul 6, 2018 at 9:45

Well the most you would have to tilt would be 23.4 degrees less aka making the planet have no tilt.

This would eliminate seasons and damage almost all life.

I have no idea what the minimum is however.

  • $\begingroup$ Interesting suggestion, could you expand on the idea of eliminating axial tilt altogether? $\endgroup$
    – Ruadhan
    Jul 6, 2018 at 13:53
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    $\begingroup$ @P.Lord i think you were downvoted because 23.4 degrees is not the maximum tilt at all. $\endgroup$
    – coconochao
    Jul 6, 2018 at 15:45
  • $\begingroup$ He said what direction of slightly tilting it. I stated the maximum angle, any more than that would not achieve more destruction. Therefore the maximum tilt you need to achieve most desctruction is 23.4 $\endgroup$
    – P.Lord
    Jul 6, 2018 at 15:53
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    $\begingroup$ You could clarify your verbiage: you say “maximum tilt” where it seems that “maximal delta” — which, of course, isn't exactly the case, either: the most comparative change would be 180° of arc, because at that point it is equivalent to a lesser change from the other direction. All that is, of course, measured from its present tilt as the 0 angle — which is, of course, presently 23° (approx.) between the axis of the Earth's internal rotation and the axis of its orbit with the Sun. $\endgroup$ Jul 6, 2018 at 23:30
  • $\begingroup$ You managed to read my entire reply and miss the point. I do not mean that is the maximum amount that the earth can rotate. I am explaining that is the maximum amount NEEDED to reach 100% worst effects. No matter how much more you tilt it that is the maximum tilt for the worst outcome. The maximum amount that could be stated to be the smallest amount to reach the maximum outcome. $\endgroup$
    – P.Lord
    Jul 6, 2018 at 23:49

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