
The climate of a retrograde rotating Earth (2018) - otagekki
https://www.earth-syst-dynam.net/9/1191/2018/
======
ncmncm
This is a very surprising topic. Why should anything be different?

But it's not about rotation not matching direction of motion around the sun.
It's more about how climates on the continents, as they lie, would be affected
by jet streams and ocean currents which are driven by earth's rotation. They
would encounter the coastlines and mountain ranges from different directions.
On the real earth, for example, we see England and Norway oddly warm,
equatorial Africa oddly dry, the Amazon uniquely wet. This being about fluid
dynamics, every detail is unpredictable, from an armchair perspective. Some
alterations seem sensible, but that sense is too frequently illusory.

~~~
gus_massa
The direction of the Trade Winds [1] is determined by the rotation of the
Earth due to the Coriolis effect. They would reverse, and I guess it would
cause more humidity in West Africa and less humidity in East Africa.

The effect of the big mountain range is more difficult to estimate (without a
good simulation). In South America the Andes cover all the West Cost. In the
South part the winds go mostly to the East, so it rains a lot in the small
west past of the Andes, and there is a semi desert part in the big part to the
ease of the Andes. In the North part of South America, the winds go mostly to
the West, so you get a big humid part in the Amazon. If the winds are
reversed, the semi desert part and the rainforest part somewhat exchange
positions.

I don't understand the sea currents enough for handwaving, but a big change in
the Gulf Stream [2] would make the United Kingdom much cooler.

[1]
[https://en.wikipedia.org/wiki/Trade_winds](https://en.wikipedia.org/wiki/Trade_winds)

[2]
[https://en.wikipedia.org/wiki/Gulf_Stream](https://en.wikipedia.org/wiki/Gulf_Stream)

------
gus_massa
In a previous post of a map of a retrograde Earth(based on this?) I notice the
change of climate in Central America, and I thought it was weird.

In the real Earth there is a lot of wind from the Caribean to the Pacific that
caries a lot of humidity and rain.

In a retrograde Earth, the winds in that area go from north to south, and
don't have so much humidity. (I expected winds going from the Pacific to the
Caribean, without a big change in humidity.) (It is still weird.)

------
perl4ever
The abstract confused me.

Near the beginning, it refers to "the switch in the character of the
European–African climate with that of the Americas, with a drying of the
former and a greening of the latter"

Later on, it says "the temperature gradient between Europe and eastern Siberia
is reversed, and the Sahara greens, while large parts of the Americas become
deserts"

These seem somewhat contradictory, and I'm wondering if something was
inadvertently reversed.

------
chrisco255
Does anyone know if Earth's rotation is influenced by it's electromagnetic
polarity and if shifts in rotation are possible during magnetic pole shifts?

~~~
jcranmer
Earth's rotation is almost certainly affected by the magnetic field, and I
suspect a complete reverse of the field would flip the sign contribution.

But recall that there is conservation of angular momentum, and there is an
awful lot of mass spinning at high speed and large radius to Earth's center of
inertia. The contribution of the magnetic field to the rotation time of
Earth's surface is on the order of ms, or parts per million, as the total term
itself is 86.4 ks.

In comparison to the effects of things such as the orbit of the Moon, the
magnetic field doesn't have enough energy to meaningfully affect the Earth's
rotation.

~~~
ClumsyPilot
This doesn't seem right to me, If earth were a rotating magnet in free space,
it would have to interact with another magnet to experience any net force.

Also Earth magnetic field is very weak, think of how much force a compass
needle has, and that's while you are standing right on the surface - it falls
off with distance.

~~~
jcranmer
There are lots of magnets in the solar system, chief of all this giant ball of
hydrogen fusion.

Even ignoring the effects of the interplanetary medium, Earth isn't a
homogeneous object. There's a solid core, a liquid sheath around that, a
plastic sheath around that, and then the lithosphere we are intimately
familiar with, followed by a few levels of gaseous atmosphere. These layers
are not fixed to rotate at the same speed. If you speed up the lower mantle,
then the lithosphere needs to slow down to conserve angular momentum,
lengthening the day. The effect is undoubtedly small, though: as I said, this
is on the order of parts per million.

------
h2odragon
Yeah sure fancy plans but how do you implement them? Just grabbing the earth
to stop it is hard, and thats just half the acceleration. It turns out the
planet is distressingly blobby for such geoengineering projects.

~~~
jvm_
Just strap a bunch of rockets and point them to the horizon... until you
realize that the earths crust isn't that deep and your rockets just end up
ripping a scab of earth off and flying off into space. I guess that would be
one way to make a local volcano.

~~~
HocusLocus
[Mom pops down to the basement to say Hi and see what you're up to] ;-)

------
perl4ever
aka "Velikovskian climate change"...

