<p>I had this thought the other day, not as a good idea but as a thought experiment. What would be the effects of putting some kind of sun-blocking satellite/s at the <a href="https://solarsystem.nasa.gov/resources/754/what-is-a-lagrange-point/" rel="nofollow noreferrer">L1 Lagrange point</a> which blocked 90% of sunlight above a latitude so that 1/4 of the earth received the reduced sunlight at any part of the year?</p>
<p>IIUC the &quot;line&quot; would move throughout the year due to the tilt of the earth, shifting between northern and southern hemispheres.</p>
<p>Obvious changes:</p>
<ul>
<li>radically reduced temperatures in the northern and southern hemispheres</li>
<li>at least moderately (?) reduced temperatures on the whole earth</li>
</ul>
<p>Less obvious would be the near-immediate radical changes to weather patterns, likely resulting in chaos for many years but eventually stabilizing to some form of steady state. What would the new steady-state look like?</p>

CC BY-SA 4.0
2023-01-16T22:50:37.740Z
I’m voting to close this question because it belongs in https://astronomy.stackexchange.com/
arkaia
CC BY-SA 4.0
2023-01-17T06:07:10.220Z
I don't entirely think it doesn't belong here, as it's a weather/climate question in general.  But it's probably leaning a bit more obscure-hypothetical (as of now) rather than particularly productive.  Any question that starts what if changed this by X [some arbitrary number] mostly leads me away (and those tend to belong more on WorldBuilding).  But yet this isn't as hypothetical as most, it's at least a conceivable thing with a path, albeit one likely centuries away and then some before plausible?
JeopardyTempest
CC BY-SA 4.0
2023-01-17T06:11:11.733Z
You don't fully make clear your method though.  So you're completely blocking it in some quadrant (1/2 of it, since 1/2 the Earth sees the sun at any time anyways) rather than bulk-filtering it?  (Or is that due to the 1/4 factor in some solar equations?)  The less convoluted, the better.  If Earth is going to someday seek to reduce insolation (to deal with global warming??  Or massive microwave solar power ala Sim City 2000), it'd be as a whole almost certainly, not some quadrant of the sun?
JeopardyTempest
CC BY-SA 4.0
2023-01-17T06:24:10.633Z
A 90% reduction in insolation as a whole would mean a blackbody temp of about -115C, so the average Earth temp would be about -100C very roughly (Greenhouse Effect takes a bit more work, so that's why estimated).  Even if you reduce a quarter section by 90%, that's a global reduction of almost 20C (not considering the math of Greenhouse).
JeopardyTempest
CC BY-SA 4.0
2023-01-17T06:35:53.487Z
Either way as I can figure it, the temporary and eventual steady states would be a larger contrast Equator to Pole, meaning more vigorous transport = "more weather". A reduction to the summer hem I'd think is less extreme (Poles actually receive 30% more energy on their Solstice than Equator), so thinking that'd have jets/frontal zones further Equatorward, but not as extreme as a winter hem reduction, which further exaggerates jet/front gradients and amplifies the wave pattern in that Hem? And more cross-Equator transport. But just quick theories, as your Q will likely gets moved/deleted?
JeopardyTempest
CC BY-SA 4.0
2023-01-17T14:28:14.027Z
Thanks JeopardyTempest (good name for this Q btw), that's all I was looking for! If you put that as an answer I'd accept, although I'm not sure it will matter if it's deleting.
vitiral
CC BY-SA 4.0
2023-01-17T14:31:37.257Z
Roughly the "method" would be a large "ring" spinning at the La Grange point. I'm writing a fictional story where such a ring is put at the L1. It is _supposed_ to expand in-wards (be a disk) to cover the whole earth, then modulated to say 5% sunlight reduction -- but something goes wrong and it is frozen in the state I gave. I was hoping someone could give me at least a basic idea of the impact of such an event, thanks!
vitiral
CC BY-SA 4.0
2023-01-17T14:37:07.017Z
Also, you're probably right that it belongs in WorldBuilding.
vitiral
<meteorology><geoengineering>
What would the effect on the weather be if the southern and northern latitudes received 90% less sunlight?
vitiral
# What would the effect on the weather be if the southern and northern latitudes received 90% less sunlight?

(Asked by: username_0 on 2023-01-16)

I had this thought the other day, not as a good idea but as a thought experiment. What would be the effects of putting some kind of sun-blocking satellite/s at the [L1 Lagrange point](https://solarsystem.nasa.gov/resources/754/what-is-a-lagrange-point/) which blocked 90% of sunlight above a latitude so that 1/4 of the earth received the reduced sunlight at any part of the year?

IIUC the "line" would move throughout the year due to the tilt of the earth, shifting between northern and southern hemispheres.

Obvious changes:

* radically reduced temperatures in the northern and southern hemispheres
* at least moderately (?) reduced temperatures on the whole earth

Less obvious would be the near-immediate radical changes to weather patterns, likely resulting in chaos for many years but eventually stabilizing to some form of steady state. What would the new steady-state look like?

**Tags:** meteorology, geoengineering

> **Comments:**
> **username_1**: I’m voting to close this question because it belongs in https://astronomy.stackexchange.com/  
> **username_2**: I don't entirely think it doesn't belong here, as it's a weather/climate question in general.  But it's probably leaning a bit more obscure-hypothetical (as of now) rather than particularly productive.  Any question that starts what if changed this by X [some arbitrary number] mostly leads me away (and those tend to belong more on WorldBuilding).  But yet this isn't as hypothetical as most, it's at least a conceivable thing with a path, albeit one likely centuries away and then some before plausible?  
> **username_2**: You don't fully make clear your method though.  So you're completely blocking it in some quadrant (1/2 of it, since 1/2 the Earth sees the sun at any time anyways) rather than bulk-filtering it?  (Or is that due to the 1/4 factor in some solar equations?)  The less convoluted, the better.  If Earth is going to someday seek to reduce insolation (to deal with global warming??  Or massive microwave solar power ala Sim City 2000), it'd be as a whole almost certainly, not some quadrant of the sun?  
> **username_2**: A 90% reduction in insolation as a whole would mean a blackbody temp of about -115C, so the average Earth temp would be about -100C very roughly (Greenhouse Effect takes a bit more work, so that's why estimated).  Even if you reduce a quarter section by 90%, that's a global reduction of almost 20C (not considering the math of Greenhouse).  
> **username_2**: Either way as I can figure it, the temporary and eventual steady states would be a larger contrast Equator to Pole, meaning more vigorous transport = "more weather". A reduction to the summer hem I'd think is less extreme (Poles actually receive 30% more energy on their Solstice than Equator), so thinking that'd have jets/frontal zones further Equatorward, but not as extreme as a winter hem reduction, which further exaggerates jet/front gradients and amplifies the wave pattern in that Hem? And more cross-Equator transport. But just quick theories, as your Q will likely gets moved/deleted?  
> **username_0**: Thanks username_2 (good name for this Q btw), that's all I was looking for! If you put that as an answer I'd accept, although I'm not sure it will matter if it's deleting.  
> **username_0**: Roughly the "method" would be a large "ring" spinning at the La Grange point. I'm writing a fictional story where such a ring is put at the L1. It is _supposed_ to expand in-wards (be a disk) to cover the whole earth, then modulated to say 5% sunlight reduction -- but something goes wrong and it is frozen in the state I gave. I was hoping someone could give me at least a basic idea of the impact of such an event, thanks!  
> **username_0**: Also, you're probably right that it belongs in WorldBuilding.  

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