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Comment by mseepgood | Hacker News Reader

First we should turn the Sahara into a lush green forest as an exercise. Terraforming a remote planet will be a million times more difficult.

Oh, wait, we can't even work together as humanity to contain a virus.

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(disclaimer: I work in a climate group)

Please do not do this :).

Deserts are great for shedding heat into space (highly reflective in the visible, highly emissive in the infrared, low moisture in the atmosphere).

We had a theory (not yet published, so take it with a grain of salt) that desertification might buffer the radiative forcing effects of CO2. Unfortunately, when we analyzed the last 20 years of satellite data, the opposite is happening--people have been watering the desert like crazy, leading to a net reduction on the order of ~100-200,000km^2.

Better to experiment off earth than on it in such planet changing endeavors. You can afford less attention to (safety)detail in that scenario.

Or maybe not. Turning the Sahara into a forest would have a massive climate impact.

I am not a climate scientist but I’d imagine there would be significant changes to rainfall patterns over most of Europe, Africa, and the Middle East

Edit - sorry, reply was meant to be to parent

There is a nice article about some paper modeling the climate if all the Sahara was covered with solar panels and wind turbines.The temperature on the Sahara would actually increase on average.rain would also

https://arstechnica.com/science/2018/09/carpeting-sahara-wit...

A fair amount of the phosphorus in the Amazon comes from dust storms originating in the Sahara.

[1] https://www.nasa.gov/content/goddard/nasa-satellite-reveals-...

given that the Sahara is only a couple thousand years old does that mean the amazon is just as young?

An interesting article on how people shaped the Amazon.

https://www.theatlantic.com/science/archive/2017/03/its-now-...

The Amazon is much younger; much of what is jungle today wasn't before the Columbian Exchange.

There is a theory that American reforestation was responsible for the Little Ice Age.

Very good question.

Potentially habitable planets close enough to colonize are rare enough that we can’t afford mistakes either way.

There's a theory that the Sahara alternates between desert and green every X thousand years, dramatically altering the Mediterranean, European, and African climates.

And BTW our species is conducting its largest peaceful "mobilization" ever to deal with this virus; it's actually quite inspiring.

> a theory that the Sahara alternates between desert and green every X thousand years, dramatically altering the Mediterranean, European, and African climates.

This is a funny way to phrase the causation. The state of the Sahara is surely not exogenous -- the transition must be caused by the climate. (It can then contribute further, but why attribute the changes to an intermediary effect?)

fewer dissenting voices to deal with on another planet, for the time being

If you have the industrial capacity to handle metallic lead precipitation and strip away 92 times as much atmosphere as the total on planet Earth, dissenting voices are of less relevance than the contents of your spam folder.

Those are not exclusive options.

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