Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

REB · 2004-04-08 12:10:19

First of all, has this topic been discussed before, here? I couldn't find a thread on it, but I hate to start a new one if it has.

In my story, "War Against Gravity," set 200 years in our future, the Sahara had been 'terraformed,' into a rainforest. The Gobi and central desert of Australia had also been terraformed.

To do this, orbital lenses evaporated vast amounts of sea water up wind of the deserts. Over time, dense forest grew and locked in water. Also, great aquifers were created.

Orbital lenses may not be practical. Perhaps we could turn vast amounts of sea water into freshwater (Using Solar Power, of course) and pump it to these deserts (using pipes, much like we do for oil). I believe that eventually a large rainforest would lock in water locally so that a wet climate would remain stable without having to pump in more water.

The timeframe I am envisioning is just over a hundred years to get a stable rainforest. (Maybe sooner if it was aggressively pursued)

bolbuyk · 2004-04-08 12:16:00

I think this must be rather easy to obtain. To turn salt water into fresh water different technics exist already. It's possible to evaporate water, to freeze or to put through nanoflters (this I'm not totally sure).

The only point is the energy: Nuclear fusion would work. :laugh:

clark · 2004-04-08 12:26:18

Where are you getting the biomass to grow a rain forest in the desert?

Not very up to date on orbital lenses, but wouldn't the creation of steam (via light from the orbital mirror on the sea water) diminish the power of the beam?

I would also imagine that you would quickly have to try and contain any 'unintended' consquences from changing global weather patterns. If it rains here, it means it might not rain as much there...

What happens to all the little fishy's in the Med?

C M Edwards · 2004-04-08 13:05:30

Why does the seawater have to arrive distilled and ready to go? Why not create a set of large inland saltwater reservoirs to serve as evaporating ponds? The only difficulty would lie in dealing with the excess salt, but if continuous flow could be arranged over a wide enough area, there’s no need to evaporate the brine down to the point where it couldn’t be pumped back out.

RobertDyck · 2004-04-08 14:16:01

I've often thought of terraforming Earth. To start with, how can we warm winters in Winnipeg? It's freeze-your-ass-off cold in December and January, although summers are beautiful. The typical low is -17°C but a couple nights last winter got down to -40ºC. Could we plant a dense forest of genetically engineered trees with black needles, black bark, and natural antifreeze in the sap; say 100 million hectares upwind of Winnipeg? Warmer temperatures would increase evaporation rates, and water escapes from stomata in plant leaves or needles. This would increase winter humidity and precipitation downwind. El Niño causes increased precipitation over North America, which depletes rain clouds causing reduced precipitation on Africa. Would increased evaporation from the Canadian prairie cause increased rainfall on northern Africa?

Africa can do other, simpler things to reduce desertification. Somalia is on the edge of the desert. There are vehicles driving across fields with no regard to roads. This is ripping up plant life, exposing sandy soil to dry out and blow in the wind. This is causing expansion of the desert. Simply building dirt roads with fences on either side to keep vehicles off fields will greatly help. Perhaps deep ditches with steep sides to force vehicles to stay on the road. Restoring farm fields can ensure people in Somalia can grow their own food.

The climate on Earth is changing. The oceans are still warming from the last ice age; this is tripping a point in Pacific Ocean currents that cause cold water from the arctic to follow the ocean floor rather than staying on the surface. That carries nutrients with those currents into the deep ocean at tropical latitudes rather than near the surface, so it starves near-surface ocean fish. It also leaves warm tropical water on the surface, which warm air currents and evaporate more water causing El Niño. This is happening with less time between occurances, and each time lasts longer. Global warming caused by human activity is warming the arctic and melting pack ice, so we are accelerating the processes that cause El Niño.

What I'm trying to say is that terraforming Earth requires taking the entire planet's climate into account. Global warming in the northern hemisphere causes melted arctic pack ice, which causes increased occurrence of El Niño, which causes flash floods in California and drought in Africa. Atmosphere and ocean currents are interconnected, and ocean currents react very slowly.

SBird · 2004-04-08 16:10:30

The difficulty in trying to manipulate even minor climactic changes are why I usually regard terraforming schemes with a great del of skepticism. So far, the sum total of human industrial effort for several hundred years has merely managed to raise average planetary temperatures by 1 degree C. What happens when we start pushing the climate harder is anyone's guess - some climate researchers are even predicting a shift to an ice age. What ever happens, though we have minimal control over the system. The energy fluxes that flow through the Earth's atmosphere are so far beyond what we can generate and mainpulate that we're much better off going with the flow and moving agricultre around than trying to actively fight it.

China has been actively trying to stop desertification for decades now. It's approach has been to plants tens of millions of trees. This has resulted in China being the only nation to have a net increase in forestation in the last 50 years (a 100% increase, last I checked) however even this effort seems to be having mixed success.

MarsDog · 2004-04-12 01:19:24

With human activity recently surpassing geological processes, Earth is being "terra formed". Greenhouses and enclosed
shopping malls create their own micro climate. Spaceship Earth is having the plumbing reworked with river diversion and
artificial lakes. The Bering Straight could be dammed, selectively letting the tide in, but not out, creating a flow of warmth from the Japanese current.
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Maximum Earth population will be within a well regulated, interconnected, greenhouse environment.

REB · 2004-04-12 06:26:21

Several of you mentioned Earth’s climate, and the good or bad of causing change. What we need to learn how to do is to control the Earth’s climate. We need to learn how to control the amount of solar radiation reaches any given point on the Earth, and exactly what effect that will have locally and globally.

This could be done with orbital mirrors, shades and lenses. Imagine being able to cut a hurricanes energy by casting a shadow on it. Or end a drought by evaporating sea water and creating rain clouds.

For long term, stopping any greenhouse threat, or ice age threat. And then there is the greatest threat to the Earth’s climate- the Sun. The Sun is slowly aging. As it gets older, it is predicted to get hotter, and eventually it will make the Earth uninhabitable. Some scientists have predicted this could start in as little as 10,000 years, while other say a million years or more(So we do not know for sure, but the Sun will get hotter as it ages).

Before the human race can take on such a risky and challenging endeavor, we need to have a greater understanding on how our weather and climate works. We are getting better, but we still can not make precise long term predictions of the weather. We’ll need to have a much greater understanding before we tamper with the cliamte. We’ll need to know thinks like, “If I keep Houston, TX at a nice 80 degrees all summer, what kind of long term effect will that have on the global climate and can I counter that effect?”

We could also learn a lot by terraforming Venus and Mars, especially Venus. Venus would be a great place to perfect controlling a global climate from orbit. We could learn a lot from Venus.

I don’t expect humans will be controlling the Earth’s weather and climate any time soon, but one day, a few hundred years from now (built on the foundation of the knowledge and experience gained over the years) humans will be in control of the solar radiation reaching the Earth. The threat of becoming too hot or too cold will be a thing for history.

MarsDog · 2004-04-15 08:06:07

We are affecting global climate.
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Already the polar regions have become warmer,
Cities have become "heat islands"
The deserts will become great greenhouses.
Moving mountains, creating canals, lakes and seas will reduce the air conditioning costs.
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Just think of the Earth as a giant dispersed air conditioning system; the poles have to become a lot warmer to make the equatorial regions more comfortable.

REB · 2004-04-15 09:39:06

Humans have had an effect on the Earth’s climate, but then again, life has always effected the climate. Early life added oxygen to the Earth’s Atmosphere. But Mother Nature has us all beat. She has caused ice ages and warm periods. She has caused the sea level to rise and fall. One thing that has been constant about the Earth’s Climate is that it is always changing. I sometimes wonder if we really have as big of impact as we think.

As our knowledge of the Earth’s climate and weather improve, and as our technology advances, I think the human race will take control of the Earth’s climate and weather. It might come after Mars and Venus is terraformed. Sooner or later, thou, the Sun is going to get uncomfortably warmer (a normal part of its aging) and our descendants will have to do something if they want to keep the Earth habitable.

The key to controlling the Earth’s climate and weather is controlling the amount of solar radiation reaching the Earth. This can be done from orbit, using similar tools needed to terraform Venus. Perhaps some sort of solar shade that can let various amounts of sunlight through, on any given area on it.

For example, one spot on the shade is not letting any light through, to cast a shadow on a hurricane and kill it. Another part it letting 70% light through to cool off an area in a drought. Orbital lenses and mirrors might be helpful as well. An orbital lense could be used to increase water vapor by evaporating ocean water. It could also be used to warm frozen areas and to help grow crops in places like Sibera. Mirrors could also help crops by extending daylight hours over farmland.

MarsDog · 2004-04-16 06:59:55

We are part of Nature, as a Mother and Protector.
Similar reasoning as in "is it genetics or environment ?"
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Megaprojects are becoming more common; changing rivers and lakes. Next may be leveling mountains so that the rain is not blocked, and creating a larger land area in the process.
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Space based efforts could supplement work on Earth's surface, I wonder if a space mirror could be used to melt a whole mountain.

Earthfirst · 2004-04-19 11:05:43

I think that the saharia desert could be made more hossbitable by creating canals to bring in water from the meditearean sea and the atlantic ocean. I know that there are many basins in the sharia, water from these canals would fills these to make many large lakes. The reason why the saharia is a desert is that at it latatide 20 degree to 35 the air from the tropics is decening, and has lost all its mosisture over the rain forest. High pressure make it hot and dry, but you can still get rain. With the new lakes as a water source day time heating would create thunderstorms and rain. To make a big difference in rain fall. The lakes would have to be large, but the basins are large and should become large lakes. There are mountains in the middle of the desert they will create orgraphical leth and Help to make stroms. Rain fall in the region could increase from just few hunderhs of an inch to ten inches and maybe 20 in mountains. It would be like a northern extension of the shael, and a southern extion of the meditream type plants. Much more habital, as a added bounes you get a new fisher in the salt water lakes.
Eype is going to do the same thing by diverting the nile into a large basin, to make a second nile valley, a simialer thing could be done with the nirger river.

clark · 2004-04-19 13:38:36

What you do to the climate is but one portion of the equation. It's the effect and ripple effect of interdependant eco-systems that will cause you the greatest headache. Then comes the food chain...

REB · 2004-04-19 14:29:29

Earthfirst, Flooding parts of the Sahara with the Mediterranean is not a bad idea. It might help lower the total seal level some.

I have thought about pumping seawater into central Antarctica to lower the sea level. Doing so would help increase the total land area of the Earth. For example, here in Texas, during the last couple of Ice Ages, the coast was over 100 miles downriver from where it is today.

MarsDog · 2004-04-20 00:22:32

Maximum result comes from controlling an enclosed environment.
Well developed greenhouse technology is very efficient.
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Reworking the Earth's surface will eventually be done to increase the land area and better distribute water, but the payoff will be more and better greenhouses.
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The same goes for the other planets; large, enclosed ecosystems.

Earthfirst · 2004-04-20 09:17:30

With green houses you can control the envirnoment to some extent, but have you ever been in a green house on a summer day. It is is hot and wet not a fun place to work in but plants like it though they like moderate temps like we do.
You cant have have green houses in the desert with out a water supply, who will take care of the greenhouses if no one lives there. Because in a thousand years the population of the sahara region will still around the rivers as it has been since people first walk the earth. People in temperate wet climates forget with out water their is no society. Being from and arid region I know that no water no people.
My way would make the sahara more plensant from no rain to some. I know in the very dry sahara there is not much of an ecosystem. So by flooding some empyt basins would not be hurting much besides some insects, if any thing we would make it better. I would not turn the sahara into a forest but not make some more rain so that some rivers will flow.

The Fed Man · 2004-04-20 17:15:12

Although canaling water into the Sahara sounds like a good idea I don't think it would be too smart to experiment with orbitting mirrors and to many others things on are home planet. All the more reason to terraform other planets though. To gain experience so that when it is needed Mother Earth could be saved.

SBird · 2004-04-21 00:44:20

The biggest obstacle to using inland seawater to irrigate the Sahara is the size of the holes you'd have to dig. Nothing short of a lake the size of one of the great lakes would suffice. Of course, it wouldn't have to be deep but still, you'd have to use nukes or something to excavate the lakebeds. The current occupants of those areas might have some issues with that plan. :;):

MarsDog · 2004-04-21 14:44:47

A phrase from a Zurbin interview "micro terra forming" described greenhouses on Mars, heating, to produce a denser atmosphere.
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In the Sahara, the greenhouse could be configured to cool. For example lot of mirrors to reflect sunlight. Another concept is a tall chimney type structure reaching the colder air, above, letting it sink below. Also large sea water evaporators could cool the desert, while warming the rainfall areas in other parts of the world.
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It seems that the most control with the least cost is a controlled environment structure. Even without modern technology , the 1851 World's Fair Crystal Palace worked well.

PurduesUSAFguy · 2004-05-06 01:24:03

The biggest obstacle to using inland seawater to irrigate the Sahara is the size of the holes you'd have to dig. Nothing short of a lake the size of one of the great lakes would suffice. Of course, it wouldn't have to be deep but still, you'd have to use nukes or something to excavate the lakebeds. The current occupants of those areas might have some issues with that plan. :;):

Actually a few of my friends who are grad students in the Nuclear Engineering department here talk alot about using fusion explosives for excavation work, they are both doing research on using non-fissile means such as silicon/nitrogen based hyper explosives to obtain ignition from either tritium/deuterium gas mixtures of lithium deuteride solid cores.

SBird · 2004-05-06 10:37:10

Interesting. I know that back in the 60/70's, in a bit of misguided PR, the US military tried to sell their 100 megaton hydrogen fusion bombs as 'humane' nuclear weapons because of the low fallout.

If it weren't for the fallout from the fission portion of nukes, the old 'plowshare' nuclear programs for building things like canals would have been quite useful.

kippy · 2004-05-06 13:09:25

Setting off nukes in the Sahara desert. As if the Arab world didn't hate the west enough.

Regarding the fusion bombs, I was under the impression that the radioactive fallout of modern fusion weapons was negligable. You still need to kick off the fusion with some fission but I thought the total of fallout was like getting an x-ray or something.

REB · 2004-05-06 13:17:18

Too bad we can’t soft-land a large long asteroid across the Sahara. If the right shape, and placed right, it could trap moisture on the upside (Like the Rockies do in Washington State).

As air rose up the side of the new mountain, it would cool and loose its moisture. This moister would rain down forming rivers that would run across the deserts.

Of course, I have no idea how to soft land an asteroid, and if I did, it would be a dangerous thing to try.

What about building a man-made volcanoes? Find a way to punch down to the magma. It would take one heck of a laser and a ton of power to make a hole that deep.

MarsDog · 2004-05-07 13:49:38

The artificial mountain idea to cause precipitation sounds good. I wonder if there is a quicker way to put a large structure to intercept the wind, such as a stadium sized balloon. Moving a lot of rock takes time, and an asteroid impact would set off volcanoes.
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I also like the idea of artificial inland seas, to stabilize the ecosystem.

REB · 2004-05-07 13:56:44

MarsDog, I was thinking of a very soft landing for an asteroid. It would take technology we do not have to do something like that.

Someone needs to invent anti-gravity.

If a powerful enough laser was built, could it punch down through the crust to magma. A chain of man-made volcanoes would do the same thing.

If it is possible to use a powerful laser to create volcanoes, it might be used to create islands.

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#1 2004-04-08 12:10:19

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#2 2004-04-08 12:16:00

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#3 2004-04-08 12:26:18

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#4 2004-04-08 13:05:30

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#5 2004-04-08 14:16:01

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#6 2004-04-08 16:10:30

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#7 2004-04-12 01:19:24

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#8 2004-04-12 06:26:21

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#9 2004-04-15 08:06:07

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#10 2004-04-15 09:39:06

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#11 2004-04-16 06:59:55

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#12 2004-04-19 11:05:43

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#13 2004-04-19 13:38:36

Re: Terraforming the Earthâ€™s great Deserts - Turning the Sahara into a rainforest.

#14 2004-04-19 14:29:29

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#15 2004-04-20 00:22:32

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#16 2004-04-20 09:17:30

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#17 2004-04-20 17:15:12

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#18 2004-04-21 00:44:20

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#19 2004-04-21 14:44:47

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#20 2004-05-06 01:24:03

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#21 2004-05-06 10:37:10

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#22 2004-05-06 13:09:25

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#23 2004-05-06 13:17:18

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#24 2004-05-07 13:49:38

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#25 2004-05-07 13:56:44

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