Category Archives: geo-engineering

Reponse to “Reversing Climate Change Cannot Be Accomplished Via Geoengineering: Researchers”

Since I have made a proposal for geoengineering by building a Planetary Solar Shield this article quickly got my attention.

Geoengineering the climate has been suggested as a way to help lessen the impact of climate change, but new research published in Earth System Dynamics says this approach would not likely succeed.

German researchers say that reducing the amount of sunlight reaching the planet’s surface by geoengineering may not undo climate change.

The team used a simple energy balance analysis to explain how the Earth’s water cycle responds differently to heating by sunlight than it does to warming due to a stronger atmospheric greenhouse effect. They show that this difference implies that reflecting sunlight to reduce temperatures may have unwanted effects on the Earth’s rainfall patterns.

Many geoengineering approaches try to reduce global warming by reducing the amount of sunlight reaching the Earth’s surface. However, when the team applied their results to a geoengineering scenario like this, they found out that simultaneous changes in the water cycle and the atmosphere cannot be compensated for at the same time. This scenario would mean that reflecting sunlight by geoengineering is unlikely to restore the planet’s recent climate.

“It’s like putting a lid on the pot and turning down the heat at the same time,” Kleidon said in a statement. “While in the kitchen you can reduce your energy bill by doing so, in the Earth system this slows down the water cycle with wide-ranging potential consequences,” he says.

I agree that if you try to reduce sunlight for the whole atmosphere by spreading Aerosols you could end up with some undesirable results. We’re already experiencing disturbances in weather patterns because of warming and the melting of the Arctic. My proposal would take longer to implement but the reflecting of sunlight could be more easily controlled. It could be done just by make adjustments to the positioning and angle of the components. As I said in the post, you probably would want to situate the solar shield so that it reflects sunlight hitting one of the polar areas. They heat up much faster and they get more sunlight so the solar shield would have a much larger effect. It would be less like turning down the heat and more like moving pot so that part of it isn’t directly over the heat. You can easily experiment with this. Fill a sauce pan with water. Heat it on the stove (low or medium heat). Use a thermometer to test the temperature. When the temperature reaches the maximum possible move the pan so that about 3rd of the bottom surface area is not directly over the heating source. Wait a few minutes and take more temperature readings. This time take a reading in the center, the side closest to you and the side farthest away. If my hypothesis is correct then the water not directly over the heat source should cool down a bit and probably will reduce the average temperature of all the water a bit (after sometime being situated this way).

Another article suggest that a solar-shade could be beneficial

New research led by Carnegie’s Julia Pongratz examines the potential effects that geoengineering the climate could have on global food production and concludes that sunshade geoengineering would be more likely to improve rather than threaten food security. Their work is published online by Nature Climate Change Jan. 22.

Sometimes you have to increase the complexity of the engineering task and experiment with it in different ways to get the optimal results. I wouldn’t expect that even if the solar shield is built that we’ll return to the same climate of the previous century. By cooling the polar region(s) it might have a stabilizing effect on the weather patterns. I don’t see how anything we might do could result in returning an earlier climate situation in our history.

“It always seems impossible until it is done”
-Nelson Mandela

References

Sunshade Geoengineering More Likely to Improve Global Food Security, Research Suggests

How to build a planetary solar shield

Geoengineering Approaches to Reduce Climate Change Unlikely to Succeed

How to build a planetary solar shield

Rational

The experts warn that if we don’t get carbon dioxide emissions under control and soon we could would face an catastrophic global warming event that could lead to a runaway green house effect. Once carbon dioxide is emitted it can stay in the atmosphere for a thousand years or more. International efforts to create a climate treaty have failed. It takes a lot of convincing to get people to give up the cheap energy source that is in fossil fuels and the wealth that they can generate. All indications are that the world intends to gamble on continuing to increase, not decrease the burning of fossil fuels.

 Planetary scale engineering

 Geoengineering may be the only way that can reduce the effects of increasing green house gases and prevent a runaway green house effect. One idea that has been put forward is solar radiation management. You find some way to reflect solar radiation before it can get to the surface. Some have said that the cheapest way to do this would be to spray large quantities of aerosol particles into the stratosphere in order to reflect sunlight. This might work to manage solar radiation but it could have a lot of other undesirable effects like interacting in unexpected ways with chemistry of the atmosphere. It would be difficult to get international support for this method. Another method for solar management that was put forward is to build a massive solar shield to reflect sunlight into space. So far no one has taken this seriously since the rough estimates of size and cost of such a project seem out of reach.

 Methodology

 The method that I have thought of to build a solar shield should be significantly cheaper and easier to build. The main components of this shield would be satellites and a thin reflective material. What you would do would be to build pairs of satellites. Each one would take a large roll of light-weight, but strong reflective material. This would be attached to a long bar like structure on the satellites. After the satellites reach their desired position they would then pull apart and unroll the reflective material so that it stretches-out between them. You should be able to have each pair covering a large area with this material, maybe a thousand km2 or more. They would also need to be smart enough to always be in a good position to block sunlight but also be able to avoid collisions. Small collisions by asteroids to the reflective material would only result in tearing a hole through it that could be repaired. Large collisions would be detected and avoided. You would want to position them in orbit over a polar region to have the most effect because the polar regions heat up faster and receive more solar radiation. You also wouldn’t want to block sunlight getting to solar energy locations.

 Practicality

Even with this cheap method of building a solar shield it would still have to cover a huge surface area. I have roughly estimated it to be somewhere from 3-5 million km2. At first glance then that makes the task seem impractical because it would require too much material to be launched into space and thus would be cost prohibitive. I believe that this problem could be overcome by gathering materials and fuel from near-earth asteroids and possibly the moon. We should probably use smart robotic craft like those sent on previous missions to asteroids.

 Time to build

 Do we have time? The carbon dioxide we emit today takes about 40 years to turn into future warming. We have currently warmed the planet about 1 degree C and are already seeing some changes to weather patterns and sea level rise. Some experts think that we have until about 2100 before we would get to a highly undesirable 2.5-3.5 C warming. So we have approximately 40-70 years to build the solar shield to manage solar radiation. I think that with enough effort it could be done over a 50 year span of time. Improvements in efficiently building could increase the surface area exponentially.

Environmental Impact

 Since most of the work and materials gathering would be done in space or on the moon, it should have a negligible impact on the Earth’s environment. It would not take the place of reducing carbon dioxide emissions or reducing pollution in general. That is still extremely important to accomplish for many reasons other than warming. What this does is buy more time to reach the desired goal of zero carbon emission by replacing fossil fuels with alternative clean energy sources.

References

IPCC 5th assessment

http://www.ipcc.ch/report/ar5/wg1/

NASA New Imagery of Asteroid Missions

http://www.nasa.gov/content/new-imagery-of-asteroid-mission/#.UpH0dOL3PjM

Asteroid Mining

http://en.wikipedia.org/wiki/Mining_in_space

Geo-engineering

http://en.wikipedia.org/wiki/Geo-engineering

If you use this idea I just ask that you give me some credit for originating it.