In the acclaimed film “Kingsman: The Secret Service,” the young hero fights a villain, who, having lost faith in the ability of mankind to make the efforts to curb emissions, and fight global warming, decides to try and kill most of humanity to save the planet and himself. The idea that curbing emissions will not be enough, or will not happen fast enough and other means will be needed is gaining traction. If you are to be a villain and expect to find how to commit global scale killings, stop reading here because this piece is about geoengineering: a new field of climate science, which intends to curb global warming through global scale projects.

The technologies presented here are actually envisioned by some scientists as a way to fight global warming. These projects are assembled into a much larger field now called geoengineering. The main idea is that humanity will not be able to decrease emissions enough and that very large-scale ways of fighting global warming are all or part of the solution.

What are the common points behind these techniques? Their very wide reach. They counteract climate change not through reducing the amount of greenhouse gas emissions but using natural phenomena and enhancing them by human interaction.

There are two broad categories of geoengineering: carbon storage and solar radiation management.

Capturing carbon out of the atmosphere and storing it permanently somewhere has been in the air for quite some time now. A lot of these techniques are currently at the stage of prototyping or early production.

But let us focus on the techniques that could qualify as geoengineering by either their ability to be scaled up easily, or the broad reach of the project. A good illustration of this technology is the use of algae to store carbon. Some companies are already working on storing carbon by cultivating fast growing algae. A geoengineering technique using the same base idea is called ocean fertilizing.

Sometimes there are some seemingly spontaneous peaks of algae population in the ocean, usually so big that the ocean takes a slightly different tint that can be seen from space. The factor limiting the occurrence of such phenomena is usually the amount of iron in the water. So, some scientists had the idea to drop iron in the ocean in order to spur the growth of the algae, and increase the carbon storage potential of the oceans.

Another process, that uses the same approach to speed up the natural carbon storage process is weathering. Through its history, Earth naturally regulated the CO2 amounts in the atmosphere by a process called weathering. When it rains a part of the atmospheric CO2 is diluted in the rain and when the rain comes in contact with certain minerals, a reaction takes place whereby the CO2 is permanently stored in the mineral.

The main problem of this process, in the fight against manmade emissions, is that it is very slow. But some scientists had ideas for speeding up the process: by breaking up the rocks, they increased the available surface area for the reaction to happen, and by putting those rocks in naturally CO2 rich waters, the amounts of CO2 captured could be greatly increased. The applications are vast by putting them on the coast, rivers, even in fields.

In Solar radiation management (SRM) the idea is to counteract the effects of greenhouse gases by decreasing the amount of solar radiation that the earth receives. It is actually an old idea used in many Maghreb countries, where in traditional medinas, all the buildings were painted in white. This idea, that clearer colours of materials reflect more of the energy and tend to stay colder is regaining traction. Recently, Los Angeles made the headlines, by painting all the streets of a few block in white to decrease the temperature of the city that suffers a lot from the urban heat island phenomenon.

A wide scale unintended proof of the efficiency of this phenomenon is in Almeria, Spain, where most of the land is covered in greenhouses that reflect much more of the energy than the land. As a consequence the average temperature decreased by 1.2 C°.

Many technologies use different variants of this wide principle. Some proposed to genetically engineer whiter crop varieties, which would make the whole cultivated land surfaces part of the process. Other techniques play with the idea, such as spraying clouds with salted water so they become whiter, thus diminishing the amount of solar radiation reaching the ground.

But the most promising technology of all is sulphur dioxide. The idea is to use balloons that would spray a thin layer of sulphur dioxide in the stratosphere, therefore reflecting the solar radiation back into space, even before it reaches the lower layer of the atmosphere. This technology is the most mature one since it is readily available. The effects on global warming are pretty certain and the cost is reasonable.

Some of the technologies exposed here are mature and economical enough to be commissioned by one country, and have a very significant impact on global climate. The second part of our little 2040 fiction makes the challenges ahead in terms of ethics huge. The one causing the most ethical problems is the sulphur dioxide technology, which is able to be commissioned today at a price bearable for a state, but would have global averted effect. The problem with many of these aforementioned technologies are that their side effects are not well understood, and we could make mistakes that would have long term consequences.

Let us focus on the possible consequences of the sulphur dioxide seeding as it is currently the most likely to be implemented, but also the one raising the most issues. The problem is that the effects of climate change could be mitigated by such technology at a price lower than the cost of reducing drastically the level of CO2 emissions.

The second problem is how to deal with the negative externalities that would be bear by some, while implemented by others. If it was implemented, climate scientists expect that the monsoon cycle would be significantly affected, and the sub-Saharan Africa would face terrible drought. However, a question arises: are dire prospects faced by some countries due to climate change legitimate to trigger geoengineering project that could be detrimental to other nations?

Another substantial problem is the fact that such solar radiation does not solve all of the issues raised by ever-increasing CO2 levels in the atmosphere, such as ocean acidification. The ocean is the main CO2 sinkhole, but as the CO2 dissolves, it is increasing the acidity of the ocean, that could lead to dramatic loss of biodiversity. By acting on the temperature problem alone, the SRM solutions are not addressing the other problems that comes with anthropogenic CO2 emissions.

The other main issue is the fact that such programs should be maintained and expanded, as the CO2 levels would continue to increase in order to keep earth temperature balanced. Once the technology is implemented, humanity would have to ensure that the sulphur shield is maintained to keep the temperature at reasonable levels. If these programs suddenly stopped, the global warming would resume at a much faster pace as the CO2 levels would be much higher than what they currently are, and the status quo would have been only artificially maintained by the program.

With risks that are not so well understood, these projects are still in test phase and some countries are actually thinking of banning them. The London convention on marine pollution banned ocean fertilization in 2008 by classifying it as pollution. These technologies might ensure, that global warming stays contained while our societies transition to a greener organisation, but the power of them might lure some into thinking that is actually dispensing us to go green. Can we trust ourselves on this one?

by Arthur Hill


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