Solar geoengineering: how to change the climate with the help of mirrors in space and artificial volcanic eruptions

In fact, there is progress, but it seems not enough: now most scientists agree that

Climate change is real and happening quickly.Over the last century, the Earth's surface temperature has increased by almost 1°C and, according to the IPCC (Intergovernmental Panel on Climate Change - Hi-Tech), by 2100 it will rise by another 0.3–1.7°C (with a significant reduction emissions) or 2.6–4.8°C (with increasing emissions). The worst news: Earth is not under threat. The planet will continue to exist no matter what we do to it. All life, which is definitely not yet adapted to a different climate, is under threat.

This is why some scientists talk aboutthe need for more decisive action to stop the planetary catastrophe. Geoengineering is among them. More and more researchers are talking about the need to “edit” the temperature on Earth.

Melting Antarctic glaciers is slowing down the processglobal warming. As a result of their disappearance, a critical increase in the temperature of the Earth’s atmosphere by 2°C will occur not in 2053, as previously thought, but in 2065.

Geoengineering or "Earth Engineering" - trendya term for large-scale interventions in the work of the planet to slow down or reverse the effects of climate change. Theoretically, the term “geoengineering” can be used to describe any large-scale problem solving scheme. For example, if millions of people plant on a tree, this will reduce the amount of carbon dioxide — this can also be called geo-engineering. If everyone switched to using recycled paper at the same time, this could be called geo-engineering, since we will reduce the number of trees cut down. This also fits the massive construction of wind turbines.

But more often we mean unusual projects,who are trying to restore the balance of the Earth’s climate by direct, large-scale anthropogenic impact on the land, oceans or the planet’s atmosphere. One of the main directions of work of scientists is an attempt to cool the planet by reducing the amount of incoming solar energy. In English, this is called Solar radiation management (SRM).

Decrease in solar radiation

If the problem is that the planet gets tooa lot of solar radiation, is it possible to solve it by blocking part of the world, as farmers do - covering greenhouses with curtains or whitewash? Scientists believe that yes, and are trying to save us from the "extra" rays in completely different ways.

One of them is based on the fact that largevolcanic eruptions lead not only to new spectacular photos in the banks of files, but also to reduce the transparency of the atmosphere around. Destruction reduces incoming solar radiation by emitting sulfur dioxide. Once in the atmosphere, it reacts with water vapor, forming drops of sulfuric acid, the clouds from which scatter the sunlight back.

Can people deal with climate change,trying to artificially do something like that? To do this, you do not need to design a volcano - just “pump” sulfur dioxide into the atmosphere. One of the first to do this was proposed by the Soviet climatologist Mikhail Budyko. The American Earth explorer and oceanographer Wallace Broker took on this idea in the 1980s when he offered to hire a fleet of 700 Jumbo Jets jets to release about the same amount of sulfur dioxide per year as the Mount Pinatubo explosion.

It can cost tens of billions of dollars. Ken Caldeira from the Carnegie Institution's Global Ecology Department at Stanford University counted the numbers and suggested adding enough sulfur to the atmosphere "using one fire hose suspended from balloons" for relatively modest costs of $ 100 million a year. But he points out that the risk of other problems, such as massive air pollution or destruction of the ozone layer, is great.

Volcanic eruptions can stop the rise in Earth's surface temperature by releasing sulfur dioxide into the atmosphere.

On the other hand, there are studieswho say that the method can be safe. However, even at the same time, it is too early to deploy the mission, scientists say - the technique needs to be studied in more detail. “We cannot now say whether it is worthwhile, if global warming continues, to decide whether to start spraying the substance into the stratosphere,” said Alan Robock, a professor of geophysics and a researcher at Rutgers University in New Jersey. "We have to answer this question, but we have too little data." At the same time, practical studies of this method are already being conducted - scientists from Harvard in the first half of 2019 will launch a controlled balloon 20 kilometers above the south-west of the United States. They will spray a small amount of calcium carbonate in portions of 100 grams and will observe how they dissipate and affect the atmosphere.

Calcium carbonate is different from sulfur dioxide,emitted by the volcano Pinatubo. As noted by Josef Tollefson, one of the team members, an eruption would also hasten the depletion of the ozone layer. Researchers hope that calcium carbonate will have less impact on ozone. But since it does not naturally exist in the stratosphere, the effect of calcium carbonate is more difficult to track without an experiment.

Mirrors in space

Suppose substances can be dangerous forthe atmosphere of the planet, but scientists can do without them - why not build a mirror that will reflect the sun's rays? At the same time, even preliminary calculations are fantastic - to change the temperature on Earth, you will need a mirror the size of Greenland (there are options for which they will use several smaller mirrors). It would seem to be madness, but in 2001 this option was offered to the US government and they continue to consider it as one of the ways to maintain a normal temperature on Earth.

Roger Angel from the University of Arizona suggesteduse about a trillion ultra-thin mirrors about 60 cm thick to create an artificial cosmic cloud, whose width is about twice the width of the Earth. A rough cost estimate assumes that the plan will be too expensive - from hundreds of billions to hundreds of trillions of dollars. On the other hand, if humanity is really under threat, it is unlikely that anyone will count the number of zeros in this figure.

Sowing the clouds

The clouds naturally reflect the sun.the light is back to space, so why not just try to increase Earth’s cloud cover? Since the 1940s, several decades after the invention of the aircraft, there have been many attempts to create so-called "cloud" experiments.


They, for example, can be modified - sprayed intoseawater atmosphere and increase the reflectivity of the clouds. Or additional condensation nuclei created by spraying will change the size distribution of the droplets in the clouds, making them whiter. At the same time, according to scientists, this method will be able to maintain a normal temperature on Earth, even if the amount of CO2 doubles.

Cold roof and reflective plates

Legislation of some countries - for example, the USA,encourages painting roofing materials in white or pale to reflect solar radiation, but the 2009 Royal Society report says that this method will cover only 1% of the Earth and will be ineffective. Several more projects were added to the “unrealistic” section: located in large areas - for example, the Sahara desert, sheets that reflect the rays, but their effect will be too localized and will not help wrap glacier melting, or plant more trees or crops that more reflect solar shine.


As the Royal Society concluded in its2009 report: “Geo-engineering methods do not replace climate change mitigation and should be considered only as part of a wider package of solutions to the problem” - to put it simply, experts believe that geo-engineering will most likely not be able to help us.

There are those who are more radical -Experts from the German Climate Analytics Research Center called for a global ban on solar geo-engineering. According to scientists, the Earth's climate can be seriously affected by the cooling of the atmosphere, and the attention paid to this method distracts the attention of mankind.

According to experts of Climate Analytics, SRMcan mask more important problems that need to be addressed - reducing carbon emissions, moving from fossil fuels to renewable ones. Researchers worry that even if the methods described above work, we will effectively replace one problem with another. In their opinion, many are reassured by the idea that geoengineering slightly “corrects” the Earth’s climate and will save the world from a catastrophe relatively quickly, inexpensively and painlessly and resolutely refute such a thesis.

Almost all participants in the process are confident thatin order to understand how realistic these plans are, further research is needed. A 2015 National Research Council report on various sunlight blocking technologies concluded that they “will not require major technological innovations” but not “can eliminate damage to the Earth as a result of climate change.” In any case, it is necessary to reduce emissions, to switch to green energy too, otherwise their promises will look “irrational and irresponsible,” they summarize.