Fast, cheap, dangerous. Scientists propose to cool the Earth with aerosols

There are other ideas – a cosmic mirror, the creation of shiny marine clouds, the protection of aerosols in the stratosphere. All of these projects are still on paper or at laboratory stage, but it is possible that adverse climate change scenarios by the end of the century will be applied to them.

Volcanoes have shown an example

The special report of the Intergovernmental Panel on Climate Change (IPCC), which predicts that the atmosphere will warm up to a degree and a half by the end of the century , and the climate negotiations held in November in Katowice (Poland) under the auspices of the UN have sparked interest in the subject of global warming. In the media, there was news on geo-engineering projects to reduce the temperature. But these methods are far from new, are at the stage of calculations and are generally lacking in funding.

Solar heat enters the earth's atmosphere and warms the surface. In turn, the planet releases heat towards the outside and most of it goes into space. The rest is retained by the greenhouse gases contained in the atmosphere: water vapor, carbon dioxide, methane, ozone, nitrogen oxide. Thanks to this mechanism on the planet is relatively hot and life is possible in its current form.

In the 1960s, scientists noticed that CO, one of the potent greenhouse gases, was developing in the atmosphere. They have badumed that its excess comes from the burning of fossil fuels and if we continue to do so, the global temperature will increase and the climate will change. The pioneer of this research was the Soviet scientist Mikhail Budyko. He also expressed the ideas of the technical impact on the climate in order to cool it down. In the 2000s, his concept was developed by academician Yuri Israel.

Experts also know that, following strong volcanic eruptions, there is a cooling that lasts a year or two. This is because a large amount of mineral particles reflecting solar radiation is emitted into the atmosphere in the form of ash and gas.

What if you specifically spray a reflective aerosol into the stratosphere? Thus, the atmosphere and the surface will be less heated. Sulphates and calcium carbonate are suggested as active substances.

Balloon towards the stratosphere

Solar control projects have a lot of difficulties: it's not clear exactly how the aerosol will behave in the stratosphere, what the effect will be, how the spray will come out, what will happen to the ozone layer, or how put the aerosol in it.

Scientists from Harvard University (USA) under the direction of Frank Kech and David Keith propose to launch a balloon at a height of 20 kilometers. First, for purely scientific purposes, they plan to spray ice to test the performance of the tools, and then inject about one kilogram of calcium carbonate to create a long turbulence zone. A kilometer and a hundred meters wide and see what will happen next.

The sensors in the nacelle of a balloon that goes down through the created cloud record the physical and chemical parameters of the environment.

The Harvard experiment called SCoPEx has only been available on paper so far, the date of the experiment is unknown.

According to calculations, if the experiment succeeds, it will be necessary to spray about one-tenth of a megaton of aerosol (most likely sulfur oxide) a year, gradually increasing the volumes to reduce the rate of warming or get a cooling effect on the climate.

Scientists have suggested spraying the aerosol at latitudes 15 and 30, south and north of the equator. To deliver a substance at a higher altitude, you will need to build a new plane. Hypothetically, work can begin as early as 2033.

Extreme remedy

Scientists also suggest improving the brightness of clouds so they better reflect the heat of the sun; reduce the thickness of the cirrus at high altitude so that they allow more heat to re-emit through the surface. This does not seem to be a fiction at all and the idea of ​​creating a mirror in Earth's orbit that would reflect some of the sun's rays, although the development of this technology takes more than a century.

The aerosol spraying project is still the most developed, and the scientific community sometimes supports it. In 2006, the Dutchman Paul Krutzen, who studied ozone holes and won the Nobel Prize in Chemistry, pointed out that the reduction of industrial sulfur emissions into the atmosphere was causing an increase in the amount of sulfur in the atmosphere. greenhouse effect. The complete purification of the air from harmful substances, although beneficial for human health, contributes to the warming.

It is possible to eliminate the contradiction by creating an artificial aerosol screen in the stratosphere, while continuing to fight the polluting emissions of the lower layer of the atmosphere.

There is a persistent bias against any geoengineering project in the scientific community. It is enough to recall the disaster of the Aral Sea, which became shallow after intensive water abstraction for irrigation of the fields.

Many scientists believe that geoengineering projects related to the management of solar radiation, even if they can be implemented and are inexpensive, are dangerous and that their consequences are unpredictable.

And most importantly, they do not solve the essential task of eliminating excess greenhouse gases in the atmosphere.

In addition, it is impossible to guarantee their continued operation and if, for example, artificial aerosol protection suddenly disappears (for whatever reason), this can lead to a dramatic warming of the climate.

At the same time, it is not necessary to abandon this idea – it may be useful as a last resort if the most negative predictions about climate change come true.