DIY on a planetary scale

From the planting of forests on a continental scale to the artificial induction of precipitation, scientists have begun to propose, test, and in some cases implement large-scale geoengineering projects to radically transform the planet (1). These projects are designed to solve global problems such as desertification, drought or excess carbon dioxide in the atmosphere, but are very problematic in themselves.

The latest fantastic idea to reverse the effects of global warming repels our planet to an orbit farther from the Sun. In the recently released Chinese science fiction film The Wandering Earth, humanity changes the Earth's orbit with huge thrusters to avoid expansion (2).

Is something similar possible? Experts were engaged in calculations, the results of which are somewhat alarming. If, for example, SpaceX Falcon Heavy rocket engines were used, it would take 300 billion full-power "launches" to get the Earth into Martian orbit, while most of the Earth's matter would be used for construction and power. This is. Slightly more efficient would be an ion engine placed in orbit around the Earth and somehow attached to the planet - it would supposedly use 13% of the Earth's mass to transfer the remaining 87% to a further orbit. So maybe? It would have to be almost twenty times the diameter of the Earth, and the journey to Martian orbit would still take ... a billion years.

2. Frame from the film "The Wandering Earth"

Therefore, it seems that the project of "pushing" the Earth into a colder orbit should be postponed indefinitely in the future. Instead, one of the projects already under way in more than one location, construction of green barriers on large surfaces of the planet. They consist of native vegetation and are planted on the fringes of deserts to stop further desertification. The two largest walls are known by their English name in China, which, for 4500 km, is trying to contain the spread of the Gobi Desert, and great green wall in Africa (3), up to 8 km on the border of the Sahara.

3. Containment of the Sahara in Africa

However, even the most optimistic estimates show that we will need at least one billion hectares of additional forests to contain the effects of global warming by neutralizing the required amount of CO2. This is an area the size of Canada.

According to scientists from the Potsdam Institute for Climatic Research, tree planting also has a limited impact on the climate and raises uncertainty about whether it is effective at all. Geoengineering enthusiasts are looking for more radical ways.

Blocking the sun with gray

Technique proposed many years ago spraying of sour compounds into the atmosphere, also known as SRM (solar radiation management) is a reproduction of the conditions that occur during large volcanic eruptions that release these substances into the stratosphere (4). This contributes, among other things, to the formation of clouds and the reduction of solar radiation reaching the Earth's surface. Scientists have proven, for example, that he is great Pinatubo in the Philippines, it led in 1991 to a worldwide temperature drop of about 0,5°C over at least two years.

4. Effect of sulfur aerosols

In fact, our industry, which has been emitting huge amounts of sulfur dioxide as a pollutant for decades, has long contributed to reducing sunlight transmission. it is estimated that these pollutants in the heat balance provide about 0,4 watts of "lightening" for the Earth per square meter. However, the pollution we produce with carbon dioxide and sulfuric acid is not permanent.

These substances do not rise into the stratosphere, where they could form a permanent anti-solar film. The researchers estimate that in order to balance the effect of concentration in the Earth's atmosphere, at least 5 million tons or more would have to be pumped into the stratosphere.₂ and other substances. Proponents of this method, such as Justin McClellan of Aurora Flight Sciences in Massachusetts, estimate that the cost of such an operation would be about $10 billion a year - a considerable amount, but not enough to destroy humanity forever.

Unfortunately, the sulfur method has another drawback. Cooling works well in warmer regions. In the region of the poles - almost none. So, as you might guess, the process of melting ice and rising sea levels cannot be stopped in this way, and the issue of losses from flooding of low-lying coastal areas will remain a real threat.

Recently, scientists from Harvard conducted an experiment to introduce aerosol trails at an altitude of about 20 km - insufficient to have a significant impact on the Earth's stratosphere. They (SCoPEx) were carried out with a balloon. The aerosol contained w.i. sulfates, which create haze that reflects sunlight. This is one of many limited-scale geoengineering projects that are being carried out on our planet in surprising numbers.

Space umbrellas and the increase in the Earth's albedo

Among other projects of this type, the idea attracts attention giant umbrella launch into outer space. This would limit the amount of solar radiation reaching Earth. This idea has been around for decades, but is now in the creative development stage.

An article published in 2018 in the journal Aerospace Technology and Management describes the project, which the authors name. In accordance with it, it is planned to place a thin wide carbon fiber ribbon at the Lagrange point, which is a relatively stable point in the complex system of gravitational interactions between the Earth, the Moon and the Sun. The leaf blocks out only a small portion of solar radiation, but that could be enough to bring global temperatures below the 1,5°C limit set by the International Climate Panel.

They present a somewhat similar idea large space mirrors. They were proposed early in the 1st by astrophysicist Lowell Wood of the Lawrence Livermore National Laboratory in California. For the concept to be effective, the reflection must fall on at least 1,6% of sunlight, and the mirrors must have an area of ​​XNUMX million km².².

Others want to block the sun by stimulating and therefore applying a process known as cloud seeding. "Seeds" are needed to generate drops. Naturally, water droplets form around dust particles, pollen, sea salt, and even bacteria. It is known that chemicals such as silver iodide or dry ice can also be used for this. This can happen with those already known and used methods. brightening and whitening clouds, proposed by physicist John Latham in 1990. The Sea Cloud Lightning Project at the University of Washington in Seattle proposes to achieve a bleaching effect by spraying sea water onto clouds over the ocean.

Other notable proposals increase in the Earth's albedo (that is, the ratio of reflected radiation to incident radiation) are also applicable to painting houses white, planting bright plants, and perhaps even laying reflective sheets in the desert.

We recently described absorption techniques that are part of the geoengineering arsenal at MT. They are generally not global in scope, although if their number increases, the consequences can be global. However, searches are underway for methods deserving the name of geoengineering. CO removal₂ from the atmosphere may, according to some, pass through seeding the oceanswhich, after all, are one of the main carbon sinks on our planet, responsible for reducing approximately 30% of CO₂. The idea is to improve their efficiency.

The two most important ways are to fertilize the seas with iron and calcium. This stimulates the growth of phytoplankton, which sucks carbon dioxide out of the atmosphere and helps to deposit it on the bottom. The addition of calcium compounds will cause a reaction with CO.₂ already dissolved in the ocean and the formation of bicarbonate ions, thereby reducing the acidity of the oceans and making them receptive to absorbing more CO₂.

Ideas from Exxon Stables

The biggest sponsors of geoengineering research are The Heartland Institute, Hoover Institution, and American Enterprise Institute, all of which work for the oil and gas industry. Therefore, geoengineering concepts are often criticized by carbon reduction advocates who, in their opinion, divert attention from the essence of the problem. Besides application of geoengineering without reducing emissions makes humanity dependent on these methods without solving the real problem.

Oil company ExxonMobil has been known for its bold global projects since the 90s. In addition to fertilizing the oceans with iron and building $10 trillion solar protection in space, she also proposed bleaching the ocean surface by applying bright layers, foam, floating platforms, or other "reflections" to the water surface. Another option was to tow Arctic icebergs to lower latitudes so that the whiteness of the ice would reflect the sun's rays. Of course, the danger of a colossal increase in ocean pollution was immediately noted, not to mention the huge costs.

Exxon experts have also proposed using large pumps to move water from beneath the Antarctic sea ice and then spray it into the atmosphere to be deposited as snow or ice particles on the East Antarctic ice sheet. Supporters claimed that if three trillion tons per year were pumped in this way, then there would be 0,3 meters more snow on the ice sheet, however, due to the huge energy costs, this project was no longer mentioned.

Another idea from Exxon stables is thin-film helium-filled aluminum balloons in the stratosphere, placed up to 100 km above the Earth's surface to scatter sunlight. It has also been proposed to speed up the circulation of water in the world's oceans by regulating the salinity of some key regions, such as the North Atlantic. In order for the waters to become more saline, it was considered, among other things, the preservation of the Greenland ice sheet, which would prevent its rapid melting. However, the side effect of the cooling of the North Atlantic would be to cool Europe, making it harder for humans to survive. A trifle.

Data provided Geoengineering Monitor - a joint project of Biofuelwatch, ETC Group and Heinrich Boell Foundation - shows that quite a lot of geoengineering projects have been implemented around the world (5). The map shows active, completed and abandoned. It appears that there is still no coordinated international management of this activity. So it's not strictly global geoengineering. More like hardware.

5. Map of geoengineering projects according to the site map.geoengineeringmonitor.org

Most of the projects, more than 190, have already been implemented. carbon sequestration, i.e. carbon capture and storage (CCS), and about 80 – carbon capture, use and storage (, KUSS). There have been 35 ocean fertilization projects and over 20 stratospheric aerosol injection (SAI) projects. In the Geoengineering Monitor list, we also find some cloud-related activities. The largest number of projects was created for weather modification. The data shows that there were 222 events associated with an increase in precipitation and 71 events associated with a decrease in precipitation.

Scholars continue to argue

All the time, the enthusiasm of the initiators of the development of climatic, atmospheric and oceanic phenomena on a global scale raises questions: do we really know enough to devote ourselves to geoengineering without fear? What if, for example, large-scale cloud seeding changes the flow of water and delays the rainy season in Southeast Asia? What about rice crops? What if, for example, dumping tons of iron into the ocean wipes out the fish population along the coast of Chile?

in the ocean, first implemented off the coast of British Columbia in North America in 2012, quickly backfired with massive algal blooms. Earlier in 2008, 191 UN countries approved a ban on ocean fertilization for fear of unknown side effects, possible modifications to the food chain, or the creation of areas of low oxygen in water bodies. In October 2018, over a hundred NGOs denounced geoengineering as "dangerous, unnecessary and unfair".

As is the case with medical treatment and many drugs, geoengineering provokes side effectswhich, in turn, will require separate measures to prevent them. As Brad Plumer pointed out in The Washington Post, once geoengineering projects have started, they are hard to stop. When, for example, we stop spraying reflective particles into the atmosphere, the Earth will begin to heat up very quickly. And sudden ones are much worse than slow ones.

A recent study published in the Journal of Geosciences makes this clear. Its authors used eleven climate models for the first time to predict what might happen if the world applied solar geoengineering to offset the one percent increase in global carbon dioxide emissions annually. The good news is that the model can stabilize global temperatures, but it looks like if geoengineering were to stop once that was achieved, there would be catastrophic temperature spikes.

Experts also fear that the most popular geoengineering project - pumping sulfur dioxide into the atmosphere - could endanger some regions. Supporters of such actions oppose. A study published in the journal Nature Climate Change in March 2019 reassures that the negative effects of such projects will be very limited. Co-author of the study, prof. Harvard's David Keith, an engineering and public policy scholar, says scientists shouldn't just touch geoengineering, especially solar.

- - He said. -

Keith's paper has already been criticized by those who fear that scientists are overestimating existing technologies and that their optimism about geoengineering methods could discourage society from making efforts to reduce greenhouse gas emissions.

There are many studies showing how frustrating the application of geoengineering can be. In 1991, 20 megatons of sulfur dioxide were released into the high atmosphere, and the entire planet was covered with a layer of sulfate, reflecting a large amount of visible light. The earth has cooled by about half a degree Celsius. But after a few years, the sulfates fell out of the atmosphere, and climate change returned to its old, unsettling pattern.

Interestingly, in the subdued, cooler post-Pinatubo world, the plants seemed to do well. Especially the forests. One study found that on sunny days in 1992, photosynthesis in a Massachusetts forest increased by 23% compared to before the eruption. This confirmed the hypothesis that geoengineering does not threaten agriculture. However, more detailed studies showed that after the volcanic eruption, global corn crops fell by 9,3%, and wheat, soybeans and rice by 4,8%.

And this should cool the supporters of the global cooling of the globe.