From planting long forests in a continent to causing precipitation, researchers have begun to offer, test, and in some cases implement large scale geoengineering projects to radically transform the planet. These projects are designed to address problems such as desertification, drought or excess carbon dioxide in the atmosphere, all with the ultimate goal of combating climate change.
A recent report by the US Global Change Research Program and 13 other federal agencies describes the impact of uncontrolled climate change, such as the US economy's cost of hundreds of billions of dollars a year due to the increased incidence of extreme weather events and crop yields, among others. This has created a new impetus for radical solutions, but some have faced significant opposition as well as geoengineering in general.
Opponents argue that people do not sufficiently understand the complexity of global, natural cycles, and the mess with them can cause more problems than it does.
Large green walls
One of the types of projects that are already taking place in more than one place is the construction of green walls on large stretches of the planet. They are made of local vegetation and are planted on the edge of the deserts to stop the desertification of the surrounding area. This means that the land on the edge of the deserts is already prone to drought and overwhelmed by the communities living there, creating a vicious circle and leaving residents struggling to survive. Green walls and supportive efforts are aimed at rejuvenating the earth, making large areas of the planet more suitable for living.
The two largest walls are the China-based 3-D Forest Program, which is 4500 kilometers in length and aims to stop the spread of the Gobi Desert and the Great Green Wall of Africa, which is 8,000 kilometers long to reduce Sahara.
Wall success depends on tracking long-term changes to vegetation patterns, and for this purpose, researchers depend on satellite imagery and algorithms known as enhanced visual interpretation to analyze images. Earth Collecting, a joint effort between Google and the United Nations Food and Agriculture Organization, has created an open source interface that allows researchers to access all of this data.
Last year Harvard scientists conducted a test that involved sending traces of aerosol – not enough to have any significant effect – in the stratosphere on Earth, about 20 km. Aerosols contain compounds such as sulphate that can reflect incoming sunlight and reduce global temperatures.
A document published in 2017 in the magazine Atmospheric chemistry and physics argues that the injection of aerosol into the atmosphere essentially resembles ash ash from a volcanic eruption. Also, as ash ash, once injected into the lower stratosphere, the aerosol will rapidly spread, thus affecting large areas of the planet.
Researchers are also looking to launch a giant umbrella in space to manage the amount of solar radiation impacting the Earth. This idea has existed for decades, but has recently gained momentum.
For example, paper from 2018 by Journal of Aerospace Technology and Governance describes the launch of what the authors call HSS, or the Huge Space Shield. The plan is to put a thin, wide sheet of carbon fiber at the point of Lagrange, which is a relatively stable point in the complex system of gravitational pulls between the Earth, the Moon and the Sun. The sheet will block only a small part of solar radiation, but it may be enough to reduce global temperatures below the 1.5 degree Celsius limit set by the International Climate Change Group.
Others want to block the sun by stimulating the formation of clouds, a process known as seeding the clouds. For rain to fall, moisture in the air has to condense, which means that it needs the temperature to fall and something to condense around it – an interesting concept called nucleation. Naturally, water drops are formed around dust particles, pollen, sea salt and even bacteria, but scientists have confirmed that compounds such as silver iodide or dry ice can work just as well. The plan is to inject these atmospheres into areas prone to drought, thus increasing cloudiness and rainfall.
Removing CO2 from the atmosphere
Direct air capture (DAC) includes a cocktail of chemicals that bind to CO2 but are inert to other gases. As the air passes through DAC machines, also known as artificial trees, CO2 sticks to chemicals and releases when excited by energy, allowing it to be caught, stored and recycled or reused. A Swiss company called Climeworks has built the only commercial installation designed to capture and resell CO2. Their goal is to attract one percent of global CO2 emissions by 2025.
Removing CO2 from the atmosphere can also be achieved by seeding the oceans, which are one of the planet's main carbon sinks responsible for removing about 30% of CO2. The first two ways to do this are with iron and lime. Iron fertilization aims to stimulate the growth of phytoplankton, which sucks CO2 from the atmosphere and helps to postpone the seabed.
In a Korean article published in 2018, the authors have examined the last 25 years of ironing experiments, concluding that this may be an acceptable solution, although they recognize that much more testing is needed. Adding lime will cause a reaction with already dissolved CO2 in the ocean and convert it into bicarbonate ions, thus reducing the acidity of the oceans and making them susceptible to more CO2 absorption.
Is Cure Worse Than the Disease?
While these ideas seem promising, there are a number of potentially harmful effects. In 2008, 191 countries approved a UN ban on fertilizing the ocean with fears of unknown side effects, such as changing the food chain or creating low-oxygen regions. The Rhode Island state lawmaker adopted the Geodesy Act of 2017, which states that "geoengineering covers many technologies and methods involving dangerous activities that can harm the human health and safety, the environment and the economy of the state of Rhode Island ".
Despite the opposition, some companies lobby governments to revise geoengineering plans, and scientists continue to develop and experiment with new ideas. But some of the supposed benefits of these plans are questioned. Document recently published in nature argues that reducing the amount of solar radiation impacting the earth's surface will do little to stop the harmful effects of climate change on crops.
The point is, of course, do we really know enough to engage in geoengineering? What will happen if large-scale cloud sowing, for example, alters the jet and slows down the monsoon season in Southeast Asia? What would this do for rice crops? Or what if the discarding of tons of iron in the ocean destroys the fish population along the coast of Chile?
Nobody knows for sure what impact these geoengineering projects can have – but it is also possible that they are the solutions we were looking for.
Image Credit: FoxPix1 / Shutterstock.com