Cooling the Earth: Is Solar Radiation a Viable Climate Change Solution?

Climate Change is a big threat to mankind and the world. We have to come up with solutions urgently. While reducing greenhouse gas emissions remains the primary strategy, scientists are looking into other approaches like solar radiation management(SRM).

According to the 2022 IPCC report, titled “Climate Change 2022:Impacts, Adaptation, and Vulnerability”, human influence on climate change is undeniable and reports have confirmed that human activities are the main cause of the observed global warming which has resulted in changes in the climate patterns and extreme weather conditions like drought and floods. The report also highlighted the most vulnerable populations and ecosystems are disproportionately affected by climate extremes with irreversible damage.

According to past reports and research, carbon dioxide, a greenhouse gas, has continued to be emitted by burning fossil fuels and rising industrialization. The report emphasizes reducing global warming to 1.5℃ above pre-industrial levels to achieve a sustainable future. To achieve this ambitious goal of a 1.5℃ limit, global emissions should be at net 0%, renewables should provide 85% of electricity, coal use should be at 0% by 2050 and carbon dioxide ought to be minimized by 45% by the year 2030 while 7 million Square meters of land ought to be used for energy crops.

Also, the report mentions that there are feasible solutions to reduce climate risks with limitations. This is an ambitious goal that needs much commitment to achieve. We are currently above the 1.5℃ on a track to exceed 3 degrees more heat levels yet we have less than 5 years to 2030. This leads to extreme weather conditions including heat waves, drought, and floods. The Carbon dioxide level has also risen by 15% since 1994 increasing global warming.

Due to these extreme effects, scientists have tried coming up with a solution. On June 15th in the year 1991, North West Philippines witnessed Pinatubo Volcano, the 2nd largest eruption emitting gases miles towards the stratosphere. Although the volcano led to severe destruction of property and lives it had surprising side effects: temporary global cooling.

This phenomenon sparked the exploration of SRM, which is particularly injecting Sulfur Oxide particles into the stratosphere. These particles reflect sunlight into space mimicking the effect of volcanic ash and lowering temperatures. All these take place in the atmosphere’s stratosphere which is located 15–50km from the earth’s surface above most clouds. This is the same place where the ozone layer is located. It has no vertical motion and no precipitation, therefore, when Sulfur oxide is emitted, it will stay there for a very long time. The Sulfur Oxide emitted combines with the available moisture to form sulphuric acid which reduces the amount of radioactive energy of the sun. Thanks to the first law of Thermodynamics, “Energy cannot be created or destroyed but can be transformed from one form to another”, with the same amount of energy being thermally radiated out to space by the earth but less energy coming in from the sun, the earth’s global average temperature reduces.

Sulfur Oxide is cheap, however, delivering the particles to the stratosphere presents a significant challenge. Proposals include balloons or airplanes, but these methods raise concerns about energy consumption, cost, and potential environmental disruptions. Research by Harvard and Yale suggests that it will take 95 fleet of planes which is equal to 60,000 flights a year to spread sulfur oxide in the stratosphere for 15 years to reduce the heat by 0.3 degrees. To cool the earth permanently sulfur oxide needs to be injected over the earth over more decades and over a larger area. To lower the earth’s temperature by 1 degree requires 18 billion dollars per year. The scale is enormous, raising questions about feasibility.

While the potential benefits of SRM, including temperature reduction, are tempting, the risks are significant.SRM has potential disruptions to weather patterns, while the biggest challenges facing the SRM lie in its governance. Unclear control over large-scale implementation raises concerns about weaponization and international disagreements. Bureaucracy could further hinder research and deployment, hindering its potential as a climate solution.SRM could also be used as a climate weapon for some countries.

In 2022, the SCoPEx experiment aimed to test SRM by launching a balloon flight across Sweden. However, The Swedish Space Cooperation canceled the project after many protests from environmentalists and local communities. This scenario highlights the ethical and political complexities surrounding SRM.

With so much unknown, focusing on proven solutions remains crucial. The effects of SRM can be extreme and human beings have failed more than once to control nature. Reducing emissions through renewable energy adoption and energy efficiency is an essential first step. Planting trees offers a natural solution for carbon capture and a healthier planet.

While SRM might hold some promise, further research is needed to understand its risks and limitations. In the meantime, advocating for proven solutions and global commitment to a greener future is the most responsible course of action. Let’s focus on solutions we understand and can control, not untested methods that could have unintended consequences.

References:

Intergovernmental Panel on Climate Change. (2021). Working Group III Contribution to the Sixth Assessment Report [Special Report]. Retrieved from https://www.ipcc.ch/report/ar6/wg3/

United Nations. Net-Zero Coalition. Retrieved from https://www.un.org/en/climatechange/net-zero-coalition

DW Planet A. (2022). Solar Geoengineering: Should we artificially cool the planet? Retrieved from https://www.youtube.com/watch?v=3gvsHkLSxhY&ab_channel=DWPlanetA

Real Engineering. (2019). Can We Block the Sun to Stop Climate Change? Retrieved from https://www.youtube.com/watch?v=tJFtdvrTZs4&ab_channel=RealEngineering

Written by Fridah Joy Namudu

Environmental Engineering Scholar || Front-end Developer || UI/UX Designer