Geoengineering, Cure OR Curse
Seeing dreams has no limit, and dreams can come true. Every invention once was a dream. Scientists think, plan and experiment. The process of research, once started, takes its momentum and culminates in a discovery. We, humans, are greedy to have everything we can imagine. The same is true, with the desire to control everything around.
Such is the case with the story of geoengineering. It is no more a concept or a dream. It has emerged as a reality out of mere science fiction. With the growing pace of global warming, taking measures against it is but an acute necessity. Scientists have developed a consensus that controversial technologies such as geoengineering need serious consideration.
The concept is also known as climate engineering. The process includes the counteraction of manipulating climate changes through severe intervention in the climate system of the planet earth. Geoengineering options theoretically seem workable, but the outcome can be unexpected even worse.
Geoengineering solutions fall under the following two categories:
- Solar geoengineering
- Carbon dioxide removal
Climate changes occur due to an imbalance between the solar irradiance absorbed by the planet Earth and the volume of energy radiated and reversed back into space. The more energy absorbed by the Earth than it radiates is called greenhouse gases concentration. It leads to an increase in temperature.
The solution offered to this phenomenon is called solar geoengineering. The imbalance is addressed by increasing the Earth’s albedo, or solar reflectivity. The symptoms of climate change alone are treated through this approach. The causes of the issue, however, remain unresolved. The temperature of the planet can be reduced by radiating more energy into space than it absorbs. It has to do nothing with removing carbon dioxide from the atmosphere and other effects like the acidification of oceans.
Solar geoengineering is an option that can work well in an emergency. It is only a way to buy time to reduce emissions and remove piled-up CO2 from the atmosphere.
Stratospheric aerosol injection: This process not needing a significant technological application. It can proceed by releasing reflective aerosols like sulfur dioxide. It can be completed by using planes or high-altitude balloons. Its cooling effect is similar to volcanic ash. It can, however, play havoc if carried out in an unregulated way. Research reveals that injecting aerosols in the northern hemisphere can result in droughts and hurricanes in Africa and India.
The other risk is wiping out animal life from the planet due to rapid temperature change. This risk is known as “termination shock” and can be caused if the aerosol injection is stopped for any reason.
Marine-based brightening: The option is focused on increasing albedo. It can be done by the use of seawater and spray of sea salt from ships. It makes clouds more reflective to release microbubbles. It has an impact on the surface of the sea to make it more reflective. Using this option has an inherent risk of disturbing weather conditions in other parts of the world.
Cirrus cloud thinning: The Cirrus clouds warm the climate as they are prone to absorb longwave radiation. Such clouds can be dissipated by seeding dust or similar particles through drones. The impact of the process on the weather patterns still needs serious research.
Space shades: This approach eyes on assembling and installing “giant mirrors”. These mirrors also termed “sunshades” can be placed in orbit or possibly at the Lagrange point between the Earth and the sun. These mirrors will significantly reduce incoming sunlight that will offset warming from atmospheric CO2. This approach will attract heavy investments in technology.
Carbon Dioxide Removal
The present level of CO2 emissions is estimated to remain around the atmosphere roughly for between 300 and 1,000 years. Decarbonizing the global economy is significant but addressing the emissions accumulated since industrialization is equally a crucial issue.
Carbon dioxide removal (CDR) is possible by seizing CO2 from the atmosphere and dumping it underground for centuries. The capturing of carbon has to do nothing with CDR. It is a separate process that involves capturing carbon directly from a smokestack and sequestering it underground.
CDR methods include:
Direct air capture (DAC): CO2 is directly captured from the air by machines that use chemical processes. Machines then separate it for sequestration. The Carbon Engineering facility based in Texas uses large fans to pull in atmospheric air. It extracts the CO2 and compresses and packs it into tiny pellets for reuse or underground dumping.
Ocean fertilization: The theory says that ocean sides lacking iron can be filled with hundreds of tons of iron filings to stimulate CO2-absorbing algal blooms. A startup named Planktos experimented with it in 2011 but was opposed by the international community for illegal dumping.
Biochar: Burning organic waste in a low or zero-oxygen chamber (pyrolysis) causes burying the charcoal-like substance. The natural decay of organic matter emits CO2. The process prevents leakage of CO2 into the atmosphere.
The Moral Issues
All available solutions so far are not safe. Each process has its dark sides. The Governments are reluctant to take initiatives due to associated risks. They are perhaps hoping for more technological advancement that can safeguard against risks through more sophisticated processes.
ClimateCentral.org explains: “Nobody knows if atmospheric carbon removal… will work, and it could delay critical cuts to emissions while tacitly giving people license to pollute.”