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By Amna Abu Askar

Global climate is drastically changing, threatening ecosystems, and human survival. As global warming worsens and our governments fail to address the climate crisis effectively, it might be necessary to turn to geoengineering, an otherwise scientific taboo, to reduce rapid climate change. 

Geoengineering is a large-scale human intervention in the Earth’s natural system to halt climate change. There are two main types of geoengineering technology: one that aims to shade the Earth from solar radiation and another that aims to remove carbon dioxide and other greenhouse gases from the atmosphere. Geoengineering methods vary from constructing giant space mirrors to reflect solar radiation, seeding clouds with salt and other materials to reflect more light into space, and fertilizing the oceans with iron to stimulate the growth of CO2-absorbing algae. 

Geoengineering interventions are mainly inspired by nature. Right now, oceans are absorbing vast amounts of carbon dioxide. One way to drive oceans to take in even more carbon dioxide is to fertilize the ocean with iron to stimulate the growth of marine algae, resulting in algae blooms, which in theory would absorb the CO2 from the water and cause more CO2 absorption from the atmosphere. There are concerns, however, that this intervention might disrupt the marine food web and whether such blooms will increase the ocean’s total carbon dioxide uptake.   

Another method that has received much traction lately is Stratospheric Aerosol Injection. A technique inspired by the climatic aftermath effects of the 1991 Mount Pinatubo eruption. The volcanic explosion ejected millions of gaseous particles up into the stratosphere. What was of interest to geoengineers, however, was the way sulfur dioxide particles interacted up there. These sulfur particles produced sulfuric acid droplets, which interacted with water and created giant veils, shading the Earth from the sun and reducing sunlight by 1%.  Global average temperatures dropped by 0.5 degrees celsius, and the cooling effects lasted for three years. We can perhaps mimic this process by injecting sulfur particles into the stratosphere via specialized aircraft. Scientists assume that injecting about six megatons of material into the stratosphere would reflect enough solar radiation to slow down global warming, granting us enough time to transition to a fossil-fuel-free economy.

These interventions do not come without their side effects. Stratospheric Aerosol Injections could alter rainfall patterns, which could have negative consequences on agriculture, including poor harvest leading to famine and limited resources. Also, it turns out that the sulfuric acid veil after the Pinatubo eruption not only cooled down surfaces but also heated the stratosphere. These acids are harmful to the ozone layer, and injecting sulfur particles could cause ozone holes. Scientists have already proposed using a combination of gaseous materials that are less harmful to the ozone layer, but research in this area is still ongoing. Critics also say that researching such technology encourages politicians to delay switching to a carbon-neutral economy. Despite geoengineering efforts to slow down global warming, we are continuously adding more carbon dioxide to the atmosphere. This means that once the intervention ends, the natural cycle will take over again, and the Earth would heat up at an even faster rate than before. This temperature shock in such a short period could disrupt natural systems considerably that it would be almost impossible to adapt in time. 

There is so much controversy regarding geoengineering. It could halt climate change or escalate its effects, making things much worse. Perhaps there is a simpler answer to all of this, and hopefully, we won’t have to resort to geoengineering.