Scientists at Harvard University are working on a plan to cool down the planet and fight global warming. The solution is in the greenhouse gases effect. Infographic of how solar geoengineering works. (Image from


Climate change has been at the center of many discussions in the last couple of years, especially since the 2016 elections in the United States. The country has never been as divided on the subject of what to do about global warming and climate change as it is today. Yet, some scientists are still working on a few solutions. The latest solution is a man-made system to help the Earth fight back called Solar Geoengineering. As defined by experts at Oxford University, geoengineering is the “deliberate large-scale intervention in the Earth’s natural systems to counteract climate change.”


Geoengineering is divided into two categories: Solar Radiation Management (SRM) or Solar Geoengineering, and Carbon Dioxide Removal (CDR) or Carbon Geoengineering. The goal of SRM is to reflect some of the rays coming from the sun in order to lower the temperatures at the surface of the planet by increasing the level of greenhouse gases in the atmosphere. On the other hand, Carbon Geoengineering tries to remove carbon dioxide from the environment to reduce the greenhouse gases effect and the acidification of oceans. While either method is promising, CDR presents the challenge that to be effective the technique must be applied on a global scale. But, SRM can be utilized on a regional scale and tested before expanding it to the whole planet. That is probably why scientists are turning to this option.


There are 3 techniques applicable when it comes to Solar Geoengineering. The first one is the Albedo enhancement which tries to increase the reflectiveness of clouds or that of the ground surface so that more of the sun’s heat is sent back into space. The second technique of SRM is the use of space reflectors to block the sunlight before it reaches the surface of the planet. The third technique is the use of stratospheric aerosols which are small reflective particles introduced in the stratosphere (the upper portion of the atmosphere) to prevent sunlight from reaching the surface of the planet. While geoengineering is not a new concept, scientists at Harvard University only recently decided to test it, and they will be using the stratospheric aerosols method.


Anatomy of aerosol particles. (Image from


As explained above, this method requires that researchers inject in the stratosphere small particles that have the quality of reflecting sun rays. In this case, researchers will use tiny chalk particles. A motorized balloon carrying the particles will rise 12 miles above the earth and spray those particles in the stratosphere, covering an area long of 1km. According to the report, the experiment will happen over a period of 15 years and cost about $2.25 million per year. Researchers explained that since there is no existing aircraft that is equipped to do the job, they will need to build one, preferably a high-altitude tanker which would carry substantial payloads. Researchers also believe that they will have to conduct up to 4000 flights per year to achieve the appropriate aerosol effect. The idea was inspired by the eruption of the volcano Pinatubo in Philippines in 1991: the volcano spat 20 million tons of sulfur dioxide in the atmosphere resulting in a decrease of temperature by .5C. If the experiment with the chalk particles is conclusive, meaning if the temperature drops in the area concerned, scientists will have a way to preserve glaciers and keep them from melting away or even prevent the bleaching of corals.


However, not everyone is enthusiastic about using solar geoengineering. Even though there is hope around the experiment, there is also the danger of losing crops due to cold temperatures. Most crops need warmth to grow, and depending on how much colder the surface becomes after solar geoengineering is applied, crops won’t grow, and food might become scarce. There is also the issue of cost. Although Harvard researchers consider their solution the cheapest option, some scientists and bureaucrats can’t help but see it as a waste of money, especially if there is a doubt that climate change is a serious topic.


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