This post contributed by Monica Kanojia, Administrative Assistant/Governance for ESA
While the United Nation’s climate conference has concluded in Cancun, Mexico, discussions continue on methods for mitigating the adverse effects of climate change—one option some scientists and engineers have turned to is altering nature itself. These geoengineering proposals involve the large scale modification of the Earth’s climate with the goal of counteracting global climate change.
There are many different methods of geoengineering being researched, some of which include afforestation—planting trees in previously forest-free areas—atmospheric aerosols, ocean iron fertilization, cloud reflectivity enhancement and cool roof installations. Many of these methods fall under the broader spectrum of solar radiation management, which seeks to lessen the amount of sunlight hitting the Earth’s surface.
Cool roof installation and afforestation methods are already being implemented on a small scale. The latter involves the planting of trees to increase the amount of carbon dioxide (CO2 ) uptake from the environment and the former allows for the reflection of solar energy and heat. Cool roofs are usually a lighter color and not only have the ability to reflect the sun’s rays but to emit infrared and ultraviolet rays as well. The installation of cool roofs is considered to be a simple and practical solution for offsetting the heating and cooling costs of commercial and residential buildings.
Bill Gates is currently funding a cloud reflectivity enhancement project which involves spraying seawater into the atmosphere to increase the number of cloud nuclei, boosting their density. This process would in effect whiten the clouds, increasing their reflectivity. According to a Sunday Times article, cloud enhancement would supersede international regulations since the procedure would not add chemicals into the environment and its effects could be stopped by switching off the seawater-spraying machines.
Increasing atmospheric aerosols, on the other hand, would require the addition of sulfuric acid into the stratosphere. The sulfuric acid forms particles known as sulfate aerosols and, in turn, reflects sunlight, leading to global dimming. Ocean fertilization also involves the large scale insertion of materials into the environment—it calls for iron to be added into the ocean to stimulate phytoplankton growth. Phytoplankton gain energy from the supplemented iron and, through photosynthesis, potentially remove significant amounts of CO2 from the atmosphere.
While these geoengineering methods, if feasible, sound like quick solutions for offsetting global climate change, nothing comes without a trade- off—especially if implemented on such a large scale. For some of these proposals, there are even natural occurrences that yield similar, if not more efficient, results. For example, the eruption of a volcano can cause both ocean fertilization and an increase in atmospheric aerosols. The natural processes can help to temporarily reduce the Earth’s temperature and increase carbon sequestration; whereas the manual insertion of aerosols into the atmosphere could have adverse effects, such as damage to the ozone layer or changes in weather patterns and precipitation. This brings into discussion whether the effects of geoengineering are uniform across all regions and whether they can be bound by international regulations.
In October, the House Science and Technology Committee issued a geoengineering report that identified which organizations would be best suited for researching climate change and possible resolutions—among those listed were the National Science Foundation, National Oceanic and Atmospheric Administration, the Department of Energy and the National Aeronautics and Space Administration. The resounding message was that ignoring climate woes and sweeping them under the rug would only harm the U.S. in the future.
The U.N. Convention on Biological Diversity, also held in October, agreed to block geoengineering until sufficient scientific evidence shows that large scale environmental manipulation would not be a threat to ecosystems and biodiversity. This moratorium will last until 2012; however, it is not legally binding and still allows for small scale research.
If we can come to an agreement as an international community, barring economic and technological issues, will “quick fix” methods be able to mitigate climate change without inflicting further damage?
Monica Kanojia is a George Mason University graduate with a B.S. in Biology. She has interned at NSF and contributed articles to LiveScience.com. She has also interned with EarthShot Foundation, an environmentally based NGO focused on driving a clean energy revolution.
Photo Credit: NASA, 1968