But while Simon Nicholson believes false optimism is dangerous, he also thinks there is room for hope.
While Earth naturally goes through warmer and cooler phases, the planet’s temperature has been steadily rising, and the majority of scientists agree: humans are the cause. Use of fossil fuels has rapidly escalated greenhouse gas (GHG) emissions, and there is a strong correlation between higher concentrations of GHG in the atmosphere and Earth’s increasing temperatures.
“Am I optimistic?” asked Nicholson, director of the Global Environmental Politics program at American University’s School of International Service and co-executive director of the Forum for Climate Engineering Assessment. “No, I’m not optimistic about too much.”
But, he said, along with climate mitigation (switching to renewable energy sources, opting for more fuel-efficient vehicles, using less electricity in homes, reducing deforestation, and composting), climate engineering could help us tackle the abundance of carbon dioxide in our atmosphere.
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Climate engineering, also known as geoengineering, may sound like something from a science fiction novel, with strategies that include giant space umbrellas, millions of small mirrors launched into orbit, and artificially brightened clouds. In the past several years, two strategies have garnered attention from researchers and policymakers: solar radiation management, which reflects sunlight away from the planet, and carbon dioxide removal.
Above: An interpretation of space mirrors, which is one proposed strategy of solar radiation management.
Solar radiation management strategies focus on taking preventive measures to reflect excess sunlight before it becomes trapped in our atmosphere. Proposed methods include launching millions of small mirrors into space to deflect the sun’s rays; spraying seawater into the atmosphere to increase the clouds’ brightness, reflecting back sunlight away from Earth; and spraying aerosols into the stratosphere to make it more reflective.
Above: An interpretation of stratospheric aerosol injection, which is modeled after a natural process, in this case volcanic eruption. When a large volcano erupts, it releases gases into the stratosphere that reflect sunlight, reducing the amount of light that reaches Earth. Volcanic eruptions are rare, yet the effects on the atmosphere can last years. In order to replicate those effects without exacerbating them, a man-made stratospheric aerosol injection scheme would require constant monitoring and maintenance.
But in recent years, the policy conversation on climate engineering has shifted to the second strategy, carbon dioxide removal (CDR).
CDR schemes include planting trees; removing carbon from the air and placing it in long-term storage; spreading crushed rocks over land to absorb carbon dioxide; and adding iron to the ocean to increase algae blooms, which trap carbon and pull it to the bottom of the ocean as the algae dies.
Above: An interpretation of ocean iron fertilization, one type of carbon dioxide removal strategy.
But how would these schemes work at scale?
“You can pull out a small amount of carbon through trees, [for example],” Nicholson said. “If you want to scale that up, you can plant a forest. But doing it at a planetary scale, that’s the challenge.”
A Controversial Approach to Climate Change
Since the majority of climate engineering strategies exist only theoretically or naturally at a much smaller scale, it’s difficult to determine the potential consequences. Efforts to save Earth could have unintentional negative effects on the environment. Shielding certain regions from sunlight, for example, could cause drought in others.
Another possible danger is that some groups—policymakers, for instance, or the fossil fuel industry—could try and use climate engineering as an excuse to delay other action to mitigate climate change. Although it does offer possibilities for reducing atmospheric levels of carbon, Nicholson said, climate engineering is not an excuse to ignore mitigation efforts. Climate mitigation and climate engineering should be complementary strategies to slow climate change, rather than single silver bullets, according to Nicholson.
“We can talk about [climate change] as a pollution problem…then [pair] it with solely technological solutions,” he said. “But in fact, these are social problems. These technologies have big social implications.”
While there are potential drawbacks, noted Nicholson, climate engineering may be critical to the climate change response portfolio.
“One thing that all the available science tells us is that mitigation has to remain paramount. Humanity’s addiction to fossil fuels needs to be broken. And nothing being proposed by those looking at climate engineering options negates this fact.”
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