Greenhouse gases produced by humans, such as carbon dioxide, are the main drivers of unprecedented rises in global average temperatures at an unmatched speed in Earth's geological record. The issue is described as so severe that any attempts to mitigate greenhouse gas emissions may be too few and too late. Thus, a team at the Massachusetts Institute of Technology proposed a radical new solution: bubbles in space.
The thinking relies on two areas of concern: one being that as much as we try to reduce or even eliminate future greenhouse gas emissions, the damage already inflicted over more than a century of advanced industrialization has already set Earth’s climate on a detrimental path. It could be so bad that even if we were to completely halt all greenhouse gas emissions tomorrow, we would still need to endure the severe effects of climate change for decades and even centuries to come, including ongoing sea level rise, more extreme weather events, and disruptions in food-producing regions.
Another way to address the problem is through carbon capture or removal, or in some manner reducing the amount of sunlight that reaches Earth’s surface, for example, by releasing aerosols into the atmosphere. The team at MIT argues that this is a generally bad idea because our climate system is complex and dynamic to the extent that introducing artificial factors into the atmosphere itself cannot be reversed.
For this reason, they are considering space: the idea is to develop a set of thin, bubble-like membranes. These membranes would reflect or absorb a tiny fraction of the sunlight reaching Earth by literally blocking it. The team argues that if the amount of sunlight reaching Earth is reduced by just 1.5%, we could completely eliminate the effects of all greenhouse gases.
However, the team still needs to clarify exactly what these bubbles would produce and how they would be sent to the target location, which is near the first Lagrange point in the Earth-Sun system. They will need to maintain the stability of the buoy through balancing the gravitational forces of Earth, the Sun, and likely other planets. They will also have to contend with the radiation pressure from the Sun itself, not to mention the continuous rainfall of solar winds and micrometeoroids.
Blocking even a percentage of the Sun’s output would require a buoy several thousand miles wide, making it the largest structure we’ve ever placed in space. Thus, there exists a slight engineering challenge to make this concept work. While MIT researchers claim that this space-based approach is completely reversible, this is only true in a certain sense.
Earth’s climate is a complex system with many complicated feedback loops that we do not fully understand—what are the overall effects of blocking sunlight by one and a half percent over years, decades, and centuries? What is its impact on the biosphere or cloud cover or ocean evaporation or thousands of other considerations? Do we really believe we possess the technical and intellectual capability to get this right?
Finally, developing a solution that reduces the amount of sunlight hitting the Earth does nothing to address the underlying problem, which is that we are causing significant damage to Earth’s climate and biosphere. We need to tackle these root problems, not just dump them elsewhere.
