A wild space plot, straight up science fiction, could slow climate change

Climate change is a real problem. Human-caused emissions of greenhouse gases such as carbon dioxide and methane are the main driver of an unprecedented increase in average global temperatures at a rate never seen before in Earth’s geological record. The problem is so serious that any attempts to mitigate greenhouse gas emissions may be too little too late. So a team based at the Massachusetts Institute of Technology has proposed a radical new solution: bubbles… in space.

That’s right, bubbles in space. The thinking is based on two problem areas. One is that no matter how hard we try to reduce or even eliminate greenhouse gas emissions in the future, the damage we’ve already done from more than a century of advanced industrialization has already set the course of Earth’s climate trajectory in a bad direction.

It could be so bad that even if we completely stopped all greenhouse gas emissions tomorrow, we would still have to live with the severe impacts of climate change for decades and even centuries to come, including continued sea level rise, more extreme weather events and disturbances in food producing regions.

Another way to deal with the problem is to sequester or remove the carbon or somehow limit the amount of sunlight reaching the Earth’s surface, for example by releasing aerosols into the atmosphere. The MIT team argues that this is generally a bad idea because our climate system is so complex and dynamic that introducing artificial factors into the atmosphere itself cannot be reversed.

That’s why they think about space. The idea is to develop a raft of thin bubble-like membranes. These membranes will reflect or absorb some of the sunlight reaching Earth, literally blocking it out. The team claims that if the amount of sunlight reaching Earth was reduced by just 1.5 percent, we could completely eliminate the effects of all our greenhouse gases.

Personally, I’m pretty skeptical of this idea. For one thing, the team has not yet formulated exactly what these bubbles will be made of and how they will be sent to their destination, which is near the first LaGrange point of the Earth-Sun system. They would have to maintain the stability of the raft by balancing the gravitational forces of the Earth, the Sun, and possibly the other planets. They would also have to contend with radiation pressure from the Sun itself, not to mention the constant shower of solar wind and micrometeoroids.

To block even a percent of the Sun’s output would require a raft thousands of miles wide, making it the largest structure we’ve ever put into space. So there’s just a bit of an engineering challenge to make this thing work.

And while the MIT researchers claim that this cosmic approach is completely reversible, it is only in a sense. Yes, if we decide the raft is a bad idea or isn’t doing what we hoped it would do, we can just let it float or take it apart. But Earth’s climate is a complex system with very complex feedback loops built into it that we don’t fully understand.

What would be the total effects of blocking sunlight by one and a half percent over the years, decades, and centuries? What effect would it have on the biosphere or the level of cloud cover or ocean evaporation or a thousand other considerations? Do we really believe we have the technical and intellectual capacity to do this right?

Finally, developing a solution that reduces the amount of sunlight reaching the Earth does nothing to address the underlying problem, which is that we are causing serious harm to the Earth’s climate and biosphere. If we have covered ourselves—pun intended—to do what we want, then why should we stop polluting or emitting greenhouse gases if we can just add more bubbles to the raft? We need to address these fundamental issues, not just gloss over them.

The team admits there is still a lot of work to do, but I wouldn’t be surprised if, after years of work, the realities of the complexity of this proposed solution burst the bubble.

This article was originally published on The universe today from Paul M. Sutter. Read the original article here.

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