Normally, structures like IKAROS, shown here, are viewed as potential sails in space. But a different application, placed at the right point, could block out some of the sunlight, helping cool the Earth.(Wikimedia Commons user Andrzej Mirecki)

Ask Ethan: Can We Build A Sun Screen To Combat Global Climate Change?

If emissions don’t go down, there’s still an option for combatting global warming. We just have to effectively dim the Sun.

Global climate change is one of the most pressing long-term issues facing humanity today. The science is abundantly clear on what’s happening and why: the Earth is getting warmer, human-caused emission of heat-trapping greenhouse gases is the reason, and the concentration of these gases only continues to rise, unabated, over time. While there are a great many calls to reduce emissions, capture carbon, and move away from fossil fuels, there’s little that’s effectively been done. The Earth continues to warm, sea levels continue to rise, and the global climate continues to change. Could we take a different approach, and partially block the light coming from the Sun? That’s Tony De La Dolce’s question, as he asks:

[W]hy don’t we evaluate building a “sun screen” in space to alter the amount of light (energy) earth receives? Everybody who did feel a total eclipse knows temperature goes down and light dims. So the idea is to build something that would stay between us and sun all year long…

This is one of the most ambitious, but also one of the sanest, options we could possibly…