One scientist is advocating for a "space umbrella" or "tethered sun shield" latched to an asteroid or collected moondust to cool down our overheating planet — by blocking sunlight before it hits Earth.
The researcher with this openly shady solution, István Szapudi of the University of Hawaiʻi at Mānoa, published the concept in the Proceedings of the National Academy of Sciences in July.
"In Hawaiʻi, many use an umbrella to block the sunlight as they walk about during the day,"
Szapudi explained to University of Hawaiʻi News. "I was thinking, could we do the same for Earth and thereby mitigate the impending catastrophe of climate change?"
Szapudi proposed his planetary parasol to reduce solar radiation by 1.7% — an amount estimated "to prevent a catastrophic rise in global temperatures."
As UHN explained, Szapudi is one of many researchers to propose a solar screen or reflecting materials to limit warming. Scientists call this controversial line of thinking "solar geoengineering" or "solar radiation management."
Szapudi's contribution deals with the solar shield's size. Basically, a shield massive enough to block necessary sunlight would be too expensive to lift to the correct place in space. It would need to be positioned to limit impacts caused by gravitational and solar radiation forces.
Anchoring to a counterweight of asteroid or moondust material would provide "ballast," the paper explained. The proposed system would be about 3.5 million tons, but only 1% of that — 35,000 tons — would need to be sent from Earth.
The paper said more work is needed before the concept is possible. Today's rockets lift about 50 tons into low Earth orbit, per UHN. And the system would need stronger tethers.
Meanwhile, some online platforms have thrown shade on the concepts of solar shields and geoengineering.
Politico pointed out that the concept of a sun shield calls to mind an episode of "The Simpsons" in which Mr. Burns blocks the sun.
The Daily Beast raised criticisms that others have applied to geoengineering: way-out ideas could have dangerous consequences and distract from a need for humans to quickly reduce heat-trapping pollution.
"Does this sound insane? Well, it should!" The Daily Beast wrote. "This is a cartoonish solution to a problem that already has a clear answer (i.e., reducing greenhouse gas emissions)."
However, even that platform reported that "Szapudi is pretty clear-eyed" about the obstacles facing his concept. For his part, the scientist wrote that investment in his idea would be "an insurance policy" so that a shield could be "deployed if other efforts to mitigate climate change fail."
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