Cooling the planet is as easy as putting an umbrella on an asteroid and blocking out the sun

Who among us hasn’t gotten inebriated on a hot summer day and wondered, “Why don’t we launch a giant umbrella into space and block out the sun?”

I have, certain I had solved climate change — until I remembered my lack of credentials.

No Ph.D. in astrophysics from Johns Hopkins University. No experience as an astronomer at University of Hawaii’s Institute for Astronomy.

Well, István Szapudi has those exact bona fides, and he’s actually on board with a space-umbrella climate solution.

For real?

Szapudi published a paper on the idea last week. It proposes:

• Parking a solar shield between Earth and the sun — in a fixed spot ~1m miles from our planet — to reduce direct exposure to sunlight.
• The idea has come up before, but ran into a feasibility wall: the need for a shield light enough to be launchable, but heavy enough that gravity and solar radiation wouldn’t knock it out of position.
• Szapudi beats that with his proposal: capturing an asteroid (something that’s apparently possible) and using it as a counterweight for a screen.

The concept now theoretically works, and would offer quite a lifeline: It’d block ~1.7% of solar radiation, offering a small but meaningful global temperature drop.

Here’s the reality check

This solar shield idea entering the realm of possibility is the headline here. In practice, there’s still a long way to go.

• Today’s materials for a shield and asteroid tether are still too heavy for today’s rockets — though Szapudi suggests that may change in the next few decades.

But hey, even if we’re a lifetime away, it’s silly-hot out there; it couldn’t hurt to have more nontraditional planet-cooling solutions in the works.

P.S. This space umbrella isn’t alone — other “solar geoengineering” possibilities include adding aerosols into the atmosphere and artificially brightening clouds to reflect some sunlight back into space.