Could a giant ‘sun umbrella’ help stop climate change and is it a good idea?

We all know that seeking shade is one of the best ways to escape the heat. But could a giant ‘sun umbrella’ help block harmful UV rays and cool the Earth?

That’s the latest idea from a US astronomer at the University of Hawaiʻi.

This isn’t the first time space-based sun shields - mirrors or shades placed in orbit between the sun and Earth - have been proposed for climate change prevention.

Until now, however, scientists have struggled to design a shield that balances weight and costs.

A potential solution is to tether it to a counterweight filled with asteroid material, according to the new proposal published in the Proceedings of the National Academy of Sciences (PNAS) journal.

If the design is workable, it could start mitigating climate change within decades, the paper’s author István Szapudi claims.

'Sun blocking' technologies - also known as 'solar radiation modification' (SRM) - could theoretically cool down the Earth by shading it from some of the sun’s rays.

Until now, the solar shield concept faced a major hurdle: weight.

Previous proposals have placed the shield at the point where the Earth’s gravity and the sun’s radiation pressure are in balance.

However, these two counteracting forces mean the shield would have to meet minimum weight requirements to ensure it stays in place. This rules out low-cost, lightweight materials like graphene, which could be easily lifted into space.

By attaching the shield to a counterweight, positioned towards the sun, these weight restrictions could be circumvented, Szapudi theorises.

The shield could also be placed closer to Earth, making it more effective.

The solar shield would be attached to a counterweight by a strong graphene tether.

The counterweight would slowly open once in space,