One such idea is deflecting sun rays as a part of solar geoengineering in order to help Earth cool down. 

There are a range of different potential climate interventions to try to artificially curb global heating, such as the brightening of clouds to make them more reflective of sunlight, but the option considered most likely by scientists is the spraying of aerosol particles, such as sulphur, into the stratosphere, according to a report published by Guardian. 

What is solar geoengineering?

Solar geoengineering, or solar radiation modification (SRM), is a type of climate engineering in which sunlight (solar radiation) would be reflected back to outer space to limit or reverse human-caused climate change.

The basic mechanism behind this is well understood – volcanic eruptions similarly cause sunlight to dim – but solar geoengineering faced severe opposition when this has been attempted, due to fears of unknown environmental knock-on impacts and concerns over the lack of governance surrounding the practice.

There are several proposed solar geoengineering technologies. These include marine cloud brightening, cirrus cloud thinning, space-based techniques, and stratospheric aerosol scattering, amongst others.

A UNEP report has stated that spraying reflective particles “is the only known approach that could be used to cool the Earth within a few years” and that it would cost tens of billions of dollars a year, ongoing, to achieve a 1C reduction in global temperatures.

Support from the World

However, with governments still failing to cut emissions quickly enough to avoid disastrous climate change, support has among some powerful entities to research, if not fully deploy, solar geoengineering. 

The US government has already kicked off a research review of climate interventions. Further the United Nations’ Environment Programme (Unep) also released a report calling for further study of the options.

Negative impact

But it also acknowledges a long list of potential dangers, such as damage to the ozone layer, possible power imbalances and conflicts between countries and the risk of “termination shock”, whereby a sudden halt of spraying the particles would unleash a burst of pent-up global heating.

“The idea that we could take control of the global thermostat and dial down temperature levels to a desired state has been debunked by the scientific community again and again. But it is a very attractive idea for big polluters and governments who are unwilling to invest in the radical system change transformation that is so urgently needed,” said Lili Fuhr, deputy director of climate and energy at the Center for International Environmental Law.

“Climate model simulations consistently show that SRM could offset some of the effects of increasing greenhouse gases on global and regional climate, including carbon and water cycles, but there could be substantial residual or overcompensating climate change at the regional scales.” according to a report from the United Nations.