Geoengineering climate change

The search for climate-change hacks is ramping up across the world as the window to reduce greenhouse gas emissions narrows, with scientists in China experimenting with new ways of blocking out the sun.

Geoengineering is the intentional altering of the planet’s climate or earth systems. Not a new concept, the practice has long drawn criticism for being a high-risk alternative to reducing the amount of carbon released into the atmosphere in the first place.

Despite the inherent dangers of playing God, geoengineering appears to be firmly on the agenda for many scientists and entrepreneurs, with a story published by The Fifth Estate in February noting there are around 800 projects underway worldwide aimed at controlling pollution and the way the climate evolves.

Those nations already feeling the effects of a warming climate, such as China, have an even greater incentive to start investigating future-proofing options.

According to China Dialogue, the nation is focusing its efforts on solar geoengineering – one of two overarching methods for counteracting climate change (the other being sucking carbon dioxide out of the atmosphere).

One of the main solar geoengineering techniques involves injecting sulfate aerosols into the stratosphere so the reflective particles block and reflect the sun. Theoretically, this will help cool the Earth.

The process is meant to mimic the effects of a volcano erupting and releasing sulphur dioxide into the atmosphere to form sulphate aerosols, which has historically caused the Earth’s temperature to drop.

For researchers, the unintended consequences of this method are extremely concerning, with a Nature Ecology & Evolution paper published earlier this year suggesting that an abrupt halt in this practice could see the Earth heat up at such a rapid rate that many animals and plants would not have time to adapt.

Another potential solar geoengineering solution is “marine cloud brightening”, which involves spraying saltwater into clouds above ocean to boost their ability to reflect sunlight. 

This technology is currently also being developed by Australian oceanographer Daniel Harrison to protect the Great Barrier Reef from coral bleaching, according to the Sydney Morning Herald.

To form a cloud, every droplet needs a speck of dust in the atmosphere to condense into. Unlike over land where there is dust everywhere, sea clouds rely on sea salt to form.

Mr Harrison says it is possible to shoot up a fine mist of sea water using a specially designed nozzle, where these sea water nano-particles evaporate into sea salt crystals.

Geoengineering experiments range from the wacky to the somewhat reasonable, provided extreme efforts are made to avoid possible unintended consequences.

In other local geoengineering efforts, the Victorian government has recently backed a study by CarbonNet into the potential for commercial scale carbon capture and storage offshore in Gippsland.

Another new scientific study also funded jointly by the state and federal government will assess the suitability of the region’s Bass Strait rock formations for storing carbon dioxide captured from industrial processes.

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