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ENVIRONMENT

Sulphur sunshade is a stupid pollution solution

  • 14 April 2016

 

It's a credo of consumer capitalism: never address the cause when you can create an industry treating the symptoms.

This is the logic behind many profitable businesses, from cholesterol-lowering pills that compensate for poor diet and lack of exercise to factories that recycle unnecessary packaging.

Now there's a new technofix on the table, and it's called geoengineering. Geoengineering means intervening in the Earth's climate to counter, or offset, global warming. It's hacking the planet on a monumental scale.

Some proposals sound like pure science fiction. Building 'artificial trees' to suck in carbon dioxide. Fertilising entire oceans with iron, trigging carbon-sequestering algal blooms. Launching a fleet of ships to patrol the ocean, pumping seawater into the air to 'brighten' marine clouds.

The most ambitious and widely studied is spraying sulphate particles into the upper atmosphere to reflect sunlight, cooling the planet.

The idea comes from huge volcanic eruptions, which can blast millions of tonnes of sulphur into the stratosphere, creating a kind of chemical sunshade. When Mount Pinatubo in the Philippines erupted in 1991, the Earth cooled by about half a degrees Celsius over the next year.

After decades of being taboo, this outlandish scheme, called 'solar radiation management', is now being taken seriously. It's been explored through scientific papers in major journals, reports of the UK's Royal Society, hearings in the US Congress, and a recent report of the US National Academy of Sciences.

Some environmentalists and climate scientists say it may be a 'necessary evil' to avoid catastrophic climate tipping points. Controversially, the most recent IPCC Assessment Report mentioned geoengineering in the prominent final paragraph of its Summary for Policymakers.

 

"Dimming the sun wouldn't solve the other problems caused by carbon pollution. Dissolved carbon dioxide would still acidify our oceans. The climate would still change."

 

There are deep pockets behind it too. Techno-philanthropist Bill Gates is a leading financer. Venture capitalists are circling, and some proposals have already been patented.

A firm called Intellectual Ventures owns the intellectual property for the 'StratoShield', an invention to deliver sulphur dioxide into the upper atmosphere through a 30-km-long hose supported by balloons. A professor at Harvard, David Keith, is pushing for more research and testing.

Neoconservative think tanks have leapt at the technology, arguing it's a cheaper solution to global warming than cutting emissions and restructuring the economy. Once the post-Paris Agreement buzz wears off and governments realise the hard work ahead of them, they might find this line seductive.

As a thought experiment