A proposed solution to reverse the effects of global warming by spraying sulfate particles into Earth's stratosphere could make matters much worse, climate researchers said on Thursday.

They said trying to cool off the planet by creating a kind of artificial sunblock would delay the recovery of the Antarctic ozone hole by 30 to 70 years and create a new loss of Earth's protective ozone layer over the Arctic.

"What our study shows is if you actually put a lot of sulfur into the atmosphere we get a larger ozone depletion than we had before," said Simone Tilmes of the National Centre for Atmospheric Research in Boulder, Colorado, whose research appears in the journal Science. The sulfur injection idea has been proposed by a number of climate scientists as a potential solution to global warming.

Tilmes said the idea was intended to mimic the effects of a major volcanic eruption. Such eruptions in the past sent plumes of sun-blocking sulfur into an upper layer of the atmosphere known as the stratosphere that cooled temperatures on Earth.

Ozone in the stratosphere provides a protective layer high above Earth's surface that guards against harmful solar radiation.

Antarctica's ozone layer has been steadily thinning, resulting in a seasonal 'hole' above the South Pole.

"We know that particles would result in the cooling of the planet," Tilmes said in a telephone interview.

But such cooling would come with unintended side effects. She said sulfate injections could react with chlorine gases in cold polar regions, triggering a chemical reaction that would further deplete atmospheric ozone.

Tilmes and colleagues looked specifically at the impact of plans to repair holes in the ozone over the poles and concluded that regular injections of sulfates over the next few decades would destroy between one-fourth to three-fourths of the ozone layer above the Arctic.

That would affect a large part of the Northern Hemisphere because of atmospheric circulation patterns, they said. The impact would be less during the second half of the century because of international pacts to ban the production of ozone-depleting chemicals.

In the Antarctic, a sulfate-injection scheme would delay the recovery of the ozone hole by 30 to 70 years, or until the last decade of this century.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.