Injecting stratosphere with sulphate may harm zone layer

April 25th, 2008 - 4:04 pm ICT by admin  

Washington, April 25 (IANS) A much-touted idea to offset global warming by injecting sulphate particles into the stratosphere would have a drastic impact on the Earth’s protective ozone layer, new research concludes. The study, led by Simone Tilmes of the National Centre for Atmospheric Research (NCAR), warns that such an approach would delay the recovery of the Antarctic ozone hole by decades and cause significant ozone loss over the Arctic.

“Our research indicates that trying to artificially cool off the planet may be a perilous endeavour,” Tilmes said. “While climate change is a major threat, this solution could create severe problems for society.”

“The challenges of global warming mitigation are extremely complex,” said Cliff Jacobs, of National Science Foundation. “Continued investment in basic research will allow the most cost-effective solutions–and those of the most benefit to society–to be found.”

Climate scientists, concerned that society is not taking sufficient action to prevent significant changes in climate, have studied various “geo-engineering” proposals to cool the planet and mitigate the most severe impacts of global warming.

One of the most-discussed ideas is to regularly inject large amounts of sun-blocking sulphate particles into the stratosphere. The goal would be to cool the climate, much as sulphur particles from large volcanic eruptions have cooling impacts.

Since volcanic eruptions temporarily thin the ozone layer in the stratosphere, Tilmes and her colleagues looked into the potential impact of geo-engineering plans on ozone.

The new study concluded that, over the next few decades, artificial injections of sulphates could destroy between one-fourth and three-fourths of the ozone layer above the Arctic. This could affect a large part of the Northern Hemisphere because of atmospheric circulation patterns.

The sulfates would also delay the expected recovery of the ozone hole over the Antarctic by about 30 to 70 years, or until at least the last decade of the twentieth century, the authors warn.

To determine the relationship between sulphates and ozone loss, the authors used a combination of measurements and computer simulations.

The results have been published on Thursday in Science Express.

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