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Practically Speaking

Kyle and her husband moved to Brookfield in 1986. She became active in local politics and started blogging in 2004. Her focus is primarily on local issues but often includes state and national topics, too. Kyle looks at things from the taxpayers' perspective in a creative, yet down to earth way, addressing them from a practical point of view.

You want to do what? More sulfur emissions?

 http://www.abc.net.au/science/articles/2008/04/25/2227370.htm

 

Global warming 'rescue' plan may backfire

  Julie Steenhuysen
AFP/Reuters


polar stratospheric clouds

Injecting sulfur into the stratosphere would react with chlorine gases at the poles, triggering chemical reactions that would speed up ozone depletion, scientists predict (Source: Ross Salawitch)

A proposal to reverse the effects of global warming by spraying sulfate particles into the stratosphere could make matters much worse, climate researchers say.

They say trying to cool the planet by creating a kind of artificial sun block would delay the recovery of the Antarctic ozone hole by 30-70 years and create a new loss of 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," says Dr Simone Tilmes of the National Center for Atmospheric Research in Boulder, Colorado, whose research appears online today in the journal Science.

A number of climate scientists have proposed sulfur injection as a potential solution to global warming.

Tilmes says the idea is 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.

"We know that particles would result in the cooling of the planet," Tilmes says.

But such cooling would come with unintended side-effects.

She says sulfate injections could react with chlorine gases in cold polar regions, triggering a chemical reaction that would further deplete atmospheric ozone.

Repair job

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-quarter to three-quarters of the ozone layer above the Arctic.

That would affect a large part of the northern hemisphere because of atmospheric circulation patterns, they say.

The impact would be less during the second half of the century because of international pacts to ban the production of ozone-depleting chemicals.

Tilmes and colleagues used different measurements and computer models to make their predictions.

She says her findings do not close the door on the idea of artificially cooling the planet in that way but raises a flag of caution.

"We need people to have atmospheric models to understand the process in more detail," she says.

Co-author Professor Ross Salawitch of the University of Maryland says the study highlights another connection between global warming and ozone depletion.

"These traditionally had been thought of as separate problems but are now increasingly recognised to be coupled in subtle, yet profoundly important, manners," he says.

Greenhouse gases

In related research, the amount of two key greenhouse gases in earth's atmosphere rose sharply in 2007, and carbon dioxide levels this year are literally off the chart, the US government reports.

In its annual index of greenhouse gas emissions, the US National Oceanic and Atmospheric Administration found atmospheric carbon dioxide, the primary driver of global climate change, rose by 0.6%, or 19 billion tonnes last year.

The amount of methane increased by 0.5%, or 27 million tonnes, after nearly a decade of little or no change, according to preliminary figures from scientists at the Earth System Research Laboratory in Colorado.

Tags: climate-change, earth-sciences, ozone

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