Greenhouse techno-fix would kill ozone layer

Bill Weinberg

Gee, good thinking, science geeks. There’s too much junk in the atmosphere…so let’s throw even more junk into the atmosphere. Anything to avoid fat Americans having to give up their precious automobiles. From AP, April 24:

Using chemicals to cut global warming may damage ozone layer
WASHINGTON — The rule of unintended consequences threatens to strike again. Some researchers have suggested that injecting sulfur compounds into the atmosphere might help ease global warming by increasing clouds and haze that would reflect sunlight.

After all, they reason, when volcanoes spew lots of sulfur, months or more of cooling often follows.

But a new study warns that injecting enough sulfur to reduce warming would wipe out the Arctic ozone layer and delay recovery of the Antarctic ozone hole by as much as 70 years.

“Our research indicates that trying to artificially cool off the planet could have perilous side effects,” said Simone Tilmes of the National Center for Atmospheric Research in Boulder, Colo.

“While climate change is a major threat, more research is required before society attempts global geoengineering solutions,” said Tilmes, lead author of a paper appearing in Thursday’s online edition of the journal Science.

And while one study worries that fixing climate will destroy ozone, another raises the possibility that recovery of the ozone hole over Antarctica will worsen warming in that region.

A full recovery of the ozone hole could modify climate in the Southern Hemisphere and even amplify Antarctic warming, scientists from the University of Colorado at Boulder, the National Oceanic and Atmospheric Administration and NASA report in a paper scheduled for Geophysical Research Letters.

Although temperatures have been rising worldwide, there has been cooling in the interior of Antarctica in summer, which researchers attribute to the depletion of ozone overhead.

“If the successful control of ozone-depleting substances allows for a full recovery of the ozone hole over Antarctica, we may finally see the interior of Antarctica begin to warm with the rest of the world,” said Judith Perlwitz of the Cooperative Institute for Research in Environmental Sciences, a joint institute of CU-Boulder and NOAA.

The authors used a NASA supercomputer to model interactions between the climate and stratospheric ozone chemistry. A return to pre-1969 ozone levels would mean atmospheric circulation patterns now shielding the Antarctic interior from warmer air to the north will begin to break down during the summer, they concluded.

The idea of reversing global warming by injecting sulfates into the air was suggested by eruptions such as the 1991 blast by Mount Pinatubo in the Philippines, which produced a brief cooling.

The massive 1815 eruption of Tambora in what is now Indonesia produced such a strong cooling that 1816 became known as the “year without a summer” in New England, where snow fell in every month of the year.

But Tilmes knew that volcanic eruptions also temporarily thin the ozone layer, which protects people, plants and animals from the most dangerous ultraviolet rays from the sun.

So she and colleagues calculated the effect of suggested sulfate injections and concluded that the result, over the next few decades, would be to destroy between one-fourth to three-fourths of the ozone layer above the Arctic. This would 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 this century, they said.

The research was supported by the United Kingdom Meteorological Office, University Corporation for Atmospheric Research and NASA.

The study comes just a day after the National Oceanic and Atmospheric Administration reported that despite efforts to reduce greenhouse gases, the rate of increase of carbon dioxide in the atmosphere is accelerating…

Since 2000, annual increases of two parts per million or more have been common, compared with 1.5 ppm per year in the 1980s and less than one ppm per year during the 1960s, NOAA’s Earth System Research Laboratory said. Last year the increase was 2.4 parts per million.

Meanwhile, in a separate paper in Science, researchers said human activities are at least partly responsible for the Arctic having become a wetter place over the last half century.

Seung-Ki Min of Environment Canada, and colleagues, studied rain and snowfall patterns in the arctic and the factors affecting them.

They concluded that human-induced greenhouse gases have contributed to the increased precipitation rates observed in the Arctic region over the past 60 years.

They warned that this “Arctic moistening” could occur more quickly than current climate simulations indicate.

Their work was supported by the U.S. Department of Energy and the Canadian International Polar Year Program.

See our last post on global climate destabilization and ozone depletion.

  1. Arctic methane fart could doom humanity
    Oh, and on the subject… More good news from Der Spiegel, April 17:

    A Storehouse of Greenhouse Gases is Opening in Siberia
    Researchers have found alarming evidence that the frozen Arctic floor has started to thaw and release long-stored methane gas. The results could be a catastrophic warming of the earth, since methane is a far more potent greenhouse gas than carbon dioxide. But can the methane also be used as fuel?

    It’s always been a disturbing what-if scenario for climate researchers: Gas hydrates stored in the Arctic ocean floor — hard clumps of ice and methane, conserved by freezing temperatures and high pressure — could grow unstable and release massive amounts of methane into the atmosphere. Since methane is a potent greenhouse gas, more worrisome than carbon dioxide, the result would be a drastic acceleration of global warming. Until now this idea was mostly academic; scientists had warned that such a thing could happen. Now it seems more likely that it will.

    Russian polar scientists have strong evidence that the first stages of melting are underway. They’ve studied largest shelf sea in the world, off the coast of Siberia, where the Asian continental shelf stretches across an underwater area six times the size of Germany, before falling off gently into the Arctic Ocean. The scientists are presenting their data from this remote, thinly-investigated region at the annual conference of the European Geosciences Union this week in Vienna.

    In the permafrost bottom of the 200-meter-deep sea, enormous stores of gas hydrates lie dormant in mighty frozen layers of sediment. The carbon content of the ice-and-methane mixture here is estimated at 540 billion tons. “This submarine hydrate was considered stable until now,” says the Russian biogeochemist Natalia Shakhova, currently a guest scientist at the University of Alaska in Fairbanks who is also a member of the Pacific Institute of Geography at the Russian Academy of Sciences in Vladivostok.

    The permafrost has grown porous, says Shakhova, and already the shelf sea has become “a source of methane passing into the atmosphere.” The Russian scientists have estimated what might happen when this Siberian permafrost-seal thaws completely and all the stored gas escapes. They believe the methane content of the planet’s atmosphere would increase twelvefold. “The result would be catastrophic global warming,” say the scientists. The greenhouse-gas potential of methane is 20 times that of carbon dioxide, as measured by the effects of a single molecule.

    Shakhova and her colleagues gathered evidence for the loss of rigor in the frozen sea floor in a measuring campaign during the Siberian summer. The seawater proved to be “highly oversaturated with solute methane,” reports Shakhova. In the air over the sea, greenhouse-gas content was measured in some places at five times normal values. “In helicopter flights over the delta of the Lena River, higher methane concentrations have been measured at altitudes as high as 1,800 meters,” she says.

    The methane climate bomb is also ticking on land: A few years ago researchers noticed higher concentrations of methane in northern Siberia. The Siberian permafrost is known as one of the tipping points for the earth’s climate, since the potent greenhouse gas develops wherever microorganisms decompose the huge masses of organic material from warmer eras that has been frozen here for thousands of years.

    “A Wake-Up Call for Science”
    Data from offshore drilling in the region, studied by experts at the Alfred Wegener Institute for Polar and Marine Research (AWI), also suggest that the situation has grown critical. AWI’s results show that permafrost in the flat shelf is perilously close to thawing. Three to 12 kilometers from the coast, the temperature of sea sediment was -1 to -1.5 degrees Celsius, just below freezing. Permafrost on land, though, was as cold as -12.4 degrees Celsius. “That’s a drastic difference and the best proof of a critical thermal status of the submarine permafrost,” said Shakhova.

    Paul Overduin, a geophysicist at AWI, agreed. “She’s right,” he said. “Changes are far more likely to occur on the sea shelf than on land.”

    Climate change could give an additional push to these trends. “If the Arctic Sea ice continues to recede and the shelf becomes ice-free for extended periods, then the water in these flat areas will get much warmer,” said Overduin. That could lead to a situation in which the temperature of the sea sediment rises above freezing, which would thaw the permafrost.

    “We don’t have any data on that — those are just suspicions,” the Canadian scientist said. Natalia Shakhova also passed on the question of whether to expect a gradual gas emission or an abrupt burst of large quantities of methane. “No one can say right now whether that will take years, decades or hundreds of years,” she said. But one cannot rule out sudden methane emissions. They could happen at “any time.”

    One thing is clear, though: The thawing of the Arctic sea floor will create “new potential sources for methane … which no one had reckoned with until now,” said Laurence Smith, a professor for geography at the University of California in Los Angeles. Smith is researching North Pole frost zones and expects that a thawing of the permafrost will “supply fuel for methane engines.”

    The first methane rocket thruster was tested by the US’s National Aeronautics and Space Administration (NASA) in 2007, and methane from manure has been collected as “biogas” to heat and power homes (more…) in experimental German towns.

    In any case, the team taking part in the Siberian study installed a number of probes in the Laptev Sea, a central part of the broad Siberian shelf sea. These probes are measuring the temperature on the upper edge of the submarine permafrost. Overduin wants to pull up the probes in August. Then, for the first time, scientists will have access to a full year’s worth of data on the conditions of the sea floor.

    For her part, Shakhova thinks researchers should be doing a lot more. She says too little is known about the fragile shelf sediment and the methane it stores, which could be explosive for the environment. “Actually,” she says, “this is a wake-up call for science.”