http://feeds.bignewsnetwork.com/redir.php?jid=2542bb82ae055514&cat=c08dd24cec417021Global warming: Death in the deep-freeze
As global warming melts the world's ice sheets, rising sea levels are not the only danger. Viruses hidden for thousands of years may thaw and escape - and we will have no resistance to them. Kate Ravilious reports
Published: 28 September 2005
Last week, the latest study to track global warming revealed that Alaska's snowless season is lengthening. As the world warms and ice-sheets and glaciers begin to melt, most of us worry about how the earth will respond and what kind of impact climate change will have. Will flooding become a regular feature, or is the land going to become parched? Are hurricanes and typhoons going to spring up in places they have never visited before? Is the rising sea level going to swallow some of the world's most fertile farmland, along with millions of homes?
All of these are valid concerns, but now it turns out that the impact of global warming could be worse than we first imagined. Ice sheets are mostly frozen water, but during the freezing process they can also incorporate organisms such as fungi, bacteria and viruses. Some scientists believe that climate change could unleash ancient illnesses as ice sheets drip away and bacteria and viruses defrost. Illnesses we thought we had eradicated, like polio, could reappear, while common viruses like human influenza could have a devastating effect if melting glaciers release a bygone strain to which we have no resistance. What is more, new species unknown to science may re-emerge. And it is not just humans who are at risk: animals, plants and marine creatures could also suffer as ancient microbes thaw out.
In 1999, Scott Rogers from Bowling Green State University in Ohio and his colleagues reported finding the tomato mosaic tobamovirus (ToMV) in 17 different ice-core sections at two locations deep inside the Greenland ice pack. Gentle defrosting in the lab revealed that this common plant pathogen had survived being entombed in ice for 140,000 years. "ToMV belongs to a family of viruses with a particularly tough protein coat, which helps it to survive in these extreme environments," says Rogers.
Since then Rogers has found many other microbes in ice samples from Greenland, Antarctica, and Siberia. And this has turned out to be just the tip of the microbial iceberg. Over the last 10 years biologists have discovered bacteria, fungi, viruses, algae and yeast hibernating under as much as 4km of solid ice, in locations all over the world.
Most recently Rogers and his colleagues found the human influenza virus in one-year-old Siberian lake ice. "The influenza virus isn't quite as hardy as ToMV, but this finding showed that it is capable of surviving in ice," says Rogers. This particular strain of influenza had only hibernated for one year and doesn't present much of a threat to humans, but it shows that there is potential for a human virus to survive the freezing process for much longer. Imagine if older, more vicious strains, such as the virus responsible for the Spanish flu pandemic, which killed somewhere between 20 and 40 million people in 1918 - 1919, were to re-emerge.
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Ok this is like being in the Twilight Zone or XFiles!!!
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