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.
Canna 'Uncle Sam', photo by Malcolm McFarland