Gain control of climate change
Toolbox
Published: June 7, 2009
Sometimes a local story has a wider impact. The story of the bats in the caves of Dorset has a potential impact beyond imagining.
Scientists who have investigated caves in Dorset have found thousands upon thousands of bats that have died as a result of a fungus that leaves a white powder on their noses — white-nose syndrome. It is a gory scene when scientists deep underground find themselves wading among mounds of bat carcasses.
But it is more than gory. Dead bats have been found in New York, Virginia, and West Virginia, and there are fears the fungus is spreading to the Midwest and Southeast.
The loss of millions of bats will have an immediate impact upon humans because bats consume their own weight in insects each night. That's a lot of mosquitoes. Residents of the Brandon region and other parts of Vermont where mosquitoes are a problem spray larvicide to control mosquitoes, but without bats swooping down to gobble up their share each night, mosquito control — and control of the diseases mosquitoes carry — will be all the more difficult.
But beyond the immediate problem of dying bats, the bat decline signals something far more serious. Many scientists now say the world is in the midst of the kind of mass extinction that hasn't occurred since the extinction that claimed the dinosaurs 65 million years ago.
Elizabeth Kolbert, one of the leading chroniclers of the effects of global warming, wrote an article appearing in a recent New Yorker magazine describing the changing ways that scientists have accounted for extinctions. Charles Darwin believed that evolution happened slowly and that species died out gradually. That was the prevailing view until recent decades when scientists found evidence for sudden mass extinctions.
She said that during 500 million years there have been about 20 mass extinctions, including five that were so destructive that scientists refer to them as the Big Five. During the cataclysm that claimed the dinosaurs, about 75 percent of all species died out. Now scientists fear that we are in the midst of the sixth great extinction and that by the end of the century about half of all species may be gone.
Bats are just part of it. Kolbert's article also describes the sudden and mysterious disappearance of frog species that had been abundant in Panama and Costa Rica. Scientists have pinpointed a chytrid fungus known as Bd as the cause of the vast amphibian die-off.
Scientists say the present period of mass extinctions began about 50,000 when early humans began to spread to America and Australia. Humans have hunted some species to extinction. Modern humans have destroyed habitats and introduced alien species to places where they upset the balance and caused other species to disappear. Industrialization has created its own pressures, including changes in the climate.
The fungus that is claiming bats in Dorset and elsewhere in the Northeast is a minute event in the broad sweep of change that is under way. But the threats to bats, frogs, corals, birds, insects, and numerous other organisms suggest that the pace of species loss is accelerating so rapidly that unforeseen disasters could be on the horizon.
These discoveries lend urgency to efforts to gain control of climate change. It is no exaggeration to say that the human species is at risk, even if we are inclined to think that the risk is relatively low. The loss of a few key species in the web of life could undo the balance of microbes, of food plants, of ocean life that we all depend on. Already honey bees are undergoing stress, threatening the fruits and vegetables humans eat.
We cannot blame ourselves for the survival instinct of early humans who killed off species that threatened them and had no concept of where they fit in nature. But our knowledge is greater now, and we have seen the effects of human activity on the world of which we are a part.
Passage of a cap and trade program to limit carbon emissions seems like the least we can do and only a meager first step. Nobody knows if it will be enough to curb further extinctions, but what we are learning from the jungles of Panama and the caverns of Dorset ought to humble us enough to inspire serious action.
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