“2015 is the hottest year since thermometers were invented. “Blame it all on Bárðarbunga, an Icelandic volcano.”
So declares Dr. Peter Langdon Ward, who worked 27 years with the US Geological Survey studying volcanic eruptions and other geologic hazards worldwide.
Dr. Ward explains that there are two distinctly different types of volcanism: large explosive volcanic eruptions, which are well known to cause global cooling by forming aerosols that reflect and scatter sunlight in the lower stratosphere, and effusive basaltic eruptions, which do not form aerosols but do release gases that deplete the ozone layer, causing global warming.
Bárðarbunga volcano in central Iceland erupted 33 square miles of lava from August 2014 through February 2015, the largest basaltic eruption in 231 years.
“Chlorine- and bromine-bearing gases emitted from basaltic lavas deplete the ozone layer, which normally absorbs the hottest solar ultraviolet energy reaching the lower stratosphere. When the ozone layer is depleted, more of this energy reaches Earth’s surface, causing global warming and increasing the risk of sunburn and skin cancer.”
Dr. Ward will present evidence for the long history of volcanic eruptions controlling Earth’s climate this week at the Fall Meeting of the American Geophysical Union—a gathering of over 24,000 Earth scientists —in San Francisco.
He also describes this extensively in his newly released book, What Really Causes Global Warming? Greenhouse Gases or Ozone Depletion?
Dr. Ward explains that in addition to volcanic eruptions, humans depleted the ozone layer with chlorofluorocarbon gases (CFCs) used as refrigerants and spray-can propellants, which caused the Antarctic Ozone Hole and major global warming from 1970 to 1998. Humans stopped this warming by passing the Montreal Protocol on Substances that Deplete the Ozone Layer that mandated cutbacks in CFC production.
While most scientists are convinced that increasing concentrations of greenhouse gases cause global warming, none has ever shown this effect experimentally in the laboratory. Last month, Dr. Ward issued The Climate Change Challenge, offering $10,000 to the first scientist to demonstrate experimentally that greenhouse gases caused more warming from 1970 to 1998 than ozone depletion. This week, Ward is highlighting The Climate Change Challenge from his booth labeled “Science Is Never Settled” in the Exhibit Hall at the American Geophysical Union meetings.
“Climate change is a serious problem,” says Dr. Ward. “Everyone believes greenhouse gases are the culprit, but what if they’re not? It is very important for all living things on Earth that we get this right.
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