Dr. Jeremy Leggett

(Part Four)

(From Earth Crash Earth Spirit Website)

       (06/28/1999) Scientist calls unprecedented appearance of noctilucent clouds over Colorado and Utah a global warming "canary in the coal mine." A luminescent meteorological phenomenon rarely seen in the contiguous United States, noctilucent clouds, has made a surprise visit recently and one expert says increased carbon dioxide may be to blame. Noctilucent clouds are usually seen only in the far northern and southern latitudes. Occurring about 52 miles (85 kilometers) above the Earth, in the upper atmosphere, they are so high that they reflect the sun's rays even at night.  

      Scientists have had trouble explaining the clouds' existence over Colorado and Utah, but at least one researcher believes he may now have the key. Gary Thomas, a professor at the University of Colorado at Boulder's Laboratory for Atmospheric and Space Physics, is an expert on noctilucent clouds. The recent appearance came as quite a surprise to him. "I had predicted [in 1994] that we wouldn't see noctilucent clouds [south of] the latitude of 40 degrees until the 21st century. I guess I was wrong on that one." Most of the U.S.-Canadian border lies at 49 degrees latitude.  

      Thomas believes that the clouds form as methane gas rises unimpeded through the natural cold trap, an area of very cold temperatures about nine miles (15 kilometers) above the Earth. The rising methane may react with sunlight to form large quantities of water vapor that eventually freeze and circulate to the top of the atmosphere.  

      Thomas believes that noctilucent cloud formation is being hastened by increased amounts of carbon dioxide (CO2) in the Earth's atmosphere. While carbon dioxide is thought to contribute to global warming in the lower atmosphere, it has the opposite affect on the middle and upper atmospheres, where it causes cooling, he said. "This could be a natural cycle that we don't understand, it could be a fluke or a freak, but it's my opinion that increased CO2 is playing a major role in this. It is just something we don't know much about and requires more study."  

      The mesosphere, located between 31 and 56 miles (50 and 90 kilometers) above the Earth, right above the stratosphere, has been cooling by as much as one degree Celsius every year for the past 30 years, according to an article in New Scientist. That is ten times faster than anyone had predicted, said Thomas. "What we're seeing are some dramatic (upper atmospheric cooling) effects that are far greater than what the models are predicting," he said.  

       For Thomas, the cooling of the mesosphere is the canary in the coal mine. It is the most recent, biggest, and most unequivocal signal that the global climate really is changing, he says. "This is a big event," said Thomas. "While they are a beautiful phenomenon, these clouds may be a message from Mother Nature that we are upsetting the equilibrium of the atmosphere."  

      The first sighting of noctilucent clouds from the continental United States was on July 1, 1993, by Jay Brausch, an amateur sky watcher in Glenn Ullen, North Dakota. The recent sighting was reported by Richard Keen, a meteorology instructor at the University of Colorado at Boulder, and Mike Taylor, a physics professor at Utah State University. Keen's was the most southerly sighting of noctilucent clouds in the contiguous United States. "I saw silvery clouds to the northwest that were distinctly brighter and higher than the other clouds," he said. "My first thought was: It can't be. But I'd seen them before in Alaska, so I know what they look like. They have a distinctive color and features [they are silvery blue and form bands]." (Sources)  

      (09/30/2000) World famous physicist Stephen Hawking says he's worried runaway global warming could destroy human life on Earth. World renowned physicist Stephen Hawking fears the human race may not survive another millennium. "I am afraid the atmosphere might get hotter and hotter until it will be like Venus with boiling sulfuric acid," the physicist said. "I am worried about the greenhouse effect."  

      To ensure the survival of humans, he adds, efforts must be made to colonize other planets. Space travel would not solve every problem, but at least it would ensure that people don't become extinct. "It takes too many resources to send each person into space," he said. "But unless the human race spreads into space, I doubt it will survive the next thousand years." Hawking, 58, holds the Cambridge University post once held by Sir Isaac Newton and is the author of the best-selling "A Brief History of Time." (Sources)  

      (09/30/2000) Nando Times: Hawking says greenhouse effect threatens  human race survival.  

      (10/29/1999) Nando Times: Methane Gas Research Could Help Scientists                Understand Global Warming.  

      (07/19/99) San Francisco Examiner: Warning of more global warming.  

      (06/28/1999) National Geographic: Glow-in-the-Dark Clouds: A Global       Warning?  

      (12/04/1995) Center for Environmental Information/U.S. Global Change     Research Program: An Environmentalist's Perspective on the Current State of the Climate Debate.  

      (06/01/1992) Bulletin of Atomic Scientists: Global warming: The worst  case.  

      (09/01/1990) Greenpeace Climate News Database: Methane hydrates could strongly amplify global warming.