In recent years, for example, the water level of Lake Powell (it covers portions of Utah and Arizona) has dropped so far that the waterfalls and canyons drowned when Glen Canyon Dam was built are visible again. Meanwhile, in February, 2008, hydrologists reported that at current rates of decline, Lake Mead, behind Hoover Dam, on the Arizona-Nevada border, could be entirely dry in 10 years. In the span from 2000 to 2009, the lake lost half of its water. In 2008, the Scripps Institute of Oceanography issued a paper titled, "When will Lake Mead go dry?" and concluded there was a 50-50 chance that day could dawn as early as 2021. "Today, we are at or beyond the sustainable limit of the Colorado system," concluded the paper's authors. "The alternative to reasoned solutions to this coming water crisis is a major societal and economic disruption in the desert southwest; something that will affect each of us living in the region."
Bill McKibben, author, activist, and founder of 350.org, an organization dedicated to saving the planet from runaway warming caused by carbon dioxide and other emissions, says that the rise in temperatures has been accelerating and that massive, immediate response is urgent. His organization derives its name from c limate scientist James Hansen's contention that any atmospheric concentration of CO2 (carbon dioxide) above 350 parts per million was unsafe, Wikipedia notes. Hansen said, "if humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm, but likely less than that."
McKibben observed, "That's strong language. It's stronger still when you realize we're already well about 350 parts per million now, and rising two parts per million per year." At the moment, he says, temperature increase is being driven mostly by carbon dioxide in the atmosphere. It's an inevitable byproduct of fossil fuel combustion and you get a lot of it. As it accumulates it raises the temperature, but it's not the only gas that does that. There are other things that go into the atmosphere that can also perform this greenhouse function, and one of them is methane, natural gas. McKibben is the author of "The End of Nature"( Random House) and other works.
"We now face the very real danger that if carbon raises the temperature of the planet, the permafrost in the arctic will begin to melt," he said. "Stored beneath that permafrost are large quantities of methane, (CH4), and if that melts and begins to spew into the atmosphere, then at a certain point there will be nothing we can do to slow down this reaction. Even if, at that point, if Congress decided to park every car and turn off every power plant there already would have been enough carbon in the atmosphere to really initiate this melting of the north, and with it this release of methane gas, and that's one of the real fault lines we want to try to avoid."
McKibben says the signs of global warming are widely visible in the U.S. today. These include (1) a heavy increase in precipitation in New England and the Mid-Atlantic states; (2) the increased frequency of "100-year storms" which now come in a lot of places every couple of years; (3) the death of large forested areas across the U.S. and Canada "from beetles and things that are no longer kept in check by cold weather;" (4) the spread of mosquito-borne dengue fever, already affecting parts of Texas. He predicted massive crop failures as yields decline 30- to 50-percent by century's end as basic crops such as corn, rice, and wheat shrivel in the heat. "We know now that if you put a certain quantity of carbon in the atmosphere it produces a certain increase in temperature and it does it whether you want it or not." He says the human race has so far raised the temperature about 1% Celsius, or 1.3% Fahrenheit globally averaged. "We expect if we don't get things under control very quickly, unfortunately, we're going to see another three, four, five degrees (increase) in the course of this century." He warns, "The melting of the Arctic in the summer of 2007 was an ominous sign. It happened well ahead of schedule (of scientific expectations) and it should give us great pause. There are a number of other physical features that are displaying the same kind of flux, rapid melt of glaciers and rapid acidification of the oceans being two prominent examples."
Interviewed by law professor Kurt Olson on the Comcast SportsNet show "Educational Forum," produced by the Massachusetts School of Law at Andover, McKibben warned of the necessity of prompt action against global warming. "I think the next few years will tell the tale. If we're not able to get real control of this problem pretty soon, then our odds of really slowing it down diminish dramatically. It's going to be a hundred year fight in the best of cases. But we better win some pretty big victories in the next few years or that hundred year fight is going to be a rout (for us)." The "Educational Forum" interview with McKibben will be broadcast Sunday, November 21st at 11 A.M. Eastern time.
The world's temperature has been "very stable for the ten thousand years of human civilization," McKibben said. "It's varied by well less than a degree centigrade globally averaged because carbon levels in the atmosphere have been relatively stable at 275 parts per million, plus or minus a little bit, until the beginning of the industrial revolution." He stressed that the human race cannot afford a temperature jump that would raise sea levels as "most of our big cities are built along the sea and those that aren't are often in the tropics built high enough up the sides of mountains that they used to be resistant to malaria. Mosquitoes couldn't ever winter there because of the cold. That's no longer true." At the same time, McKibben says, we "should also save a tear or two for the rest of DNA that we're likely to take down with us in the process. E were born into a very beautiful, intricate world with deep communion with species of all kinds on all sides and we're wiping a lot of them out."
In his own state of Vermont, McKibben said, as in the rest of New England, there has been "a dramatic increase in heavy precipitation." He explains it this way: "Warm air holds more water vapor than cold. And hence we get more drought in those arid areas where that water's evaporating. But once it's up in the air it's going to come down and so around here we get real gulley washers. My town, Ripton, had the two largest rain storms ever the summer before last that managed to wash out our roads and cut us off from the rest of the world. The governor had to fly in in a helicopter. And this is in a town with mostly intact forest that should be able to survive normal rainfall. But this isn't normal rainfall. This is something new, and in some sense, artificial." McKibben goes on to point out that "Engineers are having a much more difficult time because the hundred year storm, the hundred year flood, seems to be coming in a lot of places every couple of years. And that's testing design parameters of bridges, road, sewer systems, whatever."
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