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Ozone Hole Science Revisited

Ozone Hole Science Revisited



Scientists are commemorating the discovery 20 years ago that man-made chlorofluorocarbons (CFCs) used chiefly in refrigerators and air-conditioners were responsible for creating the "ozone hole" over the Antarctic. The scientists concluded that CFCs would drift into the stratosphere where they would produce chlorine compounds that react with ice particles and sunlight to efficiently destroy ozone molecules that shield the surface from ultraviolet light streaming from the sun. In 1987, the world adopted the Montreal Protocol to eventually eliminate the production of CFCs. Activists often cite the Montreal Protocol as a model for a future treaty addressing man-made global warming by banning the emission of greenhouse gases. A Nobel Prize in chemistry was awarded in 1995 to the three scientists who identified the ozone/CFC connection.


This neat story of the scientific identification of a man-made cause for stratospheric ozone depletion followed by a successful international response to the threat is now being challenged by some very recent research. News@nature.com (sub required) is reporting a new analysis by Markus Rex, an atmosphere scientist at the Alfred Wegener Institute of Polar and Marine Research in Potsdam, Germany, which finds that the data for the break-down rate of a crucial molecule, dichlorine peroxide (Cl2O2) is almost an order of magnitude lower than the currently accepted rate.


What this could mean according to the Nature news article is that:

"This must have far-reaching consequences," Rex says. "If the measurements are correct we can basically no longer say we understand how ozone holes come into being." What effect the results have on projections of the speed or extent of ozone depletion remains unclear.

The rapid photolysis of Cl2O2 is a key reaction in the chemical model of ozone destruction developed 20 years ago2 (see graphic). If the rate is substantially lower than previously thought, then it would not be possible to create enough aggressive chlorine radicals to explain the observed ozone losses at high latitudes, says Rex. The extent of the discrepancy became apparent only when he incorporated the new photolysis rate into a chemical model of ozone depletion. The result was a shock: at least 60% of ozone destruction at the poles seems to be due to an unknown mechanism, Rex told a meeting of stratosphere researchers in Bremen, Germany, last week.


Other groups have yet to confirm the new photolysis rate, but the conundrum
is already causing much debate and uncertainty in the ozone research community. "Our understanding of chloride chemistry has really been blown apart," says John Crowley, an ozone researcher at the Max Planck Institute of Chemistry in Mainz, Germany.


"Until recently everything looked like it fitted nicely," agrees Neil Harris, an atmosphere scientist who heads the European Ozone Research Coordinating Unit at the University of Cambridge, UK. "Now suddenly it's like a plank has been pulled out of a bridge." ...


Nothing currently suggests that the role of CFCs must be called into question, Rex stresses. "Overwhelming evidence still suggests that anthropogenic emissions of CFCs and halons are the reason for the ozone loss. But we would be on much firmer ground if we could write down the correct chemical reactions."

Of course, it may be that Rex's research has gone wrong somehow or that another chemical mechanism involving CFCs will turn out to be chiefly responsible for ozone depletion. Nevertheless, it is good to keep in mind that all scientific results are provisional and may change in the light of new evidence.

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Challenge to Scientific Consensus on Global Warming


Challenge to Scientific Consensus on Global Warming: Analysis Finds Hundreds of Scientists Have Published Evidence Countering Man-Made Global Warming Fears



WASHINGTON, Sept. 12  /PRNewswire-USNewswire/ -- A new analysis of peer-reviewed literature reveals that more than 500 scientists have published evidence refuting at least one element of current man-made global warming scares. More than 300 of the scientists found evidence that 1) a natural moderate 1,500-year climate cycle has produced more than a dozen global warmings similar to ours since the last Ice Age and/or that 2) our Modern Warming is linked strongly to variations in the sun's irradiance. "This data and the list of scientists make a mockery of recent claims that a scientific consensus blames humans as the primary cause of global temperature increases since 1850," said Hudson Institute Senior Fellow Dennis Avery.


Other researchers found evidence that 3) sea levels are failing to rise importantly; 4) that our storms and droughts are becoming fewer and milder with this warming as they did during previous global warmings; 5) that human deaths will be reduced with warming because cold kills twice as many people as heat; and 6) that corals, trees, birds, mammals, and butterflies are adapting well to the routine reality of changing climate.


Despite being published in such journals such as Science, Nature and Geophysical Review Letters, these scientists have gotten little media attention. "Not all of these researchers would describe themselves as global warming skeptics," said Avery, "but the evidence in their studies is there for all to see."


The names were compiled by Avery and climate physicist S. Fred Singer, the co-authors of the new book Unstoppable Global Warming: Every 1,500 Years, mainly from the peer-reviewed studies cited in their book. The researchers' specialties include tree rings, sea levels, stalagmites, lichens, pollen, plankton, insects, public health, Chinese history and astrophysics.


"We have  had a Greenhouse Theory with no evidence to support it-except a moderate warming turned into a scare by computer models whose results have never been verified with real-world events," said co-author Singer. "On the other hand, we have compelling evidence of a real-world climate cycle averaging 1470 years (plus or minus 500) running through the last million years of history. The climate cycle has above all been moderate, and the trees, bears, birds, and humans have quietly adapted."


"Two thousand years of published human histories say that the warm periods were good for people," says Avery. "It was the harsh, unstable Dark Ages and Little Ice Age that brought bigger storms, untimely frost, widespread famine and plagues of disease."  "There may have been a consensus of guesses among climate model-builders," says Singer. "However, the models only reflect the warming, not its cause." He noted that about 70 percent of the earth's post-1850 warming came before 1940, and thus was probably not caused by human-emitted greenhouse gases. The net post-1940 warming totals only a tiny 0.2 degrees C.


The historic evidence of the natural cycle includes the 5000-year record of Nile floods, 1st-century Roman wine production in Britain, and thousands of museum paintings that portrayed sunnier skies during the Medieval Warming and more cloudiness during the Little Ice Age. The physical evidence comes from oxygen isotopes, beryllium ions, tiny sea and pollen fossils, and ancient tree rings. The evidence recovered from ice cores, sea and lake sediments, cave stalagmites and glaciers has been analyzed by electron microscopes, satellites, and computers. Temperatures during the Medieval Warming Period on California's Whitewing Mountain must have been 3.2 degrees warmer than today, says Constance Millar of the U.S. Forest Service, based on her study of seven species of relict trees that grew above today's tree line.


Singer emphasized, "Humans have known since the invention of the telescope that the earth's climate variations were linked to the sunspot cycle, but we had not understood how. Recent experiments have demonstrated that more or fewer cosmic rays hitting the earth create more or fewer of the low, cooling clouds that deflect solar heat back into space-amplifying small variations in the intensity of the sun.


Avery and Singer noted that there are hundreds of additional peer-reviewed studies that have found cycle evidence, and that they will publish additional researchers' names and studies. They also noted that their book was funded by Wallace O. Sellers, a Hudson board member, without any corporate contributions.


For more information, please contact Dennis Avery, Hudson Institute Senior Fellow and co-author of Unstoppable Global Warming: Every 1500 Years, at 540-337-6354: Email: cgfi@hughes.net


Hudson Institute
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