Friday, May 24, 2013

Joseph Farman, Discovery of Hole In the Ozone Layer

Excerpts from 5/18/2013 Paul Vitello article in The New York Times:

Joseph Farman, a British researcher whose... study of atmospheric changes in the Antarctic established the existence of a hole in the ozone layer over the South Pole approximately the size of the United States...      
Mr. Farman studied the Antarctic atmosphere for 25 years...       
When he began collecting ozone readings in 1957 as a young geophysicist at the Halley Bay research base in Antarctica, scientists had already come to understand the basic Jekyll-and-Hyde facts of ozone: that it was a pollutant when clumped in high concentrations near the ground and a vital shield when concentrated in the upper atmosphere, absorbing the sun’s most perilous ultraviolet rays.
After 1974, when two American scientists, Mario Molina and F. Sherwood Rowland, proved that chlorofluorocarbons, commonly used in aerosol spray cans and refrigeration, could destroy ozone in the upper atmosphere, the United States and a few other countries began regulating their use and scrutinizing the ozone readings already being collected by NASA satellites.
But Mr. Farman refused to stop making ground-level readings, despite his superiors’ questions about their usefulness, and despite his lack of standing in the field of ozone research. He did not have a Ph.D., and his primary work was in meteorological science...      
“His willingness to do research he thought was important, even when others did not, made him a model scientist,” said Sharon Roan, author of the 1989 book “Ozone Crises: The 15-Year Evolution of a Sudden Global Emergency.” ...             
In an interview years later, Mr. Farman recalled budget-cutters in his office telling him: Your ozone records show little change over the last 25 years; the ozone problem is under control now; the Americans are tracking all this with their orbiting satellites; and there is no point in our doing it too.
[H]e argued that the agency’s Antarctic ozone level readings were valuable because they were the longest continuous record maintained anywhere...       
About a year later, in October 1982, Mr. Farman collected Antarctic ozone readings so radically different from anything seen before that he assumed that his 25-year-old Dobson meters had given out. He ordered new ones. (The devices calculate ozone thickness by measuring the amount of ultraviolet radiation penetrating the atmosphere. They had been found to work best when their photographic plates and other sensitive instruments were wrapped in heavy quilts.)
The new machines produced results even more startling. “It just went haywire,” Mr. Farman said.
After a series of double- and triple-check tests, Mr. Farman and his colleagues Jonathan Shanklin and Brian Gardiner published a paper in the journal Nature in May 1985 showing that ozone levels over Antarctica had fallen by about 40 percent from 1975 to 1984. The ozone hole was no longer a theoretical possibility, as Dr. Molina and Dr. Rowland had postulated, it was a real and present danger to life on earth.
Based on the Britons’ findings, and later readings taken by American high-altitude aircraft, the Environmental Protection Agency concluded in 1986 that the increased exposure to ultraviolet radiation caused by the ozone hole could be responsible for 40 million cases of skin cancer and 800,000 cancer deaths in the United States over the next 88 years.       
How NASA’s satellites missed it has been answered in various ways. In one version, the ozone hole was detected by NASA’s monitors but discarded by data-analysis computer software intended to dismiss wild anomalies...       
The paper by Mr. Farman and his colleagues, coupled with the research of Dr. Molina and Dr. Rowland — who with a Dutch scientist, Paul Crutzen, shared the 1995 Nobel Prize for chemistry for their ozone research — changed the international politics of environmental regulation. A treaty, the Montreal Protocol, intended to phase out the production of ozone-depleting compounds, was signed by 24 countries in 1987 and has since been ratified by almost 200...      
Though ozone depletion is said to have leveled off in the early 2000s, the effects of long-living, ozone-depleting chemicals already in the atmosphere will continue for an additional 80 to 100 years, by most accounts...