Old Air, Sealed Against Time, Sought for Study of Greenhouse Effect
LOS ANGELES (AP) _ Add old air to the list of valued antiques.
Scientists, hoping to learn how much carbon dioxide has increased in the atmosphere, have asked museums nationwide to look for historic objects holding sealed air.
″There is some fear that increasing levels of carbon dioxide as the result of increased fossil fuel use will cause severe climate changes because of the so-called greenhouse effect,″ says Allen Ogard, a researcher at Los Alamos (N.M.) National Laboratory, operated by the University of California for the U.S. Department of Energy.
The greenhouse effect occurs when carbon dioxide traps solar radiation in the atmosphere, raising temperatures worldwide - possibly by several degrees over the next century, according to the Environmental Protection Agency.
That could melt polar ice caps and raise the sea level, eroding shorelines, some scientists have speculated.
To measure the increase in carbon dioxide accurately, scientists needed accurate samples of air as it used to be.
″To do that we needed historical air,″ said co-researcher Jane Poths.
So Los Alamos asked the nation’s museums and other institutions to look for such things as old brass buttons, antique telescopes and ancient hour glasses that may contain sealed air from specific periods of history.
Ogard says a sunken river boat in the Mississippi River could have many items containing old air.
″Maritime museums and exhibits have become particularly interesting because of their navigational and optical instruments and hollow brass buttons from officers’ uniforms,″ Ms. Poths says. ″There are good historical records for many of these old instruments. We know exactly when some of them were last serviced and resealed.″
The Adler Planetarium in Chicago yielded a 17th century hour glass.
Researchers also found ″some drug bottles in Maine″ that were sealed ″close to 100 years ago,″ Ogard said.
But pickings have been slim, he conceded.
″We are finding that most things that can be opened, have been,″ Ogard said.
They hoped sealed cremation urns at a Buddhist temple in Hawaii would yield some old air, but ″they weren’t sealed tight enough,″ Ogard said.
The presence of carbon dioxide in the air has been measured in some areas as high as 330 parts per million, believed by some scientists to be substantially higher than the level before the start of the Industrial Revolution. However other scientists disagree whether a greenhouse effect is actually occurring.
Needles that can be inserted into the sealed objects are now being made.
Still, a method must be found to prove the air is as old as the records indicate. It also will be important to know if the carbon dioxide was in the air when the item was sealed. The item, for instance, can’t be flame-sealed because burning produces carbon dioxide, Ogard said.