WASHINGTON (AP) --
Some dirty old birds are helping scientists better understand one of the
more baffling climate change mysteries.
University of
Chicago researchers Shane DuBay and Carl Fuldner examined 1,347 dead birds
in museums in Chicago, Detroit and Pittsburgh, comparing birds from the
1900s and 1910s to birds from decades later.
The difference was
black and white.
Feathers of birds
in the 1900s were blacker than birds just 20 or 30 years later, suggesting
that there was more soot in the atmosphere than scientists originally
thought, according to a study published Monday in the Proceedings of the
National Academy of Sciences.
This is important
because scientists believe soot, also called black carbon, has an important
role in climate change. They know it traps heat, but scientists haven’t been
able to study it well because it doesn’t stay in the atmosphere long.
“The problem
previously is that there was no way to characterize the particles from this
early industrial era,” Fuldner said. “You can’t look at the soot particles
coming out of the 1910 manufacturing plant in Joliet, Illinois.”
Black carbon in the
air comes from inefficient burning of fossil fuels, especially coal. Some
recent studies call it the second most potent greenhouse “molecule” --
because unlike the most important, carbon dioxide, it is a solid, not a gas.
The black carbon
coating the birds stuffed long ago now give scientists a better record,
showing past pollution may have been underestimated, Fuldner and DuBay said.
Black carbon emissions dropped around 1930 as homes turned away from coal
for heat. Coal was used more and more for manufacturing and electric power,
but that produces less soot than burning it in homes for heat, they said.
The study is
fascinating to experts who are trying to predict future warming from black
carbon.
Some scientists say
reducing black carbon emissions may be an easier way to fight climate change
than by just reducing carbon dioxide emissions.
Other scientists
say the impacts of the study on projections for future warming would likely
be modest -- at best -- in part because black carbon stays in the atmosphere
for such a short time.
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