August 15, 2000
WASHINGTON (Reuters) -- Does your sneezing and hay fever seem to
be getting worse each year? Blame global warming.
Researchers with the U.S. Agriculture Department said Tuesday
that higher carbon dioxide (CO2) levels linked to gradually
increasing temperatures on earth may also be responsible for
doubling the amount of ragweed pollen during the past four
decades.
Another doubling could occur by the end of this century, they
said.
"This research may help us better understand the troubling impact
of high carbon dioxide levels on our environment and our health,"
Agriculture Secretary Dan Glickman said in a statement.
The USDA study showed pollen production rose almost 400 percent
with a 200 percent increase in the amount of C02. The high CO2
levels also appeared to encourage ragweed to produce pollen
earlier than usual.
Lewis Ziska, a USDA plant physiologist, measured pollen counts on
ragweed grown in the laboratory at various levels of atmospheric
CO2, from the 1900 level of 280 parts per million (ppm) to
today's levels of 370 ppm, and at the future predicted level of
600 ppm.
Pollen production soared from 5.5 grams to 10 grams to 20 grams
as CO2 moved through the three levels.
An estimated 40 million Americans suffer from allergies, mostly
from airborne pollens such as ragweed, grass, spruce, cedar,
juniper and other trees.
The U.S. Senate has yet to ratify the Kyoto Treaty, negotiated in
late 1997 to curb global warming by limiting the fossil fuel
emissions of industrialized nations. The emissions have been
linked to the steady rise in carbon dioxide in the earth's
atmosphere.
SOURCE: CNN
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