IS THE LATEST ON GLOBAL WARMING?
by Whit Gibbons
September 5, 2004
Philadelphia Inquirer on target last month when they accused the
Bush administration of having a "head-in-the-sand approach"
about global warming? Or was a contrasting view given in the National
Review Online more accurate in stating that the cost of taking steps
to remedy global warming would outweigh the benefits of doing nothing?
Determining whether the economic costs are worth the environmental benefits
of the United States' launching a conscientious offensive against global
warming and its known and perceived causes is problematic. The issue swirls
as much or more around politics, business interests, and nationalistic
agendas as around the actual facts. What is true or not true about the
environmental consequences of carbon dioxide emissions is controversial.
But some facts related to global warming are incontestable.
of plants unquestionably bloom earlier each year, and many animals indisputably
breed earlier in the season now than they did a few years ago. Most scientists
agree that global climate change resulting in warmer average temperatures
around the globe is the underlying cause of the shifting reproductive
patterns. By some measurements, the earth's temperature has risen more
than one degree Fahrenheit over the last century and is steadily going
up. A degree or so may seem trivial, but some ecologists consider the
gradual warming of the globe to be responsible for observations being
made about changing botanical and wildlife patterns.
documentation of a change in seasonal activity of plants has been presented
by Richard Primack and Abraham Miller-Rushing, biologists from Boston
University who looked at the flowering dates of 229 individual plants
that had been growing in the Arnold Arboretum in Boston for more than
half a century. Their study used the long-term records of the time of
flowering by particular plants on the grounds of the arboretum.
examined more than 60 species of plants, with the blooming records for
some long-lived trees such as magnolia and dogwood going back more than
a hundred years. Based on meteorological records for Boston, which not
surprisingly encompass at least a couple of centuries, the average annual
temperature has risen almost 3 degrees F since the late 1800s. One finding
from the comparison of blooming dates was that during the last 20 years
or so plants in the arboretum have flowered on average more than a week
earlier than they did in the early 1900s.
British scientists determined that flowers of nearly 400 species of plants
for which records were available were blooming earlier than they once
did. The average time of blooming in the period from 1990 to 2000 was
advanced by more than 4 days when compared to blooming dates beginning
in the 1950s. Some of the species flower as much as a month earlier now
than they did in the last century. The results from both America and England
are dramatic and should convince anyone that things are changing in the
became aware of the advanced reproduction phenomenon a few years ago when
Robert Kennamer of the Savannah River Ecology Laboratory showed me his
two decades of data on South Carolina wood ducks. In short, wood ducks
began to lay eggs earlier in the year during the 1990s than they did in
the 20 years before. Nesting seasons, which typically began in mid-February
in the 1970s, began in mid-January by the middle of the 1990s. From 1982
to 1996 alone, the average nesting date in the population advanced by
about 10 days. Confirmed examples exist for other animal species responding
to global warming, such as the elimination of lower elevation populations
of pikas. These small, western North American relatives of rabbits require
cool temperatures and many populations now live higher up mountain slopes
than they did earlier in the century.
warming a problem caused by greenhouse emissions that could be regulated
by the ruling industrial nations to reduce the continued rise in temperatures
predicted throughout the world? The point is likely to be debated nationally
and internationally while temperatures continue to increase at least a
few more degrees. But what cannot be argued is that many plants and animals
are already changing their biology and reproducing earlier than ever before.
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