RED GROUSE TELLING US ABOUT GLOBAL CLIMATE CHANGE?
by Whit Gibbons
October 16, 2005
read that one of the problems we face today about accepting and solving
global climate change problems is political denial. The point was that
some politicians have ignored scientific evidence and proceeded as if
no problem existed. Consequently, no government controls, regulations,
or meaningful appeals for conservation have been instituted to reduce
carbon dioxide emissions through moderation in energy consumption.
On the other
side are those, including a few respected scientists, who remain unconvinced
that global climate change, based on the geological record, is any more
dramatic than has occurred in former eras. In other words, the world’s
climates have changed at other times before people were involved, and
the U.S. culture of overconsumption is not affecting global climate change.
of whether humans are affecting the world’s weather, the scientific
evidence indubitably supports that the climate has changed. For example,
in a study of red grouse, the climate had changed enough in a century--not
a long time on a geological timescale--for scientists to test two hypotheses
that depended on climate change. Red grouse are a common game bird for
which long-term records were available. Records of red grouse in northern
England taken since the 1800s were used to reveal how climate change can
influence population levels of grouse and other forms of wildlife.
In a study to explain why all grouse populations in a particular year
either increased or decreased, even though they were from five distinct
regions, I. M. Cattadori and P. J. Hudson of Pennsylvania State University
teamed with D. T. Haydon of the University of Glasgow to examine a century-old
data set. One hypothesis was that what determined fluctuations in grouse
population size were direct effects of the climate on the breeding success
and survival of grouse chicks. The alternative hypothesis was that the
climate affected the interaction between the host (grouse) and a parasitic
worm that reduced fecundity in the grouse. A parasite that lowers reproductive
capacity could be a driving force affecting the abundance of the bird
The investigators used elaborate statistical models and detailed weather
data for each of the five regions to verify that environmental conditions
favorable for the spread of parasite infection led to widespread population
declines in grouse. Years that were unfavorable for the parasite infection
resulted in increases in grouse survival. The findings are important in
their applicability to the management of grouse populations. But they
are also another example of how regional changes in climate can result
in local changes in ecological factors, in this case parasite burdens,
that can lead to significant changes in animal population sizes and ultimately
biodiversity patterns in a region.
evidence that the world is warming also came from British scientists who
determined that flowers of nearly 400 species of plants for which records
were available are now blooming more than 4 days earlier than they did
half a century ago and more than a month earlier than they did a century
ago. Likewise in North America, a comparison of blooming dates of plants
in the Arnold Arboretum in Boston during the last 20 years revealed that
they have flowered on average more than a week earlier than they did in
the early 1900s.
themselves may solve the overconsumption problem. But Americans need to
be aware that by some reports the United States is the major industrial
country unwilling to cut back on the use of oil and coal for fuel that
leads to greenhouse emissions that cause global warming. Understandably,
such an unyielding position in the face of what the rest of the world
views as overwhelming evidence has led some to wonder if U.S. political
connections with the fossil fuel industry are so strong that even decisions
in the best interest of the nation and the world are brushed aside.
of whether politicians in power are using their influence to continue
a dependence on the oil industry for personal profit will probably remain
unresolved for many more years. But the fact that climate change is occurring
and that it is affecting plants and animals on a global scale seems incontestable.
you have an environmental question or comment, email