Advanced Degrees
Got an opinion on global warming? Science backs it up.
Rely on daily media reports,
and you’ll probably think any question of whether or why
the Earth is warming was disposed of long ago. But tens of thousands
of scientists have about as many questions concerning both the
mechanism and the reality of destructive planetary warming as
postulated by the United Nations’ International Panel
on Climate Change (IPCC) and the many who embrace its view.
To get the benefit of differing
views, the Wisconsin Electric Cooperative Association invited
two distinguished University of Wisconsin scientists to the
2004 joint annual meeting of the Wisconsin Federation of Cooperatives
and Minnesota Association of Cooperatives at Eau Claire.
Dr. John Magnuson is a professor
emeritus in zoology. He’s specialized in researching how
temperature variation affects aquatic organisms, and his ideas
on global warming have made him a quoted source for National
Geographic magazine. Dr. Ed Hopkins is Wisconsin’s assistant
state climatologist. He’s authored a book called Wisconsin
Weather and Climate and has more than two decades’ experience
teaching meteorology at the Universities of Wisconsin and Northern
Illinois.
In mid-November, a large and fully
engaged annual meeting crowd heard the two debate this proposition:
“Resolved, to avoid a ruinous increase in global temperatures
and resulting adverse climate events, human-induced carbon dioxide
emissions must be significantly curtailed.”
Climate’s Changing; We Can Prove
It
John Magnuson has no doubt that
the climate is warming, that this spells trouble, and that people
are causing it by doing things that increase atmospheric carbon
dioxide. Among the consequences, he says, will be just about
every imaginable climate- and weather-related event: dryer,
warmer summers and more drought, but also more frequent heavy
rainfall. Wisconsin can expect to have winters like Iowa and
summers like Arkansas by 2090, he says.
Ed Hopkins doesn’t doubt
that average temperatures have risen over the past 140 years,
but he is less certain than his counterpart about how long this
will continue and how damaging it might be. Claims that recent
temperatures are the warmest ever and that CO2 is the culprit,
he considers “hogwash.”
Magnuson supports his view by
showing the annual-meeting audience a selection of graphs and
charts illustrating the greenhouse effect—the variable
heat-trapping property of Earth’s atmosphere—and
several things that are beyond dispute.
Among these are surface-station
temperature records showing a sharp rise that spans the 20th
century, and the recorded duration of winter ice cover on Madison’s
Lake Mendota going back 150 years.
“Ice is what I do research
on,” Magnuson explains, saying it’s “a most
sensitive indicator of change and so it’s sort of an early
warning.” He hears a loud, clear warning from Lake Mendota,
noting that its typical 1850s ice cover of four months has dwindled
by as much as a month and a half.
Magnuson says on lakes all over
Wisconsin, “breakup is occurring earlier and freeze is
occurring later,” citing Chequamegon Bay, Shell Lake,
and southern Wisconsin lakes where longer historical records
are available. He says the same is happening in Minnesota, New
York, Ontario, Finland, and Russia.
“Just recently the Arctic
Council released its Arctic report,” he says, “And
what they report is the average amount of ice in the Arctic
has declined 8 percent in the past 30 years.” This represents
an area “larger than the states of Texas and Arizona combined.”
“Impacts have already occurred
and will get worse,” Magnuson says.
Hopkins responds, “I feel
like a court-appointed lawyer for the defense.” Changes
are occurring, he says, “but the climate has always been
changing and I just want to caution that there is doubt, at
least in my mind, that we can attribute everything in this complex
climate system that we have, all to carbon dioxide.”
He presents his own charts and
graphs, showing several periods in history that were warmer
than the present. Human-induced CO2 emissions couldn’t
have been responsible.
Nothing New in the World
Hopkins contends our understanding
of climate change is hobbled by “certain common fallacies,”
the first being that “the current atmospheric warming
is unprecedented and unique.”
The idea that today’s temperatures
are uniquely warm and growing relentlessly warmer has been fed—indeed
was arguably spawned—by a 1999 IPCC historical temperature
graph known as “the hockey stick” because its shape
resembles one. A long, straight line representing steady average
temperatures over the past thousand years suddenly shoots up
at about a 70-degree angle, implying unprecedented 20th century
warming that accelerates during the 1990s.
Hopkins never mentions the hockey
stick, nor the fact that its 20th century temperature spike
amounts to less than one degree, Celsius, above what it depicts
as the thousand-year norm. He does bring up lots of established
temperature history the hockey stick seems to overlook. “In
at least the last few years it has been fairly warm,”
he says. “But if you go back about a thousand years to
a fairly good warming time they call the Mediaeval Warm Period,”
you’ll find warmer temperatures than today’s, he
says. “That’s when the Vikings were here in North
America and then they faded out because of the cooling”
between about 1500 and the mid-19th century, known as the “Little
Ice Age.”
There’s no shortage of climatologists
who say today’s rising temperatures only signify an ongoing
recovery from the Little Ice Age. But Hopkins adds that things
were still warmer about 6,000 years ago and even warmer than
that before the Wisconsin glaciation period that ended about
10,000 years ago—with the retreat of ice sheets miles
thick that reached all the way to southern Wisconsin.
About 160,000 years ago, he says,
before that big chill, temperatures were 2 to 3 degrees Celsius
(3.6–5.4 degrees Fahrenheit) higher than now. “We
are not at the warmest time,” Hopkins says. “Be
very careful when people say this is the warmest.”
In fact, he says, the highest
temperatures recorded in Madison since the 1860s occurred almost
70 years ago. Blistering summers, especially that of 1936, prompted
large migrations as people fled the “Dust Bowl”
of the central United States for points west. His counterpart
has warned that global warming will bring “more”
days over 97 degrees, but Hopkins notes dryly that high temperatures
in Madison during the summer of 2004 never once reached 90.
He also denies carbon dioxide
is the most important greenhouse gas. “To my way of thinking
it’s water vapor. It does a much better job of absorbing
heat,” Hopkins says, offering the example of a cloudy
winter night versus a clear one.
Magnuson promptly acknowledges
that computerized models used to generate IPCC climate scenarios
are not good at accounting for the role played by clouds—water
vapor. He says the models will get better.
What to Do?
Even if you believe global warming
is utter nonsense, it’s not unreasonable to ask whether
some things done in response to it might independently make
sense. After all, with governments worldwide blaming human economic
activity (chiefly that of Americans, who Hopkins points out
are only the 12th largest per-capita emitters of CO2, well behind,
for instance, Bahrain) for the anticipated destruction of the
planet, it’s a pretty good bet we’ll be doing something.
Magnuson lists major sources of
greenhouse gas emissions: combustion by energy utilities, about
30 percent; fuels burned for transportation, 20–30 percent;
residential energy use, about 8 percent. Those are the big targets,
but anyone who needs global warming as a reason to practice
energy efficiency hasn’t paid the bills or filled the
gas tank lately.
Magnuson rejects the idea that
the hundreds of billions of dollars in direct expenditures and
other economic impacts associated with curbing greenhouse emissions
ought to be held off until we’re more certain what’s
really happening.
“If you wait until uncertainty
is gone, you will not make any decisions on this issue,”
he says. “Thirty years from now, fundamental uncertainties
in our understanding of the climate system and how we interact
with it will continue.” Later, he adds, “The greater
the uncertainty, the higher the economic benefits are to beginning
to abate greenhouse gases,” and, “To pass on the
cost of this to future generations without taking a bite out
of ourselves, I think, verges on the immoral.”
Whether morality might also be
served by helping, in our poorly understood way, to delay freezing
of the planet is a question not raised—but Hopkins comes
close. “When you look at certain records, the changes
in how the Earth’s orientation with respect to the sun
changes,” he says, “we could start going back to
an ice age. Now human activity will push that time back a few
centuries, possibly.” But human activity, he hastens to
point out, involves more than emitting CO2.
Hopkins endorses his counterpart’s
views on stewardship of the land. “We should use it wisely,”
he says. “My only argument is that when people, scientists,
and the media get out there and say it’s the warmest ever
and carbon dioxide is the only thing that’s affecting
our climate, I say, ‘hogwash.’
“My opinion,” Hopkins
adds, “is that you should take a look and of course act
responsibly, but also that you should at least go through and
try to ferret out what is nonsense and what is fact.”—Dave
Hoopman
For many, the approach of each new year brings
thought of renewal and resolutions. And for every adult soul,
you can add a third “R” to that list of year-end
ruminations: revenue, as in taxes.