Is Earth near its 'tipping points' from global warming?
Pastor Dale Morgan
Is Earth near its 'tipping points' from global warming?*
By Dan Vergano and Patrick O'Driscoll, USA TODAY
Earth is spinning toward many points of no return from the damage of
global warming, after which disease, desolation and famine are
inevitable, say scientists involved in an international report due
Friday on the effects of climate change.
Opinions vary about how long it will take to reach those "tipping
points" and whether attempts to cut planet-warming gases churned out by
power plants, vehicles and other human industry can slow, halt or
reverse the harmful effects in coming decades. Some suggest it might be
cheaper for society to adapt to the changing climate than to roll back
the pace of warming.
But in the report, the second of three this year by the
Intergovernmental Panel on Climate Change, thousands of climate
scientists and representatives of more than 100 nations, including the
USA, present in the most stark terms the "key global risks" — serious
environmental consequences from the changing climate — that threaten
humanity.
"It's time (a report) puts people on the planet into the picture" of
global warming, says economist Gary Yohe of Wesleyan University, a lead
author of the report.
Concerning the USA, the report will reference numerous scientific
studies on the effects of spring arriving weeks earlier, says University
of Montana ecologist Steve Running, an author of the chapter on North
America. The "big climate signal and impacts" will be in the West, he
says. Earlier melting of mountain snow, on which much of the region
depends for water, would mean more severe dry spells and droughts that
would trigger worse wildfire seasons. Lower stream flows also would
threaten fish and wildlife.
Research also has predicted more frequent heat waves, increased rainfall
and flooding in northern states, and more severe tropical storms on the
Gulf and East coasts.
In its first report in February, the panel, backed by the World
Meteorological Organization and conducted under the auspices of the
United Nations Environmental Programme, concluded that "unequivocal"
evidence shows industrial releases of greenhouse gases have warmed the
Earth an average of about 1 degree Fahrenheit in the past century. That
makes it "very likely" that temperatures will rise 3 to 7 degrees this
century, depending on future emissions.
This week's report, essentially a review and condensation of climate
research since 2001, is designed to identify the dangers that the
failure to curb emissions of carbon dioxide, methane and other
greenhouse gases present for the planet. Just as new buildings in
earthquake zones are designed to handle more than everyday shocks, and
fire insurance is meant to cover more than burnt toast, politicians and
planners want to know worst-case scenarios, says Stanford University
climatologist Stephen Schneider.
"In a sense, we are looking at a series of tipping points for humanity
and climate," says Richard Moss, director of the U.S. Global Change
Research Program Office.
Irreversible effects on plants, animals, farming and weather already are
apparent, says biologist Camille Parmesan of the University of Texas in
Austin, one of the scientists assigned to review the report. Studies
weighed in the report show that warming has eliminated about 70 animal
species and affects 59% of wild species surveyed.
"We are seeing plenty of potentially dangerous outcomes where the hotter
it gets, the worse it gets," Stanford's Schneider says.
Moss says the roughly 5-degree rise in global average temperatures
envisioned in the February report will cause damage that cannot be
recovered. He echoes a warning by NASA scientist James Hansen in 2004
that the window for action is only 10 years. The Stern Review, a
high-profile report last year by the United Kingdom's chief economist,
Nicholas Stern, warns of serious financial threats to agriculture and
commerce.
Some scientists question such concerns. Danish statistician Bjorn
Lomborg has become a spokesman for the view that trying to repair global
warming will cost more money than just working to adapt the world to it.
He suggests, for instance, that it would be cheaper to cure and
eradicate malaria than to attack the rising temperatures that could
expose millions more people to the disease.
Gore makes his case
Last month, Lomborg followed former vice president Al Gore to the
microphone in testifying before a House committee. Gore, star of the
Oscar-winning documentary on warming, An Inconvenient Truth, called the
phenomenon a "planetary emergency." Lomborg countered that Gore "has
gotten carried away and has come to show only worst-case scenarios."
Schneider argues that worst-case scenarios are still real threats. A
collapse of the Greenland and Antarctic ice sheets, which Lomborg
downplayed at the hearing, genuinely worries scientists such as Stefan
Rahmstorf of Germany's Potsdam Institute for Climate Impact Research.
Rahmstorf has suggested sea levels could rise as much as 4.6 feet
worldwide by 2100. Schneider says a simple cost-benefit analysis ignores
the reality that poor people in Bangladesh and other low-lying lands
would have to bear the brunt of climate change.
In Brussels this week, about 60 lead authors are working with
representatives of more than 100 nations to distill, clarify and approve
the panel's findings in a short summary for policymakers. The summary is
out Friday; the scientific chapters arrive Tuesday.
Environmental and energy analyst Anthony Patt of Boston University, a
report co-author, says the report will divide the possible effects of
temperature increases this century into three grades: a 3.6-degree rise
with warmer winters but few human catastrophes; an up to 7.2-degree rise
that wealthy nations could handle but would prove calamitous to poor
nations and many species; and an even higher rise, which "would prove
difficult for any society to adapt to."
What are the yardsticks?
In grades of scientific certainty, physical effects such as temperature,
sea level rise and concentrations of greenhouse gases are most certain,
Schneider says. Next come biological ones, such as species extinctions.
And the hardest to estimate are human effects, such as disease and hunger.
What the panel's report will not establish is whether vast infestations
by pine beetles in the forests of the western USA and Canada are tied to
warming, Running says. Although many scientists believe there is a link,
he says, research has not focused enough on temperature. "My nose is
telling me there's a climate-change signal here, but the papers in print
yet aren't doing a strong enough analysis."
Worldwide, thresholds were outlined last year in "Avoiding Dangerous
Climate Change," a summary of tipping points for which British Prime
Minister Tony Blair wrote the foreword. They include:
•At a 3.6-degree rise, all Indian Ocean coral reefs go extinct, and 97%
of the rest around the globe are "bleached" or severely damaged. All
Arctic ice disappears.
•At a 5.4-degree increase, half of all nature reserves become unable to
conserve native species. The Amazon rainforest disappears.
•At 7.2 degrees or higher, coastal flooding is seven times worse than in
1990. Malaria threatens 330 million more people a year, and hunger
jeopardizes 600 million. Australia no longer can grow food.
All of this leaves aside the most extreme risks that Schneider calls the
"dark edge of the bell curve": melting of the vast Antarctic ice sheets;
shutdown of Atlantic Ocean circulation, which brings warm weather to the
United Kingdom; and the release of more greenhouse gases frozen in the
Arctic tundra.
Some scientists, such as Penn State's Michael Mann, worry that the
panel's reports lag behind the latest science because of a six-month
research cutoff before their release, a lifetime in climate study.
Last month, for instance, a report in Geophysical Research Letters found
that ocean acidification from increased carbon dioxide is likely to
wreak "havoc" for shellfish and coral and disrupt food chains.
A Colorado State University analysis in March said warming will make
grazing lands less productive by 2050.
A University of Minnesota team reported that Lake Superior has warmed an
average of 4.5 degrees since 1979, about twice the local atmospheric
warming.
Because the panel's reports trail such research, they are "always by
design … a little conservative," Mann says.
In May, the climate panel picks up where this month's report leaves off:
an assessment of ways to counteract and adapt to warming.
"I suspect we're reluctant to think about it because we're worried that
if we start, we will have no choice but to think about nothing else,"
John Lanchester, who reviewed recent works on climate change, wrote in a
recent London Review of Books.
"The scientists involved are not just talking in a new way, one
unfamiliar to both them and us, but are in effect trying to sell us
something," Lanchester says. "And we the public might be undereducated,
but we know not to trust entirely someone who is trying to sell us
something. … We deeply don't want to believe this story."
But James McCarthy of Harvard, incoming head of the American Association
for the Advancement of Science, says the reality of warming is accepted,
with regional climate-change trends already playing out as predicted.
The biggest tipping point already may have happened, says John Drexhage
of Canada's International Institute for Sustainable Development: Talk of
global warming has become routine and accepted for all politicians, not
just Al Gore.