PITTSBURGH -- With all due respect to teams still skating in the Stanley Cup playoffs, the world's most important "hockey stick" on this 43rd Earth Day is wielded by Michael E. Mann and other climate scientists.
Mr. Mann, a Pennsylvania State University professor and director of the school's Earth Systems Science Center, produced a graph in 1998, later dubbed the "hockey stick," that showed global temperatures were level or declining for almost 1,000 years -- the long shaft of the stick -- before spiking sharply upward over the past century.
That upward-turned hockey stick "blade" tracked climbing global temperatures that coincided with the world's growing combustion of fossil fuels and the billowing atmospheric concentration of carbon dioxide, a so-called "greenhouse gas," that has climbed from 280 parts per million in preindustrial times to 392 parts per million today.
"That buildup of carbon dioxide is not natural, and no matter how you cut it the globe is warming and the climate is changing," Mr. Mann said in an interview earlier this month.
"The hockey stick graph showed that recent warming is without precedent in the past 1,000 years and allowed the public to accept in good faith the reality of climate change."
But the hockey stick has become a lightning rod for the doubters and deniers of climate-change science, who say claims from "global-warming alarmists" are either exaggerated or fabricated.
Mr. Mann, author of the new book The Hockey Stick and the Climate Wars, said doubts sown by climate-change critics are more a product of free-market philosophy than legitimate scientific skepticism.
And he said those voices are part of a campaign financed by fossil-fuel interests that has paralyzed U.S. policy makers and delayed efforts to reduce carbon emissions even as evidence and public awareness mounts.
Recent scientific studies, global temperature data, and extreme weather events all point to growing evidence of the impact of global climate change, Mr. Mann said. For example:
The oceans are 30 percent more acidic than in preindustrial times, in part because of higher carbon dioxide levels, and studies predict that by the end of this century all coral reefs may be dead.
A 2010 study reported in the journal Nature blames global warming for a 40 percent decline in phytoplankton since 1950 in the world's oceans. The microscopic plankton form the foundation of the marine food web, ingest harmful carbon dioxide, and produce half the world's oxygen.
The thawing of the East Siberian permafrost under the Arctic Shelf and the leakage of large amounts of methane have been linked to global warming. According to research published in the journal Science in March, 2010, the permafrost, long considered an impermeable frozen barrier, is perforated. If even a fraction of the 1.5 trillion tons of frozen carbon vents into the atmosphere it could trigger abrupt climate warming.
It has been 20 years since President George H.W. Bush signed on to the United Nations' first climate-change document and challenged world leaders to act to protect the planet.
The expectation was that science would determine at what level greenhouse-gas concentrations could be and should be stabilized to prevent dangerous manmade interference with the world's climate systems, the world would listen, and then the world would act.
But that hasn't happened.
"The skeptics have made a remarkably successful effort to say the climate change is not happening, and failing that, they say it is not manmade," said M. Granger Morgan, the Lord Chair professor in engineering and head of Carnegie Mellon University's engineering and public policy department. "They have done that despite the fact that virtually all serious climate scientists would not agree with that view."
Naomi Oreskes, a professor of history and science studies at the University of California-San Diego, said climate-change doubters have been successful because they've been both consistent and persistent in delivering the message that the science is still uncertain.
"This message has proved effective: Polls show that many Americans, perhaps as many as 50 percent or so, believe that the science is still uncertain, that scientists are still arguing about it, and that climate change might just be natural variability," Ms. Oreskes said.
But the debates about the science of climate change aren't really about the science, she said, just as debates about leaded gasoline, secondhand smoke, the "ozone hole," mercury emissions, and DDT weren't about the science that resulted in governmental action to control those problems.
"Those debates were about governance, or more specifically about the role of regulation in governance," Ms. Oreskes said.
J. Scott Armstrong, a professor at the University of Pennsylvania's Wharton School of Management, is one of those who has raised questions about the need for government regulations to control emissions.
Mr. Armstrong, a forecasting expert, said almost none of the climate-change modeling work on which the dire global warming predictions are based meets scientific standards.
"The climate modeling doesn't make sense to me scientifically" said Mr. Armstrong, who is listed as a climate expert by the Heartland Institute, a Chicago-based libertarian, pro-free-market think tank with a history of questioning climate-change science. "My assessment of their methodology says there is nothing to worry about."
Gallup polls measuring awareness of climate change have found the percentage of Americans who say they're worried about global warming has declined from a high of 66 percent in 2008 to 51 percent last year, but a higher proportion, 80 percent, say they're more aware of the issue.
A poll released last week by the Yale Project on Climate Change Communication found a large majority of Americans believe several high-profile weather events in 2011 were made worse by global warming, including the unusually warm winter, record high summer temperatures, the drought in Texas and Oklahoma, the Mississippi River floods, and Hurricane Irene.
Mr. Mann said policy makers cannot wait until all the scientific questions are answered before they act because then it will be too late to have much of an effect. Already, scientists project that greenhouse gases must be reduced by 80 percent below current emissions levels to prevent catastrophic impacts.
And Carnegie Mellon University's Climate Decision Making Center Web page states flatly: "If policy makers are to do anything about global warming, they will have to make decisions now."
Myron Ebell, director of the Competitive Enterprise Institute's Center for Energy and Environment, which has opposed any attempt to regulate greenhouse-gas emissions, said even if there is global warming, Americans and the world will still need coal, gas, and other fossil fuels to run the technology, including air conditioning, to deal with it.
And he said proposals to reduce use of coal and fossil fuels will make it impossible to survive any warming that occurs.
Elephant in the room
Mr. Ebell said scientists, including Mr. Mann, who have gone public with climate-change concerns, are "not trustworthy," calling them "con men" and "bad apples." He says those who warn about global warming are engaged in a conspiracy of false science.
Ms. Oreskes said the focus now should be on solutions.
"We know that climate change is being driven almost entirely by two things: deforestation and greenhouse gas emissions. Some really good steps have already been taken to reduce deforestation; these steps need to be supported and strengthened.
"But the elephant in the room is greenhouse gases. We need an immediate program, on the scale of the Apollo program, to convert our energy economy from fossils fuels to renewables. And we know it can be done. Our energy basis was transformed before, and it can be transformed again."
Bottom line, according to Mr. Mann, is that the science of climate change is settled but the specifics of how, and how much of, those changes will play out remains unknown.
"We're still trying to understand things," Mr. Mann said. "The science is difficult and we don't have definite answers.
"But nature has already decided, and we may not like her decisions."
Block News Alliance consists of The Blade and the Pittsburgh Post-Gazette. Don Hopey is a staff writer for the Post-Gazette.
Contact Don Hopey at: firstname.lastname@example.org or 412-263-1983.