February 28, 2006
RALEIGH – North Carolina’s policymakers want to do something about global warming. They should heed the controversy about the issue among scientists before acting decisively, a climatologist warns.
Dr. Robert C. Balling, climatology professor at Arizona State University, reviews an important controversy in a new John Locke Foundation Spotlight report. The controversy surrounds the “hockey stick” graph featured prominently in recent presentations to North Carolina’s Legislative Commission on Climate Change.
The crux of the issue is whether one degree of warming (Celsius) observed over the past century is part of a natural cycle that extends for thousands of years or an anomaly that could be blamed on industrialization. If the warming is normal, then it would make no sense to adopt costly public policies to stop it.
To date, presentations to the climate commission have been based on the assumption that human activity is responsible for warming. If human activity isn’t to blame, then any attempt to stop it would be irrelevant and would harm the economy.
Evidence clearly shows climate variations over the past 1,000 or even 10,000 years, Balling says. “Literally thousands of scientists have carefully examined tree rings, ice cores, historical records, pollen spores, and a dozen or more other clever ways to peer into Earth’s climatic past, clearly documenting that the major warming and cooling episodes were apparent throughout the entire world.”
Those episodes include the Medieval Warm Period of 1,000 years ago followed by the Little Ice Age, which lasted for several centuries and ended around 1900. During the Little Ice Age, the sun had lower output and very few sunspots compared with today, Balling says.
The current controversy among scientists studying global warming is fierce, Balling reports. It is centered on the relatively new “hockey stick” graph of global warming. This graph was first introduced by the United Nations Intergovernmental Panel of Climate Change. It is frequently used to advocate for a political response to climate change.
The graph ignores important information, Balling says. “The Medieval Warm Period and Little Ice Age vanished, and now the warming of the past 100 years looked completely unlike anything observed for 1,000 years.”
The graph presents the climate for 900 years prior to 1900 as nearly static, making the last century’s warming seem completely unnatural. The graph is called the “hockey stick” because of the shape of its plot. The North Carolina climate change commission saw the graph within the past month, with no discussion of the controversies surrounding it.
“The commission needs to realize that this graph is being hotly debated among scientists,” said Dr. Roy Cordato, JLF vice president for research. “The methodology behind it is under challenge. The climatic flat-line goes against hundreds of studies documenting the Medieval Warm Period and the Little Ice Age.”
Statisticians found that a “hockey stick”-shaped graph would be generated regardless of the data used for calculations, Balling says. “The statistical methodology would generate a hockey-stick curve given almost any inputs.”
But despite scientists and statisticians severely questioning the data and techniques used to generate the graph, it still has strong advocates among climate activists. Among those, Balling says, is former Vice President Al Gore, who has a book forthcoming on global warming.
“A clear point that the North Carolina policymakers should take from all this is that despite the claims of many who advocate for strong policies to combat global warming, the science is not settled,” Balling writes. “Any policy that the state decides to adopt needs to be addressed in light of this fact.”
Dr. Robert C. Balling’s Spotlight paper, “Breaking the ‘Hockey Stick’: Global Warming’s Latest Brawl,” is available on the Locke Foundation’s web site. For more information, please contact Dr. Roy Cordato at (919) 828-3876 or [email protected]. To arrange an interview, you may also contact JLF communications director Mitch Kokai at (919) 306-8736 or [email protected].