TCS Daily

The Kyoto Cup

By Kenneth Green - May 5, 2003 12:00 AM

In the fourth overtime period of a recent Stanley Cup playoff game, I found my mind wandering to a different kind of hockey stick - the kind that UN scientists claim is sketched out by temperature records going back 1000 years or so. Since the first reports of the United Nations Intergovernmental Panel on Climate Change, UN scientists have used a reconstruction of past climates based on evidence from tree rings, coral, boreholes, and other proxy indicators that suggested the climate was mostly unchanging for the last 1000 years, with the spike of the last 150 years appearing to be clearly abnormal (Figure below) shooting upward like the blade of a hockey stick.

Source: United Nations Intergovernmental Panel on Climate Change, Third Assessment Report

But over the years, data has accumulated arguing that the "IPCC hockey stick" is fundamentally flawed. Some researchers, studying the climate of the last 1000 years argued that the IPCC scientists were refusing to acknowledge evidence indicating that in reality, the temperature from about 1,000 A.D. to 1300 A.D. was quite a bit warmer than today, while the climate from 1300 A.D to 1850 was unusually cold. As climate researcher David Wojick illustrates, a more realistic depiction of recent climate is not a hockey stick, but is more a matter of emerging from a climatic valley (see Figure below).

Despite the accumulating evidence, UN scientists have continued to assert that the medieval warm period and the little ice age were strictly local phenomenon, and hence, were not representative of the Earth's climate as a whole. That willful ignorance led Australian climate researcher John Daly to label the IPCC hockey stick "A New Low in Climate Science." Daly argued that "What is required to disprove the Hockey Stick is to demonstrate conclusively the existence of the Medieval Warm Period and/or the Little Ice Age as recorded in proxy and/or historical evidence from around the world."

Fortunately, a new study, by the Harvard-Smithsonian Center for Astrophysics offers just what Daly requested. A review of more than 200 climate studies confirms the that both the medieval warm period and the little ice age were global, not regional phenomena. As astrophysicist Sallie Baliunas explains, "For a long time, researchers have possessed anecdotal evidence supporting the existence of these climate extremes. For example, the Vikings established colonies in Greenland at the beginning of the second millennium that died out several hundred years later when the climate turned colder. And in England, vineyards had flourished during the medieval warmth. Now, we have an accumulation of objective data to back up these cultural indicators."

The question of whether we're in hockey-stick mode, or hill-and-valley mode is critical, because it cuts right to the heart of the climate change debate. Is recent climate change abnormal enough to support the assumption that it must be due to human activity, or is recent climate change within the realm of natural variation? The former argument is used to support mandatory greenhouse gas reduction schemes, like the Kyoto Protocol, while the latter view is used to support arguments that our current best response to climate change is to build resilience, and get ready for a somewhat warmer environment.

As it becomes clear that recently observed climate changes are not unusual, the case for assuming human causation is greatly weakened. If the climate is changing due to forces other than human action, then greenhouse gas controls will do nothing to protect future generations confronting the impacts of climate change. UN scientists have acknowledged that there is no evidence implicating human activity with any warming before 1950, but they continue to attribute "most" of the warming since 1950 to human activity, and continue to clamor for immediate greenhouse gas emission reductions.

The world is in the second overtime period of the Kyoto Cup, with climate change alarmists pushing economically crippling greenhouse gas controls around the world with increasing desperation, while those holding climate change to be largely natural are fighting to preserve the economic freedom that provides the resources needed to secure health, safety, and environmental protection.

A lot is riding on the Kyoto Cup. If we waste our resources in controlling carbon emissions that are not responsible for causing recently observed warming, where are we going to get the resources to help those areas that will experience the negative impacts of a changing climate caused by Mother Nature? Let's hope that the UN breaks its hockey stick, and joins in a real exploration of how we protect future generations from a largely natural climate change.

Environmental Scientist Kenneth Green is Director of the Risk and Environment Centre at The Fraser Institute. His most recent publication is "Global Warming: Understanding the Debate," a text-book for junior high school students.

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