Cold Facts on Global Warming

This article by Dr. James Schlesinger was published in The Los Angeles Times, January 22, 2004

We live in an age where facts and logic have a hard time competing with rhetoric – especially when the rhetoric is political alarmism over global warming.

We continue to hear that “the science is settled” in the global warming debate, that we know enough to take significant action to counter it. Those who hold this view believe emissions of carbon dioxide are the primary cause of any change in global temperature and inevitably will lead to serious environmental harm in the decades ahead.

In 1997, for instance, Vice President Al Gore played a leading role in the negotiation of the Kyoto Protocol, the international agreement to deal with the fears about global warming. He was willing to embrace severe reductions in U.S. emissions, even though the Clinton administration’s own Department of Energy estimated that Kyoto-like restrictions could cost $300 billion annually. Then, when it became clear that the Senate would not agree to a treaty that would harm the economy and exempt developing countries like China and India, the Clinton administration did not forward it for ratification. Since then, the treaty’s flaws have become more evident, and too few countries have ratified it to allow it to “enter into force.”

The Bush administration, as an alternative to such energy-suppressing measures, has focused on filling gaps in our state of knowledge, promoting the development of new technology, encouraging voluntary programs and working with other nations on controlling the growth of greenhouse gas emissions. Collectively, these actions involve spending more than $4 billion annually, and the U.S. is doing more than any other nation to address the climate-change issue.

Of these efforts, filling the gaps in our knowledge may be the most important. What we know for sure is quite limited. For example, we know that since the early 1900s, the Earth’s surface temperature has risen about 1 degree Fahrenheit. We also know that carbon dioxide, a greenhouse gas, has been increasing in the atmosphere. And we know that the theory that increasing concentrations of greenhouse gases like carbon dioxide will lead to further warming is at least an oversimplification. It is inconsistent with the fact that satellite measurements over 35 years show no significant warming in the lower atmosphere, which is an essential part of the global-warming theory.

Much of the warming in the 20th century happened from 1900 to 1940. That warming was followed by atmospheric cooling from 1940 to around 1975. During that period, frost damaged crops in the Midwest during summer months, and glaciers in Europe advanced. This happened despite the rise in greenhouse gases. These facts, too, are not in dispute.

And that’s just our recent past. Taking a longer view of climate history deepens our perspective. For example, during what’s known as the Climatic Optimum of the early Middle Ages, the Earth’s temperatures were 1 to 2 degrees warmer than they are today. That period was succeeded by the Little Ice Age, which lasted until the early 19th century. Neither of these climate periods had anything to do with man-made greenhouse gases.

The lessons of our recent history and of this longer history are clear: It is not possible to know now how much of the warming over the last 100 or so years was caused by human activities and how much was because of natural forces. Acknowledging that we know too little about a system as complicated as the planet’s climate is not a sign of neglect by policymakers or the scientific community. Indeed, admitting that there is much we do not know is the first step to greater understanding.

Meanwhile, it is important that we not be unduly influenced by political rhetoric and scare tactics. Wise policy involves a continued emphasis on science, technology, engagement of the business community on voluntary programs and balancing actions with knowledge and economic priorities. As a nation, by focusing on these priorities, we show leadership and concern about the well-being of this generation and the ones to follow.

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