GLOBAL WARMING WARNINGS: A Lot of Hot Air.

• Author: MICHAELS, PATRICK J.

The rise in temperature resulting from greenhouse gases predicted for the 21st century is not appreciably different from what has occurred over most of our lifetimes, a period in which a majority of people have enjoyed the prospect of later mortality, better nutrition, and increased wealth.

EVER SINCE June 23, 1988, when NASA astrophysicist James Hansen testified before Congress that there was a "strong cause and effect relationship" between "the current climate and human alteration of the atmosphere," global warming has been the world's premier environmental issue. Concern over it created an international treaty, the Framework Convention on Climate Change, and an international protocol, the Kyoto Protocol, designed to implement the original treaty. Leading up to his run for the presidency, Al Gore had written passionately that it is the number-one issue confronting mankind.

Yet, many converging lines of scientific and economic evidence lead to the inescapable conclusion that global warming is now understood to be a much more gradual, more benign process than originally thought. Further, there is no known way of significantly stopping it. Therefore, it is time to move on to more important global environmental concerns, such as poverty.

There is no doubt that Earth's surface temperature is warmer than it was 100 years ago, but warming per se can be irrelevant. What matters more is how the planet warms. For example, if human-induced warming were largely confined to the cold air of winter, few would argue that the issue would be of sufficient magnitude to invoke the enormous costs required for futile attempts at remediation. If the warming were largely confined to the heat of summer, though, the effect would be dramatically different, with withered crops and increasing drought becoming the norm in a world wherein growing population continues to pressure a finite food supply.

The same logic applies to precipitation. Most mathematical models for human-induced global warming project an overall increase in precipitation, and this has undoubtedly been observed in U.S. records. Is this necessarily a bad thing? What if the seasonality results in more water available for agriculture, while at the same time slightly increasing flood frequency? The trade-off is obvious: Many people benefit more by cheaper food than are harmed by floods, and the latter can be contained infrastructurally with modest effort over a long time.

In considering the nature of observed climate change--both before and after human activity induced significant modifications of the natural greenhouse effect--I would like to note that those who argue for large, net negative consequences have an uphill fight. As the greenhouse effect has enhanced, individuals in free societies have seen their life expectancies double, their food production quintuple, and wealth spread and democratize far beyond even the most optimistic projections of 100 years ago.

There are two distinct warmings of similar magnitude. The more recent one has occurred over the last three decades or so...