We protect the environment because we care about clean air and preserving other species, not mainly for financial reasons. But we also value inexpensive supplies of power and fast and convenient transportation.

All interesting and important policy questions involve choosing among competing values. Consider climate change. How does human action influence future climates? How willing are we to give up inexpensive fossil fuel energy? Does climate change demand drastic and dramatic action now? If so, at what cost? However well intended, it is naïve and irresponsible to ignore the unavoidable trade-offs.

We have limited resources and face many challenges. Here’s a simple truth: The money spent to combat climate change is not available to eradicate malaria, killer of 2 million people each year, 90 percent of whom are children under 5. And it takes money to increase female literacy in poor nations -- perhaps the key investment for social progress.

Those who believe climate change trumps all else ignore the reality that we must trade off among competing values. Those who deny this hold a religious position that is not open to reason.

What if those who question the need for dramatic action are all pawns of “corporate polluters”? Even if true (it’s not), the costs of addressing climate change will be paid by real people. Does anyone honestly believe Pacific Gas and Electric deliberately emits carbon to destroy our climate? Isn’t PG&E simply responding to consumers’ willingness to give up something they value (i.e., money) for the energy required to run their washing machines and PCs?

The Climate Stewardship Act was defeated last fall in the U.S. Senate. Its failure illustrates the political calculus of climate change. Politicians’ time horizons rarely extend beyond the next election cycle. When benefits accrue to future generations and the costs are borne today, politicians avoid tough decisions.

The only moral approach is to prioritize among competing values.

The Copenhagen Consensus project is a recent example of this process. It asked some of the world's leading economists to rank the world’s ten biggest problems identified by the United Nations. These challenges are: civil conflicts, climate change, communicable diseases, education, financial stability, governance, hunger and malnutrition, migration, trade reform, and water and sanitation.

Their charge: “What would be the best ways of advancing global welfare, and particularly the welfare of developing countries, supposing that an additional $50 billion of resources were at governments’ disposal?”

The highest priority was preventing the spread of HIV/AIDS. A relatively small investment ($27 billion) would yield extraordinarily high benefits -- nearly 30 million new infections averted by 2010. This is especially critical for progress in Africa, where AIDS threatens to collapse entire societies.

Climate change received the lowest ranking. Why? It takes enormous expenditures to achieve very small reductions in greenhouse gases -- and the benefits are uncertain. The panel declared current abatement strategies (e.g., the Kyoto protocol) “a bad use of our finite resources.”

Climate change is global in scale and we’re already committed to future warming, for carbon dioxide is a long-lived atmospheric resident. It’s clear: whether anthropogenic or natural, climate change is inevitable. Our challenge is to deal with it responsibly.

The great grandchildren of the world’s poorest are those most likely to be adversely affected by global warming. Here’s the key to ethical policies. The best defense against adverse consequences of warming is wealth creation in the developing world. Here’s why.

In this arena as in so many others, wealth buffers adversity. The greatest dangers are policies that stifle Third World economic progress, e.g., First World trade barriers. This great truth is often ignored in the debate over climate change.

Stephen Schneider, a Stanford biologist and global warming alarmist, criticized the Copenhagen project by saying, “Climate change is not an economics problem. It’s an ethics problem.” Mr. Schneider, indeed it is.

In a recent column I wrote that Dr. Jerry Mahlman of the National Center for Atmospheric Research noted “that regardless of what America and other developed nations do, in the next decade there is no reasonable scenario in which atmospheric CO2 will not double. It will probably quadruple.”

My notes were wrong. At our conference Dr. Mahlman stated this will occur over the next century, not decade. I apologize for the error.