Here’s another observation from my recent visit to Nicaragua: poverty is the worst polluter. In a country where one half of the population lives in poverty and 25 percent of its 5.5 million people struggle to survive on less than one dollar per day, environmental protection is not a high priority.

I wonder how Roger, our wonderful driver, might have responded to An Inconvenient Truth, Al Gore’s Oscar winning documentary. My bet is he’d agree with Naresh Chandra, former Indian Ambassador to the U.S., who said, “[A]t the moment we have a much higher and urgent priority, and that is eradication of poverty, removal of backwardness, and improving the level of living of our people. That is a much greater, urgent necessity than the long-term aim of controlling greenhouse gas emissions.”

To people who struggle every day to meet basic needs, climate change and protection of biodiversity are mere trifles. Only when people can provide the basics for their families (e.g., shelter, food, and security) does their attention turn to the environment. Increased wealth permits not only material comfort, convenience, and safety, but also a cleaner environment. It takes real resources to clean air and water and monitor natural resources.

Economic progress also enhances resilience to natural disasters. Consider the different outcome from these similar storms. In 1999, Tropical Cyclone 05B struck India. It destroyed 2 million houses and killed 10,000 people. In 2004, Hurricanes Charley, Frances, and Jeanne hit Florida. They killed 116.

The UN‘s Intergovernmental Panel on Climate Change (IPCC) just produced the most thorough work on climate change. While their process admits limitations, it’s silly to believe the people involved are engaged in a grand conspiracy. Yes, global warming is occurring.

It’s no surprise that when dealing with a complex phenomenon like the global climate, scientists struggle with uncertainties. For example, the March 16th issue of Science features articles on ice sheets in Greenland and Western Antarctica. Understanding their dynamics is critical; because if they melt rapidly (i.e., in decades rather than centuries or millennia), we will experience the catastrophic 20 feet sea level rise featured in An Inconvenient Truth.

There is some non-zero probability of this occurring; but no consensus on the odds. Sea level rose about eight inches over the past century. The latest IPCC projection is for a sea level rise between one and two feet by the end of this century.

We know enough to begin thinking about a wide range of possible responses. In addition to mitigating future carbon emissions (e.g., through a carbon tax or a cap and trade system), it’s only prudent to adapt to changes already underway. The physical chemistry of greenhouse gases and the thermal inertia of the oceans make decades of warming and rising seas a certainty—no matter what we do.

Here’s a question that disturbed me while touring Nicaragua: will the future effects of climate change cause more damage to the world’s poorest than today’s lack of modern energy supplies, access to clean drinking water, or malaria?

Mr. Gore asserts climate change is a moral issue. In order to make morally responsible decisions, we must understand the tradeoffs our policy choices imply. It’s here that he dodges.

Is it moral to spend hundreds of billions a year to meet Kyoto-like targets when these expensive policies will delay warming for a mere six years? Isn’t it better to use a small fraction of our limited resources to provide one billion people safe drinking water now? Sound policymaking requires an evaluation of the costs and benefits of limiting carbon emissions. In terms of advancing social wellbeing, Kyoto policies offer poor returns on investment, especially for the world’s poor.

What actions might we undertake to improve wellbeing for the world’s poorest today? Direct investment in public health, education, and water resources in poorer countries would yield benefits for people who face immediate threats, rather than the threat of a rising sea level in 100 years.

One thing became clear to me while traveling in Nicaragua—dealing with a warming world requires multiple strategies. Policies that increase the resilience of the world’s poorest rank high among them.