AS SUMMER approaches, global warming has vaulted into the news, thanks to the release of a film called "An Inconvenient Truth," in which former Vice President Al Gore raises the alarm about the impact of carbon emissions on our planet.
Every day we read reports about fuel-efficient cars, wind turbines, and emerging high-tech energy solutions. All seek to cut carbon emissions.
Yet, apart from Mr. Gore's own candid comments, there is near-total silence about the role of global population growth and the need for population stabilization. Serious discussion of population stabilization was absent from international climate meetings in both Kyoto and Montreal and from almost every other public forum.
Scientists warn that temperatures will continue to rise unless we stabilize greenhouse gas levels.
Global warming will be accompanied by increased average sea levels of four to 35 inches, flooding homes and destroying fragile wetlands. To stop this, it is estimated that global Co2 emissions must be cut by 2100 by at least 40 percent.
Yet the United Nations projects that world population will rise by 40 percent to 9.1 billion by 2050. Even if we change our ways, the environmental footprint of each human being will never reach zero. As population increases, the challenge becomes ever more difficult.
After all, it is people, not birds or bears, who drive the Hummers and the hybrids, who heat and cool homes and offices. Although the vast majority of population growth occurs in the least-developed nations, they, too, are using more fossil fuels every day as they seek better lives.
What can we do? The truth is that we know that family planning works everywhere. When women and couples are free to make their own informed choices and have access to education and family planning, they choose to have smaller families.
Thirty years ago, for example, Mexican women had almost seven children each. Today, thanks to education and the availability of family planning, they have an average of 2.6 children.
Globally, there are at least 350 million couples that lack family planning services. Here in the United States, one-third of all births are unplanned. And the Bush Administration's family planning failures, from its Global Gag Rule to ideologically driven abstinence-only programs that mock serious sex education, contribute directly to millions of unwanted and unplanned births.
If we could cut by half the number of unwanted births in the United States, we'd have about 5 million fewer births over 20 years. Family planning makes sense for people - and for our fragile planet.
More people will use more energy. The sooner we stabilize population growth, the more likely we are to meet the climate change challenge.
It's good to focus on thorny, highly technical issues such as tax credits, energy alternatives, and emissions trading programs. It's especially important here in the United States, where less than 5 percent of the world's population produces about one-quarter of the world's carbon dioxide emissions.
But cutting energy consumption must be coupled with stabilizing population. If we had zero population growth, part of the global warming problem would, well, melt away.
Global warming is too important to be left to politicians or energy experts. It's about people - all of us. It's about how many of us there are and how we choose to live our modern lives. It's about the very personal decisions we make about when, whether, and how many children we choose to have.
That particular truth can be convenient as long as we're willing to support the notion that every woman and every couple should have the resources and the power to control their own reproductive lives.
John Seager is president of Population Connection (formerly Zero Population Growth) in Washington, D.C.