While a great deal of attention has been paid to reducing emissions responsible for global warming, there has been far less focus on the role of population growth in climate change. The world’s population is projected to increase 40% by 2050. Thus, a 40% decrease in per capita carbon emissions in the industrialized world would be canceled out by global population growth and higher per capita emissions in the developing world.

As population increases, the challenge of slowing climate change and the risk of catastrophic consequences rise inexorably. The world is already experiencing increased sea levels, floods, violent storms, droughts, heat waves, disease transmission, and environmental refugees as a result of climate change. The World Health Organization estimates the percentage of the world’s population affected by weather disasters has doubled in the past 25 years, and the coming years may be worse.

Consider the potential impact of two climate change related issues in our own country, the United States. Some property insurance specialists estimate that losses due to extreme weather are increasing as fast as10 percent per year and could soon result in property insurance rates that will be unaffordable for many households. Respected NASA scientists have predicted that warming of two to three degrees centigrade will likely raise sea levels sufficiently to make many coastal areas uninhabitable. The earth is estimated to be currently warming up by 0.2 degrees centigrade per decade. The risk is undeniable and in years to come this issue will likely dwarf all others combined.

Demurral and denial may be more convenient and politically acceptable than the truth, but we need to face reality. While nations struggle to find the appropriate technical, economic and political framework for sharing the burden of reducing carbon emissions, there is an urgent need to open a second front in the battle against climate change by reducing population growth.

Although the first challenge is quite difficult, the second is relatively easy. We know that family planning works, and when women have free access to information and services to practice family planning they have smaller families. A Baltimore Sun editorial by John Seager put it best: “If we had zero population growth, part of the global warming problem would, well, melt away.” The Associated Press reports the head of the U.S. weather and climate research agency, Conrad Lautenbacker, agrees when he asserts that “the biggest challenge facing the world is population growth and people's desire to live in coastal areas where they can be endangered by storms.”

The focus on actions to voluntarily reduce population growth must be elevated to a status commensurate with the severity of the threat that continued rapid human growth poses to individuals, societies, our quality of life, and the very future of our planet.

We must act now to renew the focus on population growth and increase funding for international family planning programs. It is the easiest, proven, least controversial and most cost-effective way to immediately mediate an important factor driving climate change. Reducing population growth will not only contribute to stabilizing the climate, it will reduce the likelihood of fragile states, migration and emerging infectious diseases as well as improve prospects for education, governance and maternal/child health.

To the skeptics who still question the validity of global warming trends, consider the following. With increased efforts to lower population growth rates, at the very least there will be improvements in the human condition for many millions of people. Without increased efforts to lower population growth rates, significant increases in human suffering and catastrophic consequences of climate change are much more likely. This is an easy decision.

(William Johnson is Vice President for Development and Planning of the Population Institute, a Washington, D.C. based nonprofit organization seeking a more equitable balance between the world’s population, environment and resources. He can be reached at wjohnson@populationinstitute.org )