“Slower population growth would not solve the climate problem, but it could make a contribution. It is neither a silver bullet nor a red herring,” said Brian O’Neill of the National Center for Atmospheric Research at the annual Society of Environmental Journalists’ conference in Missoula, MT. On Friday, he presented the results of a new demographic study as part of a panel, “Population, Climate, and Consumption,” moderated by Ken Weiss of the Los Angeles Times.

Recently published in PNAS, “Global Demographic Trends and Future Carbon Emissions,” reports the results of a comprehensive assessment examining the impact of demographic changes – including urbanization and aging – on global carbon emissions.

To tease out the complex interactions between demography, consumption, and emissions, O’Neill and his coauthors looked beyond population size to delve into household location and composition. They found that urbanization and aging trends will have differential – and potentially offsetting – impacts on carbon emissions. Aging, particularly in industrialized countries, will reduce carbon emissions by up to 20 percent in the long term. On the other hand, urbanization, particularly in developing countries could increase emissions by 25 percent.