It would appear that Green Metropolis author, David Owen, who preaches the green virtues of New York City, may have nothing to fear in the report as the urbanization=increased emissions factor applies to developing nations, while the aging=decreased emissions relationship applies to industrialized nations.
"A team of US and Austrian researchers found that urbanisation could increase emissions by up to 25% in some developing nations.
However, industrialised countries could see emissions fall by about 20% as a result of ageing populations."
From USA Today: Study - Slower population growth could reduce climate change: "A slowing of population growth could significantly reduce greenhouse gas emissions by 2050, according to a new study published (Oct.12).
"Scientists estimate global population could rise by more than 3 billion, mostly in urban areas, by midcentury but a slower growth path could cut emissions 16% to 29%, according to the study in the Proceedings of the National Academy of Sciences."
From NCAR: Population trends: Another influence on climate change: The study "was conducted by an international team of scientists from the National Center for Atmospheric Research (NCAR)" and other organizations. "If global population growth slows down, it is not going to solve the climate problem, but it can make a contribution, especially in the long term," says the study's lead author, Brian O'Neill, an NCAR scientist."
Thanks to Gregory Bungo