Warming predictions need more than just the big numbers
It’s not just about sheer numbers when it comes to predicting how human population growth will affect climate change. An array of demographic factors – from age and sex to household size and wealth – can have sometimes surprising impacts, a new survey finds. So far, however, “population is rarely mentioned in policy debates on climate change,” notes the study, published in Population and Resources Policy Review.
“Making a clear and direct linkage between population change and climate change is complex,” write Leiwen Jiang of the National Center for Atmospheric Research in Boulder, Colorado and Karen Hardee of Population Action International in Washington, D.C. While the total number of people matters, so do factors like how rich they are, what technology they use, and where they live. But climate models have had a hard time factoring in these complications, “which may have resulted in underestimating the demographic impacts on climate change,” they note. “Furthermore, population factors have yet to be fully incorporated into adaptation strategies.”
In a bid to clarify the issues, Jiang and Hardee review a pile of recent studies on the links between demography and climate. Studies of “shrinking” households in many developed nations, for instance, show that fewer people living together tends to drive up per-capita energy use and emissions. In contrast, studies of the impact of aging populations and increasing urbanization have found mixed results, with emissions rising or falling depending on a host of other factors. Still other research suggests that climate change will have uneven impacts, depending on where you live and how much you earn, with poorer people living in warmer climes potentially most at risk.
“It is clear, in addition to population size, that analyzing the compositional change of populations, specifically the age composition, the distribution of people in urban and rural areas, and household size and composition, is very important for understanding” future climate impacts, they conclude. The survey also highlights the need for “increased resources for voluntary family planning to aid individuals, families and countries,” they argue. A lack of such resources, they add, “continues to put a greater proportion of the population in the developing world at higher risk and make emissions reductions more difficult to achieve.” – David Malakoff | March 26, 2011
Source: Jiang, L., & Hardee, K. (2010). How do Recent Population Trends Matter to Climate Change? Population Research and Policy Review, 30 (2), 287-312 DOI: 10.1007/s11113-010-9189-7
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