Climate change from a population perspective
Numerous policy discussions have emerged regarding the impact of climate change on humans; however, this interaction is a two-way street, said scientists in a Washington, DC briefing last Friday. That is, how will climate change impact human health and how will population growth affect factors like carbon emissions? The short answer is that they are closely connected; the longer answer is that scientists are currently trying to flesh out the exact effects and viable options for a future with global climate change, human expansion and urbanization.
Experts in demographics and population growth met in “Hot Times in the City: The Impact of Climate Change in an Increasingly Urban World,” hosted by the Population Association of America, to discuss current research on the topic and its policy implications. As Mark Montgomery from the State University of New York at Stony Brook and Population Council put it: “If we’re asking what is the rationale [for taking action]—it’s plain as day. It’s in our daily newspapers, it’s every day: the need to better protect the health and well-being of people.”
Montgomery referenced large scale natural disasters occurring on coasts, such as the 2007 floods in Tabasco, Mexico and the 2004 Tsunami in Sri Lanka, but he also emphasized the dangers occurring in drylands—ecosystems, like deserts or grasslands, which are characterized by limited soil moisture, low rainfall and high evaporation. That is, approximately 2 billion people (of which 9 out of 10 are in poor countries) live in drylands, and half of them are urban residents; therefore, electricity shortages from hydropower disruption and water scarcity due to drought and flooding are expected to have a greater toll.
Deborah Balk from the CUNY Institute for Demographic Research also pointed to drylands as an unexpected target for climate change—current emphasis in policy has mainly focused on the effects climate change will have on the coastal communities. However, one quarter of all urban dwellers live in drylands. Cities in these arid zones, such as in Africa, are more likely to experience both extreme drought and flooding. And people living in drylands are theoretically less prepared for excessive flooding. As a result, Balk argues, climate change could exacerbate inequalities in climate adaptation strategies, favoring coastal cities over arid ones due to the clear link between coastal urbanization and flooding and storms.
Another factor to consider, according to Brian O’Neill of the National Center for Atmospheric Research, is demographics and its impact on carbon emissions and the future demand for energy. Specifically, he found aging populations should help mitigate emissions in industrialized countries, while urbanization will likely increase emissions in developing countries over the next few decades. In other words, a younger community would see greater economic prosperity, due in large part to a changing labor supply, and would therefore have higher rates of consumption, energy usage and carbon emissions; whereas an aging nation would see a drop in labor supply and with it emissions.
While they definitely are contributing factors, the scientists caution that population growth and urbanization, especially in coastal areas, may not be the main causes of or concerns for climate change. As O’Neill concluded, slower population growth will not solely eliminate the climate problem, “but it would make the job easier.”
In weighing the projected outcomes and possible options, one factor the scientists explained could not be accounted for in their research was migration. Even with the census, they said, it is difficult to track the intra- and international movement of people. So additional questions remain: how will humans handle an increase in coastal and dryland hazards due to climate change? Will they move to other regions, and if so, how will urbanization affect, say, a forest ecozone?
Read more on human-environment interactions.