June 12, 2012

New Data On ‘Population Emissions’

Brett Smith for redOrbit.com

While many climate change studies focus on the physical and ecological processes that drive greenhouse gas emissions, a new study published this week focuses on the societal forces that could cause global warming.
In a report published Sunday in Nature Climate Change, Michigan State University professor Tom Dietz and his colleague Eugene Rosa from Washington State University looked at the various social factors that have long been prime climate-change suspects, including the role of population growth.

“How does population growth influence greenhouse gas emissions?” lead author Dietz asks. “Well, in looking at most nations of the world during the last few decades, we find that for each 1 percent increase in population, we get a bit more than a 1 percent increase in emissions.”

The report cited many societal factors besides population growth that impact emissions: consumption, affluence, urbanization, trade, institutions, and culture. Some of these factors were found to have predictable results while the investigation of others produced some surprising finds.

For example, the number of households may have a greater impact on emissions than the number of people, “as a large proportion of household energy consumption is used to heat, cool and light dwellings and power the appliances in them, and such uses may be insensitive to the number of occupants,” the study said.

The team´s focus on urbanization as a driver of emissions also produced some notable results. In their research, Dietz and Rosa found that suburban growth increases emissions, while core urban growth actually reduced emissions. Citing a Chinese study on urbanization, the research team said “the share of total energy consumption used in urban areas has remained constant even as total demand increases, suggesting that economic growth is more important than urbanization in driving increased energy use.”

In looking toward the future, Dietz mentioned some positive technological and cultural developments that could lead to lower emissions, even though the more pro-active countries have yet to achieve this.

“There are certainly plenty of examples of households, firms, industries, and communities that are reducing emissions,” he told redOrbit via email.

“Many nations are improving the ratio of gdp to emissions. They are getting more gdp per ton of emissions.   Some are improving the emissions per capita.  But none we are aware of are reducing the overall emissions level, and that of course is what in the long run leads to increased atmospheric concentrations that are the primary driver of climate change in the years to come.”

The professor said his research also uncovered a series of unanswered questions that begged further research.
“We plan to examine how forms of governance influence emissions, how the structure of international trade plays a role, how the structure of the domestic economy influences emissions and ultimately we hope to be able to look at the effects of policies.”

“Another major direction is to look at the relationship between stress placed on the environment and human well-being.  How much benefit do we gain from using the environment as a source of raw materials and as a sink for waste?  Are there ways that some nations do a much better job of improving the well-being of their people while minimizing harm to the environment?”