14 DAY TRIAL // A new research that will be published next week, concluded that changes in population growth and constitution, including criteria like urbanization and aging, will strongly affect greenhouse gas emissions on a global scale, for the next 40 years.
By 2050, the Earth's population could include an extra 3 billion people, most of them living in urban areas, according to estimates.
So the study authors wandered what would happen if the population stagnated or declined, and in what places of the globe could this diminish the global warming effect.
After several studies and theoretical analysis, along with a computer model, the researchers found that the slowest population growth – considered plausible by demographers at the United Nations, could reduce significantly greenhouse gas emissions.
Theoretically, if this happens, by 2050 there would be a 16 to 29 percent reduction in gas emissions, which would relent global warming and avoid serious consequences.
Also, by the end of the century, things could get even better if the population growth tendency is maintained.
Still, the researchers remained realistic, because as the study's lead author, Brian O'Neill, an NCAR scientist, said, “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.”
Another important variable is where this variation in population growth occurs, adds O'Neill's co-author, IIASA scientist Shonali Pachauri.
“A slowing of population growth in developing countries today will have a large impact on future global population size.
“However, slower population growth in developed countries will matter to emissions, too, because of higher per capita energy use,” he explains.
The researchers analyzed the way that demographics could influence emissions in time and in which regions of the world, accounting for aging populations, urbanization and emissions.
The results were rather conclusive: a growth in urban populations will lead to 25% more CO2 emissions in several developing countries, and aging can reduce emissions by 20% in some industrialized countries.
The explanation they give is logical: an urban labor force produces more and also consumes more, so a higher economic growth due to urbanization will increase emissions; aging, on the other hand is supposed to reduce pollution, as older populations have lower labor force, which leads to lower economic growth, thus lower emissions.
O’Neill says that “demography will matter to greenhouse gas emissions over the next 40 years, [as] urbanization will be particularly important in many developing countries, especially China and India, and aging will be important in industrialized countries.”
The problem of aging will be a reality as people live longer and their fertility declines, this is why the researchers assumed that population aging will happen in all regions of the globe.
As said before, the team also developed a computer model, called the Population-Environment-Technology model, or PET, which assessed energy use, economic growth and emissions scenarios, according to age, size of households and the differences between cities and villages.
They added data from 34 national surveys, representing 61% of the global population, in order to estimate the economic characteristics of home types over time.
“Households can affect emissions either directly, through their consumption patterns, or indirectly, through their effects on economic growth,” explains O'Neill.
All this analysis suggests that the most important areas to future emissions, in terms of urbanization and aging, are the United States, the European Union, India and China.
O'Neill adds that “further analysis of these trends would improve our understanding of the potential range of future energy demand and emissions.”
The researchers stress that their study does not say that there should be policies affecting aging and urbanization implemented in these areas, the only purpose of their findings being a better understanding of this data, for the anticipation of future changes.
This research was carried out by an international team of scientists from the National Center for Atmospheric Research (NCAR), the International Institute for Applied Systems Analysis (IIASA), and the National Oceanographic and Atmospheric Administration.
It was funded by a European Young Investigator's Award, the Hewlett Foundation, and the National Science Foundation – NCAR's sponsor, and will appear in Proceedings of the National Academy of Sciences (PNAS).
Watch an interview with Brian O'Neill (NCAR), who speaks about the impact of population trends on climate change: