The widely held belief that the wealthiest nations are solely responsible for the bulk of global carbon dioxide emissions and that population growth is exclusive to the poorest nations has sparked calls to prioritize curbing emissions per capita as a strategy to combat climate change.

However, a closer examination of the data over the last three decades in a new study from Linnaeus University reveals that this narrative may not be entirely accurate.

“This way of reasoning is not correct. Our thorough analysis suggests that climate change mitigation strategies should address population along with per capita consumption and technological innovation. A comprehensive approach to the problem is needed,” the researchers explain.

Classifying countries

The World Bank employs a four-tier system to classify countries by income, which ranges from low to high income. Gross national income (GNI) per capita is the determining factor in this classification, with 28 nations falling under the low-income category, 54 categorized as lower-middle income, 54 classified as upper-middle income, and 81 as high-income countries, according to 2021 figures.

Recently, a group of researchers, including the lead author and two colleagues, analyzed 30 years’ worth of emission data from all countries worldwide. The researchers leveraged the World Bank’s standard classification system to group countries into four income brackets, which allowed them to confirm that low-income countries make only a limited contribution to emission increases. However, their research also unveiled some crucial findings:

• Population growth was observed across all four income groups.
• The upper-middle income group had the largest impact on global carbon emissions.
• Population growth was the primary driver of increased emissions across all income groups, except for the upper-middle income group.
• The success in reducing per capita emissions in high-income countries was undermined by population growth within the same group.

“Our analysis does not support the widespread belief that increased affluence is the main driver of increased carbon emissions at the global level. It is definitely an important factor, but neglecting population growth leads to a skewed and misleading vision of reality,” the authors conclude.

“Developed nations with stable or declining populations should hence quit fighting these trends and instead embrace them. Just as a small population growth in rich countries can drive big emission increases, a population decrease in rich countries could have big emission-related benefits going forward.”