It’s a message no one wants to hear: To slow down global warming, we’ll either have to put the brakes on economic growth or transform the way the world’s economies work.
That’s the implication of an innovative University of Michigan study examining the evolution of atmospheric CO2, the most likely cause of global climate change.
The study, conducted by José Tapia Granados and Edward Ionides of U-M and Óscar Carpintero of the University of Valladolid in Spain, was published online in the peer-reviewed journal Environmental Science and Policy. It is the first analysis to use measurable levels of atmospheric carbon dioxide to assess fluctuations in the gas, rather than estimates of CO2 emissions, which are less accurate.
“If ‘business as usual’ conditions continue, economic contractions the size of the Great Recession or even bigger will be needed to reduce atmospheric levels of CO₂,” said Tapia Granados, who is a researcher at the U-M Institute for Social Research (ISR).
For the study, the researchers assessed the impact of four factors on short-run, year-to-year changes in atmospheric concentrations of CO2, widely considered the most important greenhouse gas. Those factors included two natural phenomena believed to affect CO2 levels—volcanic eruptions and the El Niño Southern oscillation—and also world population and the world economy, as measured by worldwide gross domestic product.
Tapia Granados and colleagues found no observable relation between short-term growth of world population and CO₂ concentrations, and they show that incidents of volcanic activity coincided with global recessions, which brings into question the reductions in atmospheric CO2 previously ascribed to these volcanic eruptions.