Humans are changing the climate 170 times faster than natural forces, according to a new study published in the peer-reviewed journal The Anthropocene Review. The research is the first mathematical equation to compare the impact of human activity on current climate to naturally occurring changes.
For 4 billion-plus years, astronomical and geophysical factors, such as solar heat output and volcanic eruptions, were the dominating influences on Earth’s climate, argue study authors Owen Gaffney and Will Steffan, climate scientists at Stockholm University and Australian National University, respectively. But over the past six decades, human activities like the burning of fossil fuels and deforestation “have driven exceptionally rapid rates of change,” the study says.
Writing in New Scientist magazine, Gaffney explains that natural forces still have an effect in modern times, “but currently on orders of magnitude less” than human activity. Natural forces would have driven a temperature decrease of 0.01 degrees Celsius per century; but temperatures have been rising at a rate of 1.7 degrees C per century since the mid-1900s — 170 times the natural baseline and in the opposite direction. “We conclude that the rate of change of the Earth system over the last 40 to 50 years is purely a function of industrialized societies,” he wrote.