It appears that through the burning of fossil fuels and filling the atmosphere with carbon, mankind has caused the world to “skip” an ice age, potentially postponing the next one by between 50,000 to 100,000 years. The new research came to this conclusion after modeling the conditions needed to tip the planet into a glacial period. They found that while Earth is at the right point in its orbit around the Sun, the level of carbon dioxide currently in the atmosphere is far too high.
The study reports that the onset of a major glaciation, in which ice sheets would cover most of Europe, North America, and Russia, was prevented at the start of the Industrial Revolution, as the burning of coal caused the amount of greenhouse gasses being emitted to rise above threshold levels, at 240 parts per million of carbon. Since then, as the amount of carbon in our atmosphere has been steadily rising (currently sitting at around 400 parts per million), the researchers calculate that we’ve probably pushed the event back by around 100,000 years.
“The bottom line is that we are basically skipping a whole glacial cycle, which is unprecedented,” explains Potsdam Institute for Climate Impact Research’s Andrey Ganopolski, the lead author of the study. “It is mind-boggling that humankind is able to interfere with a mechanism that shaped the world as we know it.”
The new paper gives further weight to the notion that we have entered a new geological epoch – the Anthropocene – in which the Earth and its climate is impacted by humanity, to such an extent that it will still be affected tens of thousands of years into the future.
This research, published in Nature, is the first that has been able to explain what induces an ice age. By looking at the previous eight glacial events over the past 800,000 years, the researchers were able to figure out what conditions were needed to plunge the Earth into a deep freeze. Despite the complexities of our climate, it all came down to two factors: the amount of sunlight hitting the planet in the Northern Hemisphere, and the concentration of carbon in the atmosphere. Since the latter has been relatively stable up until the Industrial Revolution, it was the cyclical nature of the former that largely determined when Earth would enter these major periods of glaciation.
“Like no other force on the planet, ice ages have shaped the global environment and thereby determined the development of human civilization,” says Hans Joachim Schellnhuber, the study's co-author. “For instance, we owe our fertile soil to the last ice age that also carved out today's landscapes. However, today it is humankind with its emissions from burning fossil fuels that determines the future development of the planet.”