Low Volcanic Carbon Emissions Triggered 57 Million-Year Ice Age, Australian Geologists Discover
In a groundbreaking study, Australian geologists have uncovered the key factors behind an extreme ice age that occurred 700 million years ago. By analyzing plate tectonic modeling and geological evidence from South Australia, the researchers have shed light on Earth’s climate sensitivity and its natural thermostat mechanisms. This research not only deepens our understanding of the planet’s climate history but also highlights the stark contrast between the slow pace of geological climate change and the rapid changes driven by human activities.
Imagine a world completely frozen over, with ice covering the entire planet from poles to equator. This is precisely what happened around 700 million years ago during a global ice age that lasted a staggering 57 million years. The cause of this ice age has long remained a mystery, but Australian geologists now believe they have cracked it. The study’s lead author, Dr. Adriana Dutkiewicz, explains that historically low volcanic carbon dioxide (CO2) emissions, coupled with the weathering of volcanic rocks in what is now Canada, played a crucial role in triggering this prolonged ice age.
The inspiration for this research came from the glacial debris left behind by the ancient glaciation period, which can be observed in the Flinders Ranges in South Australia. A recent geological field trip led by Professor Alan Collins from the University of Adelaide prompted the team to use sophisticated computer models to investigate the causes and duration of this ice age. The findings revealed that between 717 and 660 million years ago, Earth was covered in snow and ice for an astonishing 57 million years.
To understand why this ice age lasted for such an extended period, the researchers turned to plate tectonic modeling. They examined the evolution of continents and ocean basins after the breakup of the ancient supercontinent Rodina. By connecting this model to a computer program that calculates CO2 degassing from underwater volcanoes along mid-ocean ridges, they made a significant discovery. The start of the Sturtian ice age coincided precisely with an all-time low in volcanic CO2 emissions, and this low level persisted throughout the entire duration of the ice age.
During this time, Earth lacked multicellular animals and land plants. The concentration of greenhouse gases in the atmosphere was primarily determined by volcanic CO2 emissions and silicate rock weathering processes, which absorb CO2. The researchers found that a combination of plate tectonic reorganization and the erosion of a continental volcanic province in Canada led to a significant decrease in atmospheric CO2 levels. This drop in CO2 concentration triggered glaciation when it fell below 200 parts per million, less than half of today’s levels.
The implications of this research extend beyond understanding Earth’s ancient climate. It raises intriguing questions about the planet’s long-term future. Some theories suggest that over the next 250 million years, Earth could evolve into a supercontinent called Pangea Ultima, where extreme heat might lead to the extinction of mammals. However, the current trajectory of lower volcanic CO2 emissions, driven by increased continental collisions and slower plate movements, suggests that Pangea Ultima could once again become a frozen world.
Dr. Dutkiewicz emphasizes the importance of recognizing the pace of geological climate change compared to human-induced climate change. While geological climate change occurs slowly over millions of years, human activities are causing climate change at a rate ten times faster than anything seen before. This research serves as a reminder of the delicate balance that exists within Earth’s climate system and the need for urgent action to mitigate the impact of human activities on our planet.
In conclusion, Australian geologists have made a groundbreaking discovery about an extreme ice age that occurred 700 million years ago. By analyzing geological evidence and employing plate tectonic modeling, they have identified low volcanic CO2 emissions and rock weathering in Canada as the key factors behind this prolonged ice age. This research deepens our understanding of Earth’s climate sensitivity and highlights the stark contrast between geological climate change and the rapid changes driven by human activities. As we face the challenges of climate change today, it is crucial to learn from Earth’s past and take immediate action to protect our planet’s future.
