Drilling Down to the Past
Researchers at Oregon State University have made a startling discovery: Earth's current rate of natural CO2 increase is the fastest it's been in 50,000 years.
To uncover this data, the team analyzed air bubbles trapped within ice cores from the West Antarctic Ice Sheet (WAIS). These cores essentially capture a record of climate conditions that have remained relatively stable throughout the mid-Holocene period (which began around 11,700 years ago and continues today).
A Deeper Dive into Ancient Ice
The team had to drill down a staggering 3,200 meters to access ice samples dating back approximately 50,000 years. By studying the chemicals trapped within these ancient layers, they gained a glimpse into past climate conditions.
CO2 at Record Highs
Their analysis revealed that today's CO2 levels, which are driving the current climate crisis, are extreme and unusual compared to the rest of Earth's recent geological history.
Specifically, the rate of CO2 accumulation in the atmosphere is over 10 times faster than any other time in the past 50,000 years, as determined by their detailed chemical analysis of the ancient Antarctic ice.
"What our record shows is how different today is," said Kathleen Wendt, assistant professor in OSU's College of Earth, Ocean, and Atmospheric Sciences and lead author of the study. "The rate of CO2 change we're seeing today is really unprecedented. The natural rate of CO2 increase this century is the fastest we've observed in our entire record, and it's largely due to human emissions."
The Carbon Footprint and Its Consequences
Carbon dioxide, or CO2, is a greenhouse gas that occurs naturally in the atmosphere. When CO2 enters the atmosphere, it contributes to global warming through the greenhouse effect. While its levels have fluctuated naturally due to ice age cycles and other phenomena in the past, their increase today is primarily driven by human activities.
According to the International Energy Agency (IEA), global energy-related CO2 emissions rose by 1.1% in 2023, reaching a new record high of 37.4 billion tonnes of CO2. Coal-fired power plants were responsible for over 65% of the increase in emissions in 2023.
A Warning from the Past
Using the ice core samples from WAIS, Wendt and her colleagues investigated how Earth's climate behaved during the last Ice Age. They identified a pattern where these large CO2 increases occurred alongside periods of North Atlantic cooling known as Heinrich Events, which were linked to abrupt climate changes worldwide.
A Grim Picture of the Future
Normally, without human activities releasing large amounts of greenhouse gases, Earth would experience periodic increases in CO2 through an effect called a Heinrich Event.
Named after German marine geologist Hartmut Heinrich, these events coincided with periods of extreme cold in the North Atlantic caused by icebergs calving from the Laurentide ice sheet. This triggered a chain reaction that caused global climate patterns to change.
"We think that Heinrich Events were caused by catastrophic ice sheet collapses in North America," said Christo Buizert, a co-author of the study, in a press release. "This set off a chain reaction involving shifts in the tropical monsoons, the Southern Hemisphere westerlies, and large releases of CO2 from the oceans."
During the largest of these natural increases, CO2 levels rose by around 14 parts per million over a period of 55 years. And these jumps occurred roughly every 7,000 years. At today's rate, that same magnitude of increase would take only five to six years.
Other research suggests that these Southern Hemisphere westerlies will strengthen in the coming century due to climate change. The scientists note that if this happens, it will reduce the Southern Ocean's ability to absorb human-caused CO2.
The Devastating Impacts of CO2 Accumulation
The result will be a planet awash in CO2, a potent greenhouse gas that traps heat. The consequences of this are severe. Earth will experience more intense and frequent heat waves, rising temperatures will melt more ice and cause sea levels to rise, and extreme weather events such as floods and droughts will become more common.
According to the Statista report on global natural disaster deaths 2000-2023, there were an estimated 95,000 reported deaths due to natural disasters worldwide in 2023 alone—the highest number since 2010. The total economic damage from natural disasters worldwide in 2023 amounted to $380 billion.
As climate change increases the likelihood of more extreme events, the loss of life and property will continue to be a harrowing reality for the globe.
Summary
Scientists have discovered that the current rate of CO2 increase is unprecedented in the last 50,000 years, driven primarily by human activities. By drilling deep into ice cores, they have found that natural CO2 increases in the past occurred alongside significant climate changes. Today's rates of CO2 accumulation are extremely concerning and underscore the urgency of mitigating climate change to prevent the worst impacts, such as more heat waves, rising sea levels, and extreme weather events.