Ice sheets are capable of collapsing into the ocean at a rate of up to 600 meters (2,000 feet) per day, according to recent research published in the journal Nature.
This speed is up to 20 times faster than previously thought possible and is considered a “warning from the past” for our current climate crisis.
Scientists analyzed sea floor sediment formations from the last ice age, discovering that Antarctic ice sheets, including the Thwaites glacier, could experience rapid periods of collapse, further increasing the rise of sea level.
The study’s findings are significant because rising oceans are one of the most severe long-term impacts of global heating.
Hundreds of major cities around the world sit on coastlines, making them increasingly vulnerable to storm surges and flooding.
The West Antarctic ice sheet may have already passed the point where major losses are unstoppable, leading eventually to meters of sea-level rise.
Dr. Christine Batchelor at Newcastle University in the UK led the research and commented, “Our research provides a warning from the past about the speeds that ice sheets are physically capable of retreating at. It shows that pulses of rapid retreat can be far quicker than anything we’ve seen so far.”
The study used high-resolution mapping of the sea bed off Norway, where large ice sheets collapsed into the sea at the end of the last ice age 20,000 years ago.
The scientists focused on sets of small ridges parallel to the coast, which formed at the line where the base of the ice sheet met the oceans, called the grounding line.
Measuring the distance between the ridges enabled the scientists to calculate the speed of the Norwegian ice sheet collapse.
The fastest rates of ice sheet loss to the ocean were found where the ice sheet had been resting on a virtually flat sea bed.
This is because a relatively small amount of melting at the base of a flat-bedded ice sheet can lift a large section of the sheet and shift the grounding line much further inshore than if the sheet was on a steeper slope.
The research could also be used to enable computer models to make better predictions about future ice loss. Most previous estimates of the rate of ice sheet collapse have come from satellite data, which has been collected for about 50 years.
The geological data used in the study stretches back thousands of years, allowing a much greater range of conditions to be analyzed.
“Our findings suggest that present-day rates of melting are sufficient to cause short pulses of rapid retreat across flat-bedded areas of the Antarctic Ice Sheet, including at Thwaites,” Batchelor said.
“Satellites may well detect this style of ice-sheet retreat in the near-future, especially if we continue our current trend of climate warming.”
These findings are significant It highlights the urgent need for global cooperation to address the growing threat of climate change and its impact on our planet.