CO2 spike hastens melting of West Antarctic ice sheet, lethal sea surge looms, shows study by Goa-based NCPOR

Panaji: A new study by the National Centre for Polar and Ocean Research (NCPOR), Goa, warns that a critical part of the west Antarctic ice sheet is already undergoing rapid and potentially irreversible melting.

The west Antarctic ice sheet contains enough ice to raise global sea levels by over three to five metres. Once destabilised, the ice could rapidly disintegrate, discharging massive volumes into the Antarctic Ocean.

The melting is driven not only by rising air temperatures but also by the intrusion of warm ocean waters beneath the ice sheet. The findings paint a concerning picture for global sea-level rise, with direct implications for coastal regions and low-lying areas, including in India.

The research, published in the journal Nature Communications, focuses on a particularly vulnerable area known as the Amundsen Sea Embayment. This region is home to some of the world’s fastest-melting glaciers, including the Thwaites “doomsday” glacier.

The study led by NCPOR has traced the origins of stability in the west Antarctic ice sheet to a critical climate transition that occurred 2.7-2.5 million years ago — a period marking the shift from the warm Pliocene to a cold Pleistocene climate.

For climate scientists, the Pliocene period, 5.3-2.6 million years ago, is the best comparison with present-day climate conditions.

The Pliocene period experienced 2-3°C higher temperatures, and atmospheric carbon dioxide levels were between 350 parts per million (ppm) and 450ppm, which are comparable to the early 21st century and 25-60% higher than pre-industrial values.

The peer-reviewed study shows that the west Antarctic ice sheet remained remarkably stable for nearly 2.6 million years. Earlier climate models suggested that the west Antarctic ice sheet may have experienced frequent collapses during warmer interglacial periods of the Pleistocene era.

The new evidence challenges that view.

Instead, the findings suggest that once the ice sheet expanded around 2.7 million years ago, it remained stable even during the warmest intervals. The resilience that endured is now under threat.

Present-day carbon dioxide levels have crossed 420ppm. According to the study’s lead author, paleoclimatologist Waliur Rahaman, the earth is fast approaching the point of no return for ice sheet expansion and long-term stability.

“Present-day climate conditions are similar to those during the Pliocene period, suggesting we are approaching or may have already crossed a similar tipping point,” said Rahaman, a scientist at NCPOR.

Rahaman said, “Though the study does not pinpoint an exact timeline, it provides compelling evidence that we are dangerously close to crossing the threshold. The message is unequivocal: the window to prevent irreversible west Antarctic ice sheet collapse is rapidly approaching, underscoring the urgent need for immediate and decisive climate action.”

Even if global temperatures were to return to pre-industrial levels in the future, scientists warn, the ice sheet may no longer recover to its original size.

“The current phase of rapid melting and mass loss is thus considered unprecedented in the last 2.7 million years,” Rahaman said.

By providing a robust geological reference, NCPOR’s research strengthens future climate model predictions and contributes to more accurate forecasting of sea-level rise.