Greenland is losing ice at a faster rate than previously estimated due to the climate crisis, according to a study. Scientists have found that the Greenland ice cap is losing an average of 30 million tonnes of ice per hour, which is 20% higher than previously thought. This additional freshwater pouring into the north Atlantic may have implications for the collapse of the globally important north Atlantic ocean currents, known as the Atlantic meridional overturning circulation (Amoc).
The study analyzed satellite photos from 1985 to 2022 to determine the end position of Greenland’s glaciers each month. The results showed significant retreat and a total loss of one trillion tonnes of ice. The technique used in this study is different from previous methods, which focused on measuring the height and weight of the ice sheet. These techniques could not account for the retreat of glaciers that lie mostly below sea level in narrow fjords around the island.
The study’s lead researcher, Dr. Chad Greene from NASA’s Jet Propulsion Laboratory, explained that the changes in Greenland are happening everywhere, with almost every glacier experiencing retreat over the past few decades. The influx of freshwater from Greenland into the north Atlantic weakens the Amoc, which is already known to be at its weakest in 1,600 years. Warning signs of a tipping point for the Amoc have been observed, and a recent study suggested that the collapse could happen as soon as 2025.
The study, published in the journal Nature, used artificial intelligence techniques to map glacier end positions over a 38-year period. It revealed that the Greenland ice sheet lost an area of about 5,000 square kilometers of ice at its margins since 1985, equivalent to a trillion tonnes of ice. The most recent update from a project collating measurements of Greenland’s ice found that 221 billion tonnes of ice have been lost every year since 2003. The new study adds another 43 billion tonnes a year, bringing the total loss to about 30 million tonnes on average per hour.
Concerns are raised that the additional freshwater pouring into the north Atlantic could trigger a collapse of the Amoc, disrupting global weather patterns, ecosystems, and food security. The impact of this freshwater source on the formation of deep water in the subpolar gyre and its proximity to a tipping point are concerns for scientists. However, other experts believe that the pace of ice loss is still below the levels needed to disturb the Amoc.
The study’s findings have implications not only for the collapse of ocean currents but also for calculating the Earth’s energy imbalance caused by greenhouse gas emissions. The energy required to melt one trillion tonnes of ice significantly affects precise energy balanced models for the Earth. The indirect effect of ice loss includes speeding up glaciers and the potential disruption of the drainage system.
Scientists are continuing to monitor the situation and investigate the impact of Greenland’s ice loss on the Amoc and global climate patterns. The findings highlight the urgent need for action to address the climate crisis and mitigate its consequences.