A study has found that Ice sheets can collapse into the ocean in spurts of up to 600 metres (2,000 feet) a day, far faster than recorded before.
Published in the journal Nature, the researchers 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. They 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.
They scientists said that the finding, based on seafloor sediment formations from the last ice age, was a “warning from the past” for today’s world in which the climate crisis is eroding ice sheets. They said the discovery shows that some ice sheets in Antarctica, including the “Doomsday” Thwaites glacier, could suffer periods of rapid collapse in the near future, further accelerating the rise of sea level.
Reports show that the rising oceans are among the greatest long-term impacts of global heating because hundreds of major cities around the world are on coastlines and are increasingly vulnerable to storm surges and flooding. The West Antarctic ice sheet may already have passed the point at which major losses are unstoppable, which will lead eventually to metres of sea level rise.
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In his reaction, Dr Christine Batchelor at Newcastle University in the UK, who led the research said, “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”.
Speaking further, he said, “These pulses translate into sea level rise and could be really important for sea defences,” she said. The rate of loss was critical if, for example, a rise expected over 200 years could actually occur in 20 years,”.
He said that the research could also be used to enable computer models to make better predictions about future ice loss.
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 analysed.
Story was adapted from the Guardian.
