Rising seas pose a significant threat to coastal cities.
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A recent review of the latest scientific data indicates that capping global warming at 1.5°C above pre-industrial levels won’t halt sea level rise for centuries to come.
“There seems to be a widespread belief that reaching 1.5°C will solve all our problems,” explained Chris Stokes from Durham University, UK. “While it should certainly be our goal, it won’t prevent sea level rise caused by the melting ice sheets.”
At present, global warming is on track for approximately 2.9°C by 2100, noted Jonathan Bamber from the University of Bristol, UK. “In terms of long-term impacts, we’re looking at a potential sea level rise of over 12 meters,” he stated.
Stokes, Bamber, and their colleagues have compiled data from satellite observations of ice loss and rising sea levels over the last three decades, historical data from warm periods, and satellite insights from models of ice sheets.
Older models that fail to incorporate crucial processes suggest that ice sheets take a significant amount of time to respond to warming, according to Bamber. However, satellite data indicates that the Greenland and West Antarctic ice sheets are reacting much more swiftly.
“The data presents a very different narrative,” Bamber remarked. “The mass loss observed in Greenland is astonishing and truly unprecedented compared to model predictions.”
Both Greenland and West Antarctica are not only losing ice, but their rates of loss are increasing, said Stokes. “And this is occurring with just 1.2 degrees of warming,” he pointed out. “The notion that limiting warming to 1.5°C would resolve this is misleading.”
Research on previous warm spells over the past three million years reveals that sea levels were significantly higher during those times, as stated by Stokes.
The most recent report from the Intergovernmental Panel on Climate Change (IPCC), published in 2021, forecasts a sea level rise of 1 to 2 meters over the coming centuries if global temperature rise is curtailed to 1.5°C, according to Stokes.
“We are pushing these projections forward,” he said. “It’s becoming evident that we are witnessing some of the worst-case scenarios manifesting right before us, based on mass balance satellite data.”
The team estimates that merely mitigating the pace of sea level rise from melting ice sheets to manageable levels will require the average global temperature to remain below 1°C above pre-industrial levels.
While wealthier nations may bolster their coastlines against rising seas, as ocean levels continue to escalate, this becomes more challenging and costly, Bamber warned. “Certain countries simply lack the financial resources for such measures.”
This highlights the urgency of taking action, according to Stokes. “Every fraction of a degree is crucial to the ice sheet,” he stated. “While I may alter certain points and thresholds, it’s vital to recognize that all degrees matter.”
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Source: www.newscientist.com