GEORGE TOWN, Cayman Islands (CNS) — Millions of people living in low-lying areas in the Caribbean are at increased risk that rising oceans will have a greater impact and be harder to stop or reverse than previously believed, despite cuts in emissions, scientists say in a new study.
Sea level rise is a major consequences of climate change and the effects can already be observed in many areas around the world but scientists are warning that it could be far worse over the longer term even if the world sticks to the Paris climate deal goals.
A new study published in Nature Communications on Monday reveals that sea-level rise will not respond quickly to cuts in greenhouse gas because of the combination of factors forcing the water level up.
The thermal expansion of ocean water, the retreat of mountain glaciers and ice caps, and the mass loss of the Greenland and Antarctic ice sheets combine to drive the rise.
Scientists have found that these contributors respond in different ways to a warmer climate, and all respond on timescales that range from centuries to millennia. Given the current emission levels and those in the near future, the Earth is facing a sea-level rise legacy, which will only fully unfold in the centuries to come.
The researchers said each five-year delay in peaking global CO2 emissions will likely increase median sea-level rise estimates for 2300 by 20 centimeters.
“Man-made climate change has already pre-programmed a certain amount of sea-level rise for the coming centuries, so for some it might seem that our present actions might not make such a big difference – but our study illustrates how wrong this perception is,” said lead author Matthias Mengel from the Potsdam Institute for Climate Impact Research (PIK), in a press release.
“Every delay in peaking emissions by five years between 2020 and 2035 could mean additional 20cm of sea-level rise in the end – which is the same amount the world’s coasts have experienced since the beginning of the pre-industrial era.”
Global sea-level rise is driven by warming and expanding ocean water, as well as the melting of mountain glaciers, ice caps, and the vast Greenland and Antarctic ice sheets. In this work the authors point out that the Antarctic ice sheet is very sensitive to atmospheric warming.
“The uncertainty of future sea-level rise is at present dominated by the response of Antarctica. With present knowledge on ice sheet instability, large ice loss from Antarctica seems possible even under modest warming in line with the Paris agreement,” Mengel said. “Even a sea-level rise of up to three meters until 2300 cannot be ruled out completely, as we are not yet fully certain how the Antarctic ice sheet will respond to global warming.”
The scientists warn that there are quantifiable consequences of delaying action and swift climate mitigation is crucial to limit additional risks.
“For millions of people around the world living in coastal areas, every centimeter can make a huge difference – to limit sea-level rise risks immediate CO2 reduction is key,” said co-author Carl-Friedrich Schleussner.
Republished with permission of Cayman News Service