by Tom Gilbert, Co-Executive Director, New Jersey Conservation Foundation
It sounded like the setup for a joke: “Pinelands to become beachfront property?”
But the question posed by Heidi Yeh, policy director for the nonprofit Pinelands Preservation Alliance, is no laughing matter. A new study is predicting the collapse of a system of Atlantic Ocean currents, which could raise sea level enough to submerge much of New Jersey’s coast.
New Jersey’s outer coastal plain, which includes the sandy Pine Barrens, was once sea floor. At the end of the Cretaceous period 65 million years ago, when the Earth’s climate was much warmer, the Atlantic Ocean covered most of the coastal plain.
Will our changing climate turn the Pine Barrens into beachfront or ocean floor once again?
An alarming study published in the journal Nature Communications predicts that the Atlantic Meridional Overturning Current (AMOC) system – of which the Gulf Stream is a part – is nearing a tipping point and could collapse around the middle of the century … or as early as two years from now.
Sea level along New Jersey’s coast is already predicted to rise two feet by the middle of this century, and five feet by the year 2100, as a result of climate change. The collapse of the AMOC could add another two feet by reducing the Gulf Stream’s ability to hold water back from the shoreline.
“Sea level rise projections for our area are typically not including the possibility of an AMOC shutdown,” noted Yeh. “The velocity of the Gulf Stream holds about two feet of water off our shore, so eliminating currents that are part of the AMOC would quite literally release the floodgates that are currently maintaining what we think of as a ‘normal’ sea level for the Jersey shore.”
The AMOC is a complex system of currents that helps regulate global weather patterns. It has been described as a giant conveyor belt, transporting warm water northward from the tropics. As the currents reach the North Atlantic, the water cools, becomes saltier, and sinks deep into the ocean. The cooler waters then disperse southward.
An influx of fresh water from the melting of Greenland’s ice cap and other sources is disrupting AMOC’s currents, slowing down the conveyor belt. In addition to higher sea levels, the impacts of a collapse would include more extreme winters in Europe and a shifting of the monsoon rains in the tropics.
“I think we should be very worried,” said lead study author Peter Ditlevsen, a professor of climate physics at the University of Copenhagen in Denmark. “This would be a very, very large change. The AMOC has not been shut off for 12,000 years.”
Adding to the worry is new data showing that the average surface temperature of the world’s oceans has hit its highest level ever due to climate change.
The AMOC is believed to have collapsed and restarted repeatedly in the cycle of ice ages that occurred from 115,000 to 12,000 years ago. In recent years, weakening in circulation has been reported, but assessments by the Intergovernmental Panel on Climate Change (IPCC) suggested that a full collapse is unlikely within the 21st century.
The study’s authors, concerned about increasing greenhouse gas concentrations in the atmosphere, decided to investigate the AMOC’s tipping point further. For the study, they analyzed 150 years’ worth of surface ocean temperature data for the North Atlantic to see how currents behaved before human-caused climate change.
Based on their analysis, the study authors concluded that AMOC’s tipping point was coming much sooner than previous studies predicted. The study calls for swift measures to cut greenhouse gas pollution, and reduce global temperatures to slow the melting of glaciers in the Arctic.
While not all climate scientists agree with the report’s predictions of AMOC’s potentially imminent collapse, there is near universal agreement that immediate worldwide action is needed to prevent the most catastrophic impacts of climate change.
It should be noted that the AMOC study’s frightening predictions were based on greenhouse gas emissions continuing to rise at the current rate. But if emissions start to fall – the goal of climate policies — the world will have more time to try to push back the AMOC tipping point and prevent climate catastrophe.
Here in New Jersey, we’re working to do our part by transitioning from fossil fuels to clean sources of energy like responsibly-sited solar and offshore wind, adoption of electric vehicles and initial steps to electrify buildings. But we must act with even greater urgency.
Earlier this year, Governor Phil Murphy signed an executive order pushing up the state’s 100% clean electricity target date from 2050 to 2035. The Legislature should act to establish this target in state law, and step up efforts to help consumers install efficient air source heat pumps to reduce harmful emissions in the home and save consumers money.
To read the study, go to www.nature.com/articles/s41467-023-39810-w. To learn more about efforts to accelerate New Jersey’s climate policies, go to https://cleanenergyactionnow.org/.
For more information on preserving New Jersey’s land and natural resources – including forests and other places that sequester carbon to help mitigate climate change – visit the New Jersey Conservation Foundation website at www.njconservation.org or contact me at email@example.com.