Fianna Fail senator Malcolm Byrne says the government must prepare for a possible future collapse of the ocean current system known as the Atlantic Meridional Overturning Circulation (Amoc).
His call follows the publication of a study showing the Atlantic circulation is heading toward a tipping point that is “bad news for the climate system and for humanity.” Thanks to the Gulf Stream, which is part of the current system, Ireland maintains a relatively mild climate.
Senator Byrne added in the Seanad: “The collapse of Amok may not happen in our lifetime, but it will have a profound impact on future Irish generations. As a result, Ireland’s climate will change in a similar way to Iceland’s. “This could have significant implications…As a nation, we should leave nothing off the table in terms of preparedness.”
He said he was encouraged by the government’s commitment to climate adaptation to prepare for the inevitable impacts of climate change. There was engagement with all sectors on sectoral adaptation planning. “[But] We must not be complacent. This is a matter of great importance to the country’s long-term plans…If that were to happen, Ireland would be at great risk. ”
Scientists involved in the study said they could not yet predict how quickly the collapse would occur, but were shocked by the speed at which it was predicted to reach that point. They used computer models and historical data to develop an early warning indicator of Amoc’s failure, which is important for global climate regulation.
They discover that Amoc is already on track for a sudden change that won’t happen for over 10,000 years and will have disastrous effects on much of the world.
Amoc is an ocean conveyor belt that transports heat, carbon, and nutrients from the tropics to the Arctic, where it cools and sinks into the deep ocean. This stirring helps distribute energy across the planet and balances the effects of human-induced global warming.
But the system is being eroded by Greenland’s glaciers and Arctic ice sheets melting faster than expected, allowing fresh water to flow into the ocean and preventing saline, warmer water from sinking from the south. It has fallen 15% since 1950 and is at its weakest point in more than 1,000 years, according to previous research.
So far, there is no consensus on how serious this will be. A study last year suggested that the tipping point could occur between 2025 and 2095, based on changes in sea surface temperatures. However, the Met Office said it was “very unlikely” that large-scale and rapid changes to Amok would occur this century.
This recent paper published in Science Advances breaks new ground by finding red flags in the salinity of the southern tip of the Atlantic between Cape Town and Buenos Aires.
A computer model of the global climate simulated changes over 2,000 years and found that a gradual decline could lead to an abrupt collapse in less than 100 years.
The results provide a “definitive answer” as to whether such sudden changes are possible. “Until now, the Amok chip was only a theoretical concept, and it was thought that the chip would soon disappear, so this is bad news for the climate system and for humanity.” A complete climate system with all additional feedback was considered. ”
They also mapped the effects of the collapse. Sea levels in the Atlantic Ocean could rise by 1 meter in some areas, potentially flooding many coastal cities. The rainy and dry seasons in the Amazon could be reversed, pushing the already weakened rainforest beyond a tipping point.
Temperatures around the world will fluctuate even more erratically. The southern hemisphere will be warmer. Europe will become dramatically colder and have less precipitation. While this may sound attractive compared to current heating trends, changes will occur 10 times faster than they currently do, making adaptation nearly impossible.
“What surprised us was the frequency of falls,” said Dr Rene van Westen of Utrecht University. “That would be devastating.”
We don’t yet have enough data to determine whether this will happen next year or in the next century, but once it happens, the changes will be irreversible on human timescales. “We are moving in the direction of [collapse]. That’s a little scary,” Dr. Van Westen said. “We need to take climate change more seriously.”
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