A study published by the renowned Potsdam Institute in Germany this summer raises serious concerns for Ireland. It confirms that we could be on course to cross a key climate tipping point in our oceans far earlier than most had previously expected. The data suggests that the Atlantic Meridional Circulating System (Amoc) may switch off. If that were to happen it would bring about a dramatic drop in temperatures here, even as the rest of the world continues to burn.
The crossing of crucial tipping points keeps many scientists awake at night. The worry is that forest systems might collapse, ice sheets melt or ocean currents alter, in a way that leads to runaway climate change and the loss of the relatively stable environment we’ve lived within for the last 10,000 years.
As we are out in the Atlantic, what happens to the oceans should be our biggest concern. If the Amoc does switch off, the consequences for northwest Europe would be catastrophic and Ireland would be most affected. We are on the same cold latitude as Newfoundland but the Gulf Stream gives us far more temperate rainforest, grassland and wetland conditions. The warm waters from the Caribbean flow north until they mix with colder and less salty waters between Iceland and Norway, where they then start “downwelling” to return southwards in a deeper, colder current. It is part of a wider ocean conveyor belt that connects to the South Atlantic and influences what happens in the Amazon region.
We know that less salty and colder melt waters from the Greenland ice sheet could have an impact on this circulation system. The consensus to date was that the Amoc was unlikely to switch off this century, but these new studies say it could happen a lot sooner, even by the middle of this century. We also know that the Amoc has switched off in the past and there are signs it is already weakening. We may only be certain we have crossed this tipping point when it is already in-train and may be too late to stop it. That is why this issue is attracting increasing scientific attention.
This was the third year in a row that a major new study has raised similar concerns about the Amoc. While there is not yet a scientific consensus around the findings, there is growing evidence that our climate is changing faster than expected, especially in the North Atlantic. Last year there was a dramatic rise in our seawater temperatures, and all that embodied energy is likely to have been a factor in the exceptionally warm, wet and windy weather we have had over the past year.
Modelling of the Amoc is difficult because it is influenced by a variety of complex ocean and atmospheric forces and we need to do a lot more monitoring to better understand what is happening. However, what seems to be in question is when, not if, this switch off will occur, unless we dramatically cut greenhouse gas emissions.
The Environmental Protection Agency (EPA) is looking to convene various European experts to try to inform the next assessment report from the Intergovernmental Panel on Climate Change, which is a key guide for policymakers. Such analysis is always based on probability assessments. This latest study says the Amoc switch off could be one of the earliest tipping points to be crossed and the chances of it happening increases with every percentage point rise in global average temperatures. We committed in the Paris Agreement to keep that increase below 1.5 degrees, but the latest global stock take shows us heading for 2.7 degrees, which would bring us into very dangerous waters, especially in the North Atlantic.
The EPA has also been engaged in a study entitled Climate Change in the Irish Mind. It involved detailed interviews with thousands of Irish people and shows the vast majority are keen to play their part in addressing this huge challenge. We want to protect nature and the environment for future generations and we can see our weather patterns are already changing. As our emissions start to fall we are also shaking off our reputation as climate laggards. We need to use our strong and credible voice in international climate negotiations to try to halt an Amoc collapse.
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We may also have to start preparing for a different future. I think most of us thought we wouldn’t have to face some of the hardships that other hotter places might have to endure. If these new studies are correct, we could be in the worst of all worlds. We would lose our benign growing and living conditions. Rather than thinking how we manage climate refugees from the south, we might want to move south ourselves, out of the freezing cold.
Eamon Ryan is Minister for the Environment, Climate, Communications and Transport
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