Scientists detect ‘signal’ that may spell doom for our mild climate
Climate scientists have spotted an early warning signal that the North Atlantic Gulf Stream – which protects Ireland’s mild climate – may already have been irreversibly disrupted.
Up to now, the oceans have shielded us from the worst impacts of climate change, because they absorb 25pc of all carbon dioxide greenhouse gas emissions, and 90pc of the excess heat attributed to these emissions.
“We know that oceans and climate can change abruptly, and we call the times when these happen ‘tipping points’,” said Professor Gerard McCarthy, who was involved in the research.
“There is a worry that a tipping point is approaching in the North Atlantic, and in Ireland that would likely lead to drier summers and wetter, more stormy winters,” said Prof McCarthy.
That’s bad enough, but another, less likely, but still possible outcome, is that there could be a breakdown of the normal ocean currents circulating in the North Atlantic, notably the Gulf Stream.
If that happened, it could lead to huge temperature fall-offs, or even trigger a new Ice Age.
An international team of climate scientists, based in the Netherlands, France, Spain and Ireland, came together to analyse the scientific data available on climate variations in the North Sea over the past 1,000 years.
“We used computer models with artificial intelligence and machine learning to look at past data, from a number of sources,” said Prof McCarthy, based at the Irish Climate Research and Analysis Unit (ICARUS) at Maynooth University.
“We found a signal in the data that looks like a warning sign for the approach of a period of abrupt change in the North Atlantic.”
He added: “In the Atlantic, the sea surface temperatures are either a little bit warmer, or a little bit colder than usual. If you go back to the Sixties and Seventies, the Atlantic was a bit colder than usual.
“There is a natural wobble in the data, between times when the Gulf Stream is strong and when it’s not so strong,” Prof McCarthy said.
“We found that tipping points happened when the gaps between the wobbles started to lengthen and that is what we are seeing in the data right now.”
He said the study adds to growing evidence that change may already be under way in the Gulf Stream system, on which Ireland’s climate relies.
“It emphasises the importance of further understanding this critical element of the climate system so we can prepare for the future.”
Professor Simon Michel, from the Institute for Marine and Atmospheric Research in Utrecht, led the research, which was published in Nature Communications.
Yet even if the climate tipping point has now been reached in the Atlantic, Prof Michel said we should not give up on trying to reduce our emissions.
“Because we have caused, or are about to cause, irreversible changes in the climate system, climate adaptation policies are now equally important and necessary as climate mitigation policies,” said Prof Michel.