In 2014, Evelyne Dhéliat broadcast on television a predictive weather card from France in the middle of the century. The country, crushed by a heat wave, was sufficient under high temperatures. The idea – shock – was simple: to raise awareness of global warming and its consequences. This same card was updated three years ago: it now places almost the whole territory above 40 ° C, in this fictitious month of August 2050. Projections can be exceeded by reality. Will it be the same for those on the Amoc?
Minus 18 ° C in Paris, -29.3 ° C in Berlin (Germany), -34.4 ° C in Copenhagen (Denmark), -47.9 ° C in Oslo (Norway). Surely without knowing it, René Van Westen, researcher at the University of Utrecht (Netherlands), reproduced the prestator’s card at the opposite, and at European level. In a new study published this Wednesday, June 11 in the journal Geophysical Research Letters, He simulates the consequences of a collapse of the Amoc (English acronym for the “meridian circulation of the Atlantic”), this set of ocean currents in the Atlantic which contributes, among other things, to maintain a mild climate on our continent. This predictive work is one of the first to analyze the combined and superimposed effects of this possible cooling and climate change, depending on different scenarios. It is accompanied by encrypted data, which can give cold in the back.
If the Nordic countries and the United Kingdom would be the most affected, France would also undergo the effects of an amoc stop. In a world warmed of 2 ° C, therefore beyond the Paris agreement, the annual temperature in the French capital would still be lower by 1.3 ° C. An even more marked situation during the winter months. “During extreme cold period, cities could experience days at -18 ° C, 11 ° C less than compared to the pre -industrial era”, explains René Van Westen. The thermometer would fluctuate more from one day to the next, and winter storms would be more numerous and intense.
But the most striking result concerns frost days: Paris could know up to 83 per year. Almost four times more than at the end of the 19th century! This is also the case of Lille (82), according to Amocscenariosa very visual simulation tool developed by the authors based on their climatic models. Reims would know three times more frost days (93), and Le Havre eight times more (57). Overall, the southern half of the country would be relatively spared from the effects of an amoc stop.
Icebergs in the North Sea?
The cascade repercussions of such a scenario are very complex. As the express evoked it in a recent article, the seasonality of our temperate climate would be highly amplified. “While the winter months would become very cold, the summer months would be slightly or much warmer,” said the Dutch researcher. A puzzle for adaptation strategies. “Many of our infrastructure is not built for this type of time and these extremes,” he points out. Agriculture would also be upset, with lower precipitation and arable land swallowed by the cold. Energy security would also be put to the test. Just like international trade.
https://www.youtube.com/watch?v=iit_u_ttami
The study shows that these colder temperatures would result in an extension of the Arctic pack ice in certain parts of the British islands, along the west coast of the Scandinavian peninsula, and to the north of the Netherlands. “In this extreme scenario, the port of Rotterdam, which is a hub for maritime exchanges, could be confronted with ice or icebergs in the North Sea,” describes René Van Westen.
Long underestimated, perhaps in part because of the eccentricities of the film The next day, which is based on this hypothesis, the scenario of a collapse of the Amoc is the object of a renewed interest by scientific research. This prompted the IPCC to influence its position in the past ten years. Even if a consensus on the reality of this slowdown, its speed and its consequences is still far from being reached, the States begin to seize the subject, as it would have implications on all the sides of our society.
The Iris Defense & Climate Observatory was not mistaken. He has Posted in early June a note About the AMOC, hoping to “cover a blind spot linking climatic and safety issues”. The authors confirm that its collapse “could destabilize the energy and food security of northern and western Europe, but also question the challenges of crucials such as the effectiveness of defense and underwater attack capacities”. They notably propose the implementation of a watch unit and order more studies on socio-economic repercussions in France. And, to raise awareness, a new card inspired by that of Evelyne Dhéliat?
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