A Policy Brief from the Academy of Finland’s flagship Atmosphere and Climate Competence Center (ACCC) describes the current state of the climate and particularly the risks concerning the slowdown and possible shutdown of the Atlantic Meridional Overturning Circulation.
Climate change is driving the climate system toward critical tipping points, whose crossing would cause significant and irreversible changes in the system’s functioning. These tipping points include the melting of Greenland and West Antarctic ice sheets, the drying of the Amazon rainforest, and the shutdown of the Atlantic Meridional Overturning Circulation (AMOC). Currently, climate policy does not sufficiently address the risks related to climate system tipping. The policy brief advises policymakers to consider how to better prepare for and manage the risks associated with the tipping points.
Several recent studies have raised concerns about the potential shutdown of AMOC within this century. AMOC is the most significant current in the Atlantic Ocean, transporting heat from the south towards Europe, thereby warming the entire northern hemisphere. The policy brief presents assessments of the impacts of an AMOC shutdown, particularly for Europe and Finland, where the effects would be especially strong.
“Based on the current knowledge, an AMOC shutdown by the end of the century remains unlikely. However, it is expected that as climate change progresses, AMOC will continue its observed slow decline,” says Joonas Merikanto, head of the climate system modeling group at the Finnish Meteorological Institute. “Since the possibility of a shutdown cannot be completely ruled out, its impacts and risks must also be understood in national and international decision-making.”
In Finland, an AMOC shutdown would decrease the average winter temperature by about 20°C and the average summer temperature by about 5°C, not accounting for the partially compensating warming due to ongoing climate change. An AMOC shutdown would thus significantly impact housing, food production, transportation, and ecosystems.
“The nature of the shutdown itself, whether it would take a few decades or centuries, is also unclear. The concerning aspect of the AMOC slowdown, as with other potential climate tipping points, is that once the tipping point is crossed, the process can accelerate and become very difficult, if not impossible, to stop,” Merikanto explains. The most effective way to prevent crossing tipping points is to limit the rate of climate warming by rapidly reducing global greenhouse gas emissions.
An information event on the policy brief, the current state of the climate, and tipping points will be held at Tiedekulma on May 31 from 1:00 PM to 2:30 PM. The event will also feature a panel discussion on the policies and risk management related to tipping points. The panelists will include Eva Biaudet, Atte Harjanne, Kaisa Kosonen, and Yulia Yamineva. The stream of the event can be found at: https://tiedekulmamedia.helsinki.fi/fi/web/tiedekulma/player/webcast?eventId=292224401
The policy recommendation by the Academy of Finland’s ACCC flagship project “The Significance of Climate Tipping Points for Finland: Latest Information on the Possible Shutdown of the Atlantic Meridional Overturning Circulation (AMOC) and Preventive Climate Actions” will be published on May 27, 2024.
For more information: Joonas Merikanto, Ph.D., head of climate system modeling group, Finnish Meteorological Institute, email: joonas.merikanto@fmi.fi Yulia Yamineva, Ph.D., associate professor of climate law and policy, Centre for climate, energy, and environmental law, University of Eastern Finland, email: yulia.yamineva@uef.fi
The Academy of Finland’s flagship “Atmosphere and Climate Competence Center (ACCC)” is coordinated by the University of Helsinki, the Finnish Meteorological Institute, Tampere University, and the University of Eastern Finland.
www.acccflagship.fi