Sustainability Corner: The progressive slowing of AMOC
Photo courtesy of Wikimedia Commons
In a previous edition of the “Sustainability Corner," we covered the nature of climate breakdown—the accelerated processes of climate change within specific regions—and the effects and causes of this positive feedback loop; this, thereby, has only increased climate change’s efficiency in acting. One of these causes was the slowing of the Atlantic Meridional Overturning Circulation (AMOC), described by the National Ocean Service as “a system of ocean currents that circulates water within the Atlantic Ocean, bringing warm water north and cold water south.”
The reason this is important was also outlined in that article: “In Greenland, the ice caps melt at an unprecedented rate of ‘234 billion tons of ice per year,’ at minimum. This is due to the continued slowing of the AMOC, which is…caused by unprecedented low sea surface temperatures worldwide, which melting glaciers have inversely caused; it has entered a positive feedback loop devoid of a strong thermohaline circulation, which may prove impossible to pull AMOC out of.” Due to these exceptional levels of warm freshwater inclusion, the ecosystems at either Pole are amidst a shift that will wreak havoc on this process. This is a keystone process of Earth’s climate regulatory system; without it, there may be dire effects.
Vice spoke to oceanographer Stefan Rahmstorf, who laid out potential outcomes if this system collapsed outright: The stagnation of the world’s water currents with temperature consolidated by region-locked systems. They also stated, “We’d see the whole Northern Hemisphere cool compared to what it would be with just global warming [acting alone]...In the Southern Hemisphere, greenhouse warming would get worse. There would be a shift in the tropical rainfall belts…You would also get flooding from tropical rainfalls shifting to places where people and infrastructure are not used to it.”
This article continued by diving into the weather-related effects this stagnation would cause, specifically on weather systems in specific regions. The article stated that the effects will be seen through “changing how heat and precipitation are distributed globally…[and] contribut[ing] to an increased warming of the tropics, where rising temperatures have already given rise to challenging living conditions.”
This topic is explored more in-depth in a Geographical UK article where the journal stated, “The combined effects of more freshwater from increased rainfall, melting ice and river runoff is becoming more likely to push AMOC to an irreversible tipping point. A full collapse of the AMOC has happened before, during glacial periods in which ice sheets covering the planet were melting. The influx of freshwater slowed the circulation down and led to extreme climate fluctuations.” A more subtle yet dire effect is a massive increase in sea levels—flooding coastal towns without any remedy—and extreme temperatures and weather conditions within regions, such as high winds or extreme snowfall. As each region becomes more dependent on regional weather systems to regulate their temperatures, the consequences will be even more significant than this, as some ecosystems will experience entire climate shifts—removing rain seasons or increasing the winter season.
AMOC will be an unmanageable system for the foreseeable future, and because of that, researchers are doing their best to estimate the time remaining before these damning consequences occur. Sources say that “new research indicated that the risk [of AMOC’s failure] had so far been ‘greatly underestimated,’ and the ‘passing of this tipping point is a serious possibility already in the next few decades.’”
With so many unknowns surrounding this ongoing systematic disruption, there is much to look into, and people may want to keep up to date—regardless of the current political affairs in the United States. This developing issue may prove to have lasting detrimental consequences, and it may be of keen importance to be aware of any steps that can be taken to try to mitigate this system failure further.