Meanwhile, in *Other* News: Critical Ocean Current Likely in Collapse from Our Warming Planet

[SorellaLaBefana]

The formation of sea ice in the North Atlantic drives the Atlantic Meridional Overturning Circulation, and its depletion may be why it is weakening.

The Atlantic Meridional Overturning Circulation (AMOC) has slowed substantially since the mid-90s, a new study reveals. AMOC is an essential component of the systems that keep the Earth’s regional climates in balance. Without it, Europe could suffer colder winters while the tropics could heat up even faster. Climatologists have identified AMOC as one of the most vulnerable parts of the planetary heat balance for decades, but uncertainty has remained about how much change is taking place.

Ocean currents move quantities of water that make the world’s largest rivers seem small by comparison. In the process, they redistribute heat, as well as helping oxygenate deeper waters. The factors causing these currents vary, with physical processes such as the Coriolis force having an important influence. AMOC, however, is primarily the result of salty water left behind when sea ice forms sinking to the depths, leaving space for tropical waters to flow in.

Many climate models suggest that as melting ice from Greenland floods the North Atlantic with cold, but very fresh, water, it will sit above more salty water instead of sinking. Without an impulse to the depths, water will stop moving south in the deep ocean, and the Gulf Stream will flow more weakly. However, the Atlantic is a large place, and tracking the movements of this much water is hard, particularly since the data gets patchier the further back you go. Measurement efforts consistently show AMOC is weakening, but disagree on how much…

The possibility of AMOC’s collapse attracted public attention when it was the centerpiece of the Hollywood blockbuster The Day After Tomorrow. Like most disaster films it took something real and exaggerated it to ridiculous proportions. “Of course, most climate scientists do not share these Hollywood fantasies, and no one inside scientific communities believes anything remotely similar can happen,” Mishonov said. "However, most do believe that substantial slowing of AMOC might result in significant climate change that cannot be foreseen and predicted. Therefore, increased interest in AMOC functionality is fully warranted."…

https://www.iflscience.com/one-of-the-worlds-most-important-ocean-currents-really-is-slowing-down-73554

The Open Access (free to read) study the above is based on is “Revisiting the multidecadal variability of North Atlantic Ocean circulation and climate” in the journal Frontiers in Marine Science

The World Ocean’s surface, particularly in the North Atlantic, has been heating up for decades. There was concern that the thermohaline circulation and essential climate variables, such as the temperature and salinity of seawater, could undergo substantial changes in response to this surface warming. The Atlantic Meridional Overturning Circulation (AMOC) has changed noticeably over the last centennial and possibly slowed down in recent decades. Therefore, concerns about the future of the North Atlantic Ocean climate are warranted. The key to understanding the North Atlantic current climate trajectory is to identify how the decadal climate responds to ongoing surface warming. This issue is addressed using in-situ data from the World Ocean Atlas covering 1955-1964 to 2005-2017 and from the SODA reanalysis project for the most recent decades of 1980-2019 as fingerprints of the North Atlantic three-dimensional circulation and AMOC’s dynamics. It is shown that although the entire North Atlantic is systematically warming, the climate trajectories in different sub-regions of the North Atlantic reveal radically different characteristics of regional decadal variability. There is also a slowdown of the thermohaline geostrophic circulation everywhere in the North Atlantic during the most recent decade. The warming trends in the subpolar North Atlantic lag behind the subtropical gyre and Nordic Seas warming by at least a decade. The climate and circulation in the North Atlantic remained robust from 1955-1994, with the last two decades (1995-2017) marked by a noticeable reduction in AMOC strength, which may be closely linked to changes in the geometry and strength of the Gulf Stream system.



https://www.frontiersin.org/articles/10.3389/fmars.2024.1345426/full

Neither the Moon (nor Mars) can be Planet-B…