© Ulrik Pedersen/NurPhoto via Getty ImagesThe Ilulissat Icefjord in Greenland on July 3, 2024. The glacier is calving enough ice daily to meet New York City's water needs for an entire year.
An essential Atlantic Ocean current that regulates the planet's climate is weakening much faster than previously thought, according to a new study.
The Atlantic Meridional Overturning Circulation (AMOC), which includes the Gulf Stream, stabilizes climates in the Northern Hemisphere and beyond.
But a new climate model that factors in freshwater melt from Greenland's ice sheet has suggested that, at the current rate of global carbon dioxide emissions, the current could weaken by as much as one-third in the next 15 years. The researchers published their findings Nov. 18 in the journal Nature Geoscience.
The AMOC acts as a planetary conveyor belt, bringing nutrients, oxygen and heat north from tropical waters while moving colder water south — a balancing act that keeps both sides of the Atlantic 9 degrees Fahrenheit (5 degrees Celsius) warmer than it would otherwise be.
Comment: Soutwestern Canada is on the same latitude as Stonehenge in England. Compare the climates of these two regions to see the importance of the AMOC.
But research into Earth's climate history shows that the current has switched off in the past, and a growing number of studies have hinted that climate change is causing the AMOC to slow. Worst-case scenarios suggest the current may collapse.
If the current were to stop completely, it would sow chaos across the globe, causing temperatures to plummet across Europe, storms to proliferate at the equator, and other unforeseen effects to impact tipping points in the Amazon rainforest and other regions.
However, while many climate models predict a moderate slowdown in the AMOC before 2100, the Intergovernmental Panel on Climate Change (IPCC) has estimated that the probability of the system crossing a tipping point this century is less than 10%.
A simplified animation of the global AMOC "conveyor belt", with surface currents shown in red and deep sea ones in blue. (Image credit: NASA/Goddard Space Flight Center Scientific Visualization Studio)
Yet this is only the beginning of the story. Other models have suggested that the current could collapse soon, stirring up disagreement among scientists, and some have suggested that the risks of the current weakening have been underestimated and demand urgent action.
Comment: Some think this process has already begun. Witness the wild temperature swings in Europe, and massive downpours all over the world, as the monsoon belt moves northward.There is nothing that can be done about this natural cyclic process, only to note it is in play and adapt accordingly. It is hubris to think there is any other course of action.
One important piece of the puzzle is meltwater streaming into the Atlantic from Greenland and the Canadian Arctic. The AMOC works like a giant engine, taking warmer waters from the South (which are saltier and denser) northward. As it moves north, the salty water cools and becomes denser, and thus sinks. This conveyor belt of water also releases heat into the atmosphere before it returns south.
But the influx of lighter fresh water from melting glaciers is displacing some of this salty ocean water, causing it to stop sinking so deeply and slowing down the AMOC. Yet until now, this meltwater hadn't been factored into the models.
Comment: Thus global warming, triggered by other processes within the Earth, brings about global cooling. Nature will have balance, just not on a human time-scale. We are in for decades, if not centuries of severe cold.
"The scientific community is still very split on that topic," Laurie Menviel, a paleoclimatologist at the University of New South Wales (UNSW) in Sydney, told Live Science. "The first aspect is that getting precise estimates of additional meltwater and ice discharge is difficult. There was also a belief that the flux was too small to affect the system."
To investigate the possible oversight, Menviel and her colleague Gabriel Pontes, a research scientist at UNSW, created a new model that factored in the estimated meltwater outflows.
The pair's model suggests that the AMOC has been slowing at a rate of 0.46 sverdrup (a sverdrup is 1 million cubic meters of water per second) every decade since 1950, and that if humanity exceeds 3.6 degrees Fahrenheit (2 degrees Celsius) of global warming (in line with current projections), the circulation could be 33% weaker by 2040.
"This paper is important in that it confirms what many have suspected but what hasn't been shown explicitly before," Stefan Rahmstorf, an oceanographer who runs the Earth system analysis department at the Potsdam Institute for Climate Impact Research in Germany, told Live Science. "For the future, the results suggest that we must expect a faster AMOC decline than IPCC has predicted."
Reader Comments
The IPCC has predicted lots of things which haven't come to pass because their data is flawed and their models useless. When mother nature throws a curve ball, the IPCC and their NWO ilk just alter the record to fit their flawed models, hoping noone will say something or notice.
Al gore made a fortune off the very gullible or the very stupid. But that's what charlatans do.
We were warned of a coming ice age by real scientists in the 1970's, before getting rich pushing propaganda became commonplace.
One question might be, how would you explain to someone who has noticed that something is changing but attributes the change to AGW, that other factors are involved?
Another question, how would you explain to someone who insists that there is nothing to see, or comes with general statements about changes always being there, so nothing to worry about, that the Earth has gone through periods of dramatic change and that we might be experiencing the precursors to one such?
Fear is not necessarily a bad thing, it can be justified or not but shouldn't it be explored for what it is worth?
does that person think we should do better to not pollute the environment due to caring for the Earth, or is it due to fear mongering that we are to blame for cycles that have as much been proven to be as natural as the seasons changing?
If their care is due to a fear/guilt complex, their universe is too self centered for me to give a damn to even have a lengthy conversation about the subject with them. There's nothing you can say to an eco-egocentrist that they will consider worthy of further thought. There is no way for scientific debate to change their propaganda driven opinions.