Is An Crucial Atlantic Ocean Current Called AMOC Ready To Go Amok?

Warm water heads north toward Europe, cools, 
eventually sinks, goes back south, warms up
and the process repeats itself.  However,
fresh water melting off the Arctic could stop
this circulation, causing extreme, sudden
changes in climate, especially in Europe.

 Is the AMOC ready to go amok?  

I should probably explain that one. 

The AMOC is the Atlantic Meridonal Overturning Circulation. It brings warm water from south to the northern Atlantic Ocean. That rent brings carbon, nutrients and other stuff to sustain a healthy population of fish and other aquatic animals.

It also keeps western and northern Europe much warmer than it would be, considering how far north that area is. If this circulation collapses, that region of the world would turn much, much colder in the winter. And much more variable in the summer. 

The problem is, climate change could make this circulation stop. It's already slowing down. 

For years, there's been a lot of speculation among scientists as to how far climate change needs to go before AMOC collapses. Now, a group of scientists are saying the risks of this circulation collapsing are underestimated. 

 As Gizmodo reports:

"The climate scientists quoted a 2023 Intergovernmental Panel on Climate Change (IPCC) report, which said there is 'medium confidence' the AMOC won't abruptly collapse by 2100. If such a low likelihood event did happen, the report added, 'it would very likely cause abrupt shifts in regional weather patterns and water cycle."

Well, at least we have time to plan, right?

But what if it happens sooner? It seems a growing body of researchers think it might.  Some scientists say it could happen as soon as the middle of this century, say 20 or 30 years from now. That's not a lot of time for millions of people to brace themselves for sudden, radical shifts in the climate. 

Nordic nations would probably stop being able to grow their own food under the extreme weather conditions. 

That would be bad enough. But a collapse of AMOC would reverberate around the world, with big time climate changes worldwide.

An AMOC collapse would probably reverse climate change in the northern hemisphere, but that would not be a good thing.

Some European cities would get 10 to 20 degrees colder within just a few decades. Meanwhile, The Atlantic Ocean sea level would rise by more than two feet. Meanwhile, the southern hemisphere would turn much warmer than it already is, and the Antarctic ice cap would melt much faster than it is now, according to renewablematter.eu.

Overall, this circulation's shutdown would also reduce the worlds supply of food.

As I noted, we don't know when, or even if this nightmare scenario will happen. But scientists are definitely worried. 

The AMOC is slowing down, and could collapse, because of melting ice sheets in Greenland and other areas of the Arctic adjacent to the North Atlantic. 

The water flowing up from the south and keeping Europe mild in this AMOC circulation is pretty salty. Once the salty water makes it that far north, it cools and sinks because the high salinity increases its density. 

Fresh water from all that ice melting off of Greenland reduces the saltiness in the water, which in turn reduces the density of the water. So less surface water sinks, which slows the flow of the current. Scientists worry if too much fresh water from ice melt flows into the Atlantic, it'll shut off the current entirely.  

 Scientists have done research on how much fresh water it would take to shut the current off. But past studies uses simulations that provided unrealistic scenarios involving a bunch of fresh water gushing into the Atlantic all at once.

 In February this year, scientists from Utrecht University in the Netherlands used a complex climate model to simulate the collapse of the AMOC and discovered that it could be closer than previously thought.

The Dutch scientists' model kept gradually adding more and more fresh meltwater to the North Atlantic and concluded that could lead to a sudden collapse of the currents in less than 100 years. However, they weren't able to come up with a statistically reliable estimate of exactly when that would happen.  

We better hope it doesn't happen anytime soon. If it does, it'll make the kinds of climate disruptions we're already seeing now just a pleasant walk in the park. 

Greenland Ice Loss Worse Than Thought, Says New Study

A new report says ice loss from Greenland - already 
known to be bad - is even worse than thought.

 Climate scientists and others interested in climate change really monitor Greenland as one measure of how bad things are getting as the world warms. 

That's why you disproportionately read about Greenland in the news, and in this here blog thingy. 

Well, here's another one, 

It turns out Greenland has lost more ice than people thought. Even if  the original lower estimate was pretty huge. 

Per the Washington Post: 

"Researchers had previously estimated that the Greenland ice sheet lost about 5,000 gigaton of ice in recent decades, enough to cover Texas in a sheet 26 feet high. The new estimate adds 1,000 gigaton to that period, the equivalent of piling about five more feet of ice on top of that fictitious Texas-sized sheet."

According to The Guardian, if you include the ice loss found in this study, the Greenland ice cap is losing an average of 30 metric tons of ice per hour due to climate change. 

The additional ice loss researchers found came from the glacier's edge, where it meets the water. That portion of the glaciers float on the water. Any floating ice that melts won't raise sea levels like ice loss form inland portions of Greenland ice. Inland ice melt runs downhill into the ocean, raising its level. 

 The ice floating on the waters around Greenland is like the ice cubes in your gin and tonic. If the ice melts in your drink, the water level won't rise, but you won't get as much punch from the gin, as it will get diluted.

The ice loss on the edges of the glacier - on the water - has some similarities to your now ice free, diluted gin and tonic. 

The melting ice dilutes the amount of salt in the North Atlantic. That can mess up the ocean currents that bring relatively warm water - and air - to western Europe in the winter.   

The big Atlantic Ocean circulation is known as the Atlantic Meridonal Overturning Circulation, or AMOC.  Worst case scenario would be this circulation collapsing completely due to too much fresh water gumming up the system. 

A collapse of these large scale currents could really disrupt the climate of western Europe and parts of North America at the very least.  It would probably have worldwide effects, such as frigid weather in western Europe, some parts of North America turning much colder even as the world warms, while other parts of the same continent become hot and arid.

The good news is that most scientists don't see the AMOC collapsing anytime soon. But it is slowing down, so even that could cause lesser but still important weather and  climate headaches around the globe. 

Even if nothing at all happens to AMOC, all that ice melting off Greenland is of course bad news. The melt water raises ocean levels around the world. 

 Ominously, it's not just glaciers melting along the Greenland shores in just parts of that vast island. It's everywhere. "There's basically no part of Greenland that's safe from climate change," said Chad Greene, the study's lead author and a scientist at NASA's Jet Propulsion Laboratory.

Zeke Hausfther, noted on X, formerly Twitter, that the Greenland ice sheet has lost over 6 trillion metric tons of ice since 1970, or more than 700 tons of ice lost per person for every person on the planet today.    

Greenland is actually having a very cold winter. That doesn't matter very much because ice doesn't melt up there even in super warm winters. It's the summers we have to worry about. 

Last year, Greenland lost 196 billion tons of ice.  That's better than some previous years. There was a LOT of melting in 2023, but that was partly offset by lots of snow earlier in the year, which added some mass to Greenland before melt season started. Still the ice loss in 2023 was the most in four years. 

Still, the last year  Greenland actually to its ice mass was in 1996. It's been on a losing streak since. Which also means the rest of the world has been on a losing streak, too.