Thursday, March 21, 2019

Changes in ocean 'conveyor belt' foretold abrupt climate changes by four centuries

Hattip geofish

The oceans are a huge factor in global climate change. 

 A fact that is always glossed over by the  anti life carbon cult.  
How is that even realistic? Considering the oceans cover more then 70 percent of the planet. While holding 97 percent of earth's water.


The planet Earth is a planet of oceans. Oceans cover about 71 percent of the Earth's surface.
The oceans' tremendous presence causes it to have a huge effect on the planet and our civilization. It is greatly responsible for the climate of the Earth


Simplified diagram of the Atlantic Meridional Overturning Circulation. It carries warm water from the tropics (red arrows) into the North Atlantic, where the water cools and sinks before flowing back south (yellow arrows). This pattern plays an important role in regulating climate in the North Atlantic as well as the rest of the world

In the Atlantic Ocean, a giant 'conveyor belt' carries warm waters from the tropics into the North Atlantic, where they cool and sink and then return southwards in the deep ocean. This circulation pattern is an important player in the global climate, regulating weather patterns in the Arctic, Europe, and around the world. Evidence increasingly suggests that this system is slowing down, and some scientists fear it could have major effects, such as causing temperatures to dive in Europe and warming the waters off the East coast of the United States, potentially harming fisheries and exacerbating hurricanes.

A new study published in Nature Communications provides insight into how quickly these changes could take effect if the system continues weakening. Led by scientists at Columbia's Lamont-Doherty Earth Observatory in collaboration with the Norwegian Research Centre, the study is the first to precisely determine the time lags between past changes to the ocean conveyor belt and major climate changes.

The team studied a key section of the ocean current pattern, known as the Atlantic Meridional Overturning Circulation (AMOC). They zeroed in on a section where water sinks from the surface to the bottom of the North Atlantic. They confirmed that the AMOC started weakening about 400 years before a major cold snap 13,000 years ago, and began strengthening again about 400 years before an abrupt warming 11,000 years ago.

"Our reconstructions indicate that there are clear climate precursors provided by the ocean state—like warning signs, so to speak," says lead author Francesco Muschitiello, who completed the work as a postdoc at Lamont-Doherty and now works at the University of Cambridge.

Until now, it has been difficult to resolve whether past changes in the ocean conveyor belt occurred before or after the abrupt climate shifts that punctuated the last deglaciation in the Northern Hemisphere. To overcome the usual challenges, the team pieced together data from a sediment core drilled from the bottom of the Norwegian Sea, a lake sediment core from southern Scandinavia, and ice cores from Greenland. 

Readers here may recall my saying I don't long for the 'good old days' of the glaciation period when my 'neck of the woods' was buried under miles and miles of ice. And AGW did not cause that ice to retreat as it melted leaving me with the landscape I love to this day. The lakes. The escarpment. Many waterfalls. Including, but not limited to, Niagara Falls.

The study finds that changes in AMOC strength (blue line) began hundreds of years before the sharp and abrupt temperature changes over Greenland (red line) that mark the beginning and end of the hemispheric cold snap known as the Younger Dryas period

Comparing the data from the three cores revealed that the AMOC weakened in the time leading up to the planet's last major cold snap, called the Younger Dryas, around 13,000 years ago. The ocean circulation began slowing down about 400 years before the cold snap, but once the climate started changing, temperatures over Greenland plunged quickly by about 6 degrees.

Present time the AMOC is weakening- as reported.  How much weakening will bring on a cold snap? Could this be a factor in my noticing the extended cold periods we've been experiencing for years now? 
Considering Hawaii had snow. As did Arizona. Arizona had lots of snow- Very unusual.
A similar pattern emerged near the end of that cold snap; the current started strengthening roughly 400 years before the atmosphere began to heat up dramatically, transitioning out of the ice age. Once the deglaciation started, Greenland warmed up rapidly—its average temperature climbed by about 8 degrees over just a few decades, causing glaciers to melt and sea ice to drop off considerably in the North Atlantic.

"Those [400-year] lags are probably on the long side of what many would have expected," says Anders Svensson, who studies the paleoclimate at the University of Copenhagen, and who was not involved with the current study. "Many previous studies have suggested time lags of various lengths, but few have had the necessary tools to determine the phasing with sufficient accuracy."

Please read the linked information entirely as I've only included excerpts


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