Antarctic Icebergs Caused Huge Sea Level Rise 14,600 Years Ago

Antarctic Icebergs Caused Huge Sea Level Rise 14,600 Years Ago

A new study reports icebergs breaking off Antarctica caused rapid sea level rise 14,600 years ago.

A study published May 28 in the journal Nature reports that the Antarctic icebergs may have caused rapid sea level increases. The researchers identify eight events of increased iceberg numbers from the Antarctic ice sheet, happening between 20,000 and 9,000 years ago. The largest influx of icebergs, which happened 14,600 years ago, resulted in a sea level rise of 6.5 feet over 100 years. The study provides the first direct evidence for historical, significant melting of the Antarctic ice sheet.

Oregan State University climate scientist and study co-author Peter Clark says, "The Antarctic ice sheet had been considered to be fairly stable and kind of boring in how it retreated. This shows the ice sheet is much more dynamic and episodic, and contributes to rapid sea-level rise." The researchers used marine records of iceberg-rafted debris, various objects and sediments embedded in the ice that are deposited after the iceberg melts, to understand changes in Southern Hemisphere ice sheets. This technique has previously been widely used to understand variability in Northern Hemisphere ice sheets.

Antarctica's glaciers have been shrinking since the end of the last great ice age, and the study reports that the last large release of icebergs was 9,000 years ago. Those melting events were caused by natural climate warming. Scientists have pointed to sea level rise as evidence for man-made climate change, and predicted future rapid melting of the ice sheet. However, these modern models had no documented historical events of rapid glacial retreat for comparison. Modern models of glacial retreat can now be compared to the historical behavior of the ice sheet provided by the study. The latest models of climate change and recent measurements of Antarctica's biggest glaciers predict rapid shrinking of the ice sheet and a rapid rise in sea levels. The current rate of sea level rise is measured at about 0.4 inches per year. Comparatively, the melting event 14,600 years ago resulted in a rise of approximately 0.8 inches per year over 100 years.

Source: Nature via Discovery News

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Whoa, you mean ice melted before man came along and dumped excess amounts of carbon into that air! *Head Explodes*
/endsarcasm

This is not actually the first time sudden natural changes have been recorded in earths history, but it's always good to accrue plenty of evidence. There was a recorded temperature increase taken from ice core samples of between 30-50C in a few decades. That would be catastrophic of course, but in the end it happened under totally natural terms. The natural world is indeed fantastic and terrifying.

Just because this may be a natural occurring phenomena doesn't mean that we should ignore the situation we're getting into. Our intervention may prevent the earth from returning to a cooling state.

I wonder if any of these events coincide with significant volcanic or seismic activity. Not that it lets us off the hook for doing our part to try and keep our spinning blue marble healthy, but it's good to be reminded that natural forces are just as capable of making a big mess as our manufactured ones.

Pff. Must have been all that man made pollution. You know how all those filthy industrialists were back in 12600 BC.

It would be helpful for the casual reader if the author would clearly state the rapid sea level rise 15,000 years ago occurred because of natural and on-going climate change. Further research into historic sea levels would show sea levels far higher than that also occurring naturally.
It did not matter much when no one inhabited the sea shore but now we build along and love to live on the sea shore.
Honest study and analysis of climate change would likely determine the most efficient way to respond would be to protect the coastline when necessary.

Barbara Schroeder:
It would be helpful for the casual reader if the author would clearly state the rapid sea level rise 15,000 years ago occurred because of natural and on-going climate change. Further research into historic sea levels would show sea levels far higher than that also occurring naturally.
It did not matter much when no one inhabited the sea shore but now we build along and love to live on the sea shore.
Honest study and analysis of climate change would likely determine the most efficient way to respond would be to protect the coastline when necessary.

Or just not live on it. I personally prefer inland mountains. There's not the constant odor of marine life that gets washed in with the tide, less chance of a catastrophic environmental disaster destroying my home, and there are caves pocketed everywhere to explore and, if needbe, take shelter in when wood and brick just won't do.

Kieve:
I wonder if any of these events coincide with significant volcanic or seismic activity. Not that it lets us off the hook for doing our part to try and keep our spinning blue marble healthy, but it's good to be reminded that natural forces are just as capable of making a big mess as our manufactured ones.

Maybe, but that date was around the beginning of the last interglacial, IIRC the official date for it was about 12000 BP so you'd be expecting to see some melting before that.

Some info:

http://en.wikipedia.org/wiki/Milankovitch_cycles

http://en.wikipedia.org/wiki/Ice_age

http://en.wikipedia.org/wiki/Glacial_period

...having totally not in anyway just noticed wikipedia has 15,000 BP for the start of the last interglacial I will now, totally on my own, revise my previous date to 15,000BP. (I was probably confusing BP and BC...that's my absolutely true excuse)

Barbara Schroeder:
It would be helpful for the casual reader if the author would clearly state the rapid sea level rise 15,000 years ago occurred because of natural and on-going climate change.

He could, but it would be a fairly redundant statement for the audience here, at least as far as natural goes, this isn't yahoo news.

EDIT: He does mention it's natural, agree he could have mentioned it's cyclic.

MarlaDesat:
Those melting events were caused by natural climate warming.

It's reports like this that make me a skeptic. Obviously, trying to NOT trash our planet is a good thing, but the whole green thing reeks of the "feel good" movement of the last decade. Until things are more clear, I want to see more levelheadedness about this, and no more carbon hysteria.

It's funny that this ten thousand year natural cycle started up right around the time humans started dumping unprecedented amounts of greenhouse gas into the Earth's atmosphere. Oh well, I guess it was all just a coincidence and we're off the hook after all. Drill baby drill.

Nicolaus99:
Pff. Must have been all that man made pollution. You know how all those filthy industrialists were back in 12600 BC.

You know, they say that guns can kill you, but people have been dying since long before there were any guns around.

Made me think of Bayocean, Oregon. Built in 1917 & wiped off the map in 1952. Would have made a cool ghost town tourist attraction for Tillamook, if not for the whole "being underwater" thing. It seems to be more of a story of storms & construction destabilizing the land, but if melting icecaps had been popular news back then, they probably would have blamed it on that instead.

In case anyone's interested in reading about a 20th century city swimming in Davy Jone's Locker, he's an article: http://www.salem-news.com/articles/january282011/bayocean-ja.php & an old newspaper clipping from when their shore started eroding away: http://wwwhistoricalthreads.blogspot.com/2011/07/life-death-of-bayocean-oregon.html

 

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