Posted on 07/22/2013 12:37:41 PM PDT by NormsRevenge
One of the wild cards in estimating future sea level rise from global warming is the enormous East Antarctic Ice Sheet, which holds more freshwater in its icy expanse than the whole of Greenland.
Some climate models predict the giant ice sheet will undergo relatively little change as the planet warms in coming decades, while others forecast significant melting. Now, a new study suggests parts of the East Antarctic Ice Sheet underwent significant melting during the Pliocene, a recent geologic epoch when climate conditions were similar to those of today.
...
During the Pliocene epoch between 5.3 million to 2.6 million years ago, geologic evidence indicates atmospheric levels of carbon dioxide were similar to modern levels of 400 parts per million (meaning that for every 400 molecules of air, one was carbon dioxide) and global temperatures were 2 to 3 degrees Celsius (about 3.6 to 5.4 degrees Fahrenheit) higher than they are now. Sea levels stood about 66 feet (20 meters) higher, according to ancient preserved shorelines.
To raise sea level that much, all of Greenland and West Antarctica had to be ice-free and parts of East Antarctica may have melted, modeling studies show. (The Antarctic ice sheet first started forming 34 million years ago.)
(Excerpt) Read more at news.yahoo.com ...
Damn you, al gore and the internal combustion engine..
This just in: Ice has apparently melted off-and-on since the beginning of time. More at 11.
SnakeDoc
Oh the huge manatee!!!
Ping.
“400 parts per million (meaning that for every 400 molecules of air, one was carbon dioxide) “
Nice try, but WRONG. 400 ppm equates to 1 CO2 molecule per 2500 molecules of air. (Someone check my math.)
Curious that they didn't undergo serious melting during the Mideaval warm period, or the warm period before that.
Note that they aren't truly comparing similar climatic periods, but rather similar CO2 concentrations. We are supposed to presume that they are the same thing, but CO2 doesn't drive the climate. If it did, the Earth would run to the extreme of cold or hot and stay there, as there would be no mechanism to bring it back.
Wait, wait, wait, you mean that ice melts and then re-freezes again...no way!
“That means that...
our whole solar system...
could be, like...
one tiny atom in the fingernail
of some other giant being.
This is too much!
That means...
-one tiny atom in my fingernail could be—
-Could be one little...
tiny universe.
Could I buy some pot from you?”
Paleogeologists estimate that long-term ice, such as exists in Greenland and Antarctica, has only existed about 5% of time in earth’s geologic history. There is also some evidence that glaciation has been world-wide in the past, but it has been infrequent. Of course, the location of the continental land masses changes over time, so there is always room for variation.
But it always changes. It’s not just the Medieval Warm Period. It’s also the longer Interglacial Period. 70,000 years ago, where I am now was under a mile thick sheet of ice. The world is a lot longer now than it was then. Man had nothing to do with it. It was all mastodon farts.
Not “longer,” but “warmer.”
I picked a bad day to stop sniffing glue.
Fred Flintstone's SUV was the culprit.
As the saying goes, 'Close enough for government work'.
Nice try, but WRONG. 400 ppm equates to 1 CO2 molecule per 2500 molecules of air. (Someone check my math.),
BoT.
Define Air ?
East Antarctic ice sheet... East relative to what? The South Pole?
Will Durant summed it up long ago: "“Civilisation exists by geological consent, subject to change without notice.”
You are correct...
And, where, during the Pliocene epoch between 5.3 million to 2.6 million years ago, was the current continent of Antarctica positioned relative to the equator of earth at the time??
There are two statements here which are purported to be true:
... 400 parts [of CO2] per million [parts of atmosphere]= 400/1,000,000 = 0.0004
or 0.04% of the atmosphere.
Next,
... meaning that for every 400 molecules of air, one was carbon dioxide ...= 1/400 = 0.0025
or 0.25% of the atmosphere.
Question for Becky: does 0.04% = 0.25%?
Was the Pliocene melting due to Alley Oop driving an SUV or smoking too many cigars??
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