Perhaps the most visible sign that Earth’s climate is warming is the gradual shrinking of its glaciers.
Melting glaciers, dwindling sea ice, rising global temperatures, and rising sea levels. Little by little the evidence is adding up to show that Earth is getting hotter, and scientists are almost certain that people are to blame.
http://earthobservatory.nasa.gov/IOTD/view.php?id=7679
h/t to Roger K
There is overwhelming evidence that rapid glacial retreat has been happening in North America for almost 250 years. It obviously has nothing to do with humans. Why is our tax money being used to fund dangerous, dishonest drivel from supposedly scientific organisations?
As you enter Glacier Bay in Southeast Alaska you will cruise along shorelines completely covered by ice just 200 years ago.
Explorer Captain George Vancouver found Icy Strait choked with ice in 1794, and Glacier Bay was barely an indented glacier. That glacier was more than 4000 ft. thick, up to 20 miles or more wide, and extended more than 100 miles to the St.Elias Range of mountains.
By 1879 naturist John Muir found that the ice had retreated 48 miles up the bay. By 1916 the Grand Pacific Glacier headed Tarr inlet 65 miles from Glacier Bay’s mouth.
Here is where we disagree Steve. Glaciers haven’t been retreating for 250 years. They’ve been retreating for 20,000 years.
During the LIA, many glaciers expanded.
It depends in part on where on the globe you look. The LGM occurs in North America about 17,000 years ago, and the retreated of the American ice sheets begin after that. The retreat was interrupted by the Younger Dryas around 13 to 14 kya. The Younger Dryas, which seems to have pushed temperatures downward toward the LGM range, caused a significant glacial advance. The YD can be argued to have delayed the onset of the Holocene by about two thousand years. There are several other minor, local advances and retreats during the Holocene in various parts of the world, but the LIA – or Matthes advance (as it’s called in the Sierra Nevada) is the most significant. Mary Hill places the end of the Matthes at 1900, or 50 years later than the end of the LIA as commonly accepted in Europe.
In North America there is evidence of glacial retreat in the 1800s and Yosemite was already a National Park by 1900.
Between 1850 and 1979 79% of the glacial ice disappeared form Glacier National Park.
I think your 1900 date is a bit late for the end of the LIA anywhere.
As I said, the date is from Mary Hill – Geology of the Sierra Nevada. Yosemite has had major glaciers for a very long time. The terminal LIA up there had smallish ice fields in mostly sheltered high altitude valleys. As of 2006 there were at least five glaciers within the park boundary. The “the end” might also be taken with some care. Hill doesn’t define what she means by the end, but commonly the “end” of the Pleistocene is not the same as the “end” of the LGM. Instead, it would be the approximate return to “current” climatic conditions. So Hill might intend that 1900 is about the time that the state of ice in the Sierra was the same as at the beginning 0f the LIA. When someone says the “world has been warming since 1850″ does that indicate that 1850 was actually the maximum of the LIA?
No, However the region has not returned to the state prior to the LIA. For a majority of those discussing the LIA, the end is when the most recent warming began in about 1850. It is possible we are still experiencing LIA conditions because plant material, from the MWP, is still being found as the glaciers recede that were formed during the LIA. Locations where farms were in Greenland are still permafrost. The geologic history of Yosemite is only a portion of the Sierra range and Mary Hill is maybe not the best resource!
I know but the overall trend has been melting. Additionally the sea level record (for what it worth) shows relatively slow growth for the last 7,000-8,000 years but no indication of sea level drop. I’m sure there were drops (it’s an land ice thing, I’m sure you understand) but the record just isn’t sensitive enough to pick it up. Increasing glaciers should equate to a sea level drop. Now we have physical evidence of cooling and glacial growth in the past but I guess it depends on how long a trend has to be to be considered significant.
PS: Shouldn’t you be asleep?
Glaciers have not yet retreated back to where they were at the end of the MWP. Which did not reach the minimum that was reached during the RWP. Actually Sean for the last 5000 years overall glaciers ave been advancing with short periods of retreat. They are still discovering things that were buried around 1250 in Greenland by advancing glaciers. There are trees being pushed out from beneath glaciers in the Alps that had to have grown up hill from where they were discovered when the glacier retreated recently.
Sea level records are FUBAR and that is being generous!
Hilltops in Canada that were ice free 10,000 years ago became ice free again in the past decade.
Ice melts. Big deal.
Gator:
Actually it would be a big deal as melting glaciers increase biodiversity in the region. In my book that would be a good thing!
Ok.
ICE MELTS!!! BIG DEAL!!!
Better?
YEAH!!!!
Again, that sea level has been steadily rising since the LGM is open to debate. There is strong evidence of a mid-Holocene highstand between 1 and 2 meters of the present mean sea level from the Pacific, Brazil, and even Texas. Evidence has been noted in Tasmania, Australia, Micronesia and Indonesia. High stands also offer a simpler explanation for the existence of coral atols than the commoner view. You do not need wave action piling upSee for instance http://people.rses.anu.edu.au/lambeck_k/pdf/227.pdf. Running a search on mid-Holocene sea level highstands will turn up many references. One good source is the Journal of Coastal Research, which you can access via JSTOR if you have an account. There are may other papers available.
I guess climate “scientists” don’t have access to the New York Times historic archive:
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December 21, 1930,
A NEW CHAPTER IS WRITTEN BY THE GLACIERS Now in Full Retreat in the Alps, They Emphasize the Influence That They Exert on Climate and the Migrations of People
By EMIL LENGYELPhotograph Copyright by Ernst Wasmuth. ();
Section The New York Times Magazine, Page 72, Column , words
WORD comes from Switzerland that the Alpine glaciers are in full retreat. Out of 102 glaciers observed by Professor P.L. Mercanton of the University of Lausanne and his associates more than twothirds have been found to be shrinking.
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January 28, 1934,
THE WEEK IN SCIENCE: OUR MELTING NORTH; New Evidence Supports Geology’s View That the Arctic Is Growing Warmer
By WALDEMAR KAEMPFFERT. ();
Section SPECIAL FEATURES EDUCATION-SCIENCE, Page XX7, Column , words
TWO pieces of evidence were recently presented to substantiate the views held by most geologists that some day there will be no frozen North and that vessels will sail in Arctic seas now imperilled by ice floes. One piece of evidence comes from Greenland, the other from Alaska.
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June 23, 1890 – Article
THIS CLIMATE OF OURS; WHY THESE OPEN WINTERS AND TEMPERATE SUMMERS? THE GEOLOGICAL EVIDENCE OF THE ALTERNATE PREVALENCE OF A SEMITROPICAL ATMOSPHERE.
Is our climate changing? The succession of temperate Summers and open Winters through several years, culminating last Winter in the almost total failure of the ice crop throughout the valley of the Hudson, makes the question pertinent. The older inhabitants tell us that the Winters are not as cold now as when they were young, and we have all observed a marked diminution of the average cold even in this last decade.
None of these glacial retreat warmists hike in the Rockies. I can take anyone to two glacial remnants only 5 kilometers from the parking lot within a 1 1/2 hour drive from Calgary that have a dual system of lateral moraines, one recent (the post 1850 retreat continuing today) inside an older lateral moraine of a few hundred years old (probably the MWP retreat).
Too many armchair scientists, not enough field-work scientists.
The LIA was not a continuous cold period but it altered between cold and warmer periods. All the period was colder than the MWP. It is possible we are still experiencing LIA conditions and what you found was an earlier LIA termination point.