Greenland Warmer Than A/L Past 100,000 Years; Feedback Loops Accelerating

[hatrack]

Greenland is warmer than it has been in more than 100,000 years and climate disrupting feedback loops have begun. Since 2000, ice loss has increased over 600 percent, and liquid water now exists inside the ice sheet year-round, no longer refreezing during winter.

Melt and ice loss dynamics from Greenland are far more complicated than we understood just a few years ago. New discoveries have been made that add large uncertainties as to exactly how fast ice melt and iceberg discharge will increase in the future. Over the last decade, continued research into the rate of ice loss in Greenland has downplayed any rapid acceleration of current melt rates. New discoveries could be changing our understanding of this last decade's work.

About 5,000 years ago, Greenland reached its warmest period in over 100,000 years. Since this time, Greenland had been cooling and the ice sheet was stable or growing. Beginning 30 to 40 years ago, however, a rapid reversal of cooling and ice sheet growth began. The last 18 years have seen more melt than average across the ice sheet every year with an increasing trend that peaked in 2012 when the entire ice sheet surface temperature went above freezing for four days. (1) The melt line, or the elevation on the 11,000-foot-high ice sheet where the temperature does not rise above freezing in any given year, has steadily been increasing since the 1970s. (2) All of this melt is exposing areas beneath the ice sheet that have not been exposed in a very long time.

EDIT

Contrary to Popular Reporting, the 2012 "Total Ice Sheet Melt Event" Was Not a Common Thing

In 2012, when the Summit Research Station - at the highest point of the Greenland ice sheet - experienced melt for the first time since 1889, it was widely publicized that this event happens about every 150 years. But, like so many things in the media about climate change, this was a widely distorted piece of reporting. The melt event prior to the 1889 event at the Summit Station happened about 1178.

Prior to the 1178 melt event at the Summit Station, as interpreted from ice cores, there were 16 melt events at the top of the Greenland ice sheet over a 5,000-year period. So the average is much more than twice the suggested 150-year period. But more importantly, the global thermal maximum occurred in this period. It was the warmest time in the last ice age cycle that happens about every 100,000 years. Before the global thermal maximum, the top of the ice sheet did not melt a single time dating back to about 120,000 years ago.

EDIT

http://www.truth-out.org/news/item/29462-greenland-reels-climate-disrupting-feedbacks-have-begun?key=0

[Binkie The Clown]

1. I hope global warming gets much worse much faster!

As long as it pokes along at a slow enough pace people will not notice and not react. Nothing positive is going to happen to solve the problem until the problem gets so bad that EVERYONE is thrown into PANIC mode. And the sooner that happens the better for planet earth and the human race. If people don't start panicking real soon there'll be no people left to panic.

[Jim Lane]

2. In this context, what does "A/L" mean? (n/t)