Don Mikulecky / The Daily Kos & Joe Romm / Think Progress – 2015-03-07 19:30:40
http://www.dailykos.com/story/2015/03/05/1368815/-Greenland-passes-tipping-points-Positive-feedback-accelerates
Senator Sheldon Whitehouse Schools Jim Inhofe on Climate Change
ThinkProgress Video
Here Comes El Nino. Greenland Passes Tipping Points. Positive Feedback Accelerates.
Don Mikulecky / The Daily Kos
(March 5, 2015) — It has been only a matter of time but things are happening faster than most anticipated. Greenland Reels: Climate Disrupting Feedbacks Have Begun
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.
That is but part of the story.
It is a bad time to be in a learning phase, but better late than never.
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.
We humans are really much better at causing problems than we are at understanding our planet. The only real fault I can point to is the failure to realize how incomplete our knowledge is. Models and their predictions are only as good as the information used to construct them and that is the problem. If you are not aware of possibilities they do not get put into the model.
Here’s what is happening:
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.
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. All of this melt is exposing areas beneath the ice sheet that have not been exposed in a very long time.
But the melting has many consequences. Here’s a big one:
As the ice sheet melts around its edges, dust captured in eons of snow becomes exposed. Most of this dust does not get washed away by melt, partially because much of the ice loss is from sublimation, the process by which ice evaporates directly instead of changing into water.
But much of the dust also stays in place on the ice simply because the flow speed of meltwater is very low except where it concentrates into what the scientists call supraglacial stream flow, or simply melt streams on the ice.
So the ice is dusty. So what? Well the dark surface absorbs heat from the sun rather than reflecting it.
As more ice melts, more dust gets left behind on the ice. This has radical implications for increased melt because dust absorbs far more sunlight than ice. An example is that ice reflects up to 90 percent of sunlight back into space where dirt, rocks, plants and open water absorb up to 90 percent of sunlight and change it into heat.
There is more but you can read about it. Here’s the bottom line:
What Does All of This Mean?
This is a question that ice scientists ask themselves every day, and I am sure some of them have some pretty good answers. For me, what it means is that Greenland is warmer than it has been in over 100,000 years.
Since the global thermal maximum about 5,000 years ago, Greenland has cooled 5 degrees Fahrenheit, but in the last 50 years, it has warmed back up that amount and added a couple of degrees of warmth for good measure. Every year that passes sees Greenland ice getting darker and darker, as more and more dust accumulates on the surface, and more and more energy is captured, melting more and more ice.
Snow itself has darkened enough so that the energy it absorbs is increased by 20 to 25 percent. The glaciers that discharge ice from Greenland have increased discharge by an incredible 600 percent and newly discovered tunnels beneath the ice may have the capacity to channel warm ocean water to where it can do the most damage destabilizing the interior of the ice sheet.
And the oddest of all, what will happen to this perennial water aquifer in the firn zone of the southern ice sheet when melt really gets to cooking up there?
What are you going to tell your kids and grandkids about what we are leaving for them? I really have no answer. We are a very stupid species yet very powerful. All of our power seems to lead to destruction.
NOAA Announces Arrival Of El Nino,
2015 Poised To Beat 2014 For Hottest Year
Joe Romm / Think Progress
(March 5, 2015) — The National Oceanic and Atmospheric Administration (NOAA) has announced that the long-awaited El Nino has arrived. NOAA’s Climate Prediction Center says we now have “borderline, weak El Nino conditions,†and there is a “50-60% chance that El Nino conditions will continue†through the summer.
An El Nino is “characterized by unusually warm ocean temperatures in the Equatorial Pacific,†as NOAA has explained. That contrasts with the unusually cold temps in the Equatorial Pacific during a La Niña. Both are associated with extreme weather around the globe (though a weak El Niño like this will tend to have a muted effect).
El Ninos tend to set the record for the hottest years, since the regional warming adds to the underlying global warming trend. La Niña years tend to be below the global warming trend line.
If even a weak El Niño does persist through summer, 2015 will almost certainly top 2014 as the hottest year on record. But there is a good chance it will do so in any case (unless a La Niña forms). After all, 2014 was the hottest year on record even though there was no official El Niño during the year. It’s just hard to stop the march of human-caused global warming — without actually sharply cutting greenhouse gas emissions.
Significantly, because 1998 was an unusually strong “super El Niño,†and because we haven’t had an El Niño since 2010, it appeared for a while (to some) as if global warming had slowed — if you cherry-picked a relatively recent start year (and ignored the rapid warming in the oceans, where 90 percent of human-caused planetary warming goes). In fact, however, several recent studies confirmed that planetary warming continues apace everywhere you look.
And that was before 2014 set the record for the hottest year. In January, Gavin Schmidt, director of NASA’s Goddard Institute of Space Studies, tweeted, “Is there evidence that there is a significant change of trend from 1998? (Spoiler: No.)†. . . .
The latest NASA temperature data make clear that not only has there been no “pause†in surface temperature warming in the past decade and a half, there hasn’t even been a significant change in trend.
The very latest research suggests that we are about to enter a multiyear period of rapid warming. Fasten your seatbelts.
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