The polar regions are important drivers of the world's climate. When the "everlasting ice" melts at an increasing rate, the rest of the world is affected. Global sea levels are rising, dark meltwater pools absorb warmth from the sun which white ice would reflect back into space. Fresh water flows into the sea, changing ocean currents and the living conditions for marine organisms.
For 20 years satellites have been monitoring earth's biggest ice shields on Greenland and in the Antarctic, using different technologies from radar to gravity measurements. In the past, the uncoordinated publication of individual one-off measurements led to confusion, especially with regard to the state of the Antarctic ice. A new study, supported by NASA and European Space Agency ESA combines the data from different satellite missions.
The Antartic is difficult terrain for scientists to access. Here, clouds cross ice-covered polar mountains.
The Antartic is difficult terrain for scientists to access
"It's the first time all the people who have estimated changes in the size of the Antarctic and Greenland ice sheets using satellites over the past 20 years have got together to produce a single result," Andrew Shepherd from the University of Leeds in the UK explained in an interview with DW.
"Thanks to the accuracy of our data set, we are now able to say with confidence that Antarctica has lost ice for the whole of the past 20 years. In addition to the relative proportions of ice that have been lost in the northern and southern hemispheres, we can also see there's been a definitive acceleration of ice loss in last 20 years. So together Antarctica and Greenland are now contributing three times as much ice to sea levels as they were 20 years ago," says the Professor of Earth Observation.
According to the study, melting ice from both poles has been responsible for a fifth of the global rise in sea levels since 1992, 11 millimeters in all. The rest was caused by the thermal expansion of the warming ocean, the melting of mountain glaciers, small Arctic ice caps and groundwater mining. The share of the polar ice melt, however, is rising.
The pattern of change differs considerably between the Arctic and the Antarctic. Two thirds of the ice loss is happening in Greenland. "The rate of ice loss from Greenland has increased almost five-fold since the mid-1990s", says Erik Ivins, who coordinated the project for NASA.
Although the Greenland ice sheet is only about one tenth the size of Antarctica, today it is contributing twice as much ice to sea levels, according to Shepherd: "It's certainly the larger player, probably just because it is at a more equatorial latitude, further from the North pole than Antarctica from the South pole." The ice on Greenland is also melting on the surface, because of increasing air temperatures.
Oh c'mon, LJ, you have to appreciate that barren liberals like rubato and me consider the little princess and prince to be our kids, too. Mayhap you never want us to meet them, but we DO care about their future just the same!
For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
~ Carl Sagan
Climate Model Predicts West Antarctic Ice Sheet Could Melt Rapidly
By JUSTIN GILLISMARCH 30, 2016
A view from a NASA airplane of large icebergs that have broken from the calving side of Thwaites Glacier in Antarctica in November 2014. A disaster scenario of West Antarctic ice sheet disintegration could occur much sooner than previously thought, new research suggests. Credit Jim Yungel/NASA
For half a century, climate scientists have seen the West Antarctic ice sheet, a remnant of the last ice age, as a sword of Damocles hanging over human civilization.
The great ice sheet, larger than Mexico, is thought to be potentially vulnerable to disintegration from a relatively small amount of global warming, and capable of raising the sea level by 12 feet or more should it break up. But researchers long assumed the worst effects would take hundreds — if not thousands — of years to occur.
Now, new research suggests the disaster scenario could play out much sooner.
Continued high emissions of heat-trapping gases could launch a disintegration of the ice sheet within decades, according to a study published Wednesday, heaving enough water into the ocean to raise the sea level as much as three feet by the end of this century.
With ice melting in other regions, too, the total rise of the sea could reach five or six feet by 2100, the researchers found. That is roughly twice the increase reported as a plausible worst-case scenario by a United Nations panel just three years ago, and so high it would likely provoke a profound crisis within the lifetimes of children being born today.
Under the Ice Sheet
The vast West Antarctic ice sheet sits on bedrock that dips thousands of feet below sea level. New computer simulations suggest that the warming atmosphere and ocean could attack the ice sheet from above and below, causing sea levels to rise much faster than previously thought.
The situation would grow far worse beyond 2100, the researchers found, with the rise of the sea exceeding a pace of a foot per decade by the middle of the 22nd century. Scientists had documented such rates of increase in the geologic past, when far larger ice sheets were collapsing, but most of them had long assumed it would be impossible to reach rates so extreme with the smaller ice sheets of today.
“We are not saying this is definitely going to happen,” said David Pollard, a researcher at Pennsylvania State University and a co-author of the new paper. “But I think we are pointing out that there’s a danger, and it should receive a lot more attention.”
The long-term effect would likely be to drown the world’s coastlines, including many of its great cities. ... "
paraphrased:
"In principle, the level of civilization is exactly measurable by the amount people are willing to give up in the present on behalf of the future."
Bertrand Russell
Interesting that several here who do not have children are more moral and care more about the future than those who do.
I guess the more icebergs,the greater the sea level rise(because they float and displace seawater ) I will point out however that the arctic ice cap could melt and not raise the sea level an inch (because its floating already ) but the effects of the fresh water diluting the salt water could alter or stop the "Gulf stream " Antarctica will experience slower melting simply because its so dang cold down there .I know we are affecting the climate by using the atmosphere as a trash dump ,but sometimes "chicken little "cheeps a little to loudly .If the caldera at "Yellowstone " spills its insides ,we will really have problems .(be ironic if our manmade activities would trigger the eruption of yellowstone-Yes ,I can think of a scenario )make of it what you will.
"A butterfly cannot flap its wings ,without the troubling of a star "
KMC, the arctic melting discussed here is on Greenland, where it is not floating and thus will raise the mean ocean level. Likewise, most of the ice in the Antarctic is also on land, with similar results.
rubato wrote:Interesting that several here who do not have children are more moral and care more about the future than those who do.
yrs,
rubato
Not having children was a very good start - thanks!
For Christianity, by identifying truth with faith, must teach-and, properly understood, does teach-that any interference with the truth is immoral. A Christian with faith has nothing to fear from the facts
BP ,I am aware of that ,you would be suprised at the amount of "educated people" that dont realize this . The real problem will be the "conveyor " stopping because of the influx of fresh water(different density ) then we will probably get to see first hand the "carrying " capacity of ol mother "Gaia " (still going to take awhile for the antarctic ice cap to melt, still colder then h e double hockeysticks down there(most of their ice is ancient )
I just skimmed the latest issue of ANALOG magazine. It includes a letter from Rick Norwood that asks an interesting question.
the executive summary of the letter: The March '16 issue had a letter cancelling their subscription because the magazine published articles supporting the idea that fossil fuels causes global warming. The same issue had an essay by John G. Cramer expressing doubts about General Relativity. Norwood suspects that Cramer essay provoked no one to cancel their subscription because of that doubt. Both General Relativity and Global warming are scientific questions, which should be decided on scientific evidence. The question: So why all the anger about Global Warming?
Why indeed, such emotion? Is it somehow philosophically related to one's view of ultimate reality, perhaps like Earth as the center of the Universe?
