The polar
ice has melted faster in the last 20 years than in the past 10,000. A
comprehensive satellite study confirms that the melting ice caps are raising
sea levels at an accelerating rate.
"The
planet's refrigerator", "earth's weather kitchen", "barometer
of the climate system" - the polar regions are known to be 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 |
"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 Deutsche Welle.
Satellite
monitoring ends confusion
"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.
Greenland
is melting fastest
 |
Satellite photos track ice loss, as
shown in these images of Greenland |
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.
Different
conditions within the Antarctic
In the
Antarctic, the situation is a more complex one. Scientists distinguish between
the West and East, which are being affected differently by climate change. West
Antarctica is losing ice at an accelerating rate. Many of the region's glaciers
are by the sea, which is warming. It is only to be expected that the ice is
melting faster here, says Shepherd.
 |
Scientists examine the condition of
the ice at Antarctic stations like Belgium's
Princess Elisabeth Antarctica |
In the huge
area of East Antartica, the ice is mostly above sea level, Shepherd explains.
The air temperature is also much lower, and the experts do not expect the ice
to melt on account of rising temperatures. In this part of Antarctica, the ice
sheet is actually growing as a consequence of increased snowfall. This has led
some critics to question the global warming theory. However for Shepherd and
his colleagues, the changes are all consistent with patterns of climate
warming, which leads to more evaporation from the oceans and in turn more
precipitation, which falls as snow on the ice sheets.
20 years of
satellites – too short to tell?
 |
If the Greenland ice sheet were to melt
completely, sea levels could rise by seven
meters |
"20
years is a very short time-scale to draw conclusions about climate change.
"We are just beginning an observational record for ice", said
co-author of the study Ian Joughlin, a glaciologist at the University of
Washington. "This creates a new long-term data set that will increase as
new measurements are made".
But the
scientists are convinced the relatively new technology is the best way to keep
track of climate change in inaccessible polar regions. Earth observation expert
Shepherd is sure global warming is the only possible explanation for the
accelerating polar ice melt. He sees especially the rapid melt in West
Antarctica as a signal and a result of direct changes in the local balance
between the ice sheet, the ocean and the atmosphere.
If the west
Antarctic ice sheet should become unstable, it could trigger abrupt changes
globally. Joughlin sees the recent ice activity in the region as a reason to
pay attention, but not to panic.
Key data
for the IPCC
In the last
report by the IPCC (Intergovernmental Panel on Climate Change), the development
of the ice sheets was regarded as the major unknown factor with regard to
predicting future sea level rises. "The results of this study will be
invaluable in informing the IPCC as it completes the writing of its Fifth
Assessment Report next year", according to Tom Wagner, NASA's cryosphere
program manager in Washington.
The
question of how the satellite data will influence predictions of sea level rise
is not easy to answer, says Andrew Shepherd: Any model is only as reliable as
its data. He hopes the more accurate satellite measurements will help improve
the models . He does, however, have one reservation. The main uncertainty in
climate projections is not to do with the physics or processes, the scientist
says. It is the uncertainty as to what emissions scenarios nations will adopt
in the future.
Related Article:
New Mini Ice Age
Global Warming - Not long Term
" .... The weather you have today, and all the alarming attributes of it, is a scenario of what was scheduled to happen on Earth anyway. I review again that the weather changes you are seeing prophesied by myself, 21 years ago, are not a surprise. The changes are not caused by the pollutants you put in the air. You call it global warming and that's a nice phrase, and perhaps that will get you to put less pollutants in the air – a very good thing. But what you are seeing in the weather shift today was not caused by Humans putting things into the air. It would have happened anyway in about 300 years."
"We've called this process the water cycle, since it's all about water, not about air. The water is the predominant attribute of Gaia and of the weather cycle you're seeing. More predominant is the temperature of it. The cycle is ice to water and water to ice, and has been repeated on this planet over and over and over. It is not new. It is not exceptional. It is not frightening. But it's a cycle that modern humanity has not seen before, and it's a long cycle that is beyond the life span of a Human Being. Therefore, it tends to be overlooked or not seen at all !"
"In the days of the Lemurians, the water level of the Pacific Ocean was almost 400 feet lower, and that's only 50,000 years ago. [Kryon invites science to check this out – the water level at that time.] That was a water cycle working, and the reason it was lower was due to so much of the water being stored as ice. Today you're going through another water cycle that will eventually lead to cooling. The last one was in the 1400s"
"Science sees that at about 1650. As mentioned, they are so slow there is no remembrance that a Human has of them except in past writings and in the rings of the trees. The time span of the changes is so great that environmental record keeping does not exist in the form that it does today. But you can still look at the rings of the trees and at the striations of the rocks and can generally figure out that a few hundred years ago, you had a mini-ice age. Now you're going to have another one. .... " Read more ..... (THE RELATIONSHIP TO GAIA - April 2010 (Kryon Channeled by Lee Caroll))
“… Now, in the process of all of this, there's going to be renewed interest in Antarctica, and you're going to find some interesting things about the land under the ice. The topography of the land under the ice does not match the topography of the ice above. Some astonishing shapes will be revealed when you map the actual land under the ice. Points of mountains are going to be revealed, giving an entire different idea of what Antarctica might have been and what its purpose really is. The continent that is uninhabitable by Human Beings may very well be the engine of life for Human Beings. And I will leave it at that. …”
