Greenland ice sheet melt massively overestimated, satellites show

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After all the gloom here is some cheery news, well at least for some!!

New science upsets calculations on sea level rise, climate change


By Lewis Page • Get more from this author
Posted in Science, 28th November 2012 14:20 GMT


A new analysis of data from dedicated satellites shows that one of the main factors predicted to drive rising sea levels in future has been seriously overestimated, with major implications for climate talks currently underway in Doha.

The new methods involve filtering out noise from the data produced by the Gravity Recovery And Climate Experiment (GRACE) spacecraft, sent into orbit with the aim of finding out just how much ice is melting from the world's ice sheets and glaciers. Such water then runs off into the sea, providing one of the main potential drivers of sea level rise - which is itself perhaps the main reason to worry about climate change.

"GRACE data contain a lot of signals and a lot of noise. Our technique learns enough about the noise to effectively recover the signal, and at much finer spatial scales than was possible before," explains professor Frederik Simons of Princeton uni. "We can 'see through' the noise and recover the 'true' geophysical information contained in these data. We can now revisit GRACE data related to areas such as river basins and irrigation and soil moisture, not just ice sheets."

Simons and his colleague Christopher Harig tried their new methods out on GRACE data covering the Greenland ice sheet, which is of particular interest as the rest of the Arctic ice cap floats on the sea and so cannot contribute directly to sea level rise by melting. Meanwhile the Antarctic ice cap is actually getting bigger, so Greenland is probably the major worry.

According to a Princeton statement highlighting the new research:
.
While overall ice loss on Greenland consistently increased between 2003 and 2010, Harig and Simons found that it was in fact very patchy from region to region.
In addition, the enhanced detail of where and how much ice melted allowed the researchers to estimate that the annual acceleration in ice loss is much lower than previous research has suggested, roughly increasing by 8 billion tons every year. Previous estimates were as high as 30 billion tons more per year.

​
The rate of loss of ice from Greenland is estimated at 199.72 plus-or-minus 6.28 gigatonnes per year. So the possible acceleration of losses is only barely larger than the margin of error in the readings: it's very difficult to tell the supposed loss curve from a straight line.

In other words the possible acceleration in ice losses is barely perceptible: it may not really be happening at all. Similar results were seen not long ago in GRACE data for central Asian mountain glaciers, another suggested source for sea-level rises.

If the Greenland ice losses aren't accelerating, there's no real reason to worry about them. According to the Princeton statement:
.
At current melt rates, the Greenland ice sheet would take about 13,000 years to melt completely, which would result in a global sea-level rise of more than 21 feet (6.5 meters).

​
Put another way, in that scenario we would be looking at 5cm of sea level rise from Greenland by the year 2130: a paltry amount. Authoritative recent research drawing together all possible causes of sea level rise bears this out, suggesting maximum possible rise in the worst case by 2100 will be 30cm. More probably it will be less, and there will hardly be any difference between the 20th and 21st centuries in sea level terms.

The new GRACE research was published in the Proceedings of the National Academy of Sciences. Details of the computer code can be found here.
Doha delegates take note. ®



http://www.theregister.co.uk/2012/11/28/sea_levels_new_science_climate_change/
 
Sparta said:
Tom, we know that this is a BP cover up when they destroyed Greenland and made it Blackland from all thier filthy fracking disasters.
Click to expand...

I have been rumbled, my shilling days are over!! BP paid off the GRACE satellite team at NASA and the scientists at Princeton.
 
Last edited:
Greenland
Below are updated results continued from our recent paper Harig and Simons [2012]. As of the last update on November 2, 2012, these results continue to use the Release level 4 UTCSR (http://www.csr.utexas.edu/grace/) data solutions up to and including April 2012.

The past few years have seen unprecedented melting in Greenland measured by a variety of indicators (see the 2011 Arctic Report Card: Greenland for a good scientific summary). For GRACE mass measurements this means that recent years have increased the trend estimated since 2002. The latest trend estimate increased to -212 Gigatons per year by using more months from September 2011 to April 2012.
TotalTrend_website.png
Figure 1: Total mass change trend for Greenland. The solid black line is the raw GRACE monthly solution. Here we use a bandwidth of 60 spherical harmonic degrees and a 0.5 degree buffer region. The solid blue line is the best-fitting linear trend. For more technical details please see the Methods/Code webpage. CLICK HERE for a high resolution version of the published figure from Harig and Simons [2012]

In the updated total map below, we see that the overall pattern of mass change over the last 10 years is little changed other than magnitude. You can see in Figure 3 that the mass change for 2011 follow the general pattern for the previous years, so we would not expect big changes in the 10 year pattern. Note the increased scale bar in this figure compared to the previous published figure shows the increase in magnitudes for both melt on the coasts and accumulation in the high elevation interior.
TotalMassMap_website.png
Figure 2: Geographical pattern of the mass change over Greenland averaged for the period between 1/2003 and 1/2011. The integral value "Int" for the entire epoch is shown in Gigatons. The zero cm water contour shown in black. For more technical details please see the Methods/Code webpage. CLICK HERE for a high resolution version of the published figure from Harig and Simons [2012]

Below are the mass loss maps for each year, updated through 2011. We can see that 2011 was a record year for ice melt in Greenland. Nearly all coastal areas experienced mass loss and at much higher rates of loss (deeper reds) than previous years. In addition, the middle of Greenland shows increased mass accumulation, with magnitudes of over 20 cm/yr of water equivalent.
SlepMassYearly_website.png
Figure 3: Yearly-resolved maps of mass change over Greenland from 2003 to 2011. For every year we show the difference of the signal estimated between January of that year and January of the next. The integral values of the mass change per year are shown as "Int", expressed in Gigatons. The zero cm/yr water contours are shown in black. For more technical details please see the Methods/Code webpage. CLICK HERE for a high resolution version of the published figure from Harig and Simons [2012]
 
Aoxomoxoa said:
Greenland
Below are updated results continued from our recent paper Harig and Simons [2012]. As of the last update on November 2, 2012, these results continue to use the Release level 4 UTCSR (http://www.csr.utexas.edu/grace/) data solutions up to and including April 2012.

The past few years have seen unprecedented melting in Greenland measured by a variety of indicators (see the 2011 Arctic Report Card: Greenland for a good scientific summary). For GRACE mass measurements this means that recent years have increased the trend estimated since 2002. The latest trend estimate increased to -212 Gigatons per year by using more months from September 2011 to April 2012.
TotalTrend_website.png
Figure 1: Total mass change trend for Greenland. The solid black line is the raw GRACE monthly solution. Here we use a bandwidth of 60 spherical harmonic degrees and a 0.5 degree buffer region. The solid blue line is the best-fitting linear trend. For more technical details please see the Methods/Code webpage. CLICK HERE for a high resolution version of the published figure from Harig and Simons [2012]

In the updated total map below, we see that the overall pattern of mass change over the last 10 years is little changed other than magnitude. You can see in Figure 3 that the mass change for 2011 follow the general pattern for the previous years, so we would not expect big changes in the 10 year pattern. Note the increased scale bar in this figure compared to the previous published figure shows the increase in magnitudes for both melt on the coasts and accumulation in the high elevation interior.
TotalMassMap_website.png
Figure 2: Geographical pattern of the mass change over Greenland averaged for the period between 1/2003 and 1/2011. The integral value "Int" for the entire epoch is shown in Gigatons. The zero cm water contour shown in black. For more technical details please see the Methods/Code webpage. CLICK HERE for a high resolution version of the published figure from Harig and Simons [2012]

Below are the mass loss maps for each year, updated through 2011. We can see that 2011 was a record year for ice melt in Greenland. Nearly all coastal areas experienced mass loss and at much higher rates of loss (deeper reds) than previous years. In addition, the middle of Greenland shows increased mass accumulation, with magnitudes of over 20 cm/yr of water equivalent.
SlepMassYearly_website.png
Figure 3: Yearly-resolved maps of mass change over Greenland from 2003 to 2011. For every year we show the difference of the signal estimated between January of that year and January of the next. The integral values of the mass change per year are shown as "Int", expressed in Gigatons. The zero cm/yr water contours are shown in black. For more technical details please see the Methods/Code webpage. CLICK HERE for a high resolution version of the published figure from Harig and Simons [2012]
Click to expand...


Oops.
 
Rune said:
Oops.
Click to expand...

You needn't worry there will be another ice age in about 6000 years!!

A new analysis of data from dedicated satellites shows that one of the main factors predicted to drive rising sea levels in future has been seriously overestimated, with major implications for climate talks currently underway in Doha.

The new methods involve filtering out noise from the data produced by the Gravity Recovery And Climate Experiment (GRACE) spacecraft, sent into orbit with the aim of finding out just how much ice is melting from the world's ice sheets and glaciers. Such water then runs off into the sea, providing one of the main potential drivers of sea level rise - which is itself perhaps the main reason to worry about climate change.

"GRACE data contain a lot of signals and a lot of noise. Our technique learns enough about the noise to effectively recover the signal, and at much finer spatial scales than was possible before," explains professor Frederik Simons of Princeton uni. "We can 'see through' the noise and recover the 'true' geophysical information contained in these data. We can now revisit GRACE data related to areas such as river basins and irrigation and soil moisture, not just ice sheets."

Simons and his colleague Christopher Harig tried their new methods out on GRACE data covering the Greenland ice sheet, which is of particular interest as the rest of the Arctic ice cap floats on the sea and so cannot contribute directly to sea level rise by melting. Meanwhile the Antarctic ice cap is actually getting bigger, so Greenland is probably the major worry.

According to a Princeton statement highlighting the new research:
.
While overall ice loss on Greenland consistently increased between 2003 and 2010, Harig and Simons found that it was in fact very patchy from region to region. In addition, the enhanced detail of where and how much ice melted allowed the researchers to estimate that the annual acceleration in ice loss is much lower than previous research has suggested, roughly increasing by 8 billion tons every year. Previous estimates were as high as 30 billion tons more per year.

​
The rate of loss of ice from Greenland is estimated at 199.72 plus-or-minus 6.28 gigatonnes per year. So the possible acceleration of losses is only barely larger than the margin of error in the readings: it's very difficult to tell the supposed loss curve from a straight line.

In other words the possible acceleration in ice losses is barely perceptible: it may not really be happening at all. Similar results were seen not long ago in GRACE data for central Asian mountain glaciers, another suggested source for sea-level rises.

If the Greenland ice losses aren't accelerating, there's no real reason to worry about them. According to the Princeton statement:
.
At current melt rates, the Greenland ice sheet would take about 13,000 years to melt completely, which would result in a global sea-level rise of more than 21 feet (6.5 meters).
 
Last edited:
Aoxomoxoa said:
You needn't worry there will be another ice age in about 6000 years!!

A new analysis of data from dedicated satellites shows that one of the main factors predicted to drive rising sea levels in future has been seriously overestimated, with major implications for climate talks currently underway in Doha.

The new methods involve filtering out noise from the data produced by the Gravity Recovery And Climate Experiment (GRACE) spacecraft, sent into orbit with the aim of finding out just how much ice is melting from the world's ice sheets and glaciers. Such water then runs off into the sea, providing one of the main potential drivers of sea level rise - which is itself perhaps the main reason to worry about climate change.

"GRACE data contain a lot of signals and a lot of noise. Our technique learns enough about the noise to effectively recover the signal, and at much finer spatial scales than was possible before," explains professor Frederik Simons of Princeton uni. "We can 'see through' the noise and recover the 'true' geophysical information contained in these data. We can now revisit GRACE data related to areas such as river basins and irrigation and soil moisture, not just ice sheets."

Simons and his colleague Christopher Harig tried their new methods out on GRACE data covering the Greenland ice sheet, which is of particular interest as the rest of the Arctic ice cap floats on the sea and so cannot contribute directly to sea level rise by melting. Meanwhile the Antarctic ice cap is actually getting bigger, so Greenland is probably the major worry.

According to a Princeton statement highlighting the new research:
.
While overall ice loss on Greenland consistently increased between 2003 and 2010, Harig and Simons found that it was in fact very patchy from region to region. In addition, the enhanced detail of where and how much ice melted allowed the researchers to estimate that the annual acceleration in ice loss is much lower than previous research has suggested, roughly increasing by 8 billion tons every year. Previous estimates were as high as 30 billion tons more per year.

​
The rate of loss of ice from Greenland is estimated at 199.72 plus-or-minus 6.28 gigatonnes per year. So the possible acceleration of losses is only barely larger than the margin of error in the readings: it's very difficult to tell the supposed loss curve from a straight line.

In other words the possible acceleration in ice losses is barely perceptible: it may not really be happening at all. Similar results were seen not long ago in GRACE data for central Asian mountain glaciers, another suggested source for sea-level rises.

If the Greenland ice losses aren't accelerating, there's no real reason to worry about them. According to the Princeton statement:
.
At current melt rates, the Greenland ice sheet would take about 13,000 years to melt completely, which would result in a global sea-level rise of more than 21 feet (6.5 meters).
Click to expand...


21 feet is nothing is it Tom. Say, how far under water would your flat be?
 
Rune said:
21 feet is nothing is it Tom. Say, how far under water would your flat be?
Click to expand...

Do you plan to be alive in 13,000 years?? The next ice age will be in full force well before then!!

At current melt rates, the Greenland ice sheet would take about 13,000 years to melt completely, which would result in a global sea-level rise of more than 21 feet (6.5 meters).
Click to expand...
 
Aoxomoxoa said:
Do you plan to be alive in 13,000 years?? The next ice age will be in full force well before then!!
Click to expand...

Statistics can be made to indicate whatever one want them to, can't they Tom?

Your chart could also be interpreted to indicate that the loss of mass has nearly doubled since 2003, right?

2003 Int= 162
2011 Int= 302

In fact, your evidence points to significantly greater loss each year, with the exception of 2004, right? Why must you be disingenuous if the evidence is in your favor?
 
Rune said:
Statistics can be made to indicate whatever one want them to, can't they Tom?

Your chart could also be interpreted to indicate that the loss of mass has nearly doubled since 2003, right?

2003 Int= 162
2011 Int= 302

In fact, your evidence points to significantly greater loss each year, with the exception of 2004, right? Why must you be disingenuous if the evidence is in your favor?
Click to expand...

Why don't you ask the boys at Princeton? That is the raw data from GRACE before it has been subjected to analysis to remove the noise.

http://www.princeton.edu/geosciences/contact/contact.xml
 
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Aoxomoxoa said:
Where is my interpretation? I just presented the results from a team of scientists at Princeton University.
Click to expand...
[h=2][/h]
That would be this;

[h=2]
icon1.png
Greenland ice sheet melt massively overestimated, satellites show[/h]
unless someone else wrote it and posted it under your name.
 
Rune said:
[h=2][/h]
That would be this;

[h=2]
icon1.png
Greenland ice sheet melt massively overestimated, satellites show[/h]
unless someone else wrote it and posted it under your name.
Click to expand...

from the title in the link you ignorant tool

Ice sheet melt massively overestimated, satellites show
Click to expand...

poor rune, too stupid to even think of clicking a link before spouting more of his nonsense
 
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