East Antarctica Glacial Melting through the filter of BBC reporting

An indication of how little solid evidence there is for catastrophic anthropogenic global warming comes from a BBC story story carried during the COP24 Katowice conference in December. It carried the headline “East Antarctica’s glaciers are stirring” and began

Nasa says it has detected the first signs of significant melting in a swathe of glaciers in East Antarctica.

The region has long been considered stable and unaffected by some of the more dramatic changes occurring elsewhere on the continent.

But satellites have now shown that ice streams running into the ocean along one-eighth of the eastern coastline have thinned and sped up.

If this trend continues, it has consequences for future sea levels.

There is enough ice in the drainage basins in this sector of Antarctica to raise the height of the global oceans by 28m – if it were all to melt out.

Reading this excerpt one could draw a conclusion that the drainage basins on “one-eighth of the eastern coastline” have sufficient ice to raise sea levels by 28m. But that is not the case, at the melting of all of Antarctica would only raise sea levels by 60m. The map reproduced from NASA’s own website is copied below.

The study area is no where near a third or more of Antarctica. Further, although it might be one eighth of the eastern coastline, it is far less than the coastline of East Antarctica, which is two-thirds or more of the total area.

NASA does not mention the 28m of potential sea level rise in its article, only 3 metres from the disappearance of the Totten Glacier. So how large is this catchment area? From a Washington Post article in 2015 there is a map.

The upper reaches of the catchment area may include Vostok Station, known for being the location of the lowest reliably measured natural temperature on Earth of −89.2 °C (−128.6 °F). The highest temperature recorded in over 60 years is −14.0 °C. In other words, what is being suggested is that a slight increase in ocean current temperatures will cause, through gravity, the slippage of a glaciers hundreds of miles long into the ocean covering ten times the Totten Glacier catchment.

The Guardian article of 11th December also does not mention the potential 28m of sea level rise. This looks to be an insertion by the BBC making the significance of the NASA research appear orders of magnitude more important than the reality.

The BBC’s audio interview with Dr Catherine Walker gives some clarification of the magnitude of the detected changes. At 2.30 there is a question on the scale of the changes.

Physically the fastest changing one is Vincennes Bay which is why we were looking at that one. And, for instance, in 2017 they changed average about .5 meters a year. So that is pretty small.

Losing 0.5 metres out of hundreds of thousands of length is not very significant. It just shows the accuracy of the measurements. Dr Walker than goes on to relate this to Fleming Glacier in West Antarctica, which is losing about 8 meters a year. The interview continues:-

Q. But the point is that compared to 2008 there is definitely an acceleration here.
A. Yes. We have shown that looking at 2008 and today they have increased their rate of mass loss by 5 times.
Q. So it is not actually a large signal is it? How do we describe this then. Is this East Antarctica waking up? Is it going to become a West Antarctica here in a few decades time or something?
A. I think its hard, but East Antarctica given how cold it is, and it still does have that layer insulating it from warm Antarctic circumpolar current … that really eats away at West Antarctica. We’ve seen it get up under Totten, so of you know, but it is not continuous you know. Every so often it comes up and (…….) a little bit.

There is acceleration detected over a decade, but for the disappearance of the glacier would take tens or hundreds of thousands of years. 

Walker goes into say that for the small changes to further increase

you would have to change the Antarctic circumpolar current significantly. But the fact that you are seeing these subtle changes I guess you could say Antartica is waking up.
We are seeing these smaller glaciers – which couldn’t be seen before – see them also respond to the oceans. So the oceans are warming enough now to make a real difference in these small glaciers.

This last carry-away point – about glaciers smaller than Totten – is not related to the earlier comments. It is not ocean warming but movements in the warm Antarctic circumpolar current that seem to impact on West Antarctica and this small section of the East Antarctica coast. That implies a heat transfer from elsewhere could be the cause as much as additional heat.

This account misses out on another possible cause of the much higher rates of glacier movement in West Antarctica. It might be just a spooky coincidence, but the areas of most rapid melt seem to have a volcanoes beneath them.

Yet even these small movements in glaciers should be looked at in the context of net change in ice mass. Is the mass loss from moving glaciers offset by snow accumulation?
In June 2018 Jay Zwally claimed his 2015 paper showing net mass gain in Antarctica is confirmed in a forthcoming study. It is contentious (as is anything that contradicts the consensus. But the mainstream estimate of 7.6 mm of sea-level rise over 25 years is just 0.30mm a year. It is in Eastern Antarctica that the difference lies. 

From the Daily Caller

Zwally’s 2015 study said an isostatic adjustment of 1.6 millimeters was needed to bring satellite “gravimetry and altimetry” measurements into agreement with one another.

Shepherd’s paper cites Zwally’s 2015 study several times, but only estimates eastern Antarctic mass gains to be 5 gigatons a year — yet this estimate comes with a margin of error of 46 gigatons.

Zwally, on the other hand, claims ice sheet growth is anywhere from 50 gigatons to 200 gigatons a year.

In perspective the Shepard study has a central estimate of 2,720 billion tonnes of ice loss in 25 years leaving about 26,500,000 billion tonnes. That is a 0.01% reduction. 

As a beancounter I prefer any study that attempts to reconcile and understanding differing data sets. It is looking at differences (whether of different data sets; different time periods; hypothesis or forecast and empirical reality, word definitions etc.) that one can greater understanding of a subject, or at least start to map out the limits of one’s understanding. 

On the measure of reconciliation, I should tend towards the Zwally estimates with isostatic adjustment. But the differences are so small in relation to the data issues that one can only say that there is more than reasonable doubt about against the claim Antarctica lost mass in the last 25 years. The data issues are most clearly shown by figure 6 Zwally et al 2015, reproduced below.

Each colour band is for 25mm per annum whereas the isostatic adjustment is 1.6mm pa. In the later period the vast majority of Antarctica is shown as gaining ice, nearly all at 0-50mm pa. The greatest ice loss from 1992 to 2008 is from West Antarctica and around the Totten Glacier in East Antarctica. This contradicts the BBC headline “East Antarctica’s glaciers are stirring“, but not the detail of the article nor the NASA headline “More glaciers in East Antarctica are waking up“.

Concluding Comments

There are a number of concluding statements that can be made about the BBC article, along with the context of the NASA study.

  1. The implied suggestion by the BBC that recent glacier loss over a decade in part of East Antarctica could be a portent to 28m of sea level rise is gross alarmism. 
  2. The BBC’s headline “East Antarctica’s glaciers are stirring” implies the melt is new in area, but the article makes clear this is not the case. 
  3. There is no evidence put forward in the BBC, or elsewhere, to demonstrate that glacier melt in Antarctica is due to increased global ocean heat content or due to average surface temperature increase. Most, or all, could be down to shifts in ocean currents and volcanic activity. 
  4. Most, or all of any ice loss from glaciers to the oceans will be offset by ice gain elsewhere.  There are likely more areas gaining ice than losing it and overall in Antarctica there could be a net gain if ice.
  5. Although satellites can perform measures with increasing accuracy, especially glacier retreat and movement, the fine changes in ice mass are so small that adjustment and modelling assumptions for East Antarctica can make the difference between net gain or loss.

The NASA study of some of East Antarctica’s glaciers has to be understood in the context of when it was published. It was during the COP24 conference to control global emissions, with the supposed aim of saving the world from potential dangerous human-caused climate change. The BBC dressed it up the study make it appear that the study was a signal of this danger, when it was a trivial, localized (and likely) example of natural climate variation. The prominence given to such a study indicates the lack of strong evidence for a big problem that could justify costly emissions reduction policies. 

Kevin Marshall

Two Comments on Antarctic Ice Accumulation

Jo Nova blogs on a study that claims the Antarctic continent is accumulating ice mass at a rapid rate. I have made two comments. One is opposing someone who claims that Antarctica is actually losing ice. The other is that the claimed rate of ice accumulation does not make sense against known data on sea levels.

Manicbeancounter

April 17, 2013 at 6:27 am · Reply

John Brooks says

I’m also interested that the mass of antarctic land ice follows solar irradiance. This makes perfect sense. However I can’t see why the effective of an increase in the greenhouse effect wouldn’t have exactly the same result.

Maybe you should look at the period covered by the graph John. There is an 800 year correlation of mass of antarctic land ice with solar irradiance, with the biggest movements in both prior to 1800. Insofar as the greenhouse effect is significant, it is nearly all after 1945.

And for some reason, I’ve got the idea in my head that antarctic land ice is decreasing.

Sure enough from the Carbon Brief link, this quote

Measurements from the Gravity Recovery and Climate Experiment (GRACE) satellite since 2002 have shown that the mass of the Antarctic ice sheet is decreasing at an average rate of 100 cubic kilometres every year – the size of a small UK city.

(emphasis mine)
The size of a city is usually measured in area, not volume. The ancient City of York, for instance, has an area of 272 square kilometres (105 square miles) and a population of 125,000. Or maybe they mean the volume of the buildings in a city? A famous building in New York is the Empire State Building. Not only is it quite tall it also has quite a large volume. Around 1,040,000 cubic metres or 0.001 cubic kilometres in fact. So does the Carbon Brief claim that a small UK city have a volume of buildings equivalent to 100,000 Empire state buildings? Or each average person in a small UK city occupies a building volume greater than Buckingham Palace?
Alternatively, does John Brooks quote a source that does not have a clue about basic maths?

Manicbeancounter

April 17, 2013 at 8:01 am · Reply

I think this paper does not stack up. I worked as a management accountant in industry for 25 years. One thing I learnt early on when estimating or forecasting was to sense-check the estimates. No matter how good your assumptions are, when estimating or extrapolating well beyond the data trend (where there is potential for error), the best check on the data is by reconciling with other data.
From the above

“The SMB of the grounded AIS is approximately 2100 Gt yr−1, with a large interannual variability. Those changes can be as large as 300 Gt yr−1 and represent approximately 6% of the 1989–2009 average (Van den Broeke et al., 2011).”

A gigatonne of ice is equivalent to a cubic kilometre of water. If the land ice volume is increasing, the water must come from somewhere. Nearly all of that water needs to come from the oceans.
Now for some basic maths. A gigatonne is a billion tonnes. As water has a relative density of 1.0, a tonne of water (1,000 litres) is a cubic metre. Therefore a gigatonne of water is a cubic kilometre (1000^3 = 1,000,000,000 = one billion).
A further factor to consider is the area of the oceans. According to my Times Concise Atlas, the total area of the oceans and seas (excluding the enclosed waters like the Dead Sea and Lake Baykal) is 325,000,000km^2. A cubic kilometre of water added to an enclosed sea of one million square kilometres, would raise the sea level by just 1mm (1000mm x 1000m = 1,000,000mm in a kilometre). So 325km^3 = 325Gt-1 of new ice accumulation above sea level in Antarctica would reduce sea levels by 1mm, or 2100GT-1 by 6.5mm.
Some of the ice accumulation will be on ice shelves, so the impact of 2100GT-1 extra ice per annum extra ice might be to reduce sea levels by just 5mm per annum. Also sea levels might be rising by a little less than the 3.2mm a year that official figures claim, but there is no evidence that sea levels are falling. Further, any net ice melt elsewhere (mostly Greenland) is only adding 1mm to sea level rise. So the rest must be mostly due to thermal expansion of the oceans. I think that the evidence for the oceans heating is very weak and of insignificant amounts. Even Kevin Trenberth in his wildest flights of fantasy would not claim the missing heat (from the air surface temperatures) adds more than 1-2mm to sea level rise.
What this study does show is that by honestly looking at data in different ways, it is possible to reach widely different conclusions. It is only by fitting the data to predetermined conclusions (and suppressing anything outside the consensus) that consistency of results can be achieved.

My scepticism on global warming stems from a belief that scientific evidence is strengthened by being corroborated from independent sources. Honest and independent data analysis means that wildly different conclusions can be reached. Comparing and contrasting these independent sources leads me to believe that the public face of the global warming climate change consensus massively exaggerates the problem.

Kevin Marshall