By Dr. Sebastian Lüning and Prof. Fritz Vahrenholt
(German text translated, edited by P Gosselin)
In March, 2015 there was a climate alarm at German online news weekly Focus:
Gigantic Antarctic glacier is melting – Holland in an emergency: sea level rise threatens to rise 3 meters
Off the East Antarctic coast, researchers found two underwater valleys. They enable the inflow of warm sea water. beneath the largest glacier of the East Antarctic. That could explain the unusually rapid ice loss. Should the glacier collapse, sea level would rise dramatically.”
Could, would: Subjunctive speech is king. Are things really that bad with the Antarctic Totten glacier? We’ve looked at this at our site before. In May 2016 also Rud Istvan commented on this at Climate Etc. on an alarming paper publsihed at Nature by Aitken et al. 2016. He concluded:
The alarming estimates from this new Nature paper, particularly as represented by the media, are grievously wrong both with respect to the amount of and the rate of sea level rise that might be associated with melting of the EIAS Totten glacier. There is unjustified author spin in the press releases and author’s interviews. There are underlying bad assumptions never mentioned except by reference to a previously refuted [here] bad paper by Rignot. A tangled web of deceit, to paraphrase a famous poem.”
Perhaps it’s not a bad idea not to try to explain the whole globe by using a single glacier, as tempting as it may be. Just last month on May 5, 2017 the University of Bristol reminded us that East Antarctic ice has gown over the past decade, and has not shrunk. Of course the university stated it in the more politically correct “not as strong as previously thought”. The press release follows:
New research shows growth of East Antarctic Ice Sheet was less than previously suggested
Scientists have known for over a decade that the West Antarctic Ice Sheet has been losing mass and contributing to sea level rise. Its eastern neighbour is, however, ten times larger and has the potential to raise global sea level by some 50 metres. Despite its huge size and importance, conflicting results have been published on the recent behaviour of the East Antarctic Ice Sheet. A study led by a group of NASA scientists, that was published in 2015, suggested that this part of Antarctica was gaining so much mass that it compensated for the losses in the west. Determining what the largest ice sheet on the planet is doing is vital for our understanding of the factors that are influencing present day, and future, sea level rise.
To address this question, a team of scientists led by the University of Bristol and including the University of Wollongong, Australia have studied the problem by combining different satellite observations within a statistical model that is able to separate the processes related to ice mass changes over the continent. Professor Jonathan Bamber from the Bristol Glaciology Centre which is part of the School of Geographical Sciences, said: “We used similar data sets to the NASA team but added other satellite data from a mission called the Gravity Recovery And Climate Experiment (GRACE) to help solve for mass gains and losses. “We then conducted different experiments, using similar assumptions made in the NASA study but found that in every experiment, mass loss from the west always exceeded gains in the east.” The researchers concluded that over the study period, 2003-2013, Antarctica, as a whole, has been contributing to sea level rise and that the gains in East Antarctica were around three times smaller than suggested in the 2015 study.
Paper: ‘Constraining the mass balance of East Antarctica’ by A. Martin-Espanol, J. Bamber and A. Zammit-Mangion in Geophysical Research Letters. Plain language summary available at: www.globalmass.eu/constraining-the-mass-balance-of-east-antarctica/“
New studies on the East Antarctic further supports the trend of more ice. A team led by Morgane Philippe published a paper in 2016 in The Cryosphere which examined the coastal strip of the Dronning Maud Land. The result is already given in the title: The abstract:
Ice core evidence for a 20th century increase in surface mass balance in coastal Dronning Maud Land, East Antarctica
Ice cores provide temporal records of surface mass balance (SMB). Coastal areas of Antarctica have relatively high and variable SMB, but are under-represented in records spanning more than 100 years. Here we present SMB reconstruction from a 120 m-long ice core drilled in 2012 on the Derwael Ice Rise, coastal Dronning Maud Land, East Antarctica. Water stable isotope (δ18O and δD) stratigraphy is supplemented by discontinuous major ion profiles and continuous electrical conductivity measurements. The base of the ice core is dated to AD 1759 ± 16, providing a climate proxy for the past ∼ 250 years. The core’s annual layer thickness history is combined with its gravimetric density profile to reconstruct the site’s SMB history, corrected for the influence of ice deformation. The mean SMB for the core’s entire history is 0.47 ± 0.02 m water equivalent (w.e.) a−1. The time series of reconstructed annual SMB shows high variability, but a general increase beginning in the 20th century. This increase is particularly marked during the last 50 years (1962–2011), which yields mean SMB of 0.61 ± 0.01 m w.e. a−1. This trend is compared with other reported SMB data in Antarctica, generally showing a high spatial variability. Output of the fully coupled Community Earth System Model (CESM) suggests that, although atmospheric circulation is the main factor influencing SMB, variability in sea surface temperatures and sea ice cover in the precipitation source region also explain part of the variability in SMB. Local snow redistribution can also influence interannual variability but is unlikely to influence long-term trends significantly. This is the first record from a coastal ice core in East Antarctica to show an increase in SMB beginning in the early 20th century and particularly marked during the last 50 years.
A paper by Vikram Goel et al further underpins the stability of the Dro