Category: Climate science

Totten hots up, ice shelves melting: it’s grim down south

AntarcticaCryosat2Much news in recent weeks from Antarctica, and none of it good. An Argentinian base on the tip of the Antarctic Peninsula recently reported a new high temperature record for the continent — 17.5ºC. A team of scientists has discovered that East Antarctica’s Totten Glacier — which drains a catchment that contains enough ice to raise sea levels by 3.5 metres — is vulnerable to melting caused by warm ocean water lapping underneath the ice and reaching inland ((Greenbaum JS et al, (2015), Ocean access to a cavity beneath Totten Glacier in East Antarctica, Nature Geoscience, doi:10.1038/ngeo2388)). Another group has stitched together satellite data on ice shelf thickness gathered from 1994 to 2012 and found that the ice shelves — mostly stable at the beginning of the period, are now losing mass fast ((Paolo, F.S. et al, (2015), Volume loss from Antarctic ice shelves is accelerating, Science, doi/10.1126/science.aaa0940)). From the abstract:

Overall, average ice-shelf volume change accelerated from negligible loss at 25 ± 64 km3 per year for 1994-2003 to rapid loss of 310 ± 74 km3 per year for 2003-2012. West Antarctic losses increased by 70% in the last decade, and earlier volume gain by East Antarctic ice shelves ceased. In the Amundsen and Bellingshausen regions, some ice shelves have lost up to 18% of their thickness in less than two decades.

The Amundsen region is home to the Pine Island Glacier, notorious for its current rapid loss of mass, and probably already past the point of no return for long term total melt. The map below shows the big picture: large red dots are ice shelves losing mass. Blue dots are shelves gaining mass.

Antarcticiceshelves

Ice shelves are important features of the Antarctic cryosphere. They buttress the ice piled up on the land, slowing down the flow of ice into the ocean. As the shelves lose mass, the flow of ice from the centre of the continent can speed up, adding to sea level rise. There’s a very good overview of the process — and the findings of the Paulo et al paper — in this excellent Carbon Brief analysis.

The study of the Totten Glacier — one of the fastest thinning glaciers in East Antarctica — is the first to look at the detail of the sea floor and ice thickness in the area. The study finds that there are “tunnels” under the ice leading into a deep trough inland that cold convey warm water inland — the same process that has destabilised the Pine Island Glacier in West Antarctica. As the authors suggest, rather drily, “coastal processes in this area could have global consequences”.

These signs of rapid changes around the coasts of Antarctica, together with hints that large parts of the huge East Antarctic ice sheet are at risk of following West Antarctica into the sea, suggest that even if sea levels only rise by a metre by the end of this century as the IPCC projected last year, the longer term picture will be a great deal wetter than that. After all, there is the equivalent of 60 metres of sea level rise locked up in East Antarctica.

For a very good overview of the state of our understanding of what’s going on in Antarctica, I recommend a listen to VUW’s Professor Tim Naish being interviewed by Radio New Zealand National’s Kim Hill last Saturday. Naish even covers what’s happening to the sea ice down there, but a longer term study of the sea ice is getting under way, led by another VUW prof — Jim Renwick.

Leyland and Carter: the rebuttal that isn’t and the hypocrisy that is

CarterFlatEarth.jpgSciblogs editor Peter Griffin recently gave climate denial activists Bryan Leyland and Bob Carter a “right of reply” to my post pointing out the errors and inconsistencies in a Dominion Post op-ed penned by the pair. Griffin took this action because of vociferous complaints from Leyland, who took offence at my discussion of his expertise (non-existent) and history of campaigning against action on climate. The result is billed as a “rebuttal”, but it isn’t, as I shall demonstrate.

The Sciblogs “rebuttal” is a mishmash of a so-called “fully referenced” version (pdf) of the op-ed that Leyland says was supplied to the Dominion Post, but he and Carter also prepared a very long-winded “response” (pdf) to the debunking of their piece by David Wratt, Andy Reisinger and Jim Renwick in the DP. The latter is a real eye-opener…

Life is too short to do another point-by-point demolition ((Leyland & Carter may be retired, with nothing better to do than promote their crank viewpoints, but I have grapes and truffles to nurture through to harvest, and a book to write)), so I’ll select a few key issues that demonstrate that although they claim to be discussing science in a scientific manner, what they are actually doing is having the equivalent of an argument in a pub — prepared to say anything if they think it will help them “win”.

Continue reading “Leyland and Carter: the rebuttal that isn’t and the hypocrisy that is”

DomPost denier debacle: science has the last word

The Dominion Post, which blotted its editorial copybook last week by publishing a factually incorrect and highly misleading opinion piece by climate denialists, has today published a heavyweight reply by three of NZ’s top climate scientists — David Wratt, Andy Reisinger and Jim Renwick ((David Wratt is an Emeritus Climate Scientist at NIWA, an Adjunct Professor in the NZ Climate Change Research Institute at Victoria University, and a Vice Chair of Working Group 1 of the IPCC. Andy Reisinger is Deputy Director (International) of the New Zealand Agricultural Greenhouse Gas Research Centre and served as coordinating lead author in the most recent IPCC report. James Renwick is a Professor of Physical Geography at Victoria University of Wellington and served as a Lead Author on the last two IPCC Reports.)). Headed “Human role in climate change is clear”, the article is clear about climate reality:

Human influence on the climate system is clear and growing, and impacts are evident on all continents. If left unchecked, climate change will increase the likelihood of severe, pervasive and irreversible impacts for people and ecosystems.

We do have options to reduce risks by reducing greenhouse gas emissions and adapting to some climate change, but time is running short if we want to limit changes to manageable levels. Ignoring or misconstruing the overwhelming evidence is not a responsible risk management strategy.

It’s not clear whether the DomPost plans any further response to the rubbish they printed from Bryan Leyland and Bob Carter, but the editorial team at the newspaper would do well to reflect on the approach to the subject adopted by Guardian editor Alan Rusbridger, introducing an important new series of features in that paper:

For the purposes of our coming coverage, we will assume that the scientific consensus about man-made climate change and its likely effects is overwhelming. We will leave the skeptics and deniers to waste their time challenging the science. The mainstream argument has moved on to the politics and economics.

Precisely. Rusbridger — who is retiring after 20 years as editor — wants his newspaper to do justice…

…to this huge, overshadowing, overwhelming issue of how climate change will probably, within the lifetime of our children, cause untold havoc and stress to our species.
So, in the time left to me as editor, I thought I would try to harness the Guardian’s best resources to describe what is happening and what — if we do nothing — is almost certain to occur, a future that one distinguished scientist has termed as “incompatible with any reasonable characterisation of an organised, equitable and civilised global community”.

That’s what a real newspaper does: takes on the big issues. If the Dominion Post wants to be more than a Noddy book newspaper publishing rubbish from the intellectual heirs to Big Ears, it’s high time it took a sensible approach to the climate debate, and followed Rusbridger’s lead.

Continue reading “DomPost denier debacle: science has the last word”

25 ways the DomPost failed its readers by publishing Leyland and Carter’s climate crap

Carter with his Flat Earth society peers
Carter with his Flat Earth society peers
The Dominion Post, the newspaper of record for New Zealand’s capital city, today gave great prominence to an opinion piece by high profile climate denialists Bob Carter and Bryan Leyland titled Hypothetical global warming: scepticism needed ((On page A7 – opposite the leader. Not currently available on the web, but a scan has been posted on Twitter — see this comment below.)). It’s a “Gish Gallop” of untruths, half-truths and misrepresentations — a piece so riddled with deliberate errors and gross misrepresentations that it beggars belief that any quality newspaper would give it space.

I will deal with the factual errors in a moment, but the DomPost‘s lack of editorial judgement extends well beyond any failure to fact check the article. Carter and Leyland’s expertise on the issue is misrepresented. The newspaper’s readers are not given a true picture of their “standing”. They are in fact paid/sponsored propagandists, way out on the crank fringes. Here’s how Carter is credited.

Professor Bob Carter is an honorary fellow of the Royal Society of NZ. His expertise is in geology and paleoclimatology — deducing past climates from geological records. He has written several books on climate change.

All of that is true ((Except perhaps for the professorship. Carter has no current academic affiliation that I know of, so I wonder why the DomPost is granting him that status? Surely he wouldn’t have misrepresented himself to the paper?)), but it is far from a full picture. In fact, Carter has been a propagandist against action on climate change since the 1990s, with a history of paid work with and for far-right wing organisations in Australia and the USA – including being paid by the notorious Heartland Institute in the US to produce shoddy pseudo-academic publications. In the right wing Australian journal Quadrant, where links to right wing organisations obviously play well, Carter’s credit runs like this:

Bob Carter is an Emeritus Fellow of the Institute of Public Affairs (IPA) and Chief Science Advisor to the International Climate Science Coalition (ICSC).

The IPA campaigns against climate action, and Carter recently starred in its Climate: Change the facts tour around Australia promoting a new propaganda pamphlet. As an adviser to the ICSC — a group attempting to promote climate denial around the world, he works to:

“…directly educate the public about what science, engineering and economics are really concluding about climate change and the downside of misguided plans (e.g., wind turbines, “carbon sequestration”, etc.) to “solve the crisis”. This includes newspaper articles, letters to the editor, radio and TV interviews, public presentations, regular postings on our, and others’, Web sites and use of all forms of popular social media.”

In other words, Carter and Leyland managed to con the DomPost into playing along with their propaganda campaign.

The DomPost credits Leyland thus:

Bryan Leyland is an engineer specialising in renewable energy. He is an accredited reviewer for the IPCC and has contributed several articles on renewable energy technologies to overseas publications.

In fact, Leyland has a long track record of activism against action to reduce carbon emissions. He was a founder member of the NZ Climate Science Coalition and a trustee of the NZ Climate Science Education Trust — formed to bring a court action against NIWA’s handling of the national temperature record. When the case was lost, the trust was folded so that Leyland and his fellow trustees could avoid paying $90,000 of court-ordered costs.

Leyland is notorious in NZ media circles for his attempts to push climate denial. It beggars belief that the DomPost did not know about his track record, and went ahead with publishing an article under his name without prominently noting his role as an activist.

As propagandists, the product that Leyland and Carter are pushing is doubt — a tactic first used by the tobacco industry, but since refined by fossil fuel interests keen to avoid emissions cuts. Leyland and Carter “win” every time a mainstream media outlet gives their views credence by giving them prominence. Newspapers do not regularly provide platforms for cranks, but that is exactly what Leyland and Carter are, as we shall see in a moment.

Continue reading “25 ways the DomPost failed its readers by publishing Leyland and Carter’s climate crap”

Antarctic ice going fast: Larsen C ice shelf primed for giant calving event

Analysis of rift propagation using Landsat data. Background image, in which the rift is visible, is from 4 December 2014. Inset graph shows the development of rift length with respect to the 2010 tip position, and rift width at the 2010 tip position, measured from 15 Landsat images (crosses). Circles and labels on the map, and dotted red lines on the graph, show the positions of notable stages of rift development.

The Larsen C ice shelf on the east coast of the Antarctic peninsula is primed for a giant iceberg calving event, and could be heading for total collapse — similar to the fate of the Larsen B ice shelf in 2002, according to scientists monitoring the ice. A huge crack (above: hover over the picture for the full caption from the paper) is propagating northwards at an accelerating rate, and could give birth to ice islands of between 4,600 km2 and 6,400 km2 — equivalent to three or four Stewart Islands floating out to sea — according to an open access paper, Jansen et al, Newly developing rift in Larsen C Ice Shelf presents significant risk to stability ((The Cryosphere Discuss., 9, 861–872, 2015)) (full pdf), published last month.

From the paper’s conclusions:

It seems inevitable that this rift will lead to a major calving event which will remove between 9 and 12 % of the ice shelf area and leave the ice front at its most retreated observed position. More significantly, our model shows that the remaining ice may be unstable. The Larsen C Ice Shelf may be following the example of its previous neighbour, Larsen B, which collapsed in 2002 following similar events.

The Larsen C ice shelf has been thinning over at least the last decade, and has shown signs of surface melting. Jansen et al developed two calving scenarios — shown below — and analysed the results with a model of the ice shelf.

Overview of the Larsen C Ice Shelf in late 2014 showing the contemporary location of the developing rift (red line), and a selection of previous and predicted future calving fronts. Background image is MODIS Aqua, 3 December 2014. Geographic features of interest are marked (R = Revelle Inlet, FI = Francis Island, TO = Tonkin Island, TI = Trail Inlet, SI = Solberg Inlet, K = Kenyon Peninsula) and the dashed box shows the extent of Fig. 2. The highlighted flow line indicates the location of the Joerg Peninsula suture zone.

For a good overview of the current state of our knowledge of Antarctic ice melt, see The big melt: Antarctica’s retreating ice may re-shape Earth from the Associated Press, which tipped me off to the Larsen C story. Larsen C is the most northerly of the remaining major Antarctic ice sheets, and the last remnant of an ice shelf that until 1995 stretched up to the tip of the east coast of the Antarctic Peninsula. After the collapses of Larsen A and B, the glaciers feeding the shelves were observed to speed up — increasing the overall ice sheet mass loss. While the loss of the ice shelf won’t itself cause any sea level rise — because it’s already floating — the resulting speed up will increase sea levels.