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 inland1. 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 fast2. 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.

  1. Greenbaum JS et al, (2015), Ocean access to a cavity beneath Totten Glacier in East Antarctica, Nature Geoscience, doi:10.1038/ngeo2388 []
  2. Paolo, F.S. et al, (2015), Volume loss from Antarctic ice shelves is accelerating, Science, doi/10.1126/science.aaa0940 []

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 demolition1, 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”

  1. 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 []

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 Renwick1. 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”

  1. 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. []

Stocker in Wellington: RSNZ to stream AR5 science workshop

Swiss climate scientist Thomas Stocker, joint chairman of the IPCC’s Working Group One, is in New Zealand for a few days, and the NZ Climate Change Centre and the Royal Society of NZ have taken the opportunity to put together a stakeholder workshop to allow Stocker and NZ lead authors to present the key findings of the recently published AR5 WG1 report. The workshop is being held tomorrow, Friday 11th, from 9am to 1pm at the RSNZ in Wellington, and is open to the public (spaces limited, register here). For the geographically challenged, the event will be web-cast live.

The workshop will open with an introduction by Richard Bedford, a council member of the RSNZ, and an overview of the IPCC process by WG1 vice-chair David Wratt. Stocker will present the key Working Group I report findings from about 9-10am. NZ’s coterie of lead authors — Dave Frame, Tim Naish, and Jim Renwick — will provide snapshots of the parts of the report they were involved with. From midday on, the Science Media Centre’s Peter Griffin will chair a “stakeholder panel” including Rod Oram, Federated Farmers vice-chair William Rolleston and Frances Sullivan from Local Government NZ to discuss how the report has been received and what it means for New Zealand.

Stocker is also being interviewed by Radio NZ National’s science correspondent Veronika Meduna, and that should be broadcast in her show next week.

A big week coming: meanwhile Anglicans divest

It’s shaping up to be a big week. On Friday in Stockholm (Saturday in NZ) the IPCC will release the final version (not the one that’s been leaked to and seen by all and sundry) of the Summary for Policy Makers of the Working Group One report of their Fifth Report (AR5 — official web site here). As you might expect, the usual suspects have been lining up to try and dominate the news media — to provide a carbon friendly “frame” through which to view the IPCC’s findings. Most of it has been singularly ineffective, as Graham Readfearn noted in the Guardian, but I’ll hold my fire until the final SPM is released. Watch this space…

Meanwhile, the Anglican Diocese of Wellington voted this weekend to join their colleagues in Auckland by divesting itself of any fossil fuel investments in its portfolio. The Auckland synod at the beginning of the month took the opportunity to listen to two presentations that I think it worth drawing attention to here. First, Jim Renwick from VUW (an IPCC lead author) lays out the basic science that underlies the case for action to reduce emissions:

…then economic commentator Rod Oram explains the “carbon bubble” in market valuations of fossil fuel energy stocks, and why it would make sense to avoid that risk:

Two compelling presentations, with an obvious conclusion that the members of the Anglican church were happy to accept. We should not be investing in companies whose value depends on the burning of excessive amounts of carbon.