Atlantic sea surface temperatures affect Antarctic climate change

A new source of warming has been found for Antarctica: the North Atlantic and tropical Atlantic Ocean.

Warm waters in the Pacific have been connected to warming in Antarctica, but this is the first time that a connection with the Atlantic Ocean sea surface temperatures has been made.

"Our findings reveal a previously unknown--and surprising--force behind climate change that is occurring deep in our southern hemisphere: the Atlantic Ocean," says Xichen Li, a doctoral student in NYU's Courant Institute of Mathematical Sciences and the study's lead author. "Moreover, the study offers further confirmation that warming in one region can have far-reaching effects in another."

Global warming in recent decades has caused dramatic warming of the Antarctic Peninsula and West Antarctica. Changes in Antarctic climate have been attributed to greenhouse gas emissions and the ozone hole , sea surface temperatures in the central tropical Pacific warming (Qinghua Ding et al 2011) and the impact of El Nino.

Antarctic ice mass accelerating according to GRACE reanalysis, Pine Island Glacier in sustained retreat

The continent of Antarctica is a land of complexity and paradox, especially when talking about climate change. It is our driest and coldest desert on the planet but locks up an enormous amount of fresh water in it's thick ice sheets. The southern ocean surrounds the continent, insulating it from warmer latitudes, but those currents also bring warmer waters from the tropics to interact with the giant ice shelves around the continent.

And of course there is the paradox of Antarctic sea ice which is recording record sea ice extent over recent years due to the complex winds, currents and dynamics of melt water.

Sea ice growth or melt does not affect sea level rise. We need to look at what the great Ice sheets are doing to determine whether they are accelerating mass loss and contributing to sea level rise.

The GRACE satellites provide us with a remote measuring tool for ice mass balance, but like all tools it comes with certain biases built in. The job of the scientist is to analyse and correct for these biases.

Volcanic activity adds further to instability of West Antarctic Ice Sheet

Volcanic activity detected near the Executive Committee range in Marie Byrd Land in West Antarctica adds another factor to the instability of the West Antarctic Ice Sheet (WAIS). A small eruption under the ice could result in melt water adding substantial lubrication to the bottom of a portion of the ice sheet, speeding up the ice stream discharge into the Ross Sea.

The West Antarctic Ice sheet is buttressed by huge ice shelves at it's edges which hold back the ice streams. Warming Southern ocean currents are melting ice shelves, causing them to retreat, allowing faster discharge of ice flows from the interior. Much of the ice sheet is grounded on a sub-glacial basin below sea level, so as the ice shelf grounding line retreats, more warm water can interact with the ice to speed the discharge and collapse of the ice sheet. Volcanic activity adds further potential instability to this process.

The Paradox of Antarctic Sea Ice 2: Research vessel trapped by summer sea ice

I came across an article lambasting the Australian Antarctic Expedition scientists on board the MV Akademik Shokalskiy trapped by fast ice since Christmas Eve in the Commonwealth Bay region of Antarctica. Climate scientists and tourists are on board the vessel on the Spirit of Mawson voyage, retracing Sir Douglas Mawson's Antarctic expedition.

The ship found itself locked in thick ice after experiencing blizzard conditions which moved and piled up ice flows.

Ships can get trapped by pack ice in polar waters very quickly during blizzards. Pack ice moves around with wind conditions, and it is not uncommon for ships to become temporarily locked in the ice even during peak summer conditions in Antarctica.

But Daniel Greenfield seems to think a ship trapped in Antarctic summer sea ice is a negation of global warming and the science involved in climate change. He is not alone...

Related: Oliver Millman: Five basic Antarctic facts for climate change sceptics | Giles Parkinson: Australia, 'hostage to climate change madness'? To say so is madness indeed

Antarctic Peninsula: nonlinear intensification of melt unprecedented in last 1000 years

This study analysing an Antarctic Peninsula ice core from James Ross island has determined that there has been a ten fold increase in melt intensity over the last 600 years. I reported recently that the Antarctic Peninsula summer melt season prolonged by global warming according to research from the British Antarctic Survey.

"The warming has occurred in progressive phases since about AD 1460, but intensification of melt is nonlinear, and has largely occurred since the mid-twentieth century. Summer melting is now at a level that is unprecedented over the past 1,000 years. We conclude that ice on the Antarctic Peninsula is now particularly susceptible to rapid increases in melting and loss in response to relatively small increases in mean temperature." concludes the study.

The information comes from a 364 meter ice core drilled by a joint UK and French research team on James Ross Island, near the northern tip of the Antarctic Peninsula. Analysis of the ice core can reveal past temperature changes as well as revealing past extent of ice melt events.

West Antarctic Ice Cores find changes at upper bound of normal

A new ice core study from the West Antarctic Ice Sheet (WAIS) concludes that current dramatic and unusual warming changes on the West Antarctic Ice Sheet may still be in the bounds of natural decadal variability.

In other words, the warming trend signal is still not strong enough to distinguish it above the noise of peak warming periods in multi-decade long cycles involving the Tropical Pacific atmospheric circulation, sea surface temperatures and the El Niño (ENSO) cycle.

While acknowledging the rapid warming over the West Antarctic Ice Sheet the authors conclude that "It is unknown whether these changes are part of a longer-term trend."

Related: Global warming in Antarctica: Thwaites and Pine Island Glaciers | Waking the giant: Global Warming in the Weddell Sea | Southern Ocean warming impact on Antarctic Ice Sheet and global sea level | Antarctic Paradox: ocean warming melting ice shelves causing sea ice expansion

Antarctic Octopus genetics reveals past West Antarctic Ice sheet collapse

It seems the genetics of the Antarctic Octopus is showing us how fragile the West Antarctic Ice sheet (WAIS) may be with global warming. It raising questions about the ice sheet susceptibility to collapse.

The Antarctic octopus - Turquet's octopus - is a little creature that doesn't like moving house. It is a stay-at-home tending to live in one place and only moving short distances to escape predators. Yet when marine scientists looked at the genetic diversity of specimens of the octopus from the Ross Sea and compared them with specimens 10,000kms by sea away in the Weddell Sea they found there was little genetic difference.

To explain how these different populations can be so alike scientists believe there has been at least partial collapse of the West Antarctic Ice Sheet, with the last time perhaps being the previous interglacial period - the Eemian some 125,000 years ago. A partial collapse may have opened up a channel between the Weddell and Ross Seas.

Arctic Sea Ice Death Spiral - Lord Monckton revealed as bad joke

Peter Sinclair has put together another educative video gem on the decline of Arctic Sea Ice, and indeed global sea ice. The video mixes together video footage of Lord Monckton from 2009, 2011, and 2013 to show his inconsistency, with the facts and observations from climate scientists on sea ice decline.

Climate scientists interviewed include Dr Walt Meier from the National Snow and Ice Data center, Dr Ken Dunton from University of Texas, Dr Jennifer Francis from Rutgers University, Dr Jeff Masters from the WeatherUnderground, Dr Claire Parkinson from the Goddard Space Flight Center NASA,

The video covers the recent and unusually extensive ice fractures seen in the Beaufort Sea from the beginning of February through March. This highlights that most of this sea ice is seasonal or first year ice. Sea ice extent continues to track well below model predictions for the disintegration of summer sea ice. Sea Ice volume trend is even more stark with a projection of a possible ice free summer as early as 2016.

Antarctic Paradox: ocean warming melting ice shelves causing sea ice expansion

Antarctic sea ice extent is a complex and puzzling beast, not following a simple process of rapid Arctic sea ice diminishment. A new paper in Nature Geoscience argues that warm deep ocean currents are contributing to ice shelf melt and causing Antarctic sea ice expansion. While ice mass loss from Antarctica is presently at 250 Gigatonnes per year and accelerating, sea ice is also expanding slowly but to record levels. What a paradox!

The trend for a gradual increase in Antarctic Sea ice has puzzled scientists for some time. The expansion is at odds with general climate model results. I reported on the puzzle of Record Antarctic Sea Ice Growth in November 2012. In that article I explained that (Holland et al 2012) argued that atmospheric variability in the form of local winds was pushing the ice northwards creating space for new sea ice to form. While climate deniers claimed record Antarctic sea-ice was a refutation of climate change, in reality it showed they could not fathom that the cryosphere and the planet's climate are complex processes which we are still trying to understand, with some surprising processees not readily open to be modelled.

Antarctic Peninsula summer melt season prolonged by global warming

The melt season on the Antarctic Peninsula has been getting much longer over the last 60 years, at some locations doubling in length according to the research lead by Dr Nick Barrand of the British Antarctic Survey.

Increased melting season increases the melting stress of ice shelves which hold back significant glacier discharge and sea level rise.

The Antarctic Peninsula is a mountainous region that extends north from the West Antarctic Ice Sheet towards South America. The area is warming much faster than the rest of Antarctica at around 3 times the global average, although the West Antarctic Ice Sheet (WAIS) also appears to be rapidly warming according to measurements at Byrd polar station. Temperatures have risen by up to 3 oC since the 1950s. The warming has been linked to a strengthening of local westerly winds, causing warmer air from the sea to be pushed up and over the peninsula.

• Antarctic Peninsula summer melt season extending
  
• Impact of warming on penguins and marine ecosystem
  
• Invasion of the King Crabs
  

Related: Real Climate - Antarctic Peninsula warming: natural variability or "global warming"?

Greens propose boost to funding for Antarctic and Southern Ocean Marine Research

Hobart as an important scientific hub and gateway for Antarctic and Southern Ocean marine research, not only for Australia but for other national scientific expeditions. That is the vision of a new policy initiative launched by the Greens today to boost the research and logistics capacity of Australian Antarctic, climate and marine scientists based in Hobart.

Tasmania presently hosts the Antarctic Climate and Ecosystems Co-operative Research centre (ACE CRC) , the Australian Antarctic Division, along with CSIRO's Division of Marine and Atmospheric Research. But funding for the ACE CRC will come to an end in the next year. The University of Tasmania, CSIRO and ACE CRC are currently working on a proposal for a new Antarctic research organisation.

Antarctica and the Southern Ocean influence the regional and global climate and in this period of climate change understanding the mechanisms and changes taking place will provide valuable information for climate adaptation. Temperatures are increasing at 3 times the global average on West Antarctica, ice streams are accelerating ice mass loss with the collapse of the West Antarctic Ice Sheet a real possibility in the decades and centuries ahead. The Southern ocean is warming and freshening at a much faster rate than the global ocean. The food web in the southern ocean is changing with Penguin numbers suffering with krill decline due to Global Warming

Is Climate Change causing an exponential rate of Ice sheet Mass Loss, sea level rise?

Climate scientist James Hansen and his colleague Makiko Sato have released a new discussion paper with updated data on ice sheet mass loss from Greenland and Antarctica, with implications for possible multi-metre sea level rise this century. It makes for some interesting reading - there is a link to Hansen's website and the paper at the end.

The thesis that Hansen has put forward for several years is that Ice Sheet collapse is a non-linear process: that with the inclusion of amplifying climate feedbacks it is likely to follow an exponential rate of acceleration - a doubling rate. It might be a 10 year doubling time, or less. This will lead to extensive sea level rise, perhaps in the order of 5 metres this century.

But accurate data measurements of ice mass loss via laboriously estimating mass input and output has only been available since the early 1990s, and accurate satellite measurements (Gravimetry) via the GRACE satellites since 2000.

What these measurements show is that ice mass loss from both Greenland and Antarctica are accelerating, but the data for the time period is still too short to determine whether ice sheet mass loss will follow a somewhat linear path, or an exponential path doubling every 10 years or shorter time period.

Caption: Figure 2: Greenland (a) and Antarctic (b) mass change deduced from gravitational field measurements by Velicogna (2009) and best-fits with 5-year and 10-year mass loss doubling times. From NASA: Earth's Climate History: Implications for Tomorrow Hansen and Sato July 2011

Update 14 Jan 2013: Matt Owens from Fairfax Climate Watch had a similar idea in reviewing Hansen's discussion paper. Read his initial analysis: Sea level rise could crimp GDP; US direct losses could top 1/4 trillion per year during 2040-2050. On 11 January 2013 he updated his analysis with a new article: Surprising negative feedback could mean epic disaster. Both are worthwhile reading.

Global Warming on West Antarctic Ice Sheet three times the global average

The West Antarctic Ice Sheet is warming at three times the global average, according to temperature measurements at Byrd Polar Station. This has implications for the melting of the West Antarctic Ice sheet (WAIS) and sea level rise.

The West Antarctic Ice Sheet is inherently unstable due to it's grounding in a deep depression below sea level. Warm Southern ocean currents are already reducing ice shelves holding back ice discharge from glaciers. As these ice shelves are undermined and break up it will allow significant acceleration of glacier discharge increasing the rate of sea level rise.

Lead study author David H. Bromwich from Ohio State University said:

"Our record suggests that continued summer warming in West Antarctica could upset the surface mass balance of the ice sheet, so that the region could make an even bigger contribution to sea level rise than it already does," said Bromwich.

"Even without generating significant mass loss directly, surface melting on the WAIS could contribute to sea level indirectly, by weakening the West Antarctic ice shelves that restrain the region's natural ice flow into the ocean."

Related: Global warming in Antarctica: Thwaites and Pine Island Glaciers | Waking the giant: Global Warming in the Weddell Sea | Southern Ocean warming impact on Antarctic Ice Sheet and global sea level

Study: Winds driving Record Antarctic Sea ice growth, global sea ice extent still declining

While the Arctic sea-ice has experienced a dramatic reduction, Antarctic sea ice continues to increase in extent hitting a new record in October this year. So what's going on?

The trend for a gradual increase in Antarctic Sea ice has puzzled scientists. Firstly, the gradual increase in Antarctic sea ice is far less than the amount of sea ice vanishing in the Arctic Sea. Global sea ice trend still shows a marked retreat.

But in the Antarctic working out why the sea ice trend has seen a one percent increase per decade since the 1970s has bamboozled the scientists. A new study based upon 18 years of detailed satellite ice motion measurements has put forward that it is primarily local winds pushing ice mainly north creating polyanas in the ice flows where more ice can easily form.

Climate change connection between Global temperatures, ice volume and sea level

There is a rapid response connection between polar temperature changes, ice volume and sea leavel according to a new method of dating of sea level records and comparing them with temperature data and ice core records for the last 150,000 years.

Previously the dating of ice-volume changes relied on the ‘Red Sea relative sea-level (RSL) record’. However this dating method did not have independent age control which inhibited detailed comparison with other well-dated climate parameters, such as temperature or CO2 records from ice cores from Greenland and Antarctica. The new method of dating the RSL record used Mediterranean data from radiometric (Uranium-series) dating of cave deposits which could be applied to the last glacial cycle reaching back 150,000 years, providing a continuous sea-level record with excellent independent age control.

According to the study sea level rise reached speeds of "at least 1.2 metres per century during all major episodes of ice-volume reduction" in the last 150,000 years.

One of the study authors, Professor Elco Rohling from the National Oceanography Centre Southampton said: "This is the first time that these rates could be measured for any other period than the end-of-ice age 'terminations/deglaciations'. Although it is always hard to step from palaeo reconstructions to future projections, it suggests that when significant ice-volume adjustments happen, they are rarely slow."

Southern Ocean warming impact on Antarctic Ice Sheet and global sea level rise

Climate change is causing the southern ocean to warm and freshen which will melt ice shelves and glacier tongues affecting glacier discharge and producing Antarctic Ice Sheet mass loss and global sea level rise. A new study shows that small temperature changes of the Southern Ocean can contribute to far-reaching changes on the Antarctic ice sheet that could lead to substantial future sea-level rise.

Related: Waking the giant: Global Warming in the Weddell Sea, West Antarctic Ice Sheet and sea level rise | Attenborough warns of ice shelf destruction in Antarctica | Global Warming in Antarctica: Thwaites and Pine Island Glaciers accelerating, West Antarctic Ice Sheet losing mass

Waking the giant: Global Warming in the Weddell Sea, West Antarctic Ice Sheet and sea level rise

Warm ocean currents are projected to melt the Filchner-Ronne Ice Shelf in the Weddell Sea area of Antarctica opening instabilities in the West Antarctic Ice sheet (WAIS) which will impact global sea level rise. Climate change is waking up the sleeping giant of Antarctica.

Significant scientific research has been published in recent weeks on the impact of global warming on changing wind patterns and southern ocean currents and the flow-on impact on Antarctic ice shelves and glaciers. The most recent studies reveal the potential instability of the Filchner-Ronne Ice Shelf in the Weddell Sea area. But the real questions to be asked concern the long term stability of the West Antarctic Ice Sheet (WAIS) and how rapidly it could collapse raising global sea levels by up to 6 metres.

I highlighted in November 2011 that the Thwaites and Pine Island Glaciers accelerating, West Antarctic Ice Sheet losing mass in the Amundsen Sea area. Now climate researchers of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association studying the opposite side of the West Antarctic Ice Sheet (WAIS) in the Weddell Sea area have discovered a mechanism which will drive warm ocean water towards the coast in the later decades of this century, allowing a higher rate of basal melting - the melting from underneath of ice shelves and glaciers by warmer ocean currents - leading to greater discharge of ice from the icesheet.

Another research team has found a large deep basin, about 20,000 square kilometres in size and up to 2 kilometres deep, underneath the ice sheet in the Weddell Sea area, which makes the ice sheet inherently unstable if pinion points for the ice shelf retreat and warmer water enters the basin.

Attenborough warns of ice shelf destruction in Antarctica

UK Naturalist and documentary maker David Attenborough has warned about the implications of melting ice sheets in the polar regions but emphasised the changes under way in Antarctica "is likely to have the most dramatic effects of all".

His comments were made in a November 2011 article in the BBC Radio Times reported by the Independent newspaper. While the title of the Independent newspaper article - Warning over melting ice at North Pole - places emphasis on processes in the Arctic, the important statement by Attenborough is about the collapse of ice shelves fringing Antarctica and the implications for the West Antarctic Ice Sheet.

Global Warming in Antarctica: Thwaites and Pine Island Glaciers accelerating, West Antarctic Ice Sheet losing mass

Scientists have been studying the climate change impacts on ice shelfs and glaciers for some time in Antarctica, and particularly around the Antarctic Peninsula where there is substantial warming occurring increasing ice shelf melt and the speed and discharge of glaciers. The most recent studies predict a faster retreat for the Thwaites Glacier and that warm ocean currents are already speeding the melting of the Pine Island Glacier and Ice Shelf and Getz Ice Shelf. A NASA Icebridge flight detected a major new rift in the Pine Island ice shelf on October 14 - the start of the calving of a massive iceberg. A recent paper in Nature Geoscience discusses the Stability of the West Antarctic ice sheet in a warming world and the likelihood of collapse that would raise sea level by more than three metres over the course of several centuries or less.

Related: The Wilkins ice Bridge collapsed in April 2009 as Polar regions felt the heat of climate change. I reported as far back as 2004 that warming in Antarctica was cause for concern with ocean food chain crashing due to Antarctic warming. More recently in April 2011 I discussed Penguin numbers suffering with krill decline due to Global Warming.

Penguin numbers suffering with krill decline due to Global Warming

A new study of declining penguin populations shows a strong correlation between penguin numbers and krill availability. Krill availability is affected by reduced sea ice conditions due to global warming and climate change.

"For penguins and other species, krill is the linchpin in the food web. Regardless of their environmental preferences, we see a connection between climate change and penguin populations through the loss of habitat for their main food source," said Dr. Wayne Trivelpiece, lead author and seabird researcher of the National Oceanic and Atmospheric Administration's Antarctic Ecosystem Research Division. "As warming continues, the loss of krill will have a profound effect throughout the Antarctic ecosystem."

Related: On the brink: Penguins face an uncertain climate future (Oct 2010)