Summer melt season is getting longer on the Antarctic Peninsula, new research shows.
New research from the Antarctic Peninsula shows that the summer melt season has been getting longer over the last 60 years — Increased summer melting has been linked to the rapid break-up of ice shelves in the area and rising sea level
New research from the Antarctic Peninsula shows that the summer melt season has been getting longer over the last 60 years. Increased summer melting has been linked to the rapid break-up of ice shelves in the area and rising sea level.
The Antarctic Peninsula – a mountainous region extending northwards towards South America – is warming much faster than the rest of Antarctica. Temperatures have risen by up to 3 oC since the 1950s – three times more than the global average. This is a result of a strengthening of local westerly winds, causing warmer air from the sea to be pushed up and over the peninsula. In contrast to much of the rest of Antarctica, summer temperatures are high enough for snow to melt.
This summer melting may have important effects. Meltwater may enlarge cracks in floating ice shelves which can contribute to their retreat or collapse. As a result, the speed at which glaciers flow towards the sea will be increased. Also, melting and refreezing causes snow layers to become thinner and more dense, affecting the height of the snow surface above sea level. Scientists need to know this so they can interpret satellite data correctly.
Dr Nick Barrand, who carried out the research while working for the British Antarctic Survey, led an analysis of data from 30 weather stations on the peninsula. “We found a significant increase in the length of the melting season at most of the stations with the longest temperature records” he says. “At one station the average length of the melt season almost doubled between 1948 and 2011.”
To build up a more complete picture across the whole peninsula, the team (funded by the European Union’s ice2sea programme) also analysed satellite data collected by an instrument called a scatterometer. Using microwave reflections from the ice sheet surface, the scatterometer was able to detect the presence of meltwater. The team were able to produce maps of how the melt season varied from 1999 to 2009, and showed that several major ice shelf breakup events coincided with longer than usual melt seasons. This supports the theory that enlargement of cracks by meltwater is the main mechanism for ice shelf weakening and collapse.
The researchers also compared data from both the satellite and weather stations with the output of a state-of-the-art regional climate model.
Dr Barrand, who now works at the University of Birmingham, says, “We found that the model was very good at reproducing the pattern and timing of the melt, and changes in melting between years. This increases confidence in the use of climate models to predict future changes to snow and ice cover in the Antarctic Peninsula.”
Trends in Antarctic Peninsula surface melting conditions from observations and regional climate modeling will be officially published in the Journal of Geophysical Research this week.
In support of J.B.’s above comment. Howdy. Good to hear from you again. Looking forward to your comments concerning up coming Arctic cooling and increased Arctic sea ice.
Record High Antarctic Sea Ice (Note the extreme AGW paradigm pushers do not discuss this issue.)
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.anomaly.antarctic.png
http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES/antarctic.seaice.color.000.png
The extreme AGW paradigm pushers preferred to discuss the ‘summer’ warming of the Antarctic peninsula (there is now a cold anomaly in the winter over the Antarctic peninsula which is logical as Antarctic sea ice is now high for both summer and winter.
http://wattsupwiththat.files.wordpress.com/2011/02/antarcticatemps19572006111.jpg
The climate specialist should explain the warming of the Antarctic Peninsula is due to changes in prevailing winds over the peninsula (from the Southern Ocean rather than Antarctic continent which has nothing to do with atmospheric CO2.)
http://www.nature.com/nature/journal/v489/n7414/full/nature11391.html?WT.ec_id=NATURE-20120906
Rapid warming over the past 50 years on the Antarctic Peninsula is associated with the collapse of a number of ice shelves and accelerating glacier mass loss1, 2, 3, 4, 5, 6, 7. In contrast, warming has been comparatively modest over West Antarctica and significant changes have not been observed over most of East Antarctica8, 9, (and William the majority of the Antarctic continent has cooled, and sea ice around the Antarctic is at a record high) suggesting that the ice-core palaeoclimate records available from these areas may not be representative of the climate history of the Antarctic Peninsula. Here we show that the Antarctic Peninsula experienced an early-Holocene warm period followed by stable temperatures, from about 9,200 to 2,500 years ago, that were similar to modern-day levels. Our temperature estimates are based on an ice-core record of deuterium variations from James Ross Island, off the northeastern tip of the Antarctic Peninsula. We find that the late-Holocene development of ice shelves near James Ross Island was coincident with pronounced cooling from 2,500 to 600 years ago. This cooling was part of a millennial-scale climate excursion with opposing anomalies on the eastern and western sides of the Antarctic Peninsula. Although warming of the northeastern Antarctic Peninsula began around 600 years ago, the high rate of warming over the past century is unusual (but not unprecedented) in the context of natural climate variability over the past two millennia. The connection shown here between past temperature and ice-shelf stability suggests that warming for several centuries rendered ice shelves on the northeastern Antarctic Peninsula vulnerable to collapse. Continued warming to temperatures that now exceed the stable conditions of most of the Holocene epoch is likely to cause ice-shelf instability to encroach farther southward along the Antarctic Peninsula.
http://climategrog.wordpress.com/?attachment_id=161
Antrctic melting period is getting longer , Arctic melting is shortening.
While Antarctic remains well below 6 month line , Arctic has recently crossed it. I don’t know whether that is a significant threshold or not but then tendency is clear at both ends.
Sea ice has be increasing in the antarctic over the last few years. Just look at the sea ice page.
This is once again a case of only telling one part of the ‘truth’, the one supporting your agenda.
It might very well be that the summer melt season on the AP has gotten much longer during the last 50-60 years and that the peninsula on average has gotten warmer, perhaps even a lot warmer, over that same period. But there is no indication of this warming continuing to this day. Not at all. This warming occurred somewhen between 30 and 45 years ago, depending on what data you’re looking at. Nothing of substance has happened temperaturewise during the last decades, the modern era of ‘global warming’.
http://i1172.photobucket.com/albums/r565/Keyell/AntarcticPeninsulatemps_zpsa98d7080.png
Lower graph: Temperatures at Larsen Ice Shelf since 1985. No visible upward tendency. Rather the opposite. Middle graph: Temperatures at Rothera Point (see map) since 1977. Since about 1981-83, no discernible increase. I can only assume the temperatures plotted are minimum temperatures, for they match pretty close the minimum temperatures at Vernadsky (Faraday) station (upper graph). At Vernadsky you can draw a line all the way back to 1970-71 without seeing much temperature rise to the present.
http://i1172.photobucket.com/albums/r565/Keyell/FaradayAntPen_zpsc6bfdaab.png
Maximum vs. minimum temperatures at Vernadsky (Faraday) station, 1951-2005. The maximum temperatures don’t exactly exhibit much of a rise over the past decades, do they?
It appears most (if not all) of the rise in AP mean temperatures over the last 60 years can be attributed to the marked upward shift in minimum temperatures in the late 60s to early 70s. And besides a few ups and downs along the way, not much of consequence has happened since, especially not during the last 30 years.
The alleged AP warming is a hype, a myth, at best a half-truth, at worst a bald-faced lie.
It is the 62nd consecutive day with higher than average global sea ice cover (relative to the 1979-2008 mean) and counting.
Who can forget RealGore’s pics of the Larsen Ice Shelf breaking up? Well, buzz on down there by Google Earth, and you will find it is reforming. Could breakup have been the result of gravity, not climate?
The Antarctic peninsula has major volcanic sites at Penguin Island and Deception Island. Any statement about warming of the peninsula needs to first rule out any contribution from geothermal activity. For example see: http://www.deceptionisland.aq/volcanic.php
I agree that the melt season for the arctic has increased over the years, mostly due to increased global temperature from increased CO2 emissions. In a current lecture I went to held by Dr. Ryan L. Fogt he told of his studies in the Antarctic and how they have found that the ice sheets have been reducing over the years. His research started in 2002 and from then to 2012 there has been a significant loss in the ice sheets of the Arctic. A case he specifically focused on was the Larsen B ice shelf on the Antarctic Peninsula that broke up that just from January 31, 2002 to March 5, 2002. The Antarctic ozone has been depleting, and in 2006 there was an all-time record ozone hole area of 27 million km^2 (ozonewatch.gsfc.nasa.gov). Westerly winds may be a cause in the reduction of ice sheets and increased melt water that could be splitting up the glaciers, but increased global temperature is a significant cause too. This article needs more facts though to back it up. Like, by how much has the summer melt season increase over the last 60 years? Did it increase steadily over the 60 years or did it shoot up particularly over certain years? Without this specific data the statements in this article cannot be taken too seriously.
Idiots: http://www.bbc.co.uk/news/science-environment-21991487