Icelandic eruption

Volcanic activity beneath Eyjafjallajoekull in south-central Iceland is continuing to cause concern in the media that a jokulhlaup may be triggered. However, it appears that either meltwater is not being generated, or it is not accumulating. The eruption site, a 1km long fissure, is situated in a relatively ice-free area and so the former explanation seems likely. Nevertheless, this is small comfort to the 600 or so people who have been evacuated from their homes as a precaution. A further concern is that activity at the nearby Katla volcano could be triggered, particularly since this has been the outcome on the previous three occasions that this volcano has been active. Further footage and reports from earlier in the week can be accessed at http://news.bbc.co.uk/1/hi/world/europe/8578576.stm.

Glaciers online

Visit Glaciers Online (click on the link above or go to http://www.swisseduc.ch/glaciers/) for access to a vast range of beautiful and spectacular glacier-related photographs. This image bank has been produced by Jürg Alean (Kantonsschule Zürcher Unterland, Switzerland) and Professor Mike Hambrey (University of Aberystwyth) and includes a glossary and excellent information to accompany each photograph. The images cover glaciers all over the world from the Himalayas to the Antarctic. Use of the images is protected by copyright but can be used free of charge for educational purposes (with a suitable acknowledgement to the authors).

Kilimanjaro icefield disappearing

A combination of recent aerial photograph interpretation and ground drilling (in 2000) has revealed the full extent of glacier retreat on the northern and southern summit ice fields of Kilimanjaro. The areal extent of ice decreased 2.5% per annum from 1989 to 2007 and thinning (lowering of the ice surface) has varied from 1.9 to 5.1m. At one locality, thinning represents 50% of the glacier thickness. The Kilimanjaro ice fields have so far survived 11,700 years since retreat of the last major ice sheet, this despite a 300-year drought c.4,200 years ago. This suggests a lack of precipitation is not the only driver for the contemporary ice retreat observed, but that observed warmer near-surface conditions are pivotal. Current rates of melting indicate that there will be no ice left on Kilimanjaro within a matter of decades.

Image and content from: Thompson, L. G., Brechera, H. H., Mosley-Thompson, E., Hardyd, D. R. and Mark, B. G. (2009).
Glacier loss on Kilimanjaro continues unabated. Proceedings of the National Academy of Sciences of the United States of America (Early Edition), 1-6. Available online at http://tiny.cc/Miub0.

Problems of Melting Permafrost, Siberia.

Problems of melting permafrost were reported by Luke Harding in Marresale, on the Yamal peninsula (NW Siberia) in The Guardian, Tuesday 20 October 2009. This report was a newspaper centre spread on: Climate change in Russia's Arctic tundra. Changing weather near the River Ob is causing major problems for reindeer herders, with late freezing, early melting and less predictable weather all disrupting the feeding and seasonal moving of reindeer herds. Geomorphological hazard effects include lake drainage which has occurred due to permafrost melting. Also coastal mass movement and recession due to permafrost melting. On a broader scale there is fear of release of large quantities of carbon dioxide and methane as permafrost melts. Many houses and other structures which rely on preservation of the permafrost to provide foundation stability are at risk due to melting of permafrost. Houses in some Arctic towns in the region are already reported as subsiding badly. The stability of 5,000 miles of railways is at risk with the continuing rise in temperatures and associated permafrost thawing, as is the stability of many roads on permafrost.

The image shows Permafrost & thaw lakes. Yamal Peninsula, Siberia. Photo from: Luke Harding, The Guardian, p19, 21 Oct 2009.

Freeze Frame archive

A new JISC-funded online resource has been launched (http://www.freezeframe.ac.uk) that makes a host of photographic images available covering Polar exploration from 1845-1982. The resources are held in a collection by the Cambridge University Scott Polar Research Institute and include biographies, expedition accounts and commentaries. More than 20,000 images are available through galleries which cover topics such as ice and icebergs, ships, and wildlife. The image bank is fully searchable and can be viewed as a slideshow.

Anatomy of a Glacier

Check out this SlideShare Presentation:

Anatomy of a Glacier

View more presentations from Alan Doherty. (tags: medial moraine lateral moraine)

Antarctica warming: New satellite data

A new study (Steig et al, 22 Jan 2009. Nature 457, 356) has combined long term data from land stations on Antarctica with new satellite data and estimated rates of warming of 0.6 degC over 50 years on Antarctica. Warming is more rapid in the west of the continent. The study concurs with the IPCC assessment that there is at least a 66% probability of warming due to anthropogenic activity. The potential impact of Antarctic warming on sea level and global warming is hard to predict. Scientists are also concerned about the apparently imminent break-away of the Wilkins ice shelf (15,000km2) from the main continent. The image (from Steig et al 2009) shows the temperature anomaly (compared with the mean for the period) for west Antarctica. The black line represents reconstructed temperature based on satellite data, the red line shows the general trend, and the shaded area shows statistical confidence limits.

Accelerated recession of Swiss glaciers

Evidence has emerged that several large Swiss glaciers are in 'full' retreat. The work has been completed by the Swiss Federal Institute of Technology and suggests that the negative mass balance trend is getting steeper (see graph). Two factors primarily determine the mass balance of a glacier - winter precipitation in the form of snow, and the efficacy of summer melting. Evidence suggests that for the glaciers studied, winter snowfall has changed little. Conversely, the summer melt season has increased in length.

In the study, glaciologists determined the total volume of ice in Swiss glaciers at 74 cubic kilometres in 1999. This was determined partly by direct measurement and partly by modeling. This figure is thought to have been reduced by 13% between 1999 and the present day. There is less concern about the medium term fate of the larger glaciers such as the Aletsch (see photo) as these contain 80% of all the ice in the Swiss glaciers. Of greater concern is the short term fate of small glaciers - many of these are unlikely to survive more than a few years. Aside from the obvious impacts on landscape and tourism, many Swiss glaciers play an important role in water supply and the generation of hydro-electric power.

Future research into frost weathering

Despite considerable progress in understanding frost weathering in recent years, a new publication by Matsuoka and Murton (2008) identifies six key research questions on which to focus future research:

1. Why and when does explosive cracking occur?
2. Are hard intact rocks damaged only by frost?
3. How can episodic rockfalls or rock avalanches associated with permafrost degradation be predicted?
4. What are the rates of and controls on ice segregation and bedrock heave in permafrost regions?
5. What was the role of frost weathering in the evolution of mid-latitude Quaternary periglacial lowlands?
6. How and to what extent does frost weathering contribute to long-term erosion of cold mountains?

The authors suggest that answers will be found with the help of new techniques (eg rock sensors to detect fluid and ice presence, 3D microtopography scanning) as well as multi-technique approaches. They also recommend particular attention be paid to distinguishing both temporal and spatial scales. The image shows frost shattered bedrock in Norway, and the development of incipient ground.

Matsuoka, N. and Murton, J. (2008). Frost weathering: Recent adavnces and future directions. Permafrost and Periglacial Processes 19, 195-210.

Paraglacial slope evolution in the Karakoram Mountains

Massive volumes of unconsolidated slope deposits on the flanks of glaciated valleys in the Karakoram Mountains are interpreted by Iturrizaga (2008) as being largely controlled by moraine re-working and mass movement induced by glacial processes. Production of debris due to weathering processed is deemed to be relatively insignificant. Talus cones that are traditionally viewed as having a periglacial origin are re-interpreted as landforms controlled by glacial activity. This paper is one of a growing number that has focussed attention on the important role of paraglacial processes on landform evolution in glacial environments. The image shows debris flanked slopes in Fåbergstølsdal, Norway, also interpreted by Ballantyne and Benn (1996) as being of paraglacial origin.

Ballantyne, C. K. and Benn, D. I. (1996). Paraglacial slope adjustment during recent deglaciation and its implications for slope evolution in formerly glaciated environments. In: M. G. Anderson and S. M. Brooks (eds). Advances in Hillslope Processes, John Wiley and Sons, Chichester. Volume 2, 1173-1195.

Iturrizaga, L. (2008). Paraglacial landform assemblages in the Hindukush and Karakoram Mountains. Geomorphology 95(1-2), 27-47.

Stone runs in the Falkland Islands: Periglacial or tropical?

Excavations of blockstreams (‘stone runs’) on the Falkland Islands reveal an inverted weathering profile that may be indicative of a tropical, rather than periglacial origin for these features. Apparent accumulations of blocks may, in fact, represent the in situ, regolith-stripped remnant of a Tertiary surface. A multi-phase evolution is presented by André et al (2008), that includes chemical weathering, mantle stripping, mass movement and soil forming processes. It is accepted that these polygenetic landforms may have undergone re-working and weathering by subsequent periglacial activity during the late stage Quaternary. The image shows blockstreams on Hardangervidda in Norway (Photo: DTN). For further details, read the full paper:

André, M-F., Hall, K., Bertran, P. and Arocena, J. (2008). Stone runs in the Falkland Islands: Periglacial or tropical? Geomorphology 95(3-4), 524-543.