Greater Snowfall Does Not Stop Glacier Melt
15.09.2014 07:37 Age: 8 hrs

Glaciers in northern Antarctic Peninsula are melting faster than ever - despite increased snowfall. Greater snowfall due to climate change will not offset the continued melting of glaciers say researchers.

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Glaciers in northern Antarctic Peninsula. Courtesy: Dr Bethan Davies.

Click to enlarge.
Professor Neil Glasser, a glacial geomorphologist at Aberystwyth University, on James Ross Island in 2011. Courtesy: Aberystwyth University.


Increased snowfall due to climate change will not prevent the continued melting of glaciers in the northern Antarctic Peninsula, according to new research published on Sunday 14 September in the journal Nature Climate Change.

Here are two news releases describing this research.
News release from Aberystwyth University:

Glaciers in northern Antarctic Peninsula melting faster than ever

Increased snowfall will not prevent the continued melting of glaciers in the northern Antarctic Peninsula, according to new research published today (Sunday 14 September) in the journal Nature Climate Change.

An international team of researchers, which includes Professor Neil Glasser from Aberystwyth University, has discovered that small glaciers that end on land around the Antarctic Peninsula are highly vulnerable to slight changes in air temperature and may be at risk of disappearing within 200 years.

Temperatures are currently rising rapidly in the Antarctic Peninsula. Because warmer air holds more moisture, the amount of snowfall has also increased. Some researchers have suggested that this may offset the melting of the glaciers in the future. However, this study found that even small increases in air temperature increased melting so much that even large amounts of extra snowfall could not prevent glacier recession.

“These small glaciers around the edge of the Antarctic Peninsula are likely to contribute most to rising sea levels over the coming decades, because they can respond quickly to climate change”, said Dr Bethan Davies, from Royal Holloway, University of London, who led the research.

“This study is the first to show how glaciers in this vulnerable region are likely to respond to climate change in future. Our findings demonstrate that the melting will increase greatly even with a slight rise in temperature, offsetting any benefits from increased snowfall.”

The researchers used a combination of glacier and climate modelling, glacial geology and ice-core data. They carried out extensive fieldwork on James Ross Island, northern Antarctic Peninsula, to map and analyse the changes to a glacier, which is currently 4km long, over the past 10,000 years.

Dr Davies added: “Geological evidence from previous studies suggests that the glacier grew by 10km within the last 5,000 years, before shrinking back to its current position. It was argued that this occurred during a warmer but wetter period, suggesting that increased precipitation in the future would offset glacier melt.

However, our study shows that this growth actually occurred during the colder ‘Little Ice Age’, reaching its largest size just 300 years ago.”

Professor Neil Glasser said: “We found that this glacier remained roughly the same size for thousands of years during the Holocene period, until it started to grow again 1,500 years ago. However, it is now melting faster than anything seen before, and over the next 200 years will become far smaller than at any point over the last 10,000 years.

“This unprecedented glacier recession, in response to climate change, will result in significant contributions to sea level rise from this and similar Antarctic Peninsula mountain glaciers and ice caps.”

Researcher Dr Nicholas Golledge, from Victoria University of Wellington, in New Zealand, added, “This glacier, though small, is typical of many of the small glaciers that end on land around the Antarctic Peninsula. This research is important, because it helps reduce some of the uncertainties about how these glaciers will react to changing temperature and precipitation over the next two centuries.”

The research was funded by grants from the Natural Environment Research Council (NERC), awarded to Professor Neil Glasser (grant number NE/F012942/1) and a Scientific Committee for Antarctic Research (SCAR) Fellowship awarded to Dr Bethan Davies.

News release from Royal Holloway College:

Glaciers in northern Antarctic Peninsula melting faster than ever - despite increased snowfall

Increased snowfall will not prevent the continued melting of glaciers in the northern Antarctic Peninsula, according to new research published in the journal Nature Climate Change.

An international team of researchers, led by Dr Bethan Davies, from Royal Holloway, University of London, has discovered that small glaciers that end on land around the Antarctic Peninsula are highly vulnerable to slight changes in air temperature and may be at risk of disappearing within 200 years.

Temperatures are currently rising rapidly in the Antarctic Peninsula. Because warmer air holds more moisture, the amount of snowfall has also increased. Some researchers have suggested that this may offset the melting of the glaciers, however this study found that just a small rise in air temperature increased melting so much that even large amounts of extra snowfall could not prevent glacier recession.

“These small glaciers around the edge of the Antarctic Peninsula are likely to contribute most to rising sea levels over the coming decades, because they can respond quickly to climate change”, said Dr Davies, from the Department of Geography at Royal Holloway. “This study is the first to show how glaciers in this vulnerable region are likely to respond to climate change in future.

Our findings demonstrate that the melting will increase greatly even with a slight rise in temperature, offsetting any benefits from increased snowfall.”

The researchers carried out extensive fieldwork on James Ross Island, northern Antarctic Peninsula, to map and analyse the changes to a glacier, which is currently 4km long, over the past 10,000 years. They used a combination of glacier and climate modelling, glacial geology and ice-core data.

Dr Davies added: “Geological evidence from previous studies suggests that the glacier grew by 10km within the last 5,000 years, before shrinking back to its current position. It was argued that this occurred during a warmer but wetter period, suggesting that increased precipitation in the future would offset the melting of the glaciers. However, our study shows that this growth occurred during the colder ‘Little Ice Age’, reaching its largest size just 300 years ago.”

Researcher Dr Nicholas Golledge, from Victoria University of Wellington, in New Zealand, said: “This glacier, though small, is typical of many of the small glaciers that end on land around the Antarctic Peninsula. This research is important, because it helps reduce some of the uncertainties about how these glaciers will react to changing temperature and precipitation over the next two centuries.”

Professor Neil Glasser, from Aberystwyth University, added: “We found that this glacier remained roughly the same size for thousands of years until it started to grow again 1,500 years ago.

However, it is now melting faster than anything seen before, and over the next 200 years will become far smaller than at any point over the last 10,000 years. This unprecedented glacier recession, in response to climate change, will result in significant contributions to sea level rise from this and similar Antarctic Peninsula mountain glaciers and ice caps.”

Abstract

The northern Antarctic Peninsula is currently undergoing rapid atmospheric warming. Increased glacier-surface melt during the twentieth century has contributed to ice-shelf collapse and the widespread acceleration, thinning and recession of glaciers.

Therefore, glaciers peripheral to the Antarctic Ice Sheet currently make a large contribution to eustatic sea-level rise but future melting may be offset by increased precipitation. Here we assess glacier–climate relationships both during the past and into the future, using ice-core and geological data and glacier and climate numerical model simulations. Focusing on Glacier IJR45 on James Ross Island, northeast Antarctic Peninsula, our modelling experiments show that this representative glacier is most sensitive to temperature change, not precipitation change. We determine that its most recent expansion occurred during the late Holocene ‘Little Ice Age’ and not during the warmer mid-Holocene, as previously proposed. Simulations using a range of future Intergovernmental Panel on Climate Change climate scenarios indicate that future increases in precipitation are unlikely to offset atmospheric-warming-induced melt of peripheral Antarctic Peninsula glaciers.

Citation

Modelled glacier response to centennial temperature and precipitation trends on the Antarctic Peninsula by Bethan J. Davies, Nicholas R. Golledge, Neil F. Glasser, Jonathan L. Carrivick, Stefan R. M. Ligtenberg, Nicholas E. Barrand, Michiel R. van den Broeke, Michael J. Hambrey & John L. Smellie published in Nature Climate Change (2014) doi:10.1038/nclimate2369

Read the abstract and get the paper here.
Source

News release from Royal Holloway College here.
News release Aberystwyth University here.

http://www.reportingclimatescience.c...cier-melt.html