Fact file – Pine Island Glacier
Four fast facts about Pine Island Glacier…
- It drains an area equivalent to two thirds the size of the United Kingdom
- It is the most rapidly shrinking glacier on the planet and is contributing more to sea level rise than any other ice stream
- It is approximately 2km thick, but is thinning by more than 1 metre per year
- There is a subglacial volcano underneath Pine Island Glacier which erupted around 2000 years ago
Where is Pine Island Glacier?
Pine Island Glacier (PIG) is a large ice stream located on the West Antarctic Ice Sheet (WAIS) in Antarctica. At around 2km thick, PIG accounts for around 10% of the WAIS and drains an area of 162,300km2, roughly two thirds the size of the United Kingdom. The glacier flows into Pine Island Bay at the southeast extremity of the Amundsen Sea.
Why is Pine Island Glacier important?
PIG is responsible for a greater contribution of ice into the sea than any other glacier on Earth which, given the global concern about rising sea level, makes it very important. Significantly, this contribution appears to be increasing. PIG is also the fastest shrinking on the planet and it is contributing to sea level rise faster than any other glacier.
Why is Pine Island Glacier getting thinner?
Over the past 15 years, PIG has thinned at a rate of more than 1 metre per year. Glaciers thin when more mass (ice) is lost during the summer than is replaced by snowfall in the winter. When this happens it is said to have a negative mass-balance. Temperature, precipitation and the speed at which a glacier is moving are the main factors controlling this relationship.
Why is Pine Island Glacier accelerating?
It is not known for certain why PIG is accelerating but one theory attributes it to the warmer sea temperatures felt around Antarctica in recent years. This warm water acts to melt the underside of an ice shelf, making it weaker and more likely to crack and fall into the sea. In recent years the location at which PIG starts to float on the sea, its grounding line, has retreated by more than 1 km per year, and in July 2013 a 720 km2 section (roughly eight times the size of Manhattan Island) of PIG’s ice shelf broke away. Having a smaller ice shelf means that less ‘back pressure’ is exerted on the rest of the glacier and results in an increased rate of flow.
How do scientists study glaciers?
Satellite observations allow for a general picture of glacial flow but finer-scale measurements are necessary in order to model PIG’s movement effectively. Aerial surveys are used to enhance satellite information and can be conducted over a relatively wide range, but to gain data at the highest resolution ‘on the ground’ observations are required. With the nearest base 800 miles away, conducting field research on PIG can be a challenging task but in 2007 and 2008 BAS researchers spent a total of six months in this remote and hostile region. Measuring ice flow with Global Positioning Systems, taking ice cores, and using a specialised radar system to map the bedrock underneath the ice, scientists gained a much better understanding of PIG’s present and historic condition. One discovery was that there is a subglacial volcano under PIG which, evidence suggests, erupted 2000 years ago.