Historic patterns of ice advance and retreat Flashcards
do glaciers respond long-term or short-term in regards to mass balance?
long term
The balance between accumulation and ablation is representative of what?
the long-term response to trends in mass balance
what is positive mass balance?
this is where accumulation exceeds ablation and the glaciers mass increases causing it to advance
what is the negative mass balance?
this is where ablation exceeds the accumulation and the mass of the glacier decreases causing it to retreat
is the mass of the glacier dependent on advance/retreat?
no, one is not always the consequence of another.
speed of retreat/advance
slow, painfully slow
over what period of time is advance/retreat recorded?
- usually annually
- over decades by the position of the glacier snout
how can you tell the glacier has advanced?
by looking at the position of the terminal moraine -whether it has moved or not
how does terminal moraine move?
terminal moraine - pushed like how a bulldozer pushes anything in its way.
how can you tell a glacier has retreated?
the terminal moraine is abandoned
how will glacial retreat be affected over the next hundred years?
- climate warmed - more retreat
- many of the world’s glaciers retreated
since 1980 have glaciers experienced considerable shrinking? what is it linked to?
yes, it is linked to climate change and global warming.
what has 2009 research by the University of Zurich shown?
- 76 out of 89 swiss glaciers were retreating
- 5 stationery
- 8 were advancing
how much of the ice mass has been lost since the 1970s in the Himalayas?
10%
The Cascades in North America
- 47 glaciers retreating
- some have disappeared completely
