The Southern Alps stretch along the west coast of New Zealand’s South Island, the mountains built up by the collision of the Pacific and Australian tectonic plates. They are home to almost all of New Zealand’s glaciers, more than 3,000, due to the heavy snow and cold temperatures at elevation. The glaciers cover more than 1000 km2/385 mi2, but are rapidly shrinking.
Glaciers of New Zealand (red dots).
During the latter stage of the last glaciation, from 20,000-18,000 years ago, a large portion of the Southern Alps were fully glaciated. That large zone of ice has shrunk to the smaller, disconnected glaciers of today.
Ice coverage, last glacial maximum (20-18 KYA).
Investigators from the University of Leeds have recently mapped the extents of a number of glaciers throughout the Southern Alps of New Zealand. They have found that in the last 400 years (since the “Little Ice Age”), glacial melt rate has doubled over that time, and the glaciers have lost more than 77% of their mass. The glaciers of New Zealand appear headed for extinction.
From the early 1980’s to early 2000’s, a number of glaciers in the region regained mass, as colder temperatures prevailed. However, that increase has again reversed, and the index glaciers have resumed their rapid loss of mass.
Estimated mass loss, 50 index glaciers from the New Zealand Southern Alps, 1977-2009.
Tomorrow: overview of the Great Barrier Reef.
Be brave, and be well.
No comments:
Post a Comment