How do we mitigate greenhouse gas emissions?

We can mitigate climate change by reducing the release of greenhouse gasses or increasing the sequestration of carbon in vegetation or by other means. Strategies include making buildings more energy efficient; adopting renewable energy sources like solar, wind and hydroelectric power; helping cities develop more sustainable transportation such as bus transit, electric vehicles and biofuels; and promoting sustainable uses of land and forests. 

Why is the glacier blue?

Ice is blue because it reflects blue light, while it absorbs the red and yellow part of the spectrum. Snow looks white because the air between the snowflakes reflects full spectrum of light (white). Thus, the more air bubbles in the ice, the whiter it looks.

The blue colours of Heinabergsjökull. Photo: Þorvarður Árnason, 2010.

What organisms live on the glaciers?

Most organisms that live on or in glacial ice or snow are tiny microbes, such as bacteria, cyanobacteria or small algae. You may have noticed the snow algae, Clamydomonas nivalis, which has red pigmentation that colours the snow red or orange. A very special form of life found on many northern glaciers are the glacier mice. These are ball-shaped bundles of mosses with a small core of stone. They form when a small pebble with a piece of moss starts rolling on the ice and the moss slowly covers the whole pebble. Glacier mice in Iceland were first described on Hrútárjökull glacier in 1950 by Jón Eyþórsson, glaciologist and meteorologist at the Icelandic Meteorological Office.

Glacial mice on Kvíárjökull outlet glacier. Photo: Hrafnhildur Hannesdóttir, 2007.

Cryoconite holes on the surface of the glacier.

Do glaciers recede during summer and advance during winter?

Some glaciers, for example in Scandinavia and Iceland, have especially fast response to mass balance variations and form small annual moraines each year. They recede slightly during summer and then the terminus advances a little during winter.

Annual moraines form when the glacier advances slightly during winter. Photo: Snævarr Guðmundsson, 2014.

When is an expanse of ice not considered a glacier?

A glacier needs to be approximately 40–50 m thick in order to deform under its own weight and flow down the slope. If it thins beyond that point, it will stagnate and may eventually vanish if he mass balance is negative, especially if the equilibrium line exceeds the maximum elevation of the glacier and snow no longer accumulates.

Ok glacier Iceland year 2003. Photo: Oddur Sigurðsson.