Glacier Course

After last weeks glacier course from the 18th to the 23rd of september at Jostedalen, I grew interest in the high frequency climate changes that have been occurring in the quaternary period of our time scale. At about 5.000 years ago the climate started cooling down and developed new glaciers after a warm period. The maximum of the "little ice age" was year 1750, since that time they have generally been withdrawing. There are several theories however none are quite sure why these phenomenon appears (Haslene, 2008 & Nesje, 1995). Three of them are described briefly in the text bellow.

The Three Theories

Sunspots

The solar radiation increase with a growing number of sunspots. The climatic effect is barley measurable in a 11 year cycle, but there have been three  periods with notably low activity during the last 1000 years; 1280-1350, 1416-1534 and 1654-1714 which is the high of the last ice age(Nesje, 1995).

The Tufte Glacier, Jostedalen

Volcanic Eruptions

Explosive eruptions can cover the stratosphere with silica particles and gases that absorbs the shortwave radiation. The stratospheric winds diverge the particles over the entire planet and they can last to at least 2 years. This can lower the yearly temperature by 1 degree.  There have been several incident like the year with no summer in 1816 related to the Mt.Tambora eruption(Rampino & Self, 1982).

Greenhouse Gasses

50% of the suns radiation absorbs in the atmosphere, while the rest break through and heats up the earth. The average temperature is around 15 degrees and will alternate if the balance of the gases in the atmosphere changes. Analysis 160.000 years back of the Arctic shows the temperature variations corresponding to the carbon and methane gases in the atmosphere(Karl, Knight & Plummer, 1995 & Nesje, 1995).

New Ice Age

I am not a scientist, and there are a lot of different theories. However, looking at the oncoming eruptions from Iceland and our ever increasing needs for more fossil fuels and waste on the earth and in the atmosphere I am not sure if there is an future ice age approaching, but everything seams to lead that way.

References:

Nesje, A.(1995). Brelære. Høyskoleforlaget, Kristiansand.

Haslene, S.(2008). Breboka - Håndbok i brevandring. DNT fjellsport, Oslo.

Rampino, M. R. & Self, S.(1982). Retrieved from:
http://www.sciencedirect.com/science/article/pii/0033589482900655(20.00, 30.09.11)

Karl, T. R, Knight, R. W. & Plummer, N.(1995). Retrieved from: http://www.nature.com/nature/journal/v377/n6546/abs/377217a0.html(16.28, 26.09.11)