Glaciers can be thought of as recorders of climate.?

Question

Glaciers can be thought of as recorders of climate. Briefly describe 2 types of climate information that can be obtained from glaciers

Answer 1

Probably the most important information on global climate comes from monitoring the Global Glacier Mass Balance. While individual glaciers will retreat and advance (depending on regional precipitation and temperature fluctuations) monitoring that process on major glaciers from different mountain ranges all over the world over decades is an extremely sensitive and good proxy measurement of global temperature changes.

The World Glacier Monitoring Service (based at the University of Zurich in Switzerland) are the recognized experts in this field.  The latest results of their measurements shows a clear and accelerating decline in the worlds glacier mass.  Go to this link and scroll 1/2 way down to see the accumulated loss of the glacier ice mass they're monitoring:

http://www.geo.unizh.ch/wgms/mbb/mbb9/su...

The dangers of receding glaciers around the world (which apparently Jim Z naively thinks is of no concern) is that much of the worlds population depends on a water supply coming down from the glaciers. Without those reservoirs, the historic fairly steady flow of many rivers and streams may be replaced by flooding (during the rainy season) and dried river beds (during the dry season).

But to more specifically answer your question, glacier ice core samples provide information on environmental conditions including droughts, temperature, volcanic activity, moisture sources, atmospheric gas levels at the time each layer was formed (including CO2), etc.  An annual layer is clearly identifiable in glacial ice core samples (kind of like rings in a tree) that can be used to date climate activity in past years.

A great study was published in 2005 entitled "Extracting a Climate Signal from 169 Glacier Records".  The abstract is here (you'll need a subscription for full access):

http://www.sciencemag.org/cgi/content/ab...

And there's a supplemental PDF file (freely down loadable) with some great charts and information here:

http://www.sciencemag.org/cgi/content/fu...

Answer 2

Do yourself a favor and ignore the fear mongering of the first post.  It is typical nonsense that you get from alarmists.  Glaciers have always gained and receded.  They gain when the precipitation is great enough and climate is cold enough for ice to accumulate.  They recede when the climate is warm and precipitating is low.  When there is a period of warming such as recently, it should be expected for glaciers to recede.  To suggest that this is somehow a dire warning is at best ignorant IMO.

Answer 3

The changing rate of warming can be determined from receding glaciers (see the article for more on the measurement mechanism):

New Research Confirms Antarctic Thaw Fears - Spiegel Online

http://www.alertnet.org/thenews/newsdesk...

"...the Pine Island Glacier has shrunk by an average of 3.8 centimeters annually over the past 4,700 years. But the Smith and Pope glaciers have only lost 2.3 centimeters of their thickness annually during the past 14,500 years. Satellite measurements taken between 1992 and 1996, though, show a loss of 1.6 meters in thickness per year on the Pine Island Glacier -- a figure that represents 42 times the average melt of the past 4,700 years."

Answer 4

from ice samples;

bubbles of air, dust.