Antarctica Ice Cap

 Irrefutable Evidence of Climate Change

Adapted from an article: Dr. T.H. Jacka, Glaciology Program,
Antarctic Cooperative Research Centre and

Australian Antarctic Division.

For the original article see:

The snow near the surface of the ice sheet is like a sponge with channels of air between the snow grains. As more and more snow is accumulated on top, the underlying snow is compressed into ice and the air forms bubbles in the ice. Ice cores therefore can be analyzed not just for the chemical and physical properties of the ice, but also for the properties of the air trapped in the ice. These bubbles are actual samples of the atmosphere up to thousands of years ago. So, analysis of them can tell us much about the atmosphere in the past.

Concentrations of carbon dioxide and methane can be measured in the air bubbles trapped in the ice.  Carbon dioxide and methane are greenhouse gases and the similarity between the graphs for their concentrations and the temperature change indicates that the greenhouse effect is real. Has there been a significant increase in the atmospheric concentration of greenhouse gases since the industrial revolution?

The answer is yes, as can be seen from the graph below which shows the concentrations of carbon dioxide in the atmosphere, measured in the bubbles from an Antarctic ice core from Law Dome near Australia 's Casey Station. The concentration of carbon dioxide has increased from about 280 parts per million to 350 parts per million, which is a rise of 25 per cent since the middle of last century. Nitrous oxide and other greenhouse gases also show similar trends from analysis of the ice-core bubbles.


Concentration of Carbon Dioxide from trapped air measurements for the DE08 ice core near the summit of Law Dome, Antarctica . (Data measured by CSIRO Division of Atmospheric Research from ice cores supplied by Australian Antarctic Division)

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