PBzeer- of course glaciers change in both directions over time. I posted this in response to an earlier post claiming that global glacier mass has not changed, with only some changes in specific glaciers. This and many other references are easily available showing global recession of glaciers. This is more objective data supporting global temperature increases, although obviously oversimplified as there are other factors which affect glaciers.
The reason for the first post regarding glaciers was in response to criticism of the quality and accuracy temperature measurements.
This is an interesting link which discusses in a slightly less biased fashion the debate about global warming. It is long, but worth reading for people on both sides of the debate:
http://en.wikipedia.org/wiki/Global_warming_controversy