Glaciers wax and wane for a variety of reasons, the cause could be on a local, continental or global scale. It may have been warmer in that area 1000 ya, I'm not sure.
The earth certainly has been warmer in the past, no doubt. But how far are we going to continue the current experiment of pumping mega tonnes of greenhouse gases into the atmosphere at a rapid rate.
A two degree increase on a global scale we may cope with but how much further do you want to push it ?; 4 degrees, 6, or even 7, with temperatures around the equator of 50-60 degrees C. An average day in Darwin then might have a min of 30 overnight and a max of 55 during the day. Jakarta might be 60 +.
Feedback in the climate system is in indeed a worry, remove ice,snow and glaciers from the earth and waters, you have less reflection of heat back into space and greater heating of the ground. Permafrost melts and hydrates in the sea sublime and mega tonnes of methane is added to the problem.
