Is there any place on Earth that is permanently a desert?
UserLTK, above, has mentioned the Dry Valleys of Antarctica and the Atacama desert as two notable examples of "permanent" deserts. It's likely that these two locations have been deserts for at lease several millions of years despite changes in global weather patterns from multiple glacial events. The Atacama is well shielded by a very old mountain range to the west, and the Dry Valleys are also well protected by both an inland location and by global ocean currents that isolate the continent from much of the world's weather.