Party balloons might disappear in the future in order to preserve limited supplies of helium, slashdot article Scientists Speak Out Against Wasting Helium In Balloons, BBC report Helium shortage prompts scientist's balloon use warning.
Of course once breeder reactors are available maybe helium can be created by splitting hydrogen. The wold needs to invest heavily in nuclear technology so we can escape the carbon trap we are currently in.
Best comment in the slashdot thread was by cellocgw, also the first comment in the thread.
There may be a free-market solution. Let's float a trial balloon and see how everyone reacts.