Australia became a commonwealth of the British Empire in
1901. It was able to take advantage of its natural resources to
rapidly develop its agricultural and manufacturing industries and to
make a major contribution to the British effort in World Wars I and
II. Long-term concerns include pollution, particularly depletion of
the ozone layer, and management and conservation of coastal areas,
especially the Great Barrier Reef. A referendum to change Australia's
status, from a commonwealth headed by the British monarch to an
independent republic, was defeated in 1999.