Toward the end of 2011, the seventh billion person in the world was born. Our rapidly expanding population is putting phenomenal pressure on Earth - we take a look at the seven major challenges we are facing for the future.
Climate change is a health hazard. More Australians face dying in heatwaves and they have a greater risk of catching infectious diseases as a result of climate change. Rising temperatures, more natural disasters and changing rainfall patterns will have to affect people's health as much as the environment.