An exercise for you. Draw a line on a sheet of paper precisely 3mm long. Then draw a line alongside that one 50cm long [you'll need another sheet of paper]
The 3mm line represents the time Europeans have inhabited Australia. The 50cm line represents the time Aboriginal people inhabited Australia [altho some people say it should be 60cm long].
If our line gets to 5mm or even 1cm in length, do you really think your science teacher, and even Ehrlich, really made a dud call?
I don't think, on present form, our [Euro] line will even make one cm!!!