Queen's University bioligist Vicki Friesen looks at the impact of 6-billion people.
Population growth is a fairly recent phenomenon.
It's estimated that 2000 years ago, a scant 300-million people populated this planet. Baby number 1,000,000,000 was not born until the turn of the 19th century. But the population boom didn't really set in until about 1950. That's when mortality rates in the less developed countries started falling dramatically, mainly because of improvements in health care and nutrition. By the late 1960's, more than 3.5-billion people called this planet home.