Is there room for us all? The ecological impact of population growth

This year, the Earth's population hit 7.7 billion people. The most populated country in the world is China, followed by India and the United States, and though there is a connection between higher populations and higher environmental impacts, the top 10 most populated countries in the world aren't also the top ten CO2 emitters.

Source: AAP

The top three spots on the CO2 emissions rankings go to China, The United States and India, in that order. This is despite the fact that India has a population of 1,3 billion people  compared to US 327 million.  Australia is ranked 55th by population size, yet is the 16th biggest emitter of CO2 in the world.  

So why aren't the numbers adding up? Professor Mark Howden, Director at the Climate Change Institute ANU, and Professor Phil McManus from the University of Sydney say that our carbon footprint, and our ecological impact, have more to do with consumption than population.