Not that you spend too much time wondering what life would be like if you were a light bulb…but, in case you’re curious, your body’s existence is equivalent to a 100-watt light bulb, left on 24 hours a day. Now, add in the amount of energy it takes to create the material goods necessary to fuel your body—the energy required for farming, manufacturing, etc.—and you and everyone you know turns out to be equal to 25 100-watt light bulbs. It’s an interesting visualization of our carbon footprint, and a handy index of our world’s supreme inefficiency, courtesy of today’s guest, the population expert Joel Cohen.

For the professor of population studies at Rockefeller and Columbia Universities, understanding the impact of human existence through light bulbs is yet another example of the rare insights gleaned through Cohen's incredibly multifaceted approach to the dynamics of the world’s population. Professor Cohen also provides a fascinating perspective on just how interconnected our world is, explaining how global populations, economics, environments, cultures and human health all intersect in meat—a discussion that ranges from Chinese pigs and American birds to religious rituals in the Atlas Mountains. 

Studying how various realms of society, nature, and individual lives interact has not only led Professor Cohen to some interesting observations, it also puts him in a prime position to define and critique some of our most glaring inefficiencies. For example, the fact that Earth has 6.8 billion residents and produces enough food to feed between 9 and 11 billion people, yet 1 billion go hungry. How can we fix this? Cohen also reveals some fascinating statistics on how much of our land and resources we use in the feeding of farm animals—instead of directly feeding humans—that will likely make you rethink your approach to meat and industrial farming.