Buzz Blog

October 31 stands out not only for torn costumes and smashed pumpkins. It was also the day our planet passed the historic population milestone of 7 billion. --- That’s 7,000,000,000 -- a number I can’t even fathom.

The BBC only made it worse by letting me know which person I am: 4,732,416,545^th alive when I was born, 79,485,810,562^nd to have lived since history began. With all of these numbers being thrown around, how is a humble Earthling supposed to make sense of them?

National Geographic’s year-long report on population, while excellent, does make me queasy with its number of approximate population at the bottom of the site. NPR’s visualization of how we got here helped a bit, but 7 billion still is hard for me to comprehend.

To grasp the impact of this milestone, I decided to break all of the numbers available down.

The population of our humble blue sphere has been increasing by roughly 200,000 people per day for several years. This is a net figure of births minus deaths each day. That’s 1 million new people every five days, and between 70-80 million new mouths to feed every year.

While the land area of Earth is approximately 57,506,055 square miles, less than half of that, 24,186,261 mi^2, is considered agricultural -- suitable for growing crops and supporting livestock -- although not necessarily year-round. If we assume that all other land on Earth is unsuitable for human life without major intervention (think McMurdo Station in Antarctica), then our current population density is approximately 290 people per square mile.

Of course, humans are not evenly spread throughout the Earth, but imagine if they were. One square mile in Salt Lake City is eight city blocks on a side. You can draw a picture of one in your head with the boundaries of State St. (west), South Temple (north), 900 East (east) and 800 South (south). Imagine you were plunked in that square (minus the current city infrastructure) with 289 other people and that was where you would all live, adding 2-3 people per year until 2100 when the United Nations estimates population growth will level out slightly above 10 billion. It doesn’t take long to envision what kind of problems could arise such as food scarcity, lack of clean water and living space, and the rampant spread of disease. Unfortunately, these symptoms of overpopulation already exist all over the world, including parts of the United States.

While the analogy above helped me to imagine the mythical 7 billion, I have no idea what to do with that information. As with most perplexing issues, I’ll just keep researching it until I am overwhelmed and start searching for cute puppy videos on the Internet.

U of U biology graduate Jessica Baker works as a research assistant at the U's School of Medicine. In her spare time, she annoys friends and family with a mind overpopulated by environmental knowledge.

Photo Credit: Ahron de Leeuw