And we are merely, uh, people on a balloon? Anyhow, balloon as the world turns out to be a pretty common metaphor, and it underscores the fragility of our planet and the delicate balance of our biosphere. Plus, both are relatively round in shape. Previously, we saw earth-themed promotional balloons were used to draw attention to greenhouse gas emissions, this time around they are raising awareness about overpopulation. See also: using a balloon to launch your logo beyond the earth, and using balloons as homage to Around the World in 80 Days.