Yesterday, the world's population reached 7 billion according to UN projections. NPR created this colorful visualization of population growth over the centuries using drips slowly filling up leaky glasses. You might also want to check out an app by BBC that estimates your number in the order of historical births.
We can't be sure who exactly was the 7 billionth person born but we know that there are now that many people in the world.
Population growth is starting to strain the systems we've built to sustain ourselves and overstress the environment upon whose resources those systems are entirely dependent. But it also gives us the opportunity to consider how they might be reshaped to better meet all of our needs in a way that the environment can support.
We just need to put all of our heads together. BP