Summary: The human population of planet Earth will top 9 billion by the year 2050, and new projections suggest it may reach a peak of 11 billion by 2070.
Why it's a Mind Blow: Simply put, that's a lot of people! The population of Asia alone will be about 5.3 billion by 2050, which is more than all the people on planet Earth in 1990. And when my father was born in 1942, the population of our world was just over 2 billion. Dad's healthy as a horse, and we just passed 7 billion, so I expect we'll see at least a four fold increase in population in the span of his lifetime alone. 2 billion to 8 or 9 billion in one lifetime, and it took us 10,000 generations to get to 1 billion in the first place!
It's very difficult, if not impossible, to perceive what a billion of anything actually is. The Earth, for example, is about 4.5 billion years old. But what does that really mean? The best our minds can do with that figure is convert it to "really, r-e-a-l-l-y old".
So allow me to try and put it all in a framework we can perceive, using a little proportional math, (now you know what I did this weekend). Let's say the planet Earth is actually a circa 1912 Model-T Ford. In other words, we're imagining 4.5 billion years of Earth history as the 100 year lifespan of the car. Let us also assume that for every 1 billion people living on the planet, the Model-T must accelerate 10 miles per hour.
Still with me? Good. Now, modern humans appeared around 150,000 years ago, give or take. That means the Model-T was stationary for a very long time. It would have started moving only yesterday morning. If Earth has been around about 100 years, humans showed up about 29 hours ago.
So, assuming the engine turns over after 99+ years, the Model-T begins rolling. It has a leisurely time accelerating to 10 mph, reaching that speed about 2.4 minutes ago (1 billion people in the year 1804). It has about a minute more to push the engines to 20 mph. From there, our buggy would have about 25 seconds to achieve it's top speed of 45 miles per hour.
Now, assuming some mysterious force could propel the car faster, things would quickly get out of hand. The Model-T would have about 15 more seconds to accelerate to 60 mph (6 billion in 1999), and an additional 8.4 seconds to reach it's present speed of 70 mph (7 billion).
What happens next? Well, obviously, the car falls apart. After sitting still for almost 100 years, the car will be forced to start up and accelerate from 60 mph to 110 mph in under 50 seconds. An impossible burden on any system and, from the Earth's perspective, an equally ludicrous and unsustainable pace.
My brain is leaking out my ear, so I'll leave it there. Needless to say, our engines need some love and care.