It took us 200,000 years to reach 1 billion people. Then 200 years only to arrive at 7 billion. At the end of the 21st century, we could be 11 billion humans on Earth.
Here is a video created by the United States Museum of Natural History, showing the evolution of the world's population throughout History. A great way to realize how much Humanity has seen its demographics really explode since the advent of the industrial age that we know today. And damage to our environment caused by too much human activity.