Humans are just one element of the biosphere, but we affect the Earth system in unique ways. Over 6 billion human beings live on our planet and each one affects the system at some level. Your own daily interactions with the other spheres may seem small, but when they are multipled by 6 billion, the effects can become noticeable. Some human activities, like the burning of fossil fuels, appear to be affecting the Earth system on a global scale. This three-dimensional graphic uses a color code to show human population density over most of the globe. Think about how human activities affect the Earth system in different parts of the world.