Chapter 2: Historic use
The subsurface has always been essential to human survival and development since human lineage diverted from that of the chimpanzee some 6 million years ago (Brunet et al. 2002). From a geological point of view humans are a relatively young species on the face of the Earth. The subsurface almost literally played a mother role for humankind, a role that is still acknowledged in certain cultures (Fig. 2.1). Newton compared the Earth with an animal or a vegetable. In his Gaia-theory, Lovelock (2003) states that the Earth behaves as a single, self-regulating system comprising physical, chemical, biological and human components. This concept was initially severely attacked, mostly by biologists, but since the mid 1990s, resistance has diminished (Lovelock 2006).