Gaia vs ecosphere

Gaia

name
  • The ecosystem of the Earth regarded as a self-regulating superorganism. 

  • A Greek goddess, the personification of the earth, and one of the primordial deities from whom all the others descend. 

ecosphere

noun
  • The portion of the atmosphere from sea-level to about 4000 meters in which it is possible to breathe without technological assistance. 

  • the biosphere 

How often have the words Gaia and ecosphere occurred in a corpus of books? (source: Google Ngram Viewer )