Past and Present Terrestrial Habitability

We are working on a Planetary Habitability Classification (PHC) based on the calculation of the Standard Planetary Habitability (SPH), which provides a measure of climate habitability for primary producers (the trophic base for life). Earth, Solar System bodies and exoplanets can be classify from F (non habitable) to A (highly habitable). The image compares current terrestrial land areas habitability, a Class D planet with a slowly increasing mean SPH = 0.34, with the potential highly habitable but decreasing conditions 65 million years ago, before the extinction of the dinosaurs.