Earth's climate and geochemistry according to Neil Shubin

The text analyzes the astronomical mechanisms controlling Earth's climatic cycles, based on the Milankovitch theory. The author explains how subtle changes in orbital geometry (eccentricity), axial tilt, and precession affect the distribution of insolation, particularly in northern latitudes. A key aspect is the nonlinear response of the climate system: a small external forcing can trigger powerful effects thanks to internal feedback loops, such as the snow-ice albedo effect. This process leads to the formation of ice sheets, which in turn modify global atmospheric circulation and the carbon cycle. In this way, celestial mechanics becomes the overarching regulator of environmental conditions, determining the timeframes for migration and species evolution, including humans.