Long-term variations in the galactic environment of the sun

We review the long-term variations in the galactic environment in the vicinity of the solar system. These include changes in the cosmic ray flux, in the pressure of the different interstellar components and possibly even gravitational tides. On very long time scales, the variations arise from the variable star formation rate of the MilkyWay, while on shorter scales, from passages through the galactic spiral arms and vertical oscillations relative to the galactic plane. We also summarize the various records of past variations, in meteorites, in the ocean sea floor and even in various paleoclimatic records.