What is the official explanation of what caused the last ice age?
The causes of ice ages remain controversial for both the large-scale ice age periods and the smaller ebb and flow of glacial–interglacial periods within an ice age. The consensus is that several factors are important: atmospheric composition (the concentrations of carbon dioxide, methane); changes in the Earth’s orbit around the Sun known as Milankovitch cycles (and possibly the Sun’s orbit around the galaxy); the motion of tectonic plates resulting in changes in the relative location and amount of continental and oceanic crust on the Earth’s surface, which could affect wind and ocean currents; variations in solar output; the orbital dynamics of the Earth-Moon system; and the impact of relatively large meteorites, and volcanism including eruptions of supervolcanoes. Some of these factors influence each other. For example, changes in Earth’s atmospheric composition (especially the concentrations of greenhouse gases) may alter the climate, while climate change itself can change the atmos
