The historic temperature pattern we observe has abrupt dips that match the emissions of known explosive volcanic eruptions; the particulates from such events reflect sunlight and cool the Earth’s surface for a few years. There are small rapid variations attributable to El Nino and other ocean currents such as the Gulf Stream. The gradual but systematic rise of 1.5 degrees C is best explained by the record of atmospheric carbon dioxide, measured from atmospheric samples and air trapped in polar ice.
