Geological Perspectives on Climate Change

Throughout Earth’s history, mass extinctions of species were closely related to physical and chemical changes in the atmosphere and the oceans. These variations were controlled by heat from the sun, the distribution of oceans and continents, the extent of ice sheets; volcanic eruptions and asteroid impacts, air-borne particles, the eruption of methane and greenhouse effects. Greenhouse episodes were amplified by carbon dioxide and methane feedback effects from warming oceans and drying vegetation, and by changed reflection effects due to the extent of ice and snow. Current climate changes, triggered by human-generated emissions, will lead to shifts in the Earth’s climate zones toward the poles. The instability of ice sheets melting may lead to significant sea level rises over a time scale of decades.