ESS205H1 Chapter Notes - Chapter 9: Pyrite, World Meteorological Organization, Chapter 27
Document Summary
Chapter 9 atmospheric evolution and climate change. Scientists believe earth"s atmosphere only had h and he at time of formation (4. 6 billion years: influences on evolution of atmosphere: 9. 1. 1 early atmosphere and effect of volcanic eruptions. Present atmosphere thought to be result of loss of gas from mantle: volcanic outgassing, vaporization by meteorites. After millions of years of outgassing, atmosphere began to change. Most important factor in getting oxygen was mean global surface temperature at time. Photosynthesis and photodissociation helped reach today"s oxygen levels atmosphere began to form. Earth in intermediate position between venus (desert) and mars (frozen planet: ensured condensation of water vapour, forming large oceans, pemitting co2 solution and leading to formation of sedimentary rocks. Once atmo established, global surface temp increased by greenhouse effect. Water important: powerful greenhouse gas, controls temp. 9. 1. 2 the rise of oxygen and the biological era. 9. 1. 4 the effect of humans on the evolution of the earth"s atmosphere.
