1. EVOLUTION OF: THE EARTH’S ATMOSPHERE and THE CHEMISTRY OF EARTH’S OCEANS PART 1

3. Greenhouse effect occurs when certain gases, particularly carbon dioxide, methane and water vapor warm the surface of the planet. Light enters easily but the gases intercept the infrared rays that the planet reflects and reradiates much of this energy toward the surface. This raises the temperature ~35°C above what it would be if they were absent

4. On Earth, water in the troposphere is blocked from entering the stratosphere by a cold trap- i.e. cold T° + relatively high ambient pressure minimize the concentration of water vapor (it condenses out)

5. On Earth, water in the troposphere is blocked from entering the stratosphere by a cold trap- i.e. cold T° + relatively high ambient pressure minimize the concentration of water vapor (it condenses out). On Venus the early sea vaporizes, gradually pushing the “cold trap” upwards. The vapor at the top of the atmosphere disassociates, losing its constituent hydrogen.

6. “THE FAINT YOUNG SUN PROBLEM” THE EARLY SUN WAS 30% LESS BRIGHT WHEN IT FIRST STARTED SHINING SO THE EARTH RECEIVED LESS ENERGY IN IT’S EARLY HISTORY

7. MAGNITUDE OF GREENHOUSE EFFECT

8. ONCE OUR SUN BEGAN TO OPERATE AT “FULL CAPACITY” WHAT ELSE CONTROLED INCOMING ENERGY?

9. ONCE OUR SUN BEGAN TO OPERATE AT “FULL CAPACITY” WHAT ELSE CONTROLS INCOMING ENERGY? Milankovitch cycles

10. 400,000 YEARS