• Energy budget determines global average temperature of Earth
• Balance between incoming shortwave radiation and outgoing longwave radiation
• Energy from Sun is emitted as shortwave radiation due to high temperature
  • Experienced as visible light and radiant heat on Earth
• Around 30% of incoming solar energy reflected by Earth as longwave radiation
• Solar radiation is able to travel through most gasses in Earth’s atmosphere
  • Greenhouse gasses allow shortwave radiation but block longwave radiation
• Scientists believe that Venus had a runaway greenhouse effect with water vapor
  • Over time, hydrogen escaped from atmosphere, leaving oxygen to combine with carbon
• Clouds impact amount of solar radiation, reducing 24% of solar radiation globally