history of the atmosphere

• describe the full evolution of the atmosphere ?

  phase 1 - first billion years volcanoes produced lots of carbon dioxide (the was almost no oxygen) they also produced nitrogen and water vapour as well as small amouts of ammonia and methane

  phase 2 - the water vapour condensed as the planet cooled forming the oceans, carbon dioxide then dissolved into the oceans plants and algae evolved and used some carbon dioxide in photosynthesis.

  phase 3- plants and algae did photosynthesis producing oxygen, our atmosphere is now 80% nitrogen 20% oxygen and >1% everything else.
• name some human causes of climate change ?

  deforestation, burning fossil fuels, agriculture
• describe the greenhouse effect ?

  the greenhouse effect is caused by greenhouse gases, the short wave radiation emited by the sun cannot be absorbed by the greenhouse gasses however the long wave radiation emited back off the earth can, the greenhouse gasses absorb this short wave radiation and re emit it back in random direction (including back to earth) this causes an insulation effect on our planet warming it since long wave radiation is thermal radiation