Climate change, drought and Amazon

• Human reasons for climate change:

  • Fossil fuels, deforestation and biofuel plantations
• Non-human reasons for climate change:

  • Orbital axis changes - greater solar insolation. Volcanic eruptions
• Amazon:

  • During major droughts, lakes fall to half capacity compared to wet season
• Amazon:

  • Amazon basin holds roughly 10% of Earth's terrestial carbon store
• Amazon:

  • Brazillian portion of Amazon now emits more carbon than absorbs - 20% more emitted than absorbed over last decade
• ITCZ:

  • = Inter tropical convergence zone
• ITCZ:

  • Region expected to narrow due to increased convection intensity due to increased temps.
• ITCZ:

  • Drought regions on border of ITCZ will expand so more droughts
• ITCZ:

  • 2 degrees of warming = 5% of Earth moves into new climate zone
• Drought:

  • Increased GHG = increased insolation = increased evaporation and less soil moisture
• Drought:

  • Changing atmospheric circulation - Hadley cell expansion pushing new areas into drought regions
• Drought:

  • Soil degradation - overgrazing = soil cannot store water = degraded soil which has less organic matter = dry out faster during droughts