Climate change

Climate change

positive feedback loop?
1. increased greenhouse effects
  1. warmer soils
    1. accelerated mineralisation of SOM
      1. higher CO2 and methane emissions
        goes in circle
Carbon cycle
1. C pool in soil = 2x that in atmosphere, ~3x that in biomass
2. rates of CO2 emitted from soils balanced by CO2 uptake by plants
3. NPP affected by CO2 and climate change
  1. affected by veg type and soil conditions
    1. affected by latitude
Biomass
1. tropical forest = HIGHEST
2. all forests much higher than grasslands
3. tundra = LOW
Carbon sequestering
1. soil restoration
2. woodland regeneration
3. no-till farming
4. cover crops
5. nutrient management
6. manuring and sludge application
7. improved grazing and agroforestry practices
8. growing energy crops on 'spare' land
9. reversing C loss => INCR in productivity
Methane
1. 25-30x as powerful a greenhouse effect as CO2
2. emitted from soils under wet anaerobic conditions
  1. paddy fields
3. under aerobic conditions can be SINK
4. livestock
5. melting permafrost
Nitrous oxide
1. 300x more powerful than CO2 as g.g
2. escapes from N cycle - aerobic and anaerobic conditions (denitrification and nitrification)
3. emission rates strongly influenced by rates and pathways by which N enters soil
4. fertilisers

Zusammenfassung der Ressource

	Erstellt von Liv vor mehr als 11 Jahre