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Positive and Negative Feedback Loops - Coggle Diagram
Positive and Negative Feedback Loops
Positive Feedback ~ Water Cycle
In a warmer world, evaporation increases and that atmosphere holds more vapour. This causes greater cloud cover and more precipitation.
Water vapour is a greenhouse gas, there is more absorption in long wave radiation causing further rises in temperature.
Negative Feedback ~ Water Cycle
The system responds to above average precipitation by increasing river flow and evaporation. Water storage in permeable rocks also increased excess water recharging.
Negative feedback loops can take place on smaller scales e.g. ensuring a tree can survive a drought.
During droughts, the system adjusts itself to lower precipitation by reducing evapotranspiration and surface run-off. To helps save groundwater stores, the water table falls and springs dry up.
Negative Feedback ~ Carbon Cycle
Carbon fertilisation is reliant on sunlight, nitrogen and water availability.
Therefore it's not possible to say that primary production has increased due to atmospheric CO2 alone.
Photosynthesis could neutralise the level of CO2 in the atmosphere (carbon fertilisation). Extra CO2 is extracted from the atmosphere and stored in the biosphere - will eventually go into sedimentary rocks and soil.
Positive Feedback ~ Carbon Cycle
Melting of cryosphere releases trapped carbon into the oceans and atmosphere.
Global warming will speed up decomposition and release CO2 into the atmosphere - contributes to greenhouse effect.
Global warming is also causing the Arctic Sea ice and snow cover to shrink so large areas of sea and land are exposed and begin to absorb more sunlight so further melting.
FEEDBACK
: an automatic response to changes which disturb a system's balance or equilibrium.
POSITIVE FEEDBACK
: occurs when an initial change causes a further change (snowball effect).
DYNAMIC EQUILIBRIUM
: a state of balance between continuous processes.
NEGATIVE FEEDBACK
: counteracts a system change and aims to restore equilibrium.