ENVS195 Lecture Notes - Lecture 6: Feedback, Polar Amplification, Exponential Growth
11 Dec 2019
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Document Summary
Negative feedbacks: initiate responses that moderate against change. Negative feedback loop = change (input) from a system moving in one direction with a response (output) that moves the system in the other direction. Most systems in nature, helps to stabilize systems. Positive feedback loop = instead of stabilizing a system, it drives it further toward one extreme or another. Exponential growth in human population, erosion, melting sea ice. Rare in nature but is common in natural systems altered by humans (ex biodiversity, creating new species) Biological geological chemical back around to biological. Speed of cycling varies by ecosystem and time of year (speeds up in warmer places and warmer weather) Proportion of nutrients varies by ecosystem and time of year. Residence time: the average length of time during which a substance, a portion of material, or an object is in a given location or condition, such as adsorption or suspension.
