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FEED BACKS
science 
Climate feedback
An interaction mechanism between processes in the climate system is called a climate feedback, when the result of an initial process triggers changes in a second process that in turn influences the initial one. A positive feedback intensifies the original process, and a negative feedback reduces it. IPCC

Global climate change science is all about feed-backs. In fact the large temperature swings fronm ice ages into warm periods like now is the result of +ve feed-backs-  loss of ice sheet albedo cooling, increase  methane and increase CO2. from planetary feedback sources (bottom of  page).. 

​​Climate change impacts is all about  the many large positive amplifying feed-backs​​. The largest feed-backs are not accounted for in climate change assessments of the projected global temperature increases. 

A positive (bad) amplifying happens when global warming causes an increase in the degree of warming (or acceleration of the rate of warming). ​​

It is the multiple large +ve Arctic feed-backs ​​that could cause abrupt warming and so called runaway climate change which would total planetary catastrophe for most life. 
The first +ve feedback ​is from water vapour which is a greenhouse ​gas.

The warmed atmosphere can hold more water vapor which increases the warming from the addition of a greenhouse gas alone. ​
The water vapor increase about doubles the greenhouse gas warming. ​​
The largest +ve feed backs are Arctic ​​(see below).

+ve feed backs​​ (amplify warming) 

​water vapor
terrestrial carbon (​soil, vegetation excluding peat lands and Arctic
forest fires
doughts (less CO2 uptake)
ground level ozone (toxic to green plants​​
reducing CO2  uptake) ​
warming peat lands (methane)
warming global wetlands ​​(excl peat land
methane)
Thawing permafrost ​
Sea floor methane hydratre​

​​Snow melting (albedo loss​)
Ice melting (esp Arctic summer sea ice)​

Arctic +ve feedbacks
Runaway 
The large temperature swings from ice ages into warm periods like now is the result of +ve feed-backs.

​​These are  loss of ice sheet albedo cooling, increase methane and increase CO2. from planetary feedback sources