1. Water vapor- warmer temperatures, lead to higher
levels of evaporation. This causes more water vapor in
the atmosphere; water vapor is a greenhouse gas. More
water vapor leads to more trapped heat in the
atmosphere, this leads to more evaporation etc. This
would be a positive fb loop. Now if the water vapor
condenses and forms clouds, these clouds could reflect
sunlight and cool the earth, (neg. fb loop)
2. Permafrost
 Melting permafrost releases methane (think peat
bog) (think rotting vegetation)
 Methane is a more powerful ghg than carbon dioxide
 This causes more heating of the atmosphere
 This causes more permafrost to melt
 Positive fb loop
3. Ocean currents
 Ocean currents depend on a combination of
temperature and salinity to distribute warm and
cold water throughout the Earth’s oceans.
 Melting ice caps and destabilized Greenland ice
sheet could inundate the oceans with fresh water
 This could slow the ocean currents
 With no warm water reaching the polar regions, we
could go into an ice age.
 Negative fb loop
4. Carbon dioxide in the oceans
 Warmer water holds less carbon dioxide than
cooler water.
 As the atmosphere warms, the oceans warm
 As ocean warms, it releases carbon dioxide
 More CO2 in atmosphere means more heat in the
atmosphere
 More heat means warmer oceans, which hold less
CO2
5. Forests/Fires
 A warming atmosphere leads to drought
 Drought causes trees to dry up and become
more susceptible to fire
 As trees burn they release CO2, they also fail
to absorb CO2.
 These more CO2 in the atmosphere and more
warming…..etc
 Positive fb loop
6. bark beetles
 Typically bark beetles kill dead and weak trees.
 Now with more drought, trees are becoming dry and
damaged and weak.
 Bark beetles are now infesting living trees and killing
them
 Bark beetles are now reproducing twice a year
instead of once a year, and they are not being killed
by winter frost
 When trees die they release CO2 and since their
dead they can’t absorb it either, this means more
CO2 in the atmosphere and the cycle continues