2.1.10: Feedback within and between carbon and water cycles Flashcards
Feedback
The automatic response of a system when a change to the flow of energy or materials occurs
Negative feedback
A system that self-corrects after a change occurs and restores equilibrium
Positive feedback
A system spirals out of control and continues to worsen when a change is made to it
Example of positive feedback
Albedo effect
The system threshold
Critical limit or level that means that potentially irreversible changes will occur if it is crossed
Example of crossing the system threshold
possible situation where the carbon or water cycle is pushed beyond possible return equilibrium
Feedback and system threshold in relation to climate change
many scientists believe that a increase in global temperatures of 2 degrees C may lead to widespread and irreversible global change to the carbon cycle
Cryospheric feedback
During periods when the Earth has grown warmer in the past, temperature changes may have accelerated the loss of ice cover
Albedo
Fraction of solar radiation that a surface reflects, white surfaces have a higher albedo
Albedo of ice
high - reflects 80% of all incoming solar radiation
Albedo if large scale ice melting turns to water
ice melted replaced by darker- coloured water which has a lower albedo and will absorb more heat
as water warms up, air masses do as well and this will accelerate the warming of the atmosphere
Methane feedback example of +/- feedback?
positive
Methane
powerful greenhouse gas with enormous volumes of it stored in the earth’s permafrost regions
Proportion of the world with permanent or sporadic permafrost and area in km2
1/4
23 million km2
Example of regions/ biomes with permafrost
Tundra, polar and mountain regions