Feedback Mechanisms And Tipping Points Flashcards
What is a feedback mechanism
A process where a change in one factors acts as a trigger to change another factor which then acts to change another factors. Eventually causing a change to the original factor
What are the two forms of feedback loop
Positive
Negative
What is a positive feedback loop
There is where the feedback mechanism increases the original factor
What is an example of a positive feedback loop
Ice growth,
increased albedo
Less insulation absorbed
Cooling
Repeat
What is a negative feedback loop
Where the feedback mechanism reduces the original factor
What is an example of a negative feedback loop
Cooling
Decreased weathering
Stronger greenhouse
Warming
What is permafrost
Soil that is saturated with water and permanently frozen
Where is permafrost found
Tundra environments
Siberia
Canada
Greenland
What % of earth is permafrost
10%
How is climate change affecting permafrost
Permafrost is melting
What is the problem with permafrost melting
This is a problem as the dead organic matter trapped inside the soil is in anaerobic conditions
When it defrosts methane which is a greenhouse gas is released contributing to more warming
What % of earths carbon is stored in the oceans
50%
What happens when more CO2 is released by humans
More is absorbed by the oceans
What is the problem with more CO2 in the ocean
This creates carbonic acid
This causes corals in the ocean to die
Therefore less carbon is stored as calcium carbonate
What does the melting of snow and ice cover cause
Reduces the amount of solar radiation reflected back out to space
More is absorbed by Darker land and ocean causing more warming
Speeds up the rate ice melts accelerating the cycle
How is methane in the ocean produced
By microbes within the sea floor that break down organic matter that sinks down from the sunlit zone near the surface
What is organic matter composed of? (methane)
Remains of dead algae and animals as well as their excrements
What happens to the organic matter under high pressure and cold temperatures
Forms a solid called methane hydrate
What happens to methane hydrate as oceans heat up
The solid may melt releasing the methane gas into the atmosphere causes further warming
What is peat?
Peat is a type of soil
Formed in wet environment
What happens to peat as the climate warms?
The peat dries out
What is the problem with dry peat?
They can catch fire and due to their high CO2 content vast amounts of carbon dioxide is released
How much carbon is in the average tree
1 tonne
Can clouds cause climate change?
Highly debated
As clouds can prevent heat leaving earth
How is decomposition affected by temperature
Enzymes evolved in decomposition have a perfect working temperature too cold and they wont be able to decompose or it will be done slowly too hit and they will denature (die)
How can increased low level cloud create a negative feedback loop
Higher temperatures trigger increased amounts of evaporation thus condensation
This forms clouds
Thick clouds can block solar radiation as the have a higher albedo than earths surface
At what temperature can plants not photosynthesise
Below 6 degrees
So a warmer climate may increase photosynthesis
How might increased photosynthesis rigger a reduction in climate temperatures?
Photosynthesis removes carbon from the atmosphere and sequesters it in the plant tissue meaning less carbon is in the atmosphere slowing rate of warming
What is a tipping point?
The concept that most human actions that have triggered NATURAL changes to earths processes causing ‘run away climate change’
What is a carbon footprint
The sum of all emissions of CO2 which were induced by your activities in a given time frame
What sort of activity add 1kg of carbon to the atmosphere?
Flying a plane 2.2km
Producing 5 plastic bags
Producing 2 plastic bottles
Driving a car 6km
What two ways are there to deal with climate change
Carry on as usual allow change to happen and adapt
Mitigate which will involve reducing emissions
What is geo engineering?
Use of untried, new technologies that might control the natural processes involved in climate change
What is geo engineering by enhancing natural carbon sinks?
Phytoplankton (microscopic ocean plants) remove CO2 by photosynthesis
When the plankton die carbon sequestered in ocean floor
If the plankton are allowed to grow by adding nutrients more CO2 is absorbed
What is geo engineering by solar shading? (Wind powered yachts)
spray sea water/ salt into sky
Increase cloud seeding= more clouds, high albedo reducing temperatures
Negative of wind powered hatch increasing cloud cover?
Doesn’t reduce CO2 emissions
How is solar shading done by rockets?
Use 100’s of rockets
Add sulphur in upper atmosphere
Block incoming radiation
Reducing temperatures
How can solar shading be done using glass?
Sun shade 100,000km long
Made of 16 trillion glass discs
Reflects some radiation
What is a flood wall?
A barrier built along river banks made of concrete, stone or brick
What is a levee?
Wide embankment built along river banks
Made from clay, sand or soil
Might be topped with sandbags
How can urban areas increase their ability to absorb surface water?
Implementing SUDS
What are SUDS?
Sustainable Urban Drainage Schemes
What is an example of a SUD?
Replacing tarmac with permeable surfaces increasing lag time reducing risk of flooding
What does river flow management do?
Controls how much water flows into or along the river
What are some examples of soft engineering?
Planting trees to absorb water preventing a such entering the river
What is hard engineering?
Building structures- dams which can regulate flow preventing down stream flooding
what can be done to areas at risk of flooding frequently?
Can be built on stilts to keep them out of reach of riding seas and floods
What do they do in India and the Netherlands?
Build homes that rise and fall with water levels
Homes are tethered but float
Prevents flood damage to housing
