Positive Feedback On Water/Carbon cycle Flashcards
Positive feedback El Niño
Burning fossil fuels lead to release of co2 into atmosphere.
Air temps rise.
Ocean warms and it’s ability to absorb moisture changes - El Niño
Warming of ocean leads to reversal of wind circulation over large areas.
Shift in normal patterns of rainfall is bad for ecosystem as drought in N.Australia water shortages, more bush fires and in turn more co2 in atmosphere
Deforestation positive feedback
Plants/ trees store and releases water and act as carbon sink (sequestration)
Tropical rainforests partially generate own rainfall daily due to their climate - high temps/ rain/ evaporation and transpiration.
Deforestation by burning destroys equilibrium and causes carbon to release into atmosphere & no store of water (or carbon)
Less of co2 in biosphere more atmospheric carbon
Local precipitation levels and patterns change - changes water cycle locally- flooding.
Weathering positive feedback
Pure water has pH of 7.0
Natural rainwater acidic 5.6.
Polluted air from sulphur divides from combustion of fissile fuels resulted in carbonic acid (4.0)
On contact with carbonate ticks the acidic rainwater converts calcium carbonate into calcium bicarbonate which is soluble.
Dissolved carbon carried away by rivers into oceans.
Used for shell growth.
Burner to form new limestone deposits.
Some carbon transferred back to atmosphere through tectonic uplift
Lag time
Lag time between increased co2 and increased warming.
Temp will increase by further 0.6 degrees because of co2 already in atmosphere.
Permafrost WATER positive feedback
Ice reflects radiation from the sun , so less heat absorbed by surface (ocean)
As arctic sea ice is melting rapidly due to enhanced greenhouse gas effect from combustion of fossil fuels there is less reflection and more absorption from ocean - ALBEDO EFFECT.
Warms water and melts ice further
Affects type/ magnitude of water transfers between land / ocean / atmosphere - evaporation
Affect local/ regional precipitation patterns and availability of fresh water.
Permafrost CARBON positive feedback
Warmer temps due to combustion of green house gassed leading to more co2 in atmosphere.
Melts permafrost.
Organic matter trapped in permafrost stores lots of co2, when melting occurs organic matter decomposes as o2 is introduced.
Co2 released into atmosphere contributing to global warming.
Negative impacts of climate change
Pattern of precipitation change. Wet areas expected to get wetter and dry areas expected to get drier. This would cause water shortages / drought and flooding.
Extreme weather effects - storms / droughts / floods. More frequent.
Agriculture productivity will decrease in some areas - food shortages.
Sea level rise - flooding / erosion of low lying areas
Species die out as can’t cope with changes in environment ( new species introduced)
Plankton / krill numbers will decline if temps increase - knock on effect to food chains
