Consequences of Global Climate Change
Carbon stored in ice, oceans & the biosphere
Case Studies
Greenland + Antarctic ice sheet
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Facts & Statistics
Glacial retreat occurring in Himalayas of Asia, Rocky mountains in NA, Andes in SA.
Since 1850, glaciers in Europe lost 30% + of their SA and V of ice.
Retreat of glaciers from 1900-2000 caused 20% rise in sea levels (0.4 mm/yr)
Study - 75% glacier loss between 1851-2010 due to natural factors
Changing sea levels + water in ice & oceans
Zone of Ablation - lower zone of glacier where moisture is lost than added (evaporation)
DYNAMIC EQUILIBRIUM - year after year if the glacier advances and retreats (same amt)
Zone of Accumulation - upper zone of glacier where moisture is added than lost (input as snow)
Glacial retreat -> inc in flow of meltwater streams, later decline cz glacier ice supply diminishes -> less evaporation -> less precipitation -> drought
Earths warm climate -> glaciers and polar ice sheets melt -> causes glacial retreat and shrinking of Arctic and Antarctic ice caps -> during winters cool temps -> glaciers and ice caps expand
69% glacier loss between 1991-2010 due to anthropogenic factors
glacial retreat -> bare rock & soil exposed -> more time to colonize by vegetation -> vulnerable to erosion, rock falls, landslides
Glacio - Eustatic rise/fall in sea level - result of begin/end of an ice age causing widespread melting/freezing
effect on tourism cz glacial retreat -> loss of tourists -> economic decline
Antarctic ice sheet - 90% world's ice - sea level rise by 40m
Arctic ice sheet - 10% world's ice - sea level rise by 7m
Eustatic Change - rise/fall in sea level occurs globally due to change in volume of ocean water
thermal expansion - temp of water inc, it expands, rise in sea level (greater cause than melting)
impact on coastal communities due to erosion by storm waves rather than simple flooding
Organic matter in ice cannot decay so carbon trapped in permafrost
Permafrost thaws -> organic matter starts to decay -> microbes consume dead matter -> CO2 and CH4 released (GHG's)
Glacial flour - as ice sheets expand and retreat, rocks below them are ground to fine powder. That mixes with dead matter and is added to soil
Net Carbon Sink - balance in Carbon since
Permafrost - 1 major carbon store. It entered as glacial ice sheets repeatedly expanded and retreated over successive ice ages
Carbon cycle - major stores like atmosphere, oceans, ice sheets, living orgs, dead matter, fossil fuel reserves, carbonate rocks.
Oceans - Carbon sink
inc in 3 Celsius
permafrost melts
CO2 & CH4 released as enhanced GH effect
leads to <---
However, balanced cz during summers, inc vegetation, plants absorb more CO2 than melting permafrost is releasing
Tipping point - balance between gains&losses switches from stable equi. to unstable
2 - no precipitation & drought -> no vegetation -> CO2 stays in atmosphere -> prone to forest fires -> if happens, more CO2 released and those plants absorbing CO2 will die
1 - as mentioned above that summer -> vegetation -> CO2 absorbed
inc in surface level of carbon in ocean
more acidic -> marine org
conc. of carbonate ions decreased
capacity of ocean to absorb CO2 decreased
marine orgs - photo plankton eaten by heterotrophs so conc of CO2 inc with every trophic level