Consequences of Global Climate Change

Case Studies

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