unit 3 outcome 1: MGIS key terms Flashcards
What are ice sheets?
vast masses of ice that are not confined to valleys and domed in shape
What are glaciers?
body of ice thats formed on land and in motion, confined by terrain such as valleys and are slow moving
what is the last glacial maximum?
most recent period in the earths history when glaciers were at the thickest and sea levels were at their lowest
21-18k calendar years ago roughly
what is the holocene climatic optimum?
roughly warm period roughly 9 thousands years before the present with a thermal maximum around 8 thousand years before the present
what is the cyrosphere?
all components of the earths surface, below, above land and oceans surface where it is frozen
what are the categories?
-sea ice
-land covered by glaciers
-land covered by ice sheets
-land such as tundra covered by snow every winter
-land underlain by permafrost
-peri-glacial zones on margins of ice bound land
what is a tundra?
biome where tree growth is less due to cold temperature and short growing seasons
what is permafrost?
permanently frozen layers on or below earths surface
what are peri-glacial zones?
cold climate frequently marginal to glacial environments
whats accumulation?
annual snowfall and ice that is gained by a glaciers that doesnt melt during summer periods
what is terminus?
where glaciers start to melt
what is ablation?
loss and melting of ice and snow from a glacier
what is the equilibrium line?
ablation is equal to accumulation
what is the glacial mass balance?
gain or loss of ice from glacial systems
Natural causes of MGIS: Variations in solar energy?
> solar radiation that the sun emits is absorbed by the earth, amount absorbed is different for different parts of the earth
> eliptical orbit of the earth influences the natural cycles of global glaciation and warming
Natural causes of MGIS: oceanic circulation changes?
> direction of oceanic current change overtime, changing climates of many continents as a result
> impact exchange of heat between oceans and atmosphere
> La nina = warmer ocean temps
> El nino = colder ocean temps
Natural causes of MGIS: Volcanic activity?
> volcanic dust and gases can either warm or cool the earth for example some dust can cool earth by reflecting suns radiation
> e.g mount agung released mounts of ash from its eruption which reflected solar radiation and reduced global temp by 0.5 degrees celsius for 2 years
Natural causes of MGIS: Plate tectonics?
> movement of continents change oceanic and atmospheric circulation patterns
> landmasses drift overtime and collide with other land masses changing latitudes of those masses
Causes of MGIS overview?
> consistent with warming of the earth by global warming which then increased ablation of glaciers in summer periods
> since 1970s earths surface temperature increased 0.94 degrees celsius which correlates to loss of ice in the artic
> industrialisation and fossil fuels increase air temperature, humidity, ocean temperature and heat which led to decline in ice in the artic due to rapid ablation
How has spatial distribution of MGIS changed?
> fewer glaciers from 2010-2015 as temperature is very warm
> geologists have identified number of ice ages in last 2000s years have had its ice levels increase
> south cascade glacier in USA has lost half its volume during 1959 to 2010 with ice lose increasing 2010 onwards
Human activities causing MGIS: alteration of gases in the atmosphere?
industrialisation has lead to the injection of greenhouse gases into the atmosphere, 60% being released from cities
methane releases areas of sub-artic permafrost which is a major issue and challenge
Human activities causing MGIS:
Alteration of landscape?
changes in solar radiation absorption due to building of cities and destruction of forests have lead to less CO2 being absorbed by trees leading to more greenhouse gases in the atmosphere
it can also lead to soil imbalance, change moisture in atmosphere leading to change in wind, heat spread across continents
Human activities causing MGIS: Direct additions to atmospheric heat?
burning of fossil fuels and burning of forests contribute to the most C02 because of more absorption
Ash and dust from australian black summer fires have caused 300+ new zealand glaciers to speed up melting up to 30%
Impacts of MGIS ON ESE:
Sea level rise?
in the 20th century sea levels rose by 20cm due to melting of glaciers and ice sheets.
Greenland is losing aproximately 250km squared of ice directly into the sea per year
rising sea levels puts coastal islands and cities at great risk of storm surges and flooding, 2/3 of cities with a population higher than 5million are at higher risk
Impacts of MGIS on ESE: People movement?
residents of tuvala have become climate refugees because of coastal flooding inundating land due to melting glaciers
inuit natives in alaska and canada have move to non traditional ways of living as the melting glaciers have caused their native species and food they hunt for to die
impacts of MGIS on ESE: Agricultural input?
UNDP have estimated that crop yields will decline by 30% by 2050
many global productive food bowls on rivers are vulnerable to soil salinisation and inundation e.g in Mekong and Ganges grow 90% of worlds rice
Impacts on MGIS on ESE: freshwater resources?
glaciers store 75% of the earths freshwater and act as natural resoivors storing water in winter and releasing in summer
enlarged glacial lakes and outburst flooding leads to freshwater becoming salty
impacts of MGIS on ESE: Plant and animal communities?
change in temperature can influence migration patterns, altitude changes and reproduction changes
loss of species, biodiversity and polar ecosystems
impacts of MGIS on ESE: Disease?
as temperature increases due to less absorption of solar radiation from ice from glaciers, diseases like malaria can be carried by mosquitos and spread around the world
cold climate can prevent diseases from spreading or even surviving , therefore less cases and deaths for people and animals in those areas
impacts of MGIS on ESE: Natural disasters?
expanding populations and deforestations have made flooding worse in himalayan regions
Glaciers melting have caused natural disasters like flooding which impact villages close to glaciers, downstream them
