environmental science

note: height = height above ground, altitude = height above sea level

ATMOSPHERE

BASICS:

IMPORTANCE OF ATMOSPHERE (for life)

Gases for biological molecules

ozone = absorbs harmful UV

GhG: absorb IR: temperature

distriputes:

heat (heated surface heats are, distriputed by wind)

nutrients (wind causing ocean currents)

water vapour (means areas get rainfall)

Atmo pressure = allows liquid water (effects ease of evaporation, if pressure was much lower, there would be little/no liquid water)

atmosphere structure:

thermosphere

mesosphere

stratosphere

troposphere

(note diagram of energy budget in atmo p88)

note: height = height above ground, altitude = height above sea level

natural greenhouse effect vs. enhanced greenhouse effect: natural vs. human

GREEHOUSES GASES:

Carbon dioxide

Methane

Oxides of nitrogen

Chlorofluorocarbons

Tropospheric ozone

Combustion of FF, ploughing of soil, draingage of marshes/bogs

anaerobic respiration by microbes in padi fields, landfill + livestock intensines + leaks from natural gas fields and pipelines

Oxygen + nitrogen reacting in high temps eg. in vehicle engines, released into atmo. in vehical exhausts + fertilizer use

aerosol propellants, fire extinguishers, refrigerators, solvents

photochemical breakdown of NO2 + subsequent reactions with oxygen

GLOBAL CLIMATE CHANGE

IMPACTS:

ecological changes

changes in abiotic factors = affect species survival eg. temp, rainfall - eg. plants growing faster = more food BUT also more toxin build up in caterpillars from leaves, wetlands may grow or shrink, changes in the timing of ecological events eg. migration, flowering, nesting, changes in species distribution, may colonise new areas slower than leaving, suitable habitats may be unavailable or no bio.corridors, loss of interdependent communities etc. + little movement between isolated communities

changes in climatic processes:

increased temps = changes atmo. pressure and evaporation

Wind pattern changes:

Rainfall pattern changes:

jet streams (strong, high wind) caused by differences in temp and density, slowing = weather remains over an area, creating longer, more intense weather eg. longer droughts, more flooding etc.

increased temps = more evapoT = more rainfall, too hot = no condense, too cold = no evapoT, wind transports humidity = increased rainfall in some areas and reduced in others

Changes in the cryosphere

warmer temps = increased ice melt BUT increased Et = more precipitation eg. snow, BUT super cold areas = low snowfall as precipitation falls before it gets there

warmer temps = increased snow + ice melt + reduced time it lasts = reduced albedo = reduced sunlight reflected -> +ve feedback

Land ice:

note: snow, compacted = ice, build up and flow downhill = glaciers

loss of ice shelves

warmer temps = front of glacier melt faster than movement forward = retreats

meltwater from surface flow down crack = lubricate = moves quicker than RoMelt = glacier extends (BUT: volume of ice still decrease if snowfall does not increase where glacier is formed)

land ice flows into sea + breaks off = iceberg

as sea levels rise, land ice doesn't need to move as far before it breaks off -> breaking off = glaciers/ ice sheets behind may flow more rapidly to sea

ice lakes - melt water collecting on glacier surface can cause sudden flooding if front wall breaks (more glacier melt = more flooding)/

rivers: less snow more rain = more uneven flow,

snowmelt = more even river flow, BUT, if snow accumulates and melts at once eg. in spring = big increase in river flow

Sea level rise

Melting LAND ice:

thermal expansion:

warmer temps = increased k.e. of water molecules = take up more space = sea level rise

LAND ice melt = increase volume of water = sea level rise

changes in ocean currents

driven by processes:

winds causing surface to move

evapo. cause water to flow in, replacing lost water

heating or cooling changes the density of surface water = affects waters ease of sinking

evapo. or inflow of freshwater = change salinity = affect density

north atlantic conveyor: warmer temps cause greenlands land ice to melt = reduce salinity = reduce density = less likely to sink - reduce pull/ flow rate = warm water not being brought up from the south = NW climate cools

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