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ENV 1101 Study Guide - Final Guide: Overgrazing, Impulse Tracker, Fluorine


Department
Environmental Studies
Course Code
ENV 1101
Professor
Sonia Wesche
Study Guide
Final

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ENVIRONMENTAL STUDIES- Notes for 2nd half- Final exam
CHAPTER 14 & 15
Air pollution and global climate change
Atmosphere- The thin layer of gasses that surround earth. We live at the bottom
(troposphere) which provides us with oxygen, absorbs hazardous solar radiation, burns
incoming meteors, transports and recycles water, nutrients and moderates climate
- It is 1/100th of earths diameter, like the fuzzy skin of a peach
- Atmosphere made up of mostly nitrogen N2 (78.08%)—Oxygen (20.95%) and
Argon (0.93%) + other permanent gases and variable gases
Troposphere – the bottommost layer that blankets the earths surface and provides us with
the air we need to live. Precipitation cycle occurs here, temperature gets colder the higher
you go, lots of mixing of the air, therefore airborne pollution can make its way to
troposphere very quickly.
Stratosphere- 15-50km above earths surface. Air is thin & doesn’t move around much,
contains ozone which absorbs some radiation causing it to be warm.
Mesosphere & thermosphere & transition to outer space are above these layers
Why is the ozone layer important?- It screens out incoming solar radiation in the ultra-
violet range (10-400nm). Nanometer= 1 billionth of a meter
Ultra-violet radiation- a little bit is good for you for vitamin D. Too much, damages the
DNA and proteins contained in living tissues. More than 99% of radiation fails to
penetrate the stratosphere.
Stratospheric processes :
•When oxygen molecules (O2) encounter UV radiation, they tend to split apart into two
O atoms
•Some free O atoms tend to quickly recombine with other O2 molecules to form ozone
(O3)
•Ozone molecules may also combine with free oxygen atoms, creating two new O2
molecules
•When an ozone molecule encounters UV radiation, it splits into O2 and O
Stratospheric ozone
Continually forming and being destroyed
•This dynamic process consumes most of the UV radiation that enters the stratosphere
•Concentrations of ozone are highest at equator, where incoming radiation is highest
•Concentrations vary seasonally as well; over Canada concentration is lowest during
winter, highest during summer

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Human interference:
In 20th century, chemists invented chlorofluorocarbons (CFC). Non-natural combination
of chlorine, Fluorine & carbon. Were useful for air conditioning, refridgeration, aerosol
etc.. But they react with UV radiation when they make their way to the stratosphere &
UV causes CFC to release chlorine, & IT attacks the OZONE
Montreal Protocal: Agreement to scale back of CFC production by 50% by 2000. IT
WORKED CFC is on a dramatic decline. Further damages seems to have stopped. Full
recovery not expected until 2050
***Solar energy heats the atmosphere, drives the movement of air, influences the weather
conditions & climate, and helps create seasons.
Weather- Specifies atmospheric conditions over short periods, typically hours of days and
within relatively small geographical areas
Climate- average weather conditions found across large geographic regions over long
periods. Seasons, years, or milenna. Mark Twain- “ Climate is what we expect; weather
is what we get”
1. Atmospheric pressure- the force per unit of area produced by a column of air, also
decreases with altitude
2. Relative Humidity- Amount of water vapour a given volume of air holds relative
to the maximum amount it could contain for a given temperature.
3. Temperature- Varies with location and time, temp differences affect air
circulation.
Front- The boundary between air masses that differ in temperature and moisture
Warm Front- boundary along which warmer, moister air replaces mass of colder, dryer air
Cold front- boundary along which colder, dryer air mass displaces a warmer, moister air
mass.
Jet Stream- At high altitudes, combination of earths rotation and pressure cells creates
fast moving air currents
Energy Balance- The amount of energy arriving at the earth from solar radiation is
balanced by a similar amount of radiation leaving earths atmosphere.
Thermohaline circulation- The global oceanic circulation system of upwelling and
downwelling currents. It connects surface water flows with deeper ones with far-
reaching effects on the global climate.
Dry continental winds hit north east atlantic, causing surface water to be drawn
northwards, Salinity is increased & water parcel sinks & the conveyor belt begins.

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El Nino Southern Oscillation (ENSO): exceptionally strong warming that occurs across
tropical pacific ocean roughly every 5 years. Affects air circulation & precipitation
patterns around the world when it occurs.
La Nina= Strong reversal of El Nino with equatorial temperatures in the pacific
ocean being cooler than ever.
Ocean- Atmosphere linkages- atmospheric systems and oceanic processes are linked to
one another. Change in one affects the other.
The Green House effect- Naturally occurring process that moderates the earths surface
temperature & creates a range of surface temperatures suitable for living creatures.
Green house gases- gases in the atmosphere that allow short-wave radiation to pass
through unhindered, and absorb & re-radiate longer-wave radiation. They cause the
greenhouse effect and are known as forcing agents
Other processes that affect the climate:
Milankovich cycles: Earths orbit is not perfectly round & tilt varies over time. Cause
distance between earth and sun to vary over time thereby influencing amount of
radiation.
Sunspots: amount of radiation earth receives from the sun is generally consistent but
sometimes there are sunspots ( flahr’s of solar activity)
Albedo- reflectivity of a surface. (snow, tops of clouds, reflect solar radiation)
Volcanic activity: can produce large amounts of smoke & temporarily block incoming
radiation & produce green house gases.
Anthropogenic Climate change- Human- generated climate change
Condtions that most likely occur from it:
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