1. Environmental Science

2. Environmental Science

3. Environment…
A person’s environment is made up of his surroundings
Main Components of the Environment
Physical Environment
NATURAL surroundings
e.g. water, rocks, weather
Human Environment
A CHANGED physical environment
e.g. urban city

4. • Cloud seeding – survival of vegetation, avoidance
of droughts
• Sustainable development – meets the need of the
present without compromising the future needs
• Over-cultivation of soils – e.g. soil erosion,
deforestation
• Nature provides resources – e.g sunlight, minerals
• Natural disasters – e.g. floods, tsunami
• Extreme weather conditions – e.g. ENSO
Inter-relationship – Human – Environment

5. Environment…
A person’s environment is made up of his surroundings
Main Components of the Environment
Non-living Environment
Geosphere, Atmosphere,
Hydrosphere, Anthrosphere
Living Environment
Biosphere

6. Environment…

7. • Geosphere –
Solid Earth - continental and oceanic crust, and
various layers of the Earth's interior
Geosphere or Lithosphere?

8. • Biosphere –
Outermost part of the planet's shell - air, land,
surface rocks & water - within which life occurs
Biosphere

9. • Cryosphere –
Frozen water part of the Earth
Cryosphere

10. • Atmosphere –
Layer of gases surrounding Earth - retained by the
Earth’s gravity
Atmosphere

11. • Hydrosphere –
Liquid water component of the Earth
Discontinuous layer of water at or near the Earth’s
surface
Hydrosphere

12. • Anthrosphere –
Part of the environment that is made or modified by
humans for use in human activities
Anthrosphere

13. • Lowest atmospheric layer ~ 11 km thick
• Most clouds and weather are found here
• Thinner at the poles – averaging about 8 km
• Thicker at the equator – averaging about 16 km
• Temperature decreases with altitude
Troposphere

14. • Found ~ 11-48 km above Earth surface
• Ozone layer – within this region
• Temperature increases slightly with altitude
• Highest temperature ~ 0 degrees Celsius
• Holds 19% of atmosphere's gases but very little water
vapor
Stratosphere

15. • Extends ~50 km – 53 km above Earth's surface
• Gases – oxygen molecules – continue to become more
dense with decreasing altitude
• Temperatures increase with decreasing altitude – max
-15°C near the bottom of the layer
• Gases thick enough to slow down meteors
• Meteors burn up and leave fiery trails in the night sky
• Stratosphere and Mesosphere – middle atmosphere
Mesosphere

16. • Extends ~ 85 km - 600 km
• Thermosphere – upper atmosphere
• Very thin layer of gases
• Incoming high energy UV and x-ray radiation –absorbed
by the molecules
• Thus, temperature increases with height – from -120°C
(bottom) to 2000°C (top)
Thermosphere

17. • Unpredictable display of light in the night sky
• Common occurrences at high northern and southern
latitudes, less frequent at mid-latitudes, and seldom seen
near the equator
• Sign that Earth is electrically connected to the Sun
• These light shows are provoked by energy from the Sun
and fueled by electrically charged particles trapped in
Earth’s magnetic field
What is Aurora?

18. • By collisions between fast-moving electrons from space
with the oxygen and nitrogen in Earth’s upper
atmosphere
• When a large number of electrons come from the
magnetosphere to bombard the atmosphere, the oxygen
and nitrogen can emit enough light for the eye to detect
• Colour of the aurora depends on
– which gas - oxygen or nitrogen - is being excited
– how excited it becomes
– how fast the electrons are moving
– how much energy they have at the time of collision
What causes Aurora?

19. Weather
• Given place at a given time
• Chaotic, non- linear dynamic system
Includes daily changes in
• Precipitation
• Barometric pressure
• Temperature
• Wind conditions
at a given location

20. Climate
• Weather averaged over a long period of time
• Fairly stable and predictable
Includes
- average weather conditions
- regular weather sequences (winter, spring, summer,
fall)
- special weather events (tornadoes, floods)

21. Climate
Tropical Climate
Subtropical Climate
Climate determines
• what plants will grow
• animals that will inhabit there etc.
Biome is created by taking climate, animals & plants
into consideration

22. Micro Climate
A local atmosphere zone where the climate
differs from the surrounding area
• Very small area – eg: garden
• Large area – eg: valley
Mostly exist near – large water bodies – dams, lakes
– urban/built up areas
– deforested areas
– large farms

23. Factors Affecting Climate
• Distance from the Sea (Continentality)
• Ocean Currents
• Direction of Prevailing Winds
• Relief
• Proximity to the Equator
• Human Influence

24. Green House Gases
- Water Vapour
- Carbon Dioxide
- Methane
- Nitrous Oxide
Necessary to keep the Earth warm enough to support
life

25. Global Warming
Causes of Global Warming:
- burning of fossil fuels
- deforestation
Effects of Global Warming:
- rise in sea level
- plants & animals becoming extinct
- people having to migrate towards inlands
- more storms, floods, fires

26. El Niño-Southern Oscillation (ENSO)
ENSO is a natural part of the Earth's climate
- important concern is whether its intensity or
frequency may change as a result of Global
Warming
- most prominent known source of inter-annual
variability in weather and climate around the
world (about 3 to 8 years)
- signatures in the Pacific, Atlantic and Indian
Oceans

27. El Niño-Southern Oscillation (ENSO)
• an abnormal warming of surface ocean waters in
the eastern tropical Pacific
• the see-saw pattern of reversing surface air
pressure between the eastern and western tropical
Pacific
• when the surface pressure is high in the eastern
tropical Pacific it is low in the western tropical
Pacific, and vice-versa
• the ocean warming and pressure reversals are, for
the most part, simultaneous

28. Impacts ….
• Dense tropical rainclouds distort the air flow. The waves
in the air flow, in turn, determine the positions of the
monsoons, and the storm tracks and belts of strong
winds aloft (commonly referred to as jet streams) which
separate warm and cold regions at the Earth's surface
• Coral reefs are sensitive ecosystems. The rise in sea
temperature caused by El Nino and exposure to the sun
combine to destroy algae that protects the coral.
Destruction of coral from the effects of El Nino can be
extensive

29. Carbon Footprint
A measure of the exclusive
global amount of Carbon
Dioxide (CO2) and other
GHGs emitted by a human
activity or accumulated over
the full life cycle of a product
or service

30. Carbon Footprint
• It is all-encompassing and includes all possible causes
that give rise to carbon emissions
- all direct (on-site, internal) and indirect emissions (off-
site, external, embodied, upstream, downstream) need to
be taken into account

31. Reducing the Carbon Footprint …
• Life Cycle Assessment (LCA) - accurately determine
the current carbon footprint
• Identification of hot-spots in terms of energy
consumption and associated CO2-emissions
• Electricity from renewable sources (wind turbines, solar
panels, hydro electrical plants or nuclear power plants)
• Optimization of energy efficiency
• Identification of solutions to neutralize the CO2
emissions that cannot be eliminated by energy saving
measures – carbon offsetting (investment in projects
that aim at the reducing CO2 emissions; eg: tree
planting)

32. Some common mistaken statements ….
• CFC molecules are heavier than Nitrogen or Oxygen
& thus can not reach the stratosphere in significant
quantities
- atmospheric gases are not sorted by weight.
- atmospheric turbulence are strong enough to fully
intermix gases
- CFCs are uniformly distributed throughout the
turbosphere & reach the upper atmosphere

33. • Manmade Chlorine is insignificant compared to
natural sources
- natural sources of tropospheric chlorine (volcanoes,
ocean spray etc.) are 4 to 5 orders of magnitude larger
than man-made sources
- tropospheric chlorine is irrelevant, it is stratospheric
chlorine that contributes towards ozone depletion
- chlorine from salt spray is soluble & thus gets washed
out by rainfall before it reaches the stratosphere
- Methyl Chloride, predominantly a natural source, is
responsible for 20% of the chlorine in the atmosphere
- rest, 80%, is a result of manmade compounds

34. Natural Causes Human Activities
Air Pollution

35. Sources of Pollution
Stationary
Mobile

36. Pollutants
Point Source – can be identified easily
Non-point Source –
difficult to identify and control
• Power plants
• Fertilizer storage locations
• Agricultural sites
• Land runoff

37. Types of Pollutants
• Primary Pollutants –
Directly emitted into the atmosphere
SO2, NO2, CO2, He
• Secondary Pollutants –
Products of chemical reactions
between pollutants & normal
atmospheric compounds
OH-, NO-, O

38. Major Air Pollutants
• Particulate Matter
• Oxides of S (SOx) – volcanic eruptions
• Oxides of N (NOx)
• Oxides of C (COx) – forest fires, vehicle emission
• Photochemical Smog – oil, soot, NO2, O3
(brown due to NO2)
• Hot spring activities (H2S, NH3)
• Radio Active substances (Sr)
• Heat
• Noise

39. Inorganic Particles
• Oxides
• Al, Fe, Ca, C, Si, Na, Cl
• Toxic & heavy metals released via garbage
• Ash from coal fuel combustion

40. Toxic Metals – Pb, Hg
• Pb – combustion of automobile engines
Gets deposited in rivers, lakes, leaves etc.
• Affects – agricultural organisms
terrestrial ecosystems
• Hg – liquid phase – NOT toxic, volatile phase – toxic
- coal combustion, volcanic eruptions
• Can be controlled by – sedimentation
particle filtrations
using scrubbers
electrostatic purification

41. NOx
• NO2 – yellow-brown in colour
results in atmospheric smog
• Main producer – human activities
* fertilizer applications
* fuel combustion
• Irritation to eyes, lungs, throat, nose
• Damage to leaf tissue

42. Particulate Matter - aerosols
• Minute solid or liquid particles
• Produces photochemical reactions
• Result of – modern farming methods
desertification
volcanic eruptions
industrial processes
• Visible as dust, mist, smoke, smog etc.
• Accumulation in lungs – chronic effect
• High concentrations damage organisms
• Changes the food chain
• Affects the ecosystem
• Micro climate changes – dust
• Reduces photosynthesis when leaves get covered with dust

43. SOx
• Mainly produced due to human activities
- burning of fossil fuel
- industrial products – paper, cement, Al etc.
• Natural phenomenon – volcanic reactions
• Reacts mainly with atmospheric O2
• H2S + H2O H2SO4
• Results in – acid rains
– respiratory difficulties
– destruction of plants, animals etc.
• Humans will be killed if SOx > 500 ppm

44. Water

45. Water …
• Study of Water – Hydrography
• Study of Ocean Water – Oceanography
• Study of fresh water – Limnology
• Vital for all.
• We depend on its good quality - and quantity -
for drinking, recreation, use in industry and
growing crops.
• Also vital to sustaining the natural systems on and
under the earth's surface.

46. Hydrological Cycle

47. • 70% - water – Standing Water (oceans, lakes etc.)
– Running Water (rivers, streams etc.)
– Rain & Water Vapour in the atmosphere
Main processes that drive the Hydrological Cycle –
• Evaporation & evapotranspiration
• Precipitation
• Air movement, including winds & weather systems

48. Water
Ground Water
Surface Water
• A hidden resource.
• Purity and availability taken for granted.
• Contamination and availability - serious issues.
• More than 95% of available fresh water
• It is the water that saturates the tiny spaces between
alluvial material (sand, gravel, silt, clay) or the
crevices or fractures in rocks.

49. Photo Album

54. THANK YOU