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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
- 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.
- 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
Editor's Notes
- NSO