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‘GEOG 227: Our Vulnerable Planet
Unit 1 - Important Things to Know
Unit 1: Intro to Systems and Intro to Anthropogenic Hazards Geography – the study of the Earth’s surface and processes that shape it, both human and physical Human Geography – Also known as Cultural Geography, it is the study of the spatial expression of culture, and culture is a learned behavior of society Example- urbanization, agriculture, mining/resource extraction Physical (Natural) Geography – the study of the Earth’s physical processes to learn how they work, how they affect humans, and how they are affected by humans in return Examples- natural disasters, erosion, weather, plate tectonics
- Technical Geography – data collection, cartography, GIS (geographic information systems), can work in human or physical geography Systems: System – a group of interacting or interdependent parts that form a complex whole. Systems exist at a varying scale (microscopic, small, large) Examples – hurricane, ecosystem, solar system Earth System Science – the Earth is a system made up of numerous interacting parts or subsystems 4 subsystems:
- Atmosphere The gaseous layer that surrounds the Earth, the air
- Hydrosphere Water (in liquid form)
- Geosphere (Lithosphere) Solid earth
- Biosphere All life on earth, all living things Riparian Habitat- where water and land meet Closed system - system in which energy can pass through the boundary but matter cannot Example: saucepan with a lid – energy can leave as heat, but steam and sauce are contained Open system – system in which both energy and matter can pass through the boundary Example- saucepan without a lid – energy, steam, and matter can escape
Anthropogenic Hazards Car emissions Mining/resource extraction Pesticide runoff Population growth Nuclear waste/ testing Air and water pollution deforestation Outside Materials : Video: Open and Closed Systems Closed System: no mass crosses system boundary Open System: mass can pass through, may gain or lose mass or mass may simply pass through Photo Essay: Can photography help us through an environmental crisis? Photographs were called a “terrible beauty” Video: Documenting human environmental impacts through photography.
Naturally occurring greenhouse effect – Diagram: Human-induced greenhouse effect – increase in emissions of greenhouse gases due to human activities Industrial Revolution increased the use of fossil fuels for manufacturing The level of CO2 in the atmosphere has increased continuously since the industrial revolution Evidence is showing the rates of climate change that happen naturally are being influenced by humans Impacts of increased greenhouse gases in the atmosphere More long wave heat energy is absorbed so the surface of the earth becomes much warmer what are the greenhouse gases? – CO2, methane, nitrous oxides, ozone, chlorofluorocarbons, water vapor what are the sources of the greenhouse gases?
CO2 – 1) transportation 2) electric coal/burning fossil fuels 3) manufacturing/industrial Methane – 1) wetlands 2) termites 3) oceans 4) fossil fuel production 5) rice cultivation 6) cattle, goats, camels Nitrous oxides – 1) natural soils, burning fossil fuels, oceans, chemical fertilizers Ozone – fossil fuel combustion Chlorofluorocarbons – insulation materials, refrigeration, air conditioning, aerosols rates of increase of carbon dioxide in the atmosphere? 1960 – about 320 ppm 2010 – about 390/400 ppm How the Earth’s greenhouse effect works – Increases in global greenhouse gas emissions –
Ocean volume and heat capacity make the oceans the single largest buffer against the changes in the Earths climate Have a high heat capacity – takes longer to warm than land, but retains the heat longer 3 types of ocean changes that can influence global climate
- Temperature -colder waters are more dense and subside while warmer (tropical) water is buoyant and rises
- Chemistry – changes in amount of salt (salinity)
- Circulation – deep circulation can be changed by buoyancy of water Slow circulation deep below the surface of the. Ocean moves large volumes of water Major driving force of deep circulation is differences in water buoyancy caused by differences in salinity Higher salinity – occurs where surface evaporation is rapid, causes higher seawater density, causing it to subside, sink Lower Salinity- more buoyant, when surface water is buoyant, deep water circulation slows Subsurface ocean currents are affected by water temperatures Cold water sinks (Polar areas) Warm water rises (Tropical areas) Salinity & Temperature work together and create complex subsurface flows deep within the ocean basins El Nino & La Nina El Nino/Southern Oscillation (ENSO) Example of changes in the ocean Short term changes in Pacific circulation due to upwelling (changes in buoyancy of water) 3. changes in landmass – Changes in Earth’s surface can explain lengthy periods of cold climates:
- Characteristic of all glacial periods presence of continents in polar latitudes permits glaciers to accumulate on land, results in lowered sea levels and global effects
- Formation, disappearance, or movement of a landmass that restricts oceanic or atmospheric circulation ~ Volcanic activity & mountain building processes A. Isthmus of Panama closed water pathway & changed ocean circulation B. Uplift of the Himalayas – changed atmospheric flows & monsoonal affects in Asia Both A & B predated the onset of glaciation
- Shifting landmasses (latitude or altitude) will affect distribution of vegetation, which could impact atmospheric composition & circulation patterns Changes in albedo
- Albedo is the proportion of solar radiation reflected back from a surface expressed as a percentage of radiation received on that surface
A surface with a high albedo has a high percentage of reflection; ex: snow & ice = 90-95% (Contributing reason why glaciers on high mountains do not melt away) Low albedo – forest 10-12%; need solar energy for photosynthesis
- Caused by: major snow accumulations on high-latitude land masses OR large oceanic ice sheets drifting into lower latitudes
- Increased reflection of sunlight starts a positive feedback cycle of cooling
4. impact events – Asteroids – small, rocky or metallic solar system bodies ~ less than 500 miles in diameter Meteors/Meteoroids – smaller pieces of an asteroid Comets – small rocky or iron material held together by ice NEOs – Near Earth Objects Space objects that strike Earth Most burn up in the atmosphere (smaller than 40 meters) ~ Seen as shooting stars Objects 40m to 1km Much local damage Occur about every 100 years or so 1908 Tunguska Siberia Objects greater than 1.6km (1 mile or greater) Produces severe environmental damage & climate change on a global scale “Impact Winter” – skies darkened with particulates thereby blocking insolation and causing a drastic drop in temperature Firestorms – from heated impact debris raining back down on Earth Acid Rain Results: loss of crops worldwide; result in starvation & disease K/T Boundary Impact event that killed the dinosaurs ~ 10 miles (15km) in diameter 65 mya 5. changes in Earth’s atmosphere Due to variations in natural constituents o Natural changes o Anthropogenic changes Gases that retain atmospheric heat energy (Green House Gases=GHGs) o If the levels increase, then warming occurs Evidence of Natural Changes in Composition of Atmospheric Gases: Air bubbles trapped in glacial ice o Antarctica & Greenland ice core projects
- More killer storms
- Massive crop failures
- Widespread extinction of species
- Disappearance of coral reefs impacts on agriculture: agricultural zones will shift coral reefs and coral bleaching:
- Coral reefs are important as shelter and feeding grounds for a variety of fish species.
- When there is a massive die-off of coral, the bleached coral is colonized by algae.
- The reef becomes populated by only herbivorous fish, and the reef may never recover.
- Coral scientists are not sure what causes coral bleaching, but warming water is the most likely culprit.
- Corals in the Caribbean and Florida have bleached when sea surface temperatures rose and were higher than the mean sea surface temperature for as little as one month. melting glaciers:
- Southeast Asia’s largest rivers are fed during the dry season by glaciers high in the Himalayas
- Glaciers are now melting so rapidly that they may eventually disappear
- As glacial melting accelerates, the immediate risk is flooding
- The longer-term concern is reduced dry-season flows in the rivers tropical storms: will become larger and more damaging migration climate change flowchart
Outside Materials: Main Greenhouse Gases
1. What characteristics of atmospheric gases determine the strength of their greenhouse effect? The first is the Global Warming Potential (GWP). The second is the atmospheric lifetime. 2. Explain how GWP is measured and how it is expressed. Its a measure of the radiative effect of each unit of gas over a specified period of time, expressed relative to the radiative effect of carbon dioxide (CO 2 ). 3. Will an amount of gas with a high GWP warm the Earth more or less than the same amount of carbon dioxide? An amount of gas with high GWP will warm the Earth more than the same amount of CO 2. 4. What does atmospheric lifetime measure? which measures how long the gas stays in the atmosphere before natural processes (e.g., chemical reaction) remove it. 5. Assuming GWPs are equal, would a gas with a long lifetime or short lifetime exert more warming influence? A gas with a long lifetime can exert more warming influence than a gas with a short lifetime (assuming the GWPs are equal
Population Growth World human population (important number to know): 7.7 billion Population was able to increase by the agricultural revolution, industrial revolution, and medical revolution Exponential Population Growth/J-Curve Doubling Time how long it takes to double the population if a country continued growing at its current rate Urban Sprawl City An incorporated municipality with a definite boundary and legal powers Urban Entire built-up, non-rural area and its population; includes recently added suburbs Rural
- Areas of low population density Rural-to-Urban Migration
- Movement of people from the less densely populated areas to the more densely populated areas of a city.
- Push factors- motivate people to move away from an area
- Pull factors – motivate people to move to an area 3 categories of push and pull
- Economic
- Social
- Environmental/natural disasters Urbanization Rates
- Percent of the total population who move to urban areas each year. Urban Sprawl
- The spreading of urban developments (such as houses and shopping centers) on undeveloped land near a city. Suburbs
- The residential area on the outskirts of a city or large town
- Fort Worth/Dallas Suburbs Subdivision
- A tract of land surveyed and divided into lots for purposes of sale; especially: one with houses built on it Outside Materials: Video: 200 Countries, 200 Years, 4 Minutes Video: 7 Billion: How did we get so big so fast? Video: The World in 2015: Global Population and the Changing Shape of World Demographics Article: How Cities Can Beat the Heat 1. Why will metropolitan areas be hit especially hard with future climate change? when temperatures rise, cities suffer disproportionately because of the way they are built. Dark roofs, roads and other construction materials absorb incoming short-wave radiation from the Sun and re-radiate it as long-wave energy, warming the atmosphere nearby. Air conditioning adds to the problem by pulling heat from inside buildings and vehicles and dumping it outside, further driving up urban temperatures. 2. What is the phenomena of the first question called? Urban heat island A- What was the first city in North America to adopt a green roof policy? LA 3. What is the difference between a “green roof” and a “cool roof”?
- Green roofs reflect more sunlight than conventional tar or gravel roofs, but they get much of their cooling power from moisture in the plants and soil. Cool roof is just a lighter color 5. About how hot is 40 degrees Celsius? 100 degrees Fahrenheit 6. What was the death toll from the massive, ten-day heatwave that hit Western Europe in August 2003? 70, 7. How does air conditioning of buildings and vehicles add to the Urban Heat Island Effect?
2. Why do metro systems (subways) operate at the highest capacities? They are separated from the traffic (above or below) 3. What measure of density ca support a metro system? 45 people per acre 4. Do most U.S. cities have a density high enough across a enough space to warrant putting in a metro system? No. they need a population of about 5 million 5. Other than cost and population density, what other factor effects the decision of whether a city has a metro system? Time of technological innovations or convenient government funding GEOG 227: Our Vulnerable Planet The Great Acceleration - Questions to consider The first set of questions are in order as you come to them as you read the book. There are a variety of answer lengths among the questions.
1. Compare and contrast the pollution problems associated with mining coal and oil. Coal – Deep and surface Mining coal drastically changes the landscape, and in certain cases, a deep mine collapse can cause a small earthquake. Slags leach sulfuric acid into local waters, killing aquatic life. Methane release into atmosphere. Strip mining destroys vegetation. Blowing up mountains to mine led to excess rock covering streams and forests and increased erosion. Oil drilling – leaks damage marine and aquatic life. In onshore drilling, leaks damage ecosystems and water supply, causing nearby dwellers to have increase in cancer. Spills contribute to air pollution, then acid rain, then damaged crops. Overall, they both benefitted economy and people living elsewhere. But for the places nearby the mining and extraction, the price was high as the water and land was destroyed, and the people living there were left to suffer as opposition was ignored. **2. Describe the changes in agriculture that occurred due to cheap energy.
- What is the trend of atmospheric carbon dioxide when comparing the chart on** page 75 with a more current chart found online? It increased rapidly in the chart in the book, online it is still increasing but not as sharply. 4. What is the Kyoto Protocol? Binding agreement that mandated small emissions cuts (compared to baseline year established as 1990) by the worlds richest countries 5. What is the sixth extinction? How is the sixth extinction different from the first five extinction events? Mass extinction that would overcome previous ones This one is different because it is human caused 6. Summarize the positive aspects of cities. Centers for ingenuity, creativity,wealth If well designed, can require fewer resources per capita than rural areas Densely packed cities require less fuel to keep warm or cool Help lower fertility rates – women have more job opportunity, more access to birth control, and kids are more expensive in cities so they have less of them 7. How did industrialization impact cities? Cities required greater amounts of energy afterwards initially for factories and later for technological innovations synonymous with urban living (lighting, vehicles) 8. Explain how deindustrialization and suburbanization go hand in hand. Deindustrialization involved the movement of industry from the center of te city to the periphery caused more people to move to the periphery of the city near their jobs, and suburbs popped up.
