Introduction to Environmental Science--Semester of Notes
Introduction to Environmental Science--Semester of Notes ESRM 100
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ENV 100 Notes Easter limited resources can support only a limited human population 11 Fundamental Principles 12 Human Population population bomb 13 Sustainability ecosystem must be sustainable at least in maintaining whatever it takes to produce the amount we are harvesting Sustainability of the product our harvest ecosystem itself Sustainable development society able to maintain environment while continuing to develop economy amp social institutions for an inde nite time Sustainable architecture designing buildings that do not waste energy and environmentally friendly in other ways as well Carrying Capacity max number of individuals of species that can be sustained by an environment wout lessening the environment s ability to sustain the same number of individuals in the future 14 Global Perspective fossil fuels chemicals nonhuman life Gaia hypothesis environment at a global level has been profoundly changed by life throughout the history of life on Earth and that these changes have tended ti improve the chances that life on Earth will continue 15 Cities affect the environment urbanization ppl move from farm 5 suburbs Emphasis on urban environments and its effect 16 People and Nature principle of environment unity everything affects everything else PPL changed nature 17 Science and Values has to be able to be tested by observation Environmental science 1 includes sciences but also is often linked w non scienti c elds that have to do with how we value the environment such as environmental ethics 2 Deals with many topics that have great emotional effects on people often stirring up political debate and strong feelings that sometimes override scienti c information Utilitarian justi cation views some aspect of the environment as valuable bc it is useful it provides economic bene ts or is directly necessary to ppl s survival Ecological justi caiton places value on some factor that is essential to larger life support functions even though it may not directly bene t an individual Aesthetic justi cation has to do w value we place on beauty Moral Justi cation based on one s view of right and wrong 18 system set of parts that function together to act as a whole System responds to inputs and have outputs Feedback output of the sytem also serves as input and leads to further changes in the system Negative feedback self regulating stabilizing Positive feedback occurs when an increase in output leads to further increase in the output Exponential growth characterized by doubling time time it takes for what is growing to double in size or number 70 divided by growth rate Sustainable growth oxymoron Environmental unity it is impossible to change only one thing everything affects everything else Input Output Steady state no net change in the size of the storage compartment dynamic equilibrium something is happening not still Input lt output amount of material in the storage compartment shrinks Input gt output amount of material in the storage compartment expands Average residence time how long it takes for that particular material to be cycled through the system 1 Type of disturbances and changes that are likely to occur 2 Time periods over which changes occur cities and then perhaps to 3 The importance of each change ot the long term productivity of the system Heart of understanding principles of environmental unity and sustainability Biota all living things within a given area Biosphere region of Earth where life exists energy is received from the sun and from Earth s interior and is used and given off as materials are recycled Ecosystem necessary for life to persist system that includes air and water to transport materials and energy Community of organisms and that community s local nonliving environment in which matter cycles and energy ows Global environmental problems dif cult bc 1 Exponential Growth 2 Lag time time between a stimulus and a system s response to that stimulus Long delay k overshoot carrying capacity is exceeded 3 Irreversible consequence consequences that may not be easily recti ed even within a few hundred years Ex Soil erosion Ecological footprint total area each person requires based on the resources we use and the waste we produce We use about 20 more of Earth s biological productivity than is replaced each year Precautionary Principle when there is a threat of serious perhaps even irreversible environmental damage we should not wait for scienti c proof before taking cost effective precautionary steps to prevent potential harm to the environment Proactive tool Env 100 Notes 42 Getting it Straight 1 10 11 12 Modern medical practices improved sanitation better control of organisms that spread disease and improved access to human necessities have lowered death rates and accelerated human population growth Increased per capita income a decline in birth rates B decline in death rates C decline in average family size D column type of age structure more adults Population dynamics is a study in change in population Growth rate in uences the population change the most Human population has mostly grown exponentially because of improved technology and events such as agricultural and industrial revolution which led to stability of access to food and better care etc The most important characteristic of a population to consider when forecasting population growth is age structure because it affects current and future birth rates death rates and growth rates It gives us clear insight into how that population will use resources and how it will affect its environment Also has implications for the population s current and future social and economic status Demographic transition is a pattern of change in birth and death rates as a country is transformed from undeveloped to developed 3 stages 1 In an undeveloped country birth and death rates are high and the growth rate low 2 The death rate decreases but the birth rate remains high and the growth rate is high 3 The birth rate drops toward the death rate and the growth rate therefore also decreases Factors such as industrialization access to education affect the population Death rates vary so much between developed and developing countries because developed nations have modern medicine which has greatly reduced death rates from disease particularly from acute or epidemic diseases I would talk about the overall global dynamics which is leading to overpopulation on our planet earth If a country offers speci c rewards and penalties it would be bene cial to inform that to a family as well It is important to compare and contrast the developed nations and developing nations and discuss the overall consequence of continuing the current habit The difference between longevity and life expectancy is that longevitymaximum lifetime is the genetically maximum possible age to which an individual of a particular species can live and Life expectancy is the average number of years an individual can expect to actually live given his or her present age health and other factors Long term effects of limiting factors on population growth are soil erosion decline in groundwater supplies and climate changes which can lead to decline in population growth Short term effects are disruption of food distribution in a country or outbreak of a new disease or new strain of previously controlled disease which can also lead to decline in population growth Birth control and family planning alone would be enough to cure the current exponential growth but not everyone would follow it If the population were to grow a war may break out or a disease will wipe out some portion of the population Land and soil resources are perhaps the most affected environmental issues because in order to sustain more people we need to cultivate more land so that people can live ENV 100 Notes 421 Ch9 Clean Water Farms Practice that bene t environment can be pro table as well Paddocks sections Agriculture perhaps the most sustainable Americans consume more than 410 lbs of vegetables 200 lb of grains 275 pounds of fruit almost 170 lbs of red meat and chicken more than 200 lbs of milkmilk product 33 lbs of eggs 16lbs of sh and shell sh More than half a ton of food a year 11 of world except for Antartica agriculture Only 14 plant species provide most of the world s food EX rice wheat maize potatoe Farming degrades soil fertilizerspesticides irrigation v salinization Production of food with population growth dif cult problem 1 million hectares lost each year to urbanization n soil erosion 13 of country s topsoil has been lost 80 million hectares Since end of WWII farming has damaged more than 1 billion hectares Dust Bowl major drought left loose 0 u Soil Erosion in US 17 metric tonshectareyr ju Soils of an unplowed forest more organic matter Use of Organic Fertilizer animal manure d farm on previously forested soil Chemical fertilizers important development Eroded soil travel down streams and rivers and is deposited at their mouth 27 billion metric tons yr sediments can damage coral reef in tropical ocean Soil eroded from farms carries chemicals that affect the environment eutrophication increase algae Sediments cost 500 a year Soil forms continuously slow 1mm deep 10 40yrs Sustainability of soil aided by plowingmulticulture terracing crop rotation contour plowing no till agriculture Contour plowing land plowed horizontally across the slopes No till agriculture not plowing the land suing herbicides and integrated pest management to keep down weeds and allowing some weeds to grow Pests insects mammals and birds that eat crops and seeds weeds competing with crops diseases attacking the crops US 13 loss of potential harvest and 110 of harvested crop Process of farming 1 Hold back the natural processes of ecological succession 2 Prevent migrating organisms from entering an area 3 Prevent natural interactions between populations of different species weeds grow easily US loss 16 billionyr Farmers spend 36 billion for chemical weed control 60 of all pesticide sale 500 million kg of pesticide released Program to monitor necessary Slash and burn agriculture traditional practice cut away some but not all vegetation in small patches in a forest harvest mixture of crops including root stem fruit crops Magical Bullet chemical that would have a single target 1 Arsenic K organic compounds x 3Arti cial organics DDT DDT s effect on bird s eggs banned birds recovered brown pelican DDT useful to eliminate malaria and yellow fever DDT important pest control issue worldwide can come back to developed nations Drawbacks of chemical pesticides 1 Reducing one target species reduces competiton with second species which then becomes pests 2 Pest develops resistance to the pesticides through evolution and natural selection Biological control OBacillus thuringiensis BT control epidemic of gypsy moths organic safe Wasps and Ladybugs effective too Pheromones as traps Integrated Pest Management biological control certain chemical pesticides careful scouting of elds to check for infestations methods of plating crops Ecosystem approach 2 Nicotine Natural management irrigation tree help slow Wind less deserti cation Aquifer underground area Where Water is naturally stored 913 s arming change the biosphere 1Agriculture changes land cover 2 increases CO2 in two Ways fossil fuels to run machinery clearing land for agriculture pZ decomposition of organic matter in the soil 3 Agricultural use of re and fertilizers can also affect climate add small particulates to the atmosphere and arti cial production of nitrogen compounds for use in fertilizer changes in biogeochemical cycles 4 Agriculture affects species diversity loss of competing ecosystems reduces biological diversity and increase the number of endangered species Half life ENV 100 Ch 8 Note Case Study Demasculinizationa nd Feminization of Frogs in the Environment Endocrine system composed of glands that internally secrete hormones directly into the bloodstream Hormones regulate the reproductive organs 2 Herbicide hormone disrupter Hormonally active agents substance that interact W the hormone system of an organism Whether or not they are linked to disease or abnormalities Hormonal disrupters as Well Pollution unwanted change in the environment caused by introducing harmful materials or by producing harmful conditions Contamination making something un t for a particular use through the introduction of undesirable materials Toxin substance that is poisonous to people and living things Toxicology science that studies chemicals that or could be toxic Carcinogen toxin that incrases the risk of cancer Synergism interaction of different substances Point sources amp Area sources amp Mobile sources Units ppm ppb milligrams per liter micrograms per liter Categories of pollutants infectious agents toxic heavy metals organic compounds hormonally active agents nuclear radiation thermal pollution particulates electromagnetic elds and noise pollution Heavy metals mercury lead cadmium nickel gold platinum silver bismuth arsenic selenium vanadium chromium thallium Biomagni cation bioaccumulation accumulation or increase in the concentration of a substance in living tissue as it moves through a food Web Ex Cadmium Mercury methylation greater effect ENV 100 Notes 426 Ch11 Case Study Colorado River Water Resources management Water pollution and the environment Natural disturbances necessary part of the river ecosystem if it is to function on a sustainable basis 0 create new sandbars rejuvenate marshes and backwaters 111 Water High capacity to absorb and store heat Universal Solvent Solid water is lighter than liquid water glacier Sunlight can penetrate water to variable depth permit photosynthetic organisms to live underwater Water cycle precipitation evaporation transpiration in ltration Mostly in ocean 97 ice caps and glaciers 2 More than 99 of water unsuitable for us due to salinity Water Sources groundwater and surface water or desalination Water table upper surface of the groundwater Aquifer underground layer of rock sand or gravel that contains usable groundwater and releases it in signi cant amounts Ef uent stream groundwater seeping into the stream channel from below the surface maintains the stream s ow during the dry season Perennial stream ows all year In uent stream is above the water table everywhere along the channel and ows only in response to precipitation Ephemeral only ows during or shortly after rainfall or during snowmelt Intermittent reaches combination of in uent and ef uent ow Quality of both surface water and groundwater suffers from urban and agricultural runoff interaction Desalination Seat water about 35 salt 1 Place value price rises quickly depending on how far the water msut be moved from the plant 2 Require a lot of energy Only used when other water sources are not available High salinity water displaced to another body of water may increase bay s salinity and kill some organisms there and damage ecosystems 112 Water Supply Water isn t always where you need it most Rates of precipitation evaporation transpiration stream ow ground water ow affects water supply 10 of water vapor as precipitation 23 evaporate quickly 50 of remaining 13 useful US average person use about 100 gallons a day Europe half of US Sub Saharan Africa 5 gallons a day Groundwater expensive Overdraft taking more groundwater out than is naturally replaced p and land subsidence 113 Off Stream and In Stream Water use Off Stream use removing water from its source and using it elsewhere coolantMuch of this water is returned to its source afterward Consumptive use water is consumed so it is not returned to its source In Stream use using water right where it is navigation hydroelectric power generation sh and wildlife habitats and recreation Problem sh and wildlife require certain waste levels and ow rates for biological productivity EX Mono Lake Aral Sea in Kazakhstan and Uzbekistan victim of diversion damage to river ecosystem Transport of Water ex NY Catskill forest natural processes that treat and lter water NY offered nancial incentives to the area s farmers homeowners and others to encourage a sense of responsibility to maintain high water quality when the city owns only about 8 of the land There is limit however and as population grows water demand will rise and cost go up Some Trends in Water Use We re dong better job Since 1980 water withdrawals have decreased and leveled off 114 Water Conservation Concerned both quality and quantity Agricultural use biggest water user improved irrigation could reduce use of water by 2030 Domestic use 10 of total national water withdrawals but urban areas can pose major local problems in area where water is sometimes or often short in supply EX NY South Cali Denver Chicago Tampa Florida Atlanta Georgia Use less water at home Water pricing policies can help make water expensive if a household uses more than a baseline amount that is determined by the number of ppl in home and size of property Industry and Manufacturing use increasing in plant treatment and recycle of water Precipitation and water use how ppl view their water supply affects how much they use ex Tucson Arizona Env 100 Notes 424 Ch10 Case study Winds of Change in Iowa wind power Five major kind of energy sources oil natural gas coal nuclear renewablealternative energy sources solar wind etc US use 15 of world energy Asia will grow with industrialization BTU British thermal units 425 qudrillion BTU s sued in 2003 Not ready for rapid increase in use of energy with end in sight for fossil fuels 102 Energy and work Energy ability to move matter Force Newton force needed to accelerate a mass of 1kg by 1 ms squared Joule force of 1 newton applied over a distance of 1 meter Power energy per nit time joulesec watt Kilo mega million giga billion Use energy for lighting heatingcooling doing physical work transferring and converting information 4 stages in making energy usable to us discovery extraction transport storage use 103 Type of fuels Conventional and alternative Conventional fossil fuels accustomed to using them Fossil fuel nonrenewable resource Alternative resource renewable wind solar energy water wood Water power 4 metal turbine and electric generators t3 reservoirs and dams Conventional Energy Sources 104 Petroleum Products Oil and Natural Gas Oil second most abundant uid in Earth s upper crust after water Resource entire amount on Earth Reserve what we can get at now economically proven reserve Oil shale one of synfuels liquid or gaseous fuels derived from solid fossil fuels Tar sands sedimentary rocks sands containing tar oil asphalt bitumen Natural gas clean fuel 105 Coal Most abundant and most polluting fossil fuel Coal and Nuclear fuels most polluting 106 The environmental effects of extracting delivering burning coal Strip Mining leaves behind displaced soil open to erosion derange streams likely to ood acid water Own land does not mean you own rights to minerals below the surface Coal dust and acid mine drainage serious problems w strip mining worsen lung disease such as asthma Strip mining cheaper and easier Underground mining 40 of the coal mined in US Risky collapse explosion re respiratory illness black lung disease Solution to coal problems chemicalphysical cleaning of coal syngas boil at lower temp 107 Environmental effects of extracting delivering using petroleum products Oil and natural gas and re neries pollute accidental spills and slow leaks Oil spill in transportation Exxon Valdez case BAD n Oil Pollution Act of 1990 and new technology 108 Three Basic Alternatives to Fossil Fuels Solar Geothermal and Nuclear Energy Solar energy renewable sustainable Stored in wind water tides ocean currents organic matter wood animal dung Geothermal energy heat from deep inside the Earth considered nonrenewable when developed on a large scale industrial level Nuclear energy stored in nuclei of atoms used to be called atomic energy most controversial option 3 sources conventional nuclear ssion breeder reactors and fusion Breeder renewable but conventional ssion not 109 Solar Energy Two types Passive Solar Energy system system that collect solar heat wout using moving parts Active solar energy systems convert sunlight directly to electricity or store the energy as heat and then use electric pumps to circulate air water or other uids from solar collectors to a location where the heat is stored until used Solar collector usually on rooftops at glass covered plates Photovoltaics PVC convert sunlight directly into electricity world s fastest growing energy source Solar energy variety of metal glass plastics uid may cause environmental problems during manufacturing through accident But overall solar energy has relatively little environmental impact Solar energy will likely become a major provider of the energy we use 1010 Wind Power Wind result of sun s heating of Earth s surfaces different temperature of surfaces Less reliable than solar energy P storage of wind energy important 1 of world s demand for electricity right now but could be major energy supplier Problem large birds of prey and vultures collide with them and can be killed 1011 Water power Water power form of stored solar energy Faster more powerful Environment problem arise from effects on life displacing ppl and their farms and owns threatening habitats of sh and other wildlife More water evaporates from the large surface areas of reservoirs growth of large scale water power likely be limited Tidal Power force of ocean water owing in and out with the tides more complex and change in hydrology that a dam causes in a estuary can harm vegetation and wildlife 1012 Biomass Energy Fancy term for solar energy stored in organic matter result of photosynthesis Don t contribute to greenhouse gases net zero Oldest fuel used by people Today developing countries 35 Several routes 1 Direct burning to produce electricityto heat water and air 2 Heat biomass to forma gaseous fuel gasi cation 3 Distillationprocessing of biomass to produce biofuels ethanol methanol methane Sources wood cattle manure peat forest products agricultural residues energy crops animal manure urban waste etc Converting waste fuel fuel 2 bene cial even wout a net energy gain Can lead to air pollution shortage of rewood etc 1013 Geothermal energy Natural heat from the interior of the earth Can be converted to heat buildings and to produce steam for generating electricity Renewable or nonrenewable when we use more than natural heat production Groundwater low heat source of geothermal energy Pollution on site noise emissions of gas disturbance of the land at drilling sites disposal sites road and pipelines and power plants 1014 Nuclear Energy An incredible amount of energy results from converting matter into energy Isotopes Emc2 radiocactivity ex Uranium and plutonium 3 kinds conventional nonbreeder ssion breeder ssion fusion Only 131 two exist Enrico Fermi rst human controlled nuclear ssion 1942 Major nuclear accidents something went wrong w the balance between heat removal by the coolant and heat buildup in the reactor core Smaller less complex reactors favored Pebble bed reactor might be more ef cient Breeder reactors transform lower grade uranium p ssionable material BUT waste is extremely radioactive and dangerous and the fuels they produce can be used to make atom bombs Fusion combining nuclei of light elements to form heavier ones High temperature necessary 100 million degrees celcius fuel elements must be incredibly dense plasma 1015 Environmental Problems of Nuclear Power Three Mile Island and Chernobyl Alpha particles two protons and two neutrons greatest mass of the 3 types of radiation Do not travel far Dangerous to inhale Beta particles electrons Travel farther through air than alpha particles but can be blocked by even moderate shielding Dangerous to inhale Gamma rays most penetrating Similar to X rays but more energetic and penetrating Generally somewhat safer than alpha or beta bc most of them passes out of your body Each radioactive isotope has its own characteristic emissions Tailings leftover materials from mining and generally remain at the site Effects of radioactivity are measured in units called sieverts Radioactive wastes low level waste transuranic waste high level waste Yucca mountain suitable for radioactive waste No guarantee Storing energy mechanically by moving matter chemically and electrically Pump storage facility unpopular Chemical H20 hydrogen and oxygen Battery serious environment effects Transporting energy on the grid or off the grid problem major blackout if the grid breaks down Thursday August 14 2003 Use less more ef ciently cogeneration Env 100 Notes 429 Ch11 second half 115 Sustainability and Water management Sustainable Water use use of our water sources in a way that allows society to develop and ourish into an inde nite future 116 Wetlands Salt marshes swamps bogs prairie potholes vernal pools wet at least part of the year and therefore have a particular type of vegetation and soil Natural sponge for water Areas of groundwater recharge and discharge Primary nursery ground for sh shell sh aquatic birds and other animals Natural lters that help purify water Highly productive and have nutrients and chemicals naturally cycled Coastal wetlands buffer inland areas from storms and high waves Important storage sites for organic carbon Aesthetically pleasing Freshwater wetlands and Salt marshes threatened US no national wetlands policy Wetlands to clean up agricultural run off BUT creating wetlands complex 117 Dams and the Environment Effects loss of land cultural resources biological resources in reservoir area Storage of sediment behind the dam reduce reservoir s water storage capacity Fragmentation of river ecosystems through blocking upstream migration of sh Downstream changes in hydrology and in sediment transport that change the entire river environment and the organisms Removal of Dam ex Edwards Dam near Augusta Maine Three Gorges Dam on Yangtze River China Biggest Dam 118 Channelization and the Environment Channelization straightening deepening widening clearing or lining existing stream channels control oods drain land for agriculture and urban uses control erosion and improve navigation 2 most common goal ood control and drainage improvement Problems too such as damage or loss of wetlands aesthetic degradation loss of sh habitats downstream ooding etc Ex Kissimmee River Florida 119 Flooding Floodplain atland adjacent to river River Flooding most widely experienced natural hazard in the world Over ow bene cial water and nutrients stored on ood plain deposits on ood plain gt formation of nutrient rich soils Wetlands on oodplain provide habitat oodplain function as natural greenbelt Urbanization P b ore water run off risk of oods Ex Hurrican Katrina New Orleans 1110 Global Water Shortage Linked to Food Supply Groundwater in US China India Paksitan Mexico and other countries is being used faster than it is being renewed Large bodies of water Aral Sea are drying up Large Rivers Colorado US Yellow River China do not deliver any water to the ocean in some season or years Flow of others such as Nile greatly reduced Water demand during the past half century has tripled need to control human population growth 1111 Water Pollution To decide water supply is polluted we consider 1 What we intend to use the water for 2 How different the water is from the norm 3 Its possible effects on public health 4 Its ecological effect Pollutant any biological physical chemical substance that in certain amounts is known to be harmful to living organisms heavy metals sediment radioactive isotopes heat fecal coliform bacteria phosphorus nitrogen sodium Lack of clean drinking water problem Quality of water determines potential use domestic industrial agricultural Process and materials may pollute surface water or groundwater EPA sets limits for some water pollutants Bottled water multibillion dollar industry 1112 Sources of Pollution Biochemical oxygen Demand BOD amount of oxygen consumed by microorganisms as they break down organic matter Waterborne disease public health programs have largely eliminated epidemics by treating drinking water to remove disease carrying microorganisms and by not allowing sewage to contaminate drinking water supplies but US is not immune Fecal Coliform bacteria normally found in intestines and waste of all animals not harmful but if found in water potential for waterborne diseases 200 cells of feacal coliform bacteria per 100 mm of water threshold Escherichia coil caused illness and death Nutrients Land use is the source of 2 nutrients that pollute water phosphorus and nitrogen Large industrial hog farms worrisome north Carolina Hurricane Floyd pig waste Eutrophication Cultural eutrophication cultivation process when a body of water develops a high concentration of nutrients such as nitrogen and phosphorus nutrients increase the growth of aquatic plants bacteria and algae may form surface mats shading the water and reduce light and reduce photosynthesis Bactia and algae die BOD increase decompose reduced oxygen C death of other organisms Ecosystem effect interactions and condition of the environment Dead zone wide areas of water containing so little oxygen that bottom dwelling marine organisms cannot survive there Fish and shrimp can swim away but bottom dwellers such as crabs snails and other shell sh are killed Cause Nitrogen from agricultural fertilizers Use less Nitrogen ex riparian forest forest along rivers and stream Solution reduce pollutants use phosphate free detergents control nitrogen rich runoff from agricultural and urban lands disposing of or reusing treated wastewater use more advanced water treatment methods Oil routine discharge of oil probably more than occasional oil spills which make headlines Long term effect of large oil spills uncertain Sediment By volume and mass greatest water pollutant sediment pollution results from erosion which depletes an important land resource and it lowers the quality of the water resource it enters Human activities affect runoff erosion and sedimentation Acid mine Drainage Water w a high concentration of sulfuric acid drains from mines Toxic to plants and animals of an aquatic ecosystem 113 Surface Water Pollution Flowing water has natural ability to remove or dilute harmful substance but when too much enters natural ability is overwhelmed and is polluted Point source distinct and con ned ex pipes from industrial site oxygen consumed Non Point Source runoff from an urban area less distinct in uenced by such things as land use climate hydrology topography native vegetation geology 3 approaches to deal w surface water pollution 1 Reduce the sources 2 Treat the water to remove pollutants 3 Convert the pollutants to forms that can be disposed of safely 114 Groundwater Pollution Low concentration of oxygen situation that kills microorganisms that require oxygen rich environments but may provide a happy home for microorganisms that live in environments that require little oxygen Moves through channels that are very small and variable usually moves slowly and has only limited opportunity to disperse or dilute pollutants Old leaking underground gasoline tanks polluted water and soil Treatment removal and disposal of soil vapor extraction bioremediation microorganisms consume gasoline Ex Long Island shallow aquifer pollution stemming from urbanization 115 Water Treatment Stored 0v ltered W treated Drinking water in US is among the safest in the world 11 16 Wastewater Treatment Degraded by the addition of solids salts nutrients bacteria and other material that uses up oxygen Septic Tank Disposal systems separate solid from liquid digest and store organic matter for awhile and allow the clari ed liquid to discharge into a drain eld from a system of pipes through which the treated sewage seeps into the surrounding soil May fail failure to pump out the septic tanks when it is full of solids 2 Poor soil drainage allows wastewater to rise to the surface in wet weather Treatment Plants reduce BOD and kill bacteria w chlorine Wastewater treatment primary secondary advanced Primary treatment removes 3040 of the BOD from the wastewater Secondary treatment uses bacteria to digest about 90 of the BOD that entered the plant in the sewage Ones with many pollutants are disposed Advanced treatment used when treatment beyond primary and secondary is needed Primary and Secondary treatment required by federal law some exception due to nancial burden areas such as where river w endangered sh advance treatment Moving waste disposal farther offshore is right direction but reducing the amount of pollutants at their source is important Wetlands effective in treating wastewater Municipal wastewater storm water runoff industrial wastewater agricultural wastewater mining waters groundwater seeping form land lls ex Arcata California Louisiana economically bene cial too Conclusion using wetlands to treat wastewater is a practical solution to improving water quality in small widely scattered communities in the coastal zone and constructing wetlands can serve the same purpose in the arid regions Reuse of Treated Wastewater can be piped directly Las Vegas very little direct reuse of water is planned for consumption 1117 Water Pollution and Environmental Law deals w conservation use of natural resources and pollution Refuse Act of 1899 protect streams rivers and lakes from pollution caused by navigation Goal clean up or treat pollutionwastewater but also to PREVENT Mid 1990s controversy 1994 Congress tried to rewrite major environmental laws such as Clean Water Act to give industry more exibility in choosing how to comply w regulations concerning water pollution Congress misread public s value Ppl willing to pay money to have clean air and water ENV 100 Notes 54 Ch13 Case Study Global Warming and the Polar Bears of Hudson Bay Sea ice everywhere has thinned by as much as 40 over the past 40 yrs and now covers 10 less area than it used to Ice critical habitat for hunting seals Earlier break up of ice 2 weigh less and fewer birth amp forced onto land earlier w people more likely 13 1 Is Global Temperature Rising Yes and temperature is always changing glacial ages have come and gone periods between glacial ages Interglacial Today s temperature are warmest known during the last 2 million years W dropped further dangerous contact Climate began to warm around 1850 a cool in 1940s during 1960s climbed steadily through 1990s In Last 100 yrs global average annual temperature has risen about 6 degree celcius Gotten warmer faster Persistent overall trend of rising temperatures over 3 decades global warming is real and happening 13 2 What Causes Climate Change of Any Sort and what is making it get warmer Studies of ice cores and other geologic records allow reconstruction of temperature leveled off in 1950s average temp of Earth s surface has varied over time Earth s energy balance amount of energy coming in from the sun and amount of energy radiated out by the Earth 30 of energy from sun reflected off immediately of the remaining 70 25 absorbed in upper atmosphere and 45 reaches Earth and is absorbed at surface ALBEDO of light received by a surface that is re ected and scattered the rest of energy is absorbed by the surface White higher albedo re ects more light ppl in desert wear white Positive feedback from albedo snow re ects light so keeps surface old increase amount of precipitation that falls as snow Part of infrared radiation reabsorbed by gases in the atmosphere including carbon dioxide and methane greenhouse gases ultimately is lost to space as heat completing Earth s energy balance Warmer an object the more energy it radiates amp shorter the dominant wavelengths of the energy it radiates Very hot sun radiates mostly in infrared wavelengths and visible wavelengths Earth radiates mainly in the infrared Sun s energy seems to have varied over the ages Amount of solar energy reaching Earth was relatively high compared w today around 11001300 suggeset that sun radiated less energy during the 14th century which coincide with cold period Little Ice Age 1450 Milankovich Cycle another possible explanation Spinning Earth wobbles like a top n its elliptical bit around the sun impossible to keep a constant position in relation to the sun change in climate summer and winter different in Northern Hemisphere than Southern Hemisphere Volcanic eruptions cool the climate in 2 ways 1 Dust that released into atmosphere re ects sunlight back out into space 2 less sunlight reaches Earth 2 dust s smaller particles provide surfaces for water to condense on forming clouds that also reflect incoming solar energy away from earth Smallest particle aerosols less than 10 microns across Aerosol emission from human activities increased since the Industrial Revolution o reduced amount of sunlight reaching Earth today by as much as 10 in some regions and reduced global warming due to greenhouse gases by an estimated 50 global dimming Variation in Ocean Currents may affect the climate Ocean currents together W prevailing Winds can Warm or cool our planet Current Warming trend just another natural Warming cycle of the same length from 1450 1850 human activities raising temperature even more Gulf Stream passes near Florida and ows to Europe keeping Europe Warm and cools and sink to the bottom El Nino Southern Oscillation every seven years ocean Would Warm up around Christmas shing become poor seabirds Would disappear Explanation under normal condition s there are strong vertical rising currents called upwellings off the shore of Peru Upwellings cool the surface Water and help to support bird and sh populations bring cold Water up from the depths along W important nutrients that promote the growth of algae produce a lot of reach Greenland seabirds El Nino occurs When upwellings slow or cease Air pressure is high in the eastern tropical Paci c and low in the Western tropical paci c When this reverses the Winds and upwellings off Peru fail and El Nino begins El Nino Global event 1 involve changes in rainfall temperature frequencies of storms in many parts of the World 2 El Nino likely to become more common and more intense as Earth s average temperature rises El Nino became stronger and more frequent in the 1990s but scientists are not still sure What is the rst cause of El Nino and its link to global temperature rise that started then ENV 100 Notes 56 ch12 second half 13 3 What is the Greenhouse Effect and How Does it Warm Earth s Surface Temperature at or near the surface of Earth is determined by 4 main factors 1 The amount of sunlight Earth receives 2 The amount of sunlight Earth re ects 3 Retention of heat by the atmosphere 4 Evaporation and condensation of water vapor Certain gases in Earth s atmosphere sends the sun s energy back again Earth warmer Atmosphere 78 nitrogen 21 oxygen argon 09 CO2 003 also methane ozone hydrogen sul de carbon monoxide oxides of nitrogen and sulfur hydrocarbon chloro uorocarbon and various particulates Greenhouse gases one that are especially good at absorbing infrared radiation water vapor CO2 methane nitrogen oxides ozone chloro uorocarbons Water accounts for much of the greenhouse gases 1 4 CO2 freezes at much lower temperature than water and exists at higher altitude htan water vapor Infrared radiation is absorbed and reemitted upward can be absorbed and radiated downward by CO2 so CO2 has last change at what happens it absorbs in a region of infrared light that water transmits Greenhouse gases keep earth 33 degree celcius warmer amp keep variations in Earth s surface temperature from day to night relatively small Greenhouse gases produce greenhouse effect on other planet too Mars and Venus 13 4 Greenhouse gases are increasing and we are part of the reason CO2 5060 of anthropogenic human caused greenhouse effect Trace gases CFC and methane contribute 27 45 of anthropogenic greenhouse effect Guy Stewart CO2 idea came from early 19th century after Industrial Revolution ignored pz Callendar in 1930 calcluated amount of CO2 added to atmosphere mostly ignored 20th century idea gained attention 1957 international geophysical year CO2 risen 32 from 280ppm to 380 ppm today Current rate of growth 05 yr double before the end of 22nd century Burning fossil fuel wood cut down forests removing prairies destroy living vegetation and organic I increase in CO2 Methane concentration more than doubled in the past 200 yrs Believed to account for 1220 of human caused greenhouse effect Produced by certain kinds of bacteria that cannot live where there is oxygen that are so saturated w water that they lack oxygen 2 Intestines of cattle and other ruminants 3 Intestines of termites Also released during processing of fossil fuel and by land lls 1 Increasing and size of habitats where bacteria live 2 Increasing the of domesticated ruminants 3 Burning fossil fuels 4 Destroying wetlands and thereby releasing stored methane 5 Increasing size of land lls and amount of organic matter stored in them add atmospheric methane Chloro uorocarbons CFC Used to think as harmless nontoxic nonexplosive non relatively inert chemically BUT we discovered it is greenhouse gas and destroy ozone in upper atmosphere Increasing by 5 year 1525 of anthropogenic greenhouse effect related to CFC Use of CFC as propellants was banned in US in 1978 1987 24 countries signed a treaty Montreal Protocol Production nearly phased out in 2000 Entirely a human product Nitrous Oxide contributes as much as 5 of the anthropogenic greenhouse effect agriculture and burning fossil fuels matter in soil 0b h 1 Parts of wetlands Ozone undesirable pollutant in the lower atmosphere amp blocks ultraviolet light in higher atmosphere BUT dif cult to determine the of greenhouse effect due to ozone 13 5 Would it Really be so serious if earth warmed up a bit YES 1 We need to forecast changes in the climate and physical conditions of oceans and land surface 2 We forecast how species and ecosystem will respond Comptuer models major scienti c tool in the rst step global warming will increase the average temp of earth s surface by 15 to 45 C from 1990 2100 w 3C likely Greatest change in polar region ice melt sea level rise climate change food production threatened Sea level rising naturally since the end of last ice age melting ice add to ocean water and water expands as it warms 1 meter higher than today by 2100 Rising sea level higher damage from major stomrs ooding beach erosion Glacier melting but Antartica s central ice cap has been growing more snow falls on Antarctica as Earth warms Polar ampli cation solar energy that would have been reflected back into the atmosphere by sea ice will instead be absorbed by the dark water Global warming also change the frequency and intensity of storms they derive intensity from warm water Ex hurricatne Katrina and Rita Greenhouse warming expected to cause other climate changes wetter winters hotter and drier summers increased possibility of droughts in northern temperate latitudes Agriculture Global warming may serious affect the world s food supply amount of water evaporated from warmed soils and vegetation will be greater than amount added by rain and snow Best agricultural areas may no longer be in North America shift to Canada world production especially of small grains could decline or not meet the needs of growing human population Winter snowpacks will store less water Lowering of water tables and reservoirs could cause serious shortages unsustainable Biological and Ecological Changes black guillemots on Cooper Island ice breaking away Spring now arrives up to 2 weeks earlier than it did 3 decades ago can stress some species compete for food plants damaged by spring snowstorm change in habitats Some species changing their geographic ranges skipper butter ies Subalpine forests Edith s checkerspot butter ies etc Many other species also moving northward Migration of species can spread disease mosquitos and malaria and dengue fever higher elevation in Mexico West Nile Virus in NYC in 1999 link between physical biological social systems Endangered Species Kirtland s warbler 38000 acres set aside in Michigan Scarcity of suitable habitats could cause many extinctions good news species can adjust better to changes that are slow so if we could slow the rate of climate change the undesirable biological effects would be fewer 13 6 Can we do anything to slow the temperature rise Reduce our production and release of greenhouse gases Find ways to sequester store greenhouse gases Take actions that cool the climate What did we do so far First steps in 1988 Toronto Canada recommend 20 reduction in CO2 by 2005 1992 Earth Summit in Rio de Janeiro Brazil general blueprint for reducing global emission suggested US objected as too costly December 1997 Kyoto Japan US agreed to cut emissions to about 7 below 1990 levels but far less than reduction suggested by scientists 6080 US 5 of world s population and emits about 20 of atmospheric CO2 US slow to act 13 7 Can we do anything to alleviate the effects of Global Warming We can move species to new habitats We can establish new nature preserves in areas that provide appropriate habitats We can establish wildlife corridors among these preserves We can develop new strains of crops
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