AES 103 Final
Natural Sources of Air Pollution continued
% of emissions that are natural Sulfur dioxide - 30% Nitrogen oxide - 44% VOCs - 89% In certain places, such as North America, these values are much lower, on the order of 5% for sulfur dioxide and nitrogen oxide.
Nonrenewable energy
-Accounts for most energy use worldwide -Nonrenewable = can't be replenished There are two types of nonrenewable energy Fossil fuels Nuclear
Anthropogenic Contributions to Stratospheric Ozone Destruction
-CFCs (chlorofluorocarbons)-refrigeration, air conditions, aerosol cans -Cl atoms act as catalyst to break down ozone molecules -Leads to depletion of ozone layer
Issues with irrigation
-Contributes to runoff of sediments from fields -Leaching- water carries important plant nutrients deeper in the earth where plant roots can't reach it -Salinization- water has trace amounts of salt dissolved in it → salt builds up in soil → can reach levels damaging to plants-20% world irrigated croplands affected ● Agriculture is largest draw on freshwater resources ● Water diverted from streams for irrigation ● Groundwater supplies 40% world's irrigation water ○ Slow recharge & overuse - aquifers going dry ○ Land subsidence
Fossil Fuels
-Derived from biological material that became fossilized millions of years ago -Coal, Oil, Natural Gas -Burned to harvest heat energy
Environmental Impacts of Urban Areas
-Habitat loss -Increased impervious surface (concrete & asphalt, buildings) -Heavy natural resource use & reliance on outside sources -Air, water, land & soil pollution -Light & noise pollution harmful to wildlife -Crowding = faster spread of disease (first big US coronavirus outbreaks were in large cities)
Issues with Genetic Modification
-Loss of Agrobiodiversity -Few crop varieties left due to selective breedingAbout 100 years ago, crops had hundreds of thousands of unique varieties that humans consumed After the Green Revolution, farmers focused on techniques that increased productivity, especially on only planting varieties with higher yields Additionally, fertilizers and irrigation allowed the same types of crops to be planted everywhere, rather than having crop varieties that were specific to local climates. -Decline in genetic diversity of crops = decreased resistance to change -Crops especially vulnerable to climate change and disease For example, in the 1970s, a fungus ravaged high-yielding corn grown in the southern US and half of the crop was killed. Scientists modified this corn by adding a gene from a corn variety that was resistant to the fungus. If the resistant variety had not been preserved this gene would not have been available. -Seed banks- large, secure warehouses used to store "inactive" seed varieties to preserve genetic diversity of crops
Issues with seafood
-Major energy requirement to get boats out to sea for fishing-Energy subsidy - energy input per calorie of food produced Offshore fishing has the highest energy subsidy of any food because of the gas it takes to get the boats out to sea. -Overfishing- when quantity of fish caught exceeds the productive capacity of a species -Bycatch- incidental capture of non-food species in fishing nets and linesMillions of tons of sea turtles marine mammals & fish are caught via bycatch each year Shrimp trawling produces highest bycatch- 1.5 kg bycatch for every 1 kg shrimp
Negative Effects of Urban Heat Islands
-More hot days = harm to human health (heat stroke, cardiovascular risk, especially for young children and older people)-Increased energy costs for cooling -Effects on animal populations- relocation, mating patterns My friend in grad school did her thesis research on how different species of frogs and toads changed their mating calls based on the severity of the urban heat island effect in different parts of Charlotte, North Carolina. -Effects on plant populations- phenology changes and plants bloom earlier
Albedo
-Percentage of incoming solar radiation that is reflected by a surface All kinds of surfaces have different albedos. -High albedo = more sunlight reflected-Low albedo = more sunlight absorbed -Impervious surfaces have very LOW albedo → absorb a lot of heat ● Because they have low albedo, impervious surfaces (especially asphalt) absorb a lot of solar radiation Think about walking on asphalt in bare feet in the summer-- it's hot! ● Heat is slowly released from the urban surfaces to the atmosphere ● Especially keeps nighttime air temperatures higher than surrounding areas, as heat is being released even after the sun goes down
Issues with synthetic pesticides
-Pesticide resistance can be developed among pest species -Harmful to non-target species Meaning the pests develop immunity to the pesticide, and new pesticides have to be developed -Can be harmful to humans when ingested (wash your fruits & veggies!)
Environmental Issues with Impervious Surfaces
-Replacement of natural landscape-Increased runoff from precipitation/ decreased infiltration to groundwater -Decreased albedo leads to the urban heat island effect
Genetic Modification
-Selective breeding- process used by humans to exhibit or eliminate a particular characteristic This has been going on for thousands of years, really since the beginning of the agricultural revolution. Basically, farmers would identify crops with the best yields, and cross breed them with other plants with high yields in order to produce the highest yielding plants possible. An example of this is corn. The corn we see today is really different from the corn originally grown by Native Americans starting nearly 6,000 years ago. Humans use selective breeding for both plants and animals. ● Genetic engineering- positive genetic traits from one variety of crop are inserted into the DNA of another crop ○ Developed in 1970s ○ Much faster than traditional cross-breeding ○ Have greatly helped feed the world due to increased herbicide, pest & disease resistance plus use of fastest growing/ most fruitful varieties
Environmental Benefits of Urban Living
-Walkability & Public Transportation -People take up less land -Heating/cooling use per person can decline in multi-dwelling buildings -Most cities have lower greenhouse gas emissions per capita than the national average of their country
Biomass
-Wood, charcoal, manure, plants -Burned for heat & cooking -Most used renewable source in the world, 10% world energy consumption -3.5% US energy consumption Why is it better to burn biomass rather than fossil fuels? Biomass is Carbon neutral- CO2 emitted by burning biomass is canceled out by amount of CO2 removed from atmosphere by plants
Primary Pollutants
-come directly from source- smokestack, exhaust pipe, natural emission source-CO, CO2, SO2, NOx, PM, VOCs
Secondary Pollutants
-primary pollutants that have transformed in presence of sun, water, or oxygen (sun being the major cause of these transformations)-Ozone, sulfate, nitrate, sulfuric acid, nitric acid
Issues with Synthetic Fertilizers- Ecosystem harm
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Factors that Drive Human Population Growth
1) Changes in population size2) Migration3) Fertility4) Life expectancy5) Age structure
Biomass pros and cons
Advantage: -Can be carbon neutral-Materials readily available & cheap Disadvantage: -Carbon emissions associated with farming biomass materials-Indoor cooking & heating with fire major cause of health problems in developing countries
Coal pro and cons
Advantage: -Energy-dense-Relatively easy to exploit via surface mining-Requires little refining before burning-Solid so transported easily via train, barge, truck Disadvantage: We have used up most surface coal deposits, meaning we are reliant on more -dangerous & expensive subsurface mining-contains impurities- sulfur, mercury, lead, arsenic-coal ash (We'll go into more detail on this)-burning releases CO2, greenhouse gas (more than natural gas or oil)
Hydroelectricity pros and cons
Advantage: -Impoundment plants generate lots of electricity-No air pollution, waste products or greenhouse gas emissions associated with the running of the plant. The construction of the plant uses fossil fuel energy. Disadvantage: -Reservoir floods land forcing relocation & decomp of plants → Methane-River unsuitable for organisms needing free-flowing water-Parasites more common in reservoirs in tropical regions-Blockage of sediment flow to ocean
Solar Energy pros and cons
Advantage: -No air or water pollution-No greenhouse gas emissions-Energy produced when needed most (hot days)-Once initial cost paid off, electricity basically free Disadvantage: -PV panels expensive-Long payback period when solar radiation is low-Limited technology for recycling PV panels-Emissions associated with manufacturing & transportation
Geothermal Energy pros and cons
Advantage: -No significant pollution-Massive worldwide potential Disadvantage: -High upfront costs-Many resources too expensive to access
Petroleum pro and cons
Advantages: -Energy dense-Burns more cleanly than coal -emits 85% as much CO2 as coal-Ideal for modes of transportation Disadvantage: -Produces CO2 when combusted-Contains sulfur & trace mercury, lead, arsenic-Oil spills can be disastrous-Leaks from cars & boats
Natural Gas pro and cons
Advantages: -Fewer impurities than coal & oil-Emits almost no sulfur, no SO2 emissions (acid rain)-Emits 60% as much CO2 as coal Disadvantage: -Unburned methane escapes into the atmosphere, Leaks from ground after extraction, 25x more potent as a greenhouse gas than CO2-Risks of the fracking process
Nuclear Energy pros and cons
Advantages: -No air pollution or CO2 emissions at plants However there are emissions associated with mining, processing & transporting nuclear fuel, which results in about 10% of the CO2 emissions as generating the same amount of electricity from coal.-Countries w/out fossil fuel reserves can lower dependence on foreign oil Disadvantages: -Radioactive waste which is nuclear fuel that can no longer produce enough heat to be useful in a power plant but continues to emit radioactivity. It requires very careful storage to prevent accidents or environmental pollution.-Possibility of accidents 3 mile Island, PA, 1979 Chernobyl, Ukraine, 1986 Fukushima, Japan, 2011
Wind Energy pros and cons
Advantages: -No pollution or greenhouse gas emissions-Wind farms can share land with other uses such as agriculture and grazing cattle Disadvantage: -Rely on expensive batteries to store electricity if off-grid-NIMBY- some people think they are ugly and loud and don't want them near their house-Bird and bat deathsNew locations away from migration paths
Hydrogen Fuel Cells pros and cons
Advantages: ● Acts as an energy carrier● Could be sustainable if hydrogen gas is generated using wind/solar energy● 80% efficient in converting potential energy of hydrogen and oxygen in to electricity● Water is only by-product Disadvantages: ● Need innovations in obtaining hydrogen without expending fossil fuels● Distribution network needed to safely deliver hydrogen to consumers
Irrigation Methods
Agriculture is world's largest user of water (70%) These are 4 of the main types of irrigation used today: 1) Furrow2) Flood3) Spray4) DripBut new smarter technologies are being developed.
Population Pyramids
Aka Population Age Structure Diagrams Visual representations of age structure within a country for males & females
Impervious surface
Also known as impermeable surfaces, impervious surfaces are -Areas of human-made hard ground that do not allow water to penetrate into the soil -Roads, sidewalks, parking lots, driveways, airports, rooftops -Concrete, brick, stone, asphalt-Urban areas have a very high % of impervious surfacesPicture is of uptown Charlotte, NC.
Aging and Disease
Does a high life expectancy and a low infant mortality rate equal a low crude death rate? ○ Answer: NO! ○ Example: United States has a much higher crude death rate as compared to Mexico (8 per 1000 people versus 5 per 1000 people). ■ United States has a much larger elderly population aged 65 or older (13%) ■ Mexico's elderly population is only 6 percent. Heart Disease- Leading cause of death in U.S. ● Infectious Diseases ○ Tuberculosis and malaria used to be responsible for the largest number of deaths. ○ Human immunodeficiency virus (HIV), which causes Acquired Immune Deficiency Syndrome (AIDS), is responsible for more deaths annually than either tuberculosis or malaria. ■ Between 1900 and 2007, 22 million people were killed by AIDS-related illnesses. ■ HIV disproportionately infects people aged 15-49.
Concentrated Animal Feeding Operations (CAFOs)
Good: -Super productive, helps feed world demand for meat-Uses small amounts of land Bad: -create poor conditions for animals-animals highly susceptible to disease (because living in such close quarters) → antibiotics → antibiotic resistant bacteria-large buildup of animal waste
Why do birth rates decline as income increases?
Having more children becomes a financial burden versus an economic benefit Relative affluence, more time spent pursuing education, career driven, and availability of birth control increases the likelihood that people will choose to have smaller families However, cultural, societal, and religious norms all play a role in birth rates
THOMAS MALTHUS
Human population grows exponentially, while food grows linearly Humans will eventually reach "carrying capacity"- our growth is limited by food supply
IPAT equation
Impact = Population x Affluence x Technology
Formation of Ozone in the Troposphere
NO2 broken down by sunlight into NO + O (nitric Oxide) Free oxygen bonds w/ O2 to form ozone When you add VOCs into the equation, VOCs bond with NO to form photochemical oxidants, which combine with ozone to create photochemical smog. ● UV-C radiation breaks the bonds holding together the oxygen molecule, leaving two free oxygen atoms● Free oxygen atoms combine with O2 to produce ozone● Ozone breaks down into O2 and free oxygen atoms when it absorbs both UV-C and UV-B light
Nation's population growth rate
Nat. Pop. Growth rate = [(CBR+immigration) - (CDR+emigration)] / 10 Each measurement is per 1000 individuals (which is why we divide by 10)
Particulate Matter- solid or liquid particles suspended in the air. Sources: road dust, combustion of coal & oil
PM10: -filtered by nose & throat-not regulated by EPA-scatters & absorbs sunlight, contributing to haze PM2.5: -major health concern-can be deposited deep in respiratory tract-composed of more toxic substances-contributes to haze
Equation
Population - two people consume twice as much as one person. Two countries with similar economic status will typically have different impacts based on their populations Affluence - created by economic opportunity. Think about impacts a typical middle or upper income family has versus those in poverty. More affluent, typically the more impact on the environment.
Does Organic/ Grass Fed/ Local/ Antibiotic-free = Sustainable Meat??
Positive: Better livelihood for animals,No development of antibiotic resistant bacteria,Lower carbon emissions associated with shipping,Manure fertilizes land Negative: Requires MUCH more land,Lower rates of production = more expensive,Still large methane source
Renewable Energy
Potentially Renewable :This means the resource is renewable as long as we do not consume it more quickly than it can be replenished Biomass Biofuels Non-depletable: This means that the resource can't be depleted no matter how much we use it SolarWind Geothermal Hydroelectric Tidal
Major Air Pollutants
Sulfur dioxide (SO2): -Sources: combustion of coal & oil, volcanic eruptions-Problems: respiratory irritant, harmful to plants Nitrogen oxides (NOx): -Sources: all combustion reactions, fires, lightning-cars & fossil fuel combustion-Problems: leads to formation of tropospheric ozone & smog, respiratory irritant Carbon dioxide (CO2): -Sources: complete combustion, burning of fossil fuels-Problems: greenhouse gas; colorless/ odorless Carbon monoxide (CO): -Sources: incomplete combustion, vehicle exhaust-Problems: significant in urban areas (cars); dangerous indoor air pollutant (gas powered homes); shortness of breath, loss of consciousness, death Photochemical Oxidants: Form from sunlight acting on other compounds- NOx and SO2 Ozone most common (will have a separate lecture on ozone) Harmful to plant tissue, human respiratory tissue, construction materials Volatile Organic Compounds (VOCs): Hydrocarbons (CH bonds)- gasoline, lighter fluid, perfumes, cleaning products Strong aroma, cause headaches or irritation Coniferous trees Lead to formation of ozone Lead: Present in coal & oil, used to be in gasoline, lead-based paint in old homes Toxic to central nervous system, affects child development Mercury: Amounts have increased due to combustion of fossil fuels Increased concentration in fish→ can harm people who eat fish Harmful to central nervous system
Sustainability
meeting the needs of the present without sacrificing the needs of tomorrow
The Green Revolution
the Green Revolution was a movement that took place in the -1950s&60sthat lead to the modern agricultural practices we see today. The Green Revolution was started by-Norman Borlaug- Father of Green Revolution He worked with Mexican farmers to increase their yields by breeding new varieties of wheat to reduce disease -Selective breeding for desired traits (pesticide resistance, high yield, larger plant) Encouraged-Monocropping- only growing one type of crop over a large area ● Crop production increased in many areas of the world that were struggling with food security ● Borlaug won Nobel Peace Prize in 1970 for his contributions to reducing world hunger ● Green Revolution lead to advances that improved livelihood for many people ● But had some negative environmental impacts that we're dealing with today
Crude birth rate
the number of births per 1000 individuals per year.
Crude death rate
the number of deaths per 1000 individuals per year.
Family planning
the regulation of the number or spacing of offspring through the use of birth control. As more women become better educated, the Total Fertility Rate tends to drop
Chemical Pollution
these chemicals are especially harmful to the human central nervous system and can cause other health issues Lead: -rarely found in natural sources of drinking water-water becomes contaminated as it passes through older home/buildings that contain lead pipes or cities with old water systems Arsenic: -occurs naturally in Earth's crust; dissolves in the groundwater-mining can contribute to arsenic in groundwater Mercury: -naturally occurring heavy metal-increased concentrations in water as a result of human activities-2/3 of mercury from human activity is from the burning of fossil fuels
Slums
urban area characterized by substandard housing, lock of formal property ownership, inadequate urban services & high rates of poverty, Home to nearly 1 billion people globally & projected to double by 2030, Dharavi, Mumbai population density 600,000 people/ sq mi
Requirements of sustainable agriculture
○ Socially responsible- food production for farmers & communities, maintaining good public health, improving rural quality of life ○ Profitable- farmers are making money ○ Environmentally sound- ecologically sound practices, promoting biodiversity & smart natural resources management
Clean Drinking Water Access
● 2.1 billion people do not have access to safe drinking water worldwide● People (almost always women) walk up to several hours per day to obtain water that may not even be clean● Unsafe water is responsible for 1.2 million deaths per year
Thermal Inversions
● A relatively warm layer of air at mid-altitude covers a layer of cold, dense air below.● The warm inversion layer traps emissions (pollutants) that then accumulate beneath it.● Common at night in cities surrounded by mountains
Coal
● A solid fuel formed primarily from the remains of trees, ferns and other plant materials that were preserved 280-360 mya ● In U.S., coal is most commonly used for electricity generation
Forest Conservation & Agroforestry
● Agriculture responsible for 80% of tropical deforestation ● Agroforestry- growth of trees & shrubs amongst crops & grazing land ● Improve soil health ● Help connect forest fragments ● Temperature & humidity regulation ● Provide additional income (banana & mango trees, wood) ● Coffee & cocoa grow well in shade
Environmental Issues in Slums
● Air pollution ● Lack of access to running water & indoor plumbing ● Scarcity of formal services ● Waste is deposited in open ditches, which can run into waterways, polluting the water & drinking sources ● Often tight & supportive communities with citizen-organized schools, clubs & all kinds of businesses ● UN recommends that countries upgrading existing infrastructure of slums rather than clear them out into new settlements
Rachel Carson
● American scientist & author ● 1963 book "Silent Spring" ● brought issues with DDT to the forefront ● put the environmental movement into overdrive ● Helped lead to ban of DDT in US in 1972
The Urban Heat Island Effect
● Because they have low albedo, impervious surfaces absorb a lot of solar radiation ● Heat is slowly released from the urban surfaces to the atmosphere ● Especially keeps nighttime air temperatures higher than surrounding areas, as heat is being released even after the sun goes down
Integrating Crops & Livestock
● Beef & dairy cows raised on pastures ○ Grazed grasses grow stronger roots, reducing soil erosion (when not overstocked) ○ Increase soil fertility & carbon storage ○ Fewer antibiotics ○ Meet rising demand for grass fed beef & dairy ● Reduced need for CAFOs ○ Reduced pollution from manure lagoons ○ Better animal health ● Support local market for forage crops like alfalfa, encourage crop rotation
Synthetic Pesticides
● Beginning in 1940s, synthetic fertilizers & cultivation of single species fields disrupted natural plant defenses, increasing susceptibility of crops to pests ● Pests- organisms that feed on, compete with or cause disease in crops ● Lead to increased use of pesticides, many of which were harmful to non-target species
Active Solar Energy
● Capturing the energy of sunlight with the use of a photovoltaic cell and generating hot water or electricity● Earth is bathed in an almost limitless amount of solar energy● The amount of solar energy available in a particular place varies with cloudiness, time of day, and season● The average amount of solar energy available varies geographically.
Anthropogenic Sources of Air Pollution
● Cars● Factories● Energy Production● Waste disposal● Wood combustion/ human fires
Eastern North Carolina Hog Farms
● Coastal North Carolina via satellite after hurricane Florence in 2018 ● Hurricane Michael followed a few weeks later, worsening the problem ● Many of these rural NC counties have very high rates of poverty & the hog industry supports the livelihoods of the people ● Health concerns associated with hog farms: asthma, nausea, exposure to antibiotic resistant bacteria ● Correlation between proximity to hog farms & health issues (Duke Univ. Study)
Methane from cattle?
● Cows emit a massive amount of methane through belching & flatulence ● The production of cows in mass quantities worldwide has increased the amount of methane in the atmosphere over the past century ● Methane is a super potent greenhouse gas that is 25x more effective at trapping heat than carbon dioxide
Issues with Synthetic Pesticides
● DDT & other harmful pesticides are not banned worldwide- less harmful sprays & methods becoming more common ● They are frequently used to reduce mosquito populations in tropical countries where mosquito borne diseases such as malaria are common
Issues with Synthetic Fertilizers
● Degrades natural organic matter content ● Excessive application can lead to soil acidification ● Runs off into water sources○ Nitrogen & Phosphorus → eutrophication → Harmful Algal Blooms → lower oxygen levels → Dead Zones
Electricity
● Electricity is a secondary source of energy- it is obtained from the conversion of a primary source (coal, natural gas, wind, etc.) ● Electricity is an energy carrier- moves energy in a convenient form to end users. ● Almost 40% of energy used in the US is used to generate electricity. ● Factoring in conversion losses, only about 35% of electricity generated is actually available to end users
Integrated Weed & Pest Management
● Eliminating use of chemical pesticides & herbicides ● Crop diversity & rotation ○ Dispersing preferred food sources of pests○ Blending in crops pests don't eat ○ Multiple crops attract diverse insects, some of which may be predators of pests ● Provide habitat for beneficial insects & organisms that are predators of crop eating pests (ladybugs, birds, bats)
Organic Composting
● Enriches soil, reducing need for chemical fertilizers ● Increases soil carbon storage ● Reduces organic matter that ends up in landfills → lower methane emissions
Farm-raised or wild-caught?
● Farmed fish prevent the issues of bycatch & overfishing ● Farmed fish have a smaller carbon footprint (high energy subsidy for offshore fishing) ● Not all fish farms use good practices ● Overcrowding & diseases are issues ● Health benefits between farm-raised & wild caught fish vary
Petroleum
● Fluid mixture of hydrocarbons, water and sulfur that occurs in underground deposits● Liquid fills the space in porous rock such as sandstone, and capped by non-porous rock● Wells drilled into deposit and extracted with pumps● Transported by pipeline● Most commonly used for transportation (Oil & gas in cars)
Tidal Energy
● Form of hydropower that converts energy obtained from tides into electricity● Not widely used● Good because more predictable than wind & sun● Requires tidal range of 10 ft or more● No plants in US
Hydrogen Fuel Cells
● Fuel cell- electrical-chemical device that converts fuel (like hydrogen) into an electrical current● 2H2 + O2 Energy + 2H2O● Supplying hydrogen can be a challenge because free hydrogen gas relatively rare in nature and because it is explosive● Must separate hydrogen from compounds using heat from a fossil fuel or electricity
Hydroelectricity
● Generated by kinetic energy of moving water● 2nd most common renewable energy source worldwide after biomass● Run of the river - dams do not store water behind it in a reservoir.○ Generally small○ Can be greatly affected by droughts● Water impoundment - water is held in a reservoir behind the dam○ Allows for electricity generation on demand○ Determine rates of flow of water by the opening and closing of gates
Stratospheric Ozone Depletion
● Global ozone concentrations decreased by more than 10% in the early 2000s .● Depletion is greatest at the poles (especially south pole- very cold polar stratospheric clouds).● Decreased stratospheric ozone has increased the amount of UV-B radiation that reaches the surface of Earth.
Geothermal Energy
● Heat that comes from natural radioactive decay of elements deep within Earth● Water is heated where magma comes close to groundwater, which humans can access by drilling● Heat exchangers can transfer energy from groundwater to liquids that flow through household radiators● Can be used to generate electricity similarly to a thermal plant, with the steam coming from water evaporated by Earth's internal heat
The Future of Fossil Fuel Use
● If current global use patterns continue, we could possibly run out of conventional oil in 40 -60 years● Natural gas supplies would last slightly longer● Coal supplies will last for at least 100 years, and possibly longer● Advances in technology, shifts to non-fossil fuels and change in social choices and population patterns could alter these estimates
Impervious Surfaces & Runoff
● Impervious surfaces prevent rainwater from infiltrating the soil & becoming groundwater ● The water runs off into nearby streams ● During heavy rainfall, this leads to increased chance of flooding ● Also a water quality issue- impervious surfaces tend to be polluted (trash, chemicals) ● Runoff from areas under construction increase sediments that run into streams
Fossil Fuel Formation
● In swamps, river deltas, ocean floor, a large amount of detritus (dead organic matter) can build up quickly in an anaerobic (low/no oxygen environment), and decomposers cannot break down all the detritus ● Organic material buried under succeeding layers of sediment, exposed to heat and pressure ● Organic compounds chemically transformed into high-energy solid, liquid and gases that are easily combusted.
Issues with Gas-Powered Equipment
● Increased fossil fuel consumption and greenhouse gas emissions ● Land is plowed intensively → soil vulnerable to erosion ● Eroded soil runs off into rivers & eventually to oceans○ Reduce light penetration → decreased photosynthesis by aquatic plants → less oxygen for other life
Social Factors
● Increasing income for farmers ○ Integrated pest management & composting reduces need to buy synthetic pesticides & fertilizer ○ Trees can provide additional sources of income in addition to storing carbon & increasing soil health ● Better working conditions for farmers on large farms ○ Address child & forced labor issues worldwide ○ Providing housing, protective equipment, maternity leave & living wage for farmers ● Gender equality ○ Women make up more than 40% of agricultural labor force in developing countries ○ But many can't own land or trees, denied access to education ○ Crop productivity boosted 20-30% when women have equal access to resources & opportunities ○ Women invest income in health & education of family, increasing overall human welfare
Landscape approach
● Integrating farms with the natural systems around them ● Uncultivated areas near farms foster biodiversity & provide habitat for beneficial wildlife & pollinators ● Decreased need for pesticides ● Streamside woodlots buffer waterways ● Plants and livestock intermixed
Industrial Pollution
● Leaks from vehicles & gas stations & pipelines● Lack of regulation on factory pollution into waterways for a long time● Acid rain● Acid mine drainage
Urban Agriculture
● Localized food sources reduce transportation emissions & retail cost ● Backyard & community gardens ● Urban greenhouses & indoor hydroponic farms ○ Hydroponics- crops grown with roots directly in mineral solution ● Creates green space in cities
Environmental Impacts of Suburban Sprawl
● Low density housing requires more land, converting previously agricultural or forested land to impervious surfaces like roads & parking lots ● People rely on cars to get around because things are spread out = higher carbon dioxide emissions ● Average home size is more than 2x as large as in 1950- that means more energy required to heat & cool home, more land needed per home
Cover Crops
● Many fields left bare when crops aren't growing, leaving soil vulnerable to erosion and nutrient leaching ● Cover crops- non-food crops planted during off season to protect soil and/or for livestock grazing ● Hold soil in place preventing sediment runoff ● Add organic matter to soil to help maintain long term productivity ● Increase carbon storage ● Need policies & incentives in place to encourage planting of cover crops
Pharmaceutical Drugs
● Many streams in the US & around the world contain ○ Antibiotics ○ Reproductive hormones ○ Nonprescription drugs ○ Steroids ● Drugs that mimic estrogen (birth control) connected to reproductive changes in fish
Smart Irrigation & Water Conservation
● Minimizing water use for irrigation through drip irrigation systems ● Smart irrigation- systems controlled by apps that can adjust to precipitation & soil moisture to only water when necessary ● Grow water efficient crops that are suited to regional climate conditions ● Plant tree buffers along waterways ○ Reduce erosion & polluted runoff ○ Increased carbon storage
Sediment Pollution
● Most common● Loose soil particles swept into waterways by erosion from agriculture, forestry & urban development● Causes cloudy water that restricts vegetation growth (lowering oxygen production) & alters nutrient levels View of a sedimented stream after heavy rainfall & flooding from Grandmother Mountain, NC
Crop Diversity & Rotation
● Multi-year, multi-crop rotations produce high yields for each crop in the rotation ● Reduces pests & weeds w/ less reliance on chemical pesticides ● Enhanced soil fertility because different crops use & produce different nutrients, so not all of the same nutrients get depleted ○ Peas, beans, alfalfa produce nitrogen that subsequent plants could use
Transportation
● Nearly 30% of energy use in the U.S. is for transportation ● About 90% of energy used for transportation comes from petroleum (oil)
Are GMOs bad for humans?
● No scientific evidence that GMOs are bad for human health!! But there is also no proof that they are good/ unharmful either. ● One issue- many of today's GMOs are resistant to glysophase (aka Roundup) and this has made it one of the most common pesticides because it doesn't kill the crops, just the plant pests around them ● Pesticide resistance is an issue- more pesticide ends up being used ● New studies showing glysophase may be bad for animals & possibly humans
Offshore Wind Energy
● Offshore wind conditions even more desirable for electricity generation● Denmark, Netherlands, UK Sweden● US has one offshore wind project- Block Island Wind Farm off coast of Rhode Island● More in planning
Natural Gas
● Oftentimes found at the top of oil deposits (because lighter than oil), as well as in gaseous deposits separate from petroleum● 80-95% methane (CH4), 5-20% ethane, propane, butane● Two largest uses in U.S. = electricity generation, industrial processes● Also used to manufacture nitrogen fertilizer and in homes for cooking and heating air and water
What can YOU do?
● Reduce/ eliminate meat & dairy intake● Eat pasture raised beef/ cage free eggs● Buy organic produce● Grow your own foods/ shop at local farmers markets○ Huntsville Farmers Markets● Reduce food waste○ Buy only what you can use○ Take leftovers○ Compost organic food waste
Desalination
● Removing salt from the seawater to create a supply of freshwater○ Heat evaporates the water & vapor is collected, salt left behind then vapor allowed to cool back down○ Pumps send water through membranes that filter out salt● Large-scale desalination plants common in Israel & Saudi Arabia● US has 300 desalination plants that help supply water to large coastal cities like Tampa & San Diego● Expensive & requires a lot of energy; working towards small-scale solar based technology
Renewable Energy Future
● Renewable energy solutions are not perfect, and often still rely on fossil fuels● Need to develop new technologies● Existing electrical infrastructure in the US must be improved● Smart grid being developed- efficient, self-regulating electricity distribution network that accepts any source of electricity and distributes it automatically to end users
Acid Deposition
● SO2 and NOx released into atmosphere from fossil fuel combustion● React with water vapor in the atmosphere to form sulfuric acid (H2SO4) and nitric acid (HNO3)● Blown by wind & falls as acid rain, snow or fog● Damage to vegetation, acid leaching in runoff & groundwater, acidification of aquatic ecosystems
Changing Meat Consumption Patterns
● Since 1950, both global meat & seafood consumption per person per year has doubled ● We have had a fairly high meat diet in the US & other developed countries for a while ● Developing countries that used to rely heavily on veggies for food have had a crazy uptick in demand for meat!
Do Organic Fertilizers Help?
● Still runoff of nitrogen & phosphorus from organic fertilizer ● However they tend to be less concentrated than synthetic fertilizers, so contribute less to eutrophication of waterways ● More expensive? What about free? ○ Compost! Food & yard waste can provide nutrients to your garden
Agricultural Pollution
● Synthetic & organic agricultural fertilizers run off fields into water systems → boost nutrient availability in water (eutrophication)→ promotes algae growth → dead zones● Fertilizers leach into groundwater● Manure lagoon overflow
Issues with Synthetic Fertilizers- Air Pollution
● Synthetic fertilizer application emits nitrous oxide (N2O) an air pollutant & greenhouse gas ○ Responsible for 2/3 of N2O emissions in US ○ Nitrous oxide is 300x more potent as a greenhouse gas than CO2 ● Application of synthetic fertilizers responsible for 90% of ammonia (NH3) pollution globally ○ Combines with other air pollutants to form fine particulate matter which can negatively affect human respiratory systems
Cattle Grazing in the Amazon
● The Amazon is being rapidly deforested to support cattle grazing ● Slash & burn tactics are used to clear the land for cattle ○ And contributed to significant wildfires in 2019 ● Clearing of land for agriculture accounts for 80% of deforestation in Amazon
Biomagnification
● The concentration of a pollutant increases up the food chain in a process called biomagnification ● Larger animals have to eat more of the smaller animals so the amount of chemical multiplies up the food chain; organisms can't break it down fast enough so the chemical accumulates ● Issue now for human exposure to mercury from fish
Air Pollution
● The introduction of chemicals, particulate matter or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials or to alter ecosystems ● Pollution of the troposphere (first layer of the atmosphere, ground to about 10 mi. up)- ground level pollution
Suburban Sprawl
● The spread of urban populations away from the centers of cities to widely dispersed areas that have relatively low population density ● Prominent in US, Canada, Australia & some European countries ● Separation of where people live, work & shop into isolated zones with roads & highways between them ● Less-dense & more resource-intensive form of urbanization ● Majority of US population lives in suburbs as of 2010 census ● Suburban areas now contain 90% of office space in US ● 80% of new retail space is in suburban malls & superstores ● Metropolis/ metropolitan area- the city center + its suburbs○ Ex: City of Atlanta pop = ~500,000 Atlanta Metropolitan area pop = ~6 million! ● Megalopolis- chain of roughly adjacent metropolitan areas that run together (Boston-NYC-Philly-Baltimore-DC)
What can be done?
● UN invests $10 billion per year to help improve water quality and work toward universal access to safe & affordable water and sanitation ● 2.5 billion people have gained access to improved drinking water supplies since 1990 ● Strategies: ○ Large-scale sewage treatment & water-delivery systems ○ Small scale water purification that can be used in households
Nuclear Energy
● Uranium-235, a radioactive isotope, undergoes fission (nucleus splitting), which produces heat and triggers more fission reactions, leading to immense amount of heat energy● Heat turns water to steam, which turns a turbine, generating energy
Urbanization
● Urban = large numbers of people live together in dense settlements & work non-agricultural jobs ● Rural = populations are geographically spread out and more reliant on agricultural employment
Natural Sources of Air Pollution
● Volcanoes- particulate matter and SO2 ● Forest fires - particulate matter ● Lightning- The rapid heating and cooling of the gases within a lightning bolt produces nitric oxide (NO), which combines with oxygen to create nitrogen dioxide (NO2) leads to formation of ozone ● Plants (?!)- Volatile Organic Compounds(VOCs)- terpenes emitted by coniferous trees, react with other compounds in air forming a haze
Wind Energy
● Wind turbine- converts kinetic energy of moving air into electricity● Towers up to 100 m tall with blades 40-75 m long● Under average wind conditions, a wind turbine may produce energy ~25% of the time on land● 1 turbine can power about 400 homes
Photovoltaic Cells
● generate a low-voltage electric current when they are exposed to direct sunlight● typically are 12 to 20 percent efficient in converting the energy of sunlight into electricity● in many areas, small-scale solar energy systems are economically feasible
What leads to a higher life expectancy?
1.High level of quality health care2.Adequate food supply3.Potable drinking water4.Proper sanitary living conditions5.And moderate levels of pollution
Tropospheric Ozone
1st layer of atm 10% of ozone in atm BAD ozone Toxic to humans & vegetation Leads to smog formation
Coal Ash
engineered structure used at fossil fuel power stations for the disposal of bottom ash and fly ash; used as a landfill to prevent the release of ash into the atmosphere. -Overflows common (Dan River, NC, 014)
Stratospheric Ozone
2nd layer of atm, ozone layer near bottom of stratosphere 90% of ozone in atm GOOD ozone Earth's UV radiation shield "Ozone hole"
Migration
A country may experience a change in population due to migration. Net migration rate: the difference between immigration and emigration in a given year per 1000 people in a country.
Human population growth over time
Around 1600, innovations in agriculture and sanitation lead to lower death rates, and birth rates remained high, leading to exponential population growth
Salt Pollution
Causes: ● Salt left behind from evaporated irrigation water harms the soil & can runoff into nearby water sources after rainfall● Salt concentrates in river systems when water evaporates from reservoirs behind dams Effects: ● Increases in freshwater salt concentration can disrupt particular water chemistry that aquatic species require● Salinity of CO River more than doubles as it passes through the heavily dammed & irrigated region of north-central CO and SW AZ
US Water Regulations
Clean Water Act (1972): ● maintain chemical, biological and physical integrity of the navigable waters of the United States● unlawful to discharge any pollutant from a point source into navigable waters, unless a permit was obtained Safe Drinking Water Act (1974): ● protect public health by regulating the nation's public drinking water supply● authorizes the EPA to set national health-based standards for drinking water to protect against naturally-occurring and man-made contaminants that may be found in drinking water
Human Population Facts
Current human population: 7.9 billion Every 5 days, global human population increases by roughly one million lives
Biofuels
Ethanol: ● Produced from corn● Added to gasoline● Provides less energy than gasoline, fossil fuels needed to grow corn, may not really help reduce CO2 levels● Agricultural issues associated with growing corn (fertilizer, pesticides) Biodiesel: ● Extracted from soybean & palm oils● Used restaurant grease● Palm oil plantations bad for environment & ecosystem in SE Asia● May or may not be carbon neutral ● Promise for algae-based biodiesel
ESTHER BOSERUP
Food production can, and will, increase to match the needs of population. The threat of starvation invents new technologies to produce more food
growth rates
For a country, when inputs are greater than outputs, growth rate is positive. When outputs are greater than inputs, growth rate is negative.
Modern Agricultural Practices
Gasoline or Diesel-Powered Farm Equipment - reduced time, effort & people needed to cultivate farmland ● Modern Irrigation - 20% of the world's cropland is irrigated, which allows dryer areas to grow more crops ● Synthetic Fertilizers - use has increased by more than 150 million tons per year since 1950; provide primary nutrients for plant growth ● Synthetic Pesticides - manufactured chemicals applied to combat insects & weeds ● Genetic Manipulation - selecting desirable crop varieties or inserting desirable traits into a genes of crops
Life Expectancy
Infant mortality rate: the number of deaths of children under 1 year of age per 1000 live births. Child mortality rate: the number of deaths of children under age 5 per 1000 live births.
Innovations in Food Production
Irrigation Development Creation of the tractor and 3-point hitch Genetic modifications of crops ○Scientists isolate genes associated with desirable traits (drought tolerance, high yield, herbicide resistance, bigger fruits/veggies) ○Can grow more food across less acreage
Malthus vs Boserup
Malthus says there is limited growth with food production (and other limiting factors like water, timber and fuel); Boserup states that there can be unlimited growth of food due to human innovations.
Urban Heat Islands & Thunderstorms
Many studies have been conducted to try to understand how urban heat islands may affect thunderstorms. The idea being that-Warmer air in city wants to rise above the cooler air around it-Rising air cools & forms clouds & precipitation-Many studies show that thunderstorms are more likely to initiate in cities than in their surrounding vegetated areasA 2015 study by scientists at Northern Illinois University found that there it was 5% more likely for a storm to initiate in or after passing through the Atlanta UHi than a vegetated area of similar size. Other studies have reached similar conclusions. Some studies have found that storms that are already initiated may split and move around the city. There are other factors to consider besides the urban heat island effect, such as surface roughness and air pollution. Check out the linked article to read more about this topic!
Water Pollution
The contamination of streams, rivers, lakes, oceans, or groundwater with substances produced by humans that negatively affect organisms Point sources: Distinct location causing pollution-factory pump waste into stream-sewage treatment plant dispose waste into ocean Nonpoint sources: Diffuse area causing pollution-entire farming region-runoff from large area of impervious surface
Technology
can degrade the environment or create solutions to minimize impacts○ Manufacturing of CFCs for refrigeration and air conditioning led to the destruction of the ozone layer○ Yet, the development of the electric and hybrid cars have reduced the impact of automobiles on the environment○ Perhaps a better way of writing the IPAT equation would be to write technology as "Destructive" technology.
Fertility
Total fertility rate (TFR): an estimate of the average number of children that each woman in a population will bear in her childbearing age between puberty and menopause. Replacement level fertility: the total fertility rate required to offset the average number of deaths in a population and for the current population size to remain stable. Developed countries: countries with relatively high levels of industrialization and income. TFR is typically 2.1. Developing countries: countries with relatively low levels of industrialization and income. TFR is usually greater than 2.1 to attain replacement level fertility.
Changes in Population Size
[CBR - CDR] ÷ 10 = growth rate in % [20 - 8] ÷ 10 = 1.2 percent Note that we divide [CBR - CDR] by 10 so that we can represent the change as a percent. CBR and CDR are rates expressed per 1000
