GENVI_NOTES 2.1_ATMOSPHERE PDF - Environmental Issues and Problems

SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology...

SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology MODULE 2 ENVIRONMENTAL ISSUES AND PROBLEMS UNIT 1 Problems in the Atmosphere The atmosphere is the mixture of gases that surround the Earth. It is made up of 5 layers, the innermost two of which contain most of these gases. The troposphere, the atmospheric layer nearest the Earth’s surface, contains most of the planet’s air-the mixture of gases that people depend on to stay alive. It is made up of 78% nitrogen, 21% oxygen, and 1% mixture of other gases like carbon dioxide, nitrous oxide, helium, and argon. It also contains water vapor in variable amounts depending on temperature. The troposphere is responsible for maintaining the conducive temperature of the earth, allowing various organisms to thrive. The stratosphere is the Earth’s second layer of air. It contains much of the atmosphere’s ozone gas (O 3), which lies in a sub-layer of the lower stratosphere known as the ozone layer. This stratospheric ozone gas serves as a sunscreen for the planet by filtering out about 95% of the sun’s harmful ultraviolet (UV) radiation before it can reach the Earth’s surface. Unfortunately, anthropogenic activities are causing problems in the atmosphere, problems that are affecting us in a global scale. There are four major problems involving the atmosphere namely, global warming, air pollution, acid deposition, and ozone depletion. A. Global Warming Global warming refers to the accelerating rate in the increase of the average global temperature. This is due to the rapid increase in greenhouse gases found in the atmosphere due to anthropogenic activities. The Greenhouse Effect Solar radiation that reaches the surface of the earth is absorbed and then re-emitted back by the heated surface as infrared radiation (IR). This is the heat that we feel if we touch a surface that has absorbed solar radiation. Technically, if there is no atmosphere, the infrared radiation freely escapes into space. However, the heat absorbing components of the atmosphere prevent the IR from escaping, thus the heat is trapped on earth, much like the heat trapped in a farmer’s greenhouse, thus the name greenhouse effect. Among the components of the atmosphere, nitrogen and oxygen absorb little or no radiation. However, the minor components are the effective absorbers of IR particularly carbon dioxide and water vapor. These gases are responsible for the greenhouse effect thus called greenhouse gases. Once IR is absorbed by greenhouse gases, it is once again re-emitted in all directions, warming the surrounding air. So, warming the earth is an especially important natural process. The Earth would be too cold for most life if it were not for the greenhouse effect. Unfortunately, the amount of greenhouse gases has increased rapidly over the years due to human activities. The more the greenhouse gas, the more heat is trapped by the atmosphere, the warmer the earth. This is what we now call global warming. cdfeliciano 1  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology FIG. 2.1.1 The Greenhouse Effect https://medium.com/the-science- educator/carbon-cycle-and- greenhouse-effect-a-scientific- infographic-3bb647f4867a In the early 1980s, climate scientists became increasingly concerned about rising average annual atmospheric temperatures and CO2 levels might affect the global climate. In 1988, the Intergovernmental Panel on Climate Change (IPCC), which includes climate scientists and other experts, was formed in response to these concerns. They agreed on 3 points: Since 1980, the lower atmosphere on average has warmed at an accelerating rate by about 1.4 °F and CO2 levels have been increasing since 1958. Computer models and other data indicate that most of the temperature increase since 1980 is due to human activities, especially the burning of fossil fuels, which has raised atmospheric CO2 levels, and the rapid clearing of forests and other vegetation. The climate is beginning to change, and if human activities that promote such change continue at their current or higher rates, the Earth will likely experience further rapid atmospheric warming and long-term climate disruption during this century and the next. cdfeliciano 2  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology Fig. 2.1.2 Global Warming https://mrgeogwagg.wordpress.com/2015/06/24/greenhouse-effect-and-anthropogenic-warming/ Since the pre-industrial period, human activities are estimated to have increased Earth’s global average temperature by about 1 degree Celsius (1.8 degrees Fahrenheit), a number that is currently increasing by 0.2 degrees Celsius (0.36 degrees Fahrenheit) per decade (NASA). Causes of Global Warming 1. Burning of Fossil Fuel - Fossil fuels such as coal, crude oil, and natural gas, are formed for millions of years from buried remains of plants and animals, thus rich in carbon content - When these are burned, the carbon content is released into the atmosphere in the form of carbon dioxide, a major greenhouse gas - there are also the increased amounts of tiny particles in the lower atmosphere that scientists call ‘black carbon’ (soot or smoke) - the resulting layer of black particles in the lower atmosphere absorbs heat like a black blanket contributing to the warming effect of atmospheric particles - Although black carbon falls out of the lower atmosphere in days, while it is suspended in the air, it absorbs the sun’s heat millions of times more effectively than CO2. Overall, it is considered the second biggest contributor to global warming after CO2. - Methane, another greenhouse gas, is also released in the atmosphere by this process 2. Deforestation - Photosynthetic organisms absorb carbon dioxide from the atmosphere - Trees are the largest photosynthetic organisms and responsible for absorbing the - greatest amounts of carbon dioxide from the atmosphere - Most trees on earth are found in forests, making these ecosystems especially important in regulating the amount of carbon dioxide in the atmosphere cdfeliciano 3  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology - Human activities that lead to the removal or destruction of vast amounts of trees is called deforestation - Reducing the trees available for carbon dioxide absorption relates to an increase in this greenhouse gas and therefore an increase in global warming 3. Agriculture and Farming Practices - Methane is a greenhouse gas that is produced by the anaerobic decomposition of organic matter, such as animal wastes and dead plant materials, which is a natural process - however, increased agricultural activities have also greatly increased the amount of organic matter available for anaerobic decomposition, being the number one cause of methane release in the atmosphere Effects of Global Warming Climate Change is a long-term change in the average weather patterns that have come to define Earth’s local, regional, and global climates. With global warming, the climatic patterns of the earth changed rapidly, especially for cold areas. Some of the effects of global warming, indicative of climate change include: 1. melting and shrinking of ice sheets in the Arctic Sea, decrease snow cover of ice-capped mountains, and glacial retreat, all of which bring about a rise in sea level and coastal submersion 2. intensified weather disturbances that bring about intense rain and wind (la Niña phenomenon), as well as prolonged droughts and heat wave (el Niño phenomenon) 3. biomes are defined by their climatic characteristics, to which organisms are adapted to. Change in climatic conditions of biomes likewise affect organismal survival and decreases biodiversity and loss of ecological balance 4. food crops are likewise vulnerable to climatic changes, leading to a decline in the food supply of the global population 5. high rates of evaporation dry up lands, reduce freshwater supply, and lead to desertification cdfeliciano 4  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology FIG. 2.1.3 Global Warming and Climate Change Causes and Effects https://en.wikipedia.org/wiki/Effects_of_global_warming#/media/File:20200118_Global_warming_and_cli cdfeliciano 5  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology mate_change_-_vertical_block_diagram_-_causes_effects_feedback.png Dealing with Global Warming 1. Decrease Fossil Fuel Use - Conservation of energy - Use of renewable energy resources such as solar energy, wind energy, hydrogen energy, ocean energy, hydro power, geothermal power, and bioenergy 2. Reforestation and Afforestation - The importance of trees in reducing atmospheric carbon dioxide cannot be stressed enough 3. Enacting global and national laws and agreements - Steep penalties for non-compliant industries and businesses - Regulating and taxing carbon dioxide emissions of companies 4. Sustainable land management - Managing livestock to reduce methane emission - Crop management to avoid methane and nitrous oxides, such as from fertilizers B. Air pollution Air pollution is the presence of chemicals in the air, called air pollutants, at levels high enough to harm humans, other organisms, ecosystems, or human-made materials. Primary air pollutants include all chemicals that are emitted directly into the air from natural processes and human activities and that are build up to harmful levels. Secondary air pollutants are harmful chemicals that form in the air by reacting with primary pollutants or with chemicals naturally found in the air. Major Air Pollutants Sulfur dioxide Nitrogen oxide Carbon monoxide Ozone and Photochemical oxidants Lead Particulate matter Mercury from coal Causes and Sources of Air Pollution 1. Indoor/household air pollution - Solid fuels such as charcoal, peat, coal, wood pellets, corn, wheat, rye and other grains that can be burnt to release energy - Kerosene for cooking or oil lamps release the pollutants ethylene, Sulphur dioxide, and nitrogen oxide cdfeliciano 6  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology - products with volatile organic compound (VOCs) such as air fresheners and cleaning products 2. Outdoor ambient air pollution - any activity that involves burning releases pollutants in the atmosphere - agricultural pesticides Effects of Air Pollution 1. Formation of photochemical smog and acid rain 2. Depletion of nutrients from soil and waterways 3. Can harm forests and crops 4. Damage cultural icons such as monuments and statues 5. Respiratory and related health problems for animals, especially humans Solutions to Air Pollution 1. Air pollution cleanup strategies - any method that involves collecting and disposing of air pollutants after they have been produced - Example: directly collecting air pollutants from smokestacks, usually already in ash form to be buried somewhere. 2. Pollution prevention - focuses on eliminating or sharply reducing the production of air pollutants - Examples: use of solar cells and wind turbines (renewable energy resources) to produce electricity instead of burning fossil fuels, stop cigarette smoking, avoiding household materials that contain harmful chemicals, etc. 3. Enacting laws against air pollution - like the Philippine Clean Air Act of 1999 - designating smoking areas, etc. C. Acid Deposition Acid deposition, also called acid rain, refers to acidic particles and droplets falling from the air or washed out of the air by precipitation onto land and into aquatic systems. Depending on the prevailing winds, precipitation, and other weather factors, these acidic chemicals remain in the atmosphere for two days to two weeks. Gravity and precipitation eventually return the suspended particles and droplets to the earth’s surface in two forms. One is wet deposition, which consists of acidic rain, snow, fog, and cloud vapor. The other is the dry deposition made up of acidic particles. Causes and Sources of Acid Deposition Coal burning facilities and vehicles emit sulfur dioxide (SO2) and nitrogen oxides (NOx) into the atmosphere. After release, these molecules form acids in two ways. First, they can be deposited on the earth’s surface in the form of dry deposition and are converted to acid cdfeliciano 7  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology when they are mixed with water. Wet depositions are formed when sulfur dioxide and nitrogen oxides react with atmospheric water and oxygen to form sulfuric acid (H2SO4) and nitric acid (HNO3). They are then deposited to earth as rain, snow, or sleet. FIG. 2.1.4 Acid Deposition: Wet Deposition and Dry Deposition https://science.howstuffworks.com/nature/climate-weather/atmospheric/acid-rain.htm Effects of Acid Deposition 1. Respiratory diseases such as bronchitis and asthma 2. Leaching of toxic metals such as lead and copper from water pipes into drinking water 3. Damages statues, buildings, metals, and car finishes. Limestone and marble are especially susceptible. 4. Increased acidity on aquatic ecosystems: As the pH approaches 5, some species of plankton and mosses may begin to invade and populations of fishes may start to die Below a pH of 4.5, most fishes die Aluminum ions attached to the soil can be released into lakes where they make kill populations of fishes toxic mercury emitted by smokestacks can contaminate the waters 5. Damage to crops (especially at when soil pH falls below 5.1) cdfeliciano 8  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology 6. Prevents seed germination 7. Leach essential plant nutrients such as calcium and magnesium 8. Weaken trees and other plants so they become more susceptible to other types of damage Solutions to acid deposition 1. Cleanup strategies - adding lime or phosphate to neutralize acidified lakes 2. Prevention - use of solar cells and wind turbines (renewable energy resources) to produce electricity instead of burning fossil fuels, increase the use of natural gas, burn low-sulfur coal, etc. 3. Enacting laws against air pollution - like the Philippine Clean Air Act of 1999 D. Ozone Layer Depletion Near the ground, ozone (O3) is an air pollutant that causes lung damage and asthma attacks. But 10 to 30 miles above the Earth’s surface (16-48 km), ozone molecules protect life on Earth. They help shield our planet from harmful solar radiation. Ozone in the stratosphere forms when the two oxygen atoms in an O2 molecule are broken apart by the energy of sunlight. Each lone oxygen atom can then combine with a different O2 molecule to form O3, ozone. The ozone layer is the portion of the stratosphere where ozone molecules are present, mixed in among the other gases that comprise the atmosphere. FIG. 2.1.5 The Ozone Layer https://scied.ucar.edu/ozone-layer cdfeliciano 9  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology The ozone layer is where about 90% of the ozone in the Earth system is found. But ozone makes up only one to ten out of every million molecules in the ozone layer. (The rest of the molecules are mostly nitrogen and oxygen.) Ozone absorbs the most energetic wavelengths of ultraviolet light, known as UV-C and UV-B, wavelengths that harm living things. Oxygen molecules absorb other forms of ultraviolet light, too. Together, ozone and oxygen molecules are able to absorb 95 to 99.9% of the ultraviolet radiation that gets to our planet. When UV light is absorbed by oxygen and ozone, heat is generated, which is why the stratosphere gets warmer with altitude. Cause of Ozone Layer Depletion Ozone (O3) is a highly reactive gas. Its concentration in the atmosphere naturally fluctuates depending on seasons and latitudes, but it generally was stable when global measurements began in 1957. Groundbreaking research in the 1970s and 1980s revealed signs of trouble. In 1974, Mario Molina and Sherwood Rowland, two chemists at the University of California, Irvine, published an article detailing threats to the ozone layer from chlorofluorocarbon (CFC) gases. At the time, CFCs were commonly used in aerosol sprays and as coolants in many refrigerators. As they reach the stratosphere, the sun's UV rays break CFCs down into substances that include chlorine. One atom of chlorine can destroy more than 100,000 ozone molecules, according to the U.S. Environmental Protection Agency, eradicating ozone much more quickly than it can be replaced. Molina and Rowland’s work received striking validation in 1985, when a team of English scientists found a hole in the ozone layer over Antarctica that was later linked to CFCs. The "hole" is actually an area of the stratosphere with extremely low concentrations of ozone that reoccurs every year at the beginning of the Southern Hemisphere spring (August to October). Spring brings sunlight, which releases chlorine into the stratospheric clouds. Once in the stratosphere, CFCs and other ozone depleting substances (ODS) destroy ozone molecules. In the case of CFCs, UV light in the stratosphere knocks loose a chlorine atom from the molecule, which can then destroy numerous ozone molecules. cdfeliciano 10  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology FIG. 2.1.6. Destruction of Ozone Layer by CFCs Credit: UCAR https://openoregon.pressbooks.pub/envirobiology/chapter/10-2-ozone-depletion/ cdfeliciano 11  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology FIG. 2.1.7 Ozone Formation and Destruction: Depletion begins when CFC’s get into stratosphere. Ultraviolet radiation from the sun breaks up these CFCs. The breaking up action releases Chlorine atoms. Chlorine atom react with ozone, starting a chemical cycle that destroys the good ozone in that area. One chlorine atom can break apart more than 100,000 ozone molecules https://in.pinterest.com/pin/510454938985115333/ FIG. 2.1.8. Ozone Layer over the South Pole https://scied.ucar.edu/ozone-layer Effects of Ozone Layer Depletion 1. Effect on climate a. A hole in the ozone layer decreases the temperature of the adjacent troposphere, making it colder than usual, which increases air circulation that affects wind patterns, weather, and climate. b. CFCs also cause increase of CO2. Depletion of O3 leads to increase of H2O2 in troposphere. cdfeliciano 12  SAINT LOUIS UNIVERSITY SAINT LOUIS UNIVERSITY SCHOOL OF NURSING, ALLIED HEALTH, SCHOOL OF NATURAL SCIENCES AND BIOLOGICAL SCIENCES Department of Biology Department of Biology c. Induces acid rain formation. 2. Effect on human beings a. Increases incidences of Skin cancer b. Decrease in immunity level makes people prone to infectious diseases c. Retards physical growth and affects mental development of human beings 3. Effect on biotic communities a. Decrease in photosynthesis by plants b. Fertilized crops are affected easily by UV radiation c. When the amount of P increases resistivity to UV radiation decreases d. Rate of evaporation of water increases which results reduction in soil moisture e. Phytoplankton are also affected Protection and Maintenance of O3 layer Recognition of the harmful effects of CFCs and other ozone-depleting substances led to the Montreal Protocol on Substances That Deplete the Ozone Layer in 1987, a landmark agreement to phase out those substances that has been ratified by all 197 UN member countries. More than 30 years after the Montreal Protocol, NASA scientists documented the first direct proof that Antarctic ozone is recovering because of the CFC phase-down: Ozone depletion in the region has declined 20 percent since 2005. And at the end of 2018, the United Nations confirmed in a scientific assessment that the ozone layer is recovering, projecting that it would heal completely in the (non-polar) Northern Hemisphere by the 2030s, followed by the Southern Hemisphere in the 2050s and Polar Regions by 2060. Some hydrochlorofluorocarbons (HCFCs), transitional substitutes that are less damaging but still harmful to ozone, are still in use. Developing countries need funding from the Montreal Protocol's Multilateral Fund to eliminate the most widely used of these, the refrigerant R-22. The next generation of coolants, hydrofluorocarbons (HFCs), do not deplete ozone, but they are powerful greenhouse gases that trap heat, contributing to climate change. Though HFCs represent a small fraction of emissions compared with carbon dioxide and other greenhouse gases, their planet-warming effect prompted an addition to the Montreal Protocol, the Kigali Amendment, in 2016. The amendment, which came into force in January 2019, aims to slash the use of HFCs by more than 80 percent over the next three decades. In the meantime, companies and scientists are working on climate- friendly alternatives, including new coolants and technologies that reduce or eliminate dependence on chemicals. To promote reduction in the production and consumption of O3 depleting chemicals Produce and propagate use of alternative chemicals Enactment of Montreal Protocol cdfeliciano 13