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Atmosphere and Global Climate Change Nitrogen (78%) • Fundamental nutrient for living organisms • Deposits on Earth through nitrogen fixation and reactions involving lightening and precipitation • Returns to the atmosphere through combustion of biomass and denitrification. Oxygen (21%) • Oxygen molecules are produced through photosynthesis and are utilized in cellular respiration Water Vapor (0-4%) • Largest amounts occur near the equator, over oceans and in tropical regions • Areas where atmospheric water vapor can be low are polar areas and desert Carbon Dioxide (<<1%) • Volume has increased about 25% in the last 300 years because of the burning of fossil fuels • CO2 is produced through cellular respiration and the decay of organic matter • It is a reactant in photosynthesis • CO2 is also a major greenhouse gas • Humans are responsible for 5,500 million tons of CO2 per year • The average time CO2 molecules stay in the atmosphere is about 100 years. Methane (<<<1%) • Contributes to the greenhouse effect • Since 1750, methane has increases 150% due to the use of fossil fuels, mining, landfills, grazers and flooding of rice fields • Human activity is responsible for about 400 million tons per year compared with the 200 million tons produced naturally • Average cycle of a methane molecule in the atmosphere is about 10 years. Nitrous Oxide (<<<1%) • Concentrations have increased about 0.3% per year. • Burning fossil fuels, use of fertilizers, burning biomass, deforestation and conversion to agricultural land increase concentrations • Humans are responsible for 6 million tons per year • Contributes to the greenhouse effect • Average time of a N2O molecule in the atmosphere is about 170 years. Ozone (<<<1%) • 97% of the Ozone is found in the stratosphere • Ozone absorbs UV radiation • Ozone is produces in the production of photochemical smog • A “hole” in the Ozone layer occurs over Antarctica. • CFCs are the main cause of the breakdown of the ozone layer. Layers of the Atmosphere • Troposphere: 0-7 miles above surface. 75% of atmosphere’s mass. Temps decrease with altitude reaching -76 F near the top. Weather occurs in this layer • Stratosphere: Temps increases with altitude due to absorption of heat by ozone. Ozone is produced by UV radiation and lightening. Contains the Ozone Layer. Layers of the Atmosphere • Mesosphere: Temps decrease with altitude. Coldest layer. Ice clouds occur. Meteors burn up in this layer • Thermosphere (Ionosphere): Temps increase with height due to gamma rays, X-rays, and UV radiation. Molecules are converted into ions which results in the aurora borealis in the northern hemisphere and the aurora australis in the southern hemisphere. Changes in Temperature in the Atmosphere Weather • Weather is caused by the movement of heat energy which influences the following physical properties: – – – – – – – Temperature Air pressure Humidity Precipitation Available sunshine determined by cloud cover Wind speed Wind direction Climate • Describes the total of all weather occurring over a period of years in a given place Energy • Energy can be transferred wherever there is a temperature difference between two objects. • Radiation: flow of electromagnetic radiation. It is the method by which Earth received solar energy • Conduction: transferred by the collisions that take place between heat-carrying molecules Energy- Convection • Convection: primary way energy is transferred from hotter to colder regions in the atmosphere and the primary determinant of weather patterns • Involves the movement of warmer and therefore more energetic air • Takes place both vertically and horizontally • When air near the ground becomes warmer and therefore less dense, the air rises. • Pressure differences that develop because of temperature differences result in wind or horizontal convection. Energy- Convection • Regions nearer the equator receive much more solar energy that near the poles and are much warmer. • There latitudinal differences in surface temp create global-scale flows of energy within the atmosphere, giving rise to the major weather patterns of the world. • Without convection and the transfer of energy, the equator would be about 27 F warmer and the Arctic would be about 45 F colder Evidence for Climate Change • Comes from data used to measure climate (only aviable for the last 100 years or so), written accounts (subjective), and data materials present at the time: – – – – – – – – Tree rings Gas bubbles trapped in glaciers Deep ice core samples Lake sediments Marine fossils Sediments Dust analysis Isotope ratios in fossilized remains • Bottom line: the earth has gone through periods of warming and periods of cooling Factors the influence climate • Air Mass: large body of air that has similar temperature and moisture contents. Can be categorized as equatorial, tropical, polar, arctic, continental or maritime • Air Pressure: Gravity on an air mass results in air pressure. Air pressure decreases with altitude. Low pressure usually produces cloudy and stormy weather. High pressure masses contain cool, dense air that descends towards the surface and becomes warmer. High pressure is associated with fair weather. Factors the Influence Climate • Albedo: Reflectivity. Ocean = Low albedo, Land = moderate albedo. Snow and Ice = Largest albedo. Dust in the atmosphere has a positive feedback effect. Dust forms a high albedo veil around earth so solar radiation is reflected. • Altitude: for every 1,000 feet up there is a 3 F drop in temp. Every 300 feet up is equivalent to a 62 mile shift in latitude north. Altitude Factors the Influence Climate • Angle of Sun: in the Northern Hemisphere winter, the earth is closest to the sun. Areas closest to the equator receive the most sun and therefore have higher temps. • Carbon Cycle: Consumption of carbon in the form of CO2 results in cooling. Consuming CO2 from: carbonate rock weathering and silicate rock weathering. Production of CO2 results in warming. Breakdown of carbonate rocks and carbonate formation in oceans lead to warming. Factors the Influence Climate • Clouds: collections of water drops or ice crystals suspended in the atmosphere. As warmer air rises it expands due to decreasing air pressure and drops in temp- making it rain. • Distance to Oceans: Oceans are thermally more stable than landmasses. The specific heat of water is 5X greater than that of air. Because of this, changes in temp are more extreme over land than at sea Factors the Influence Climate • Fronts: when 2 air masses meet, the boundary is called a front. A warm front is a boundary between an advancing warm air mass and the cooler one replacing it. Since warm air is less dense, it rises and cools and the moisture it contains is released as rain. A cold front is the leading edge of an advancing cool air mass. Cold fronts are associated with thunderhead clouds, high winds and thunderstorms. Fronts Factors the Influence Climate • Greenhouse Effect: most important greenhouse gasses are: water, carbon dioxide, and methane. Without the effect the earth would be too cool to live on • Heat (Convection): Climate is influenced by how heat energy is exchanged between air over the ocean and air over the land • Land Changes: Climate is influenced by urbanization and deforestation. Factors the Influence Climate • Latitude: higher latitudes mean less solar radiation • Location: location of high and low air pressure zones and where land masses are distributed • Moisture Content of Air (Humidity): determinant of plant growth and distribution of biome type. More water vapor in the air leads to more clouds and rainfall. Water vapor is also a greenhouse gas and traps heat energy . The dew point is the temperature where water condenses. Factors the Influence Climate • Mountain Ranges: Rain shadow Effect. Side facing the ocean is the windward side and receives the rain. Side opposite the ocean is the leeward side and is dry. Orographic lifting occurs when an air mass is forces from low elevation to a high elevations. As it rises it expands and cools that can create clouds and precipitation. Orographic Lifting/Rain Shadow Effect Factors that Influence Climate • Plate Tectonics and Volcanoes: Plate tectonics affect CO2 (a greenhouse gas). Volcanoes produce it. • Pollution: Greenhouse gasses are emitted from both natural and anthropocentric sources • Precession: the wobble of the Earth on its axis changes the amount of energy received by the sun Factors that Influence Climate • Human Activity: Deforestation, urbanization and heat island effects, release of pollutants, burning of fossil fuels and production of acid rain are factors that affect climate. Increased pollution alone, combined with an increase in convectional uplift in urban areas increases the amount of rainfall as much as 10% compared to undeveloped areas. Factors that Influence Climate • Rotation: Daily temp cycles are primarily influenced by earths rotation on its axis. At night, heat escapes. Daily minimum temps occur just before sunrise • Solar output: Changes in solar output only 1% per 100 years would change the temp by 1 F. Times of sunspot activity correspond to decreases in solar radiation reaching Earth. The sun’s magnetic field reverses every 22 years. Factors that Influence Climate • Volcanoes: Sulfur-rich volcanic eruptions can eject material into the stratosphere and cause troposphereic cooling and stratospheric warming. They stay in the atmosphere for 1-3 years. Over the course of millions of years volcanic ash deposited in oceans can increase iron content in seawater which can promote biotic activity. But that decreases CO2 levels in the water and therefore in the atmosphere result in in global cooling. Recent research also suggest that large eruptions may trigger El Nino events. Factors that Influence Climate • Wind Patterns: Influenced by temp and pressure differences (gradients). • 1. The sun heats the atmosphere unevenly. 2. The air closest to the surface is warmer and rises 3. Air at higher elevations cools and sinks- this creates a convection process and is the primary cause of winds. • Winds are effected by: – – – – – Uneven heating of the surface Seasons The Coriolis Effect Amount of solar radiation reaching the Earth over a period of time Convection cells created by areas of warm ocean water which in turn are caused be differences in water density, winds and earths rotation. Factors the Influence Climate • Winds: During calm sunny days, land warms up faster than the sea. This causes the air above the land to become more dense than air above the sea. This creates sea breezes. • Anabatic Winds: develop in hilly or mountainous areas during the day, especially if weather is calm and has some sun. In situations like this, the air around the hilltops becomes warmer than the air at the same altitude over adjacent valleys. • Katabactic Winds: occur on clear still nights when the air that is in contact with the ground loses heat quickly by radiations back to space. The result is that the air near the ground over hill and mountain summits becomes colder than air at that same altitude over adjacent valleys. Atmospheric Circulation • Air closer to the earths surface is the warmest and rises • At high elevations air is cooler and much more dense and sinks • This sets up a convection process and is the primary cause of winds • Global Air Circulation is also affected by: seasons, the Coriolis Effect, convection cells. Atmospheric Circulation • Trade winds are the prevailing pattern of easterly surface winds found in the tropics, within the lower portion of the earths atmosphere. • Trade winds blow mainly from the northeast in the Northern Hemisphere (northeast trade winds) and from the southeast in the Southern Hemisphere (southeast trade winds) • Trade winds act as the steering flow for tropical storms that form over the Atlantic, pacific and south Indian oceans. Atmospheric Circulation • Horizontal winds move from areas of high pressures to areas of low pressures. • Wind speed is determined by pressure differences between the air masses • More pressure= higher wind speed • Wind direction is based on where the wind is coming from, wind from the east is called an easterly. Atmospheric Circulation • Earths rotation on its axis causes winds not to travel straight- Coriolis Effect • It causes the prevailing winds in the Northern Hemisphere to spiral clockwise from highpressure areas and counter clockwise from low-pressure areas. Hadley Air Circulation Cells • Air heated near the equator rises and spreads our north and south • After cooling in the upper atmosphere it sinks back within earths surface within the subtropical climate zone (25-49 degrees N and S of the equator) • The equatorial regions of Hadley Cells are characterized by high humidity, high clouds and heavy rains • The subtropical regions of Hadley cells are characterized by low relative humidity, little cloud formation, high ocean evaporation and many of the worlds deserts. Warm to hot summers and mild winters • The tropical wet and dry (or savanna) climate has a dry season more than 2 months long. Yearly loss of water through evaporation exceeds water gains from precipitation Ferrel Air Circulation Cells • Form 30-60 degrees north and south of the equator • The descending winds of Hadley cells diverge as moist tropical air moves toward the poles with westerly winds • Mid latitude climates can have severe winters and cool summers due to mid-latitude cyclone patterns. • The climate of this area is governed by both tropical and polar air masses. • They have distinct winters and have lots of broadleaf deciduous and coniferous evergreen forests. Polar Air Circulation Cells • Originate as icy cold, dry , dense air descending from the troposphere to the ground • The air meets with warm tropical air from mid-latitudes. • Air then returns to the poles, cooling than sinking. The sinking suppresses precipitations (thus polar regions are deserts) • Two major biomes are tundra and taiga. Hurricanes • Begin over warm oceans in areas where tread winds converge • A subtropical high-pressure zone creates hot day temps with low humidity that allows for large evaporations. The Coriolis effect initiates the cyclonic flow • The cyclonic circulation allows them to pick up moisture and latent heat energy from oceans • In the center of the hurricane is the eye, a descending air and low pressure area • In 2005, Hurricane Katrina hit New Orleans and was responsible for 1,830 deaths and $75 billion in damages Tornadoes • Swirling masses of air with wind speeds close to 300 mph. • The center or the tornado is an area of low pressure • Diameters of hundreds of meters and are produced from a single convection storm • In the US tornado season is April-July • Because of advances in weather modeling, forecasting and warning systems, deaths are rare. Tropical Cyclones • Diameters of hundreds of meters and comprised of many convection storms. • An oceanic phenomenon and die out over land. • Lifetimes measured in days. Monsoons • Strong and violent winds that change direction with the seasons • Monsoon winds blow from cold to warm regions because cold air takes up more space • India’s climate is dominated by monsoons • During the Indian winter, which is hot and dry, the monsoon winds blow from northeast and carry little moisture. • The temp is high because the Himalayas form a barrier that prevents cold air from passing onto the subcontinent • India lies between the Tropic of Cancer and the equator so the suns rays shine directly on the land • During the summer monsoons move onto the subcontinent from the southwest • The winds carry moisture from the Indian ocean and bring heavy rains from June to September. • Farmers in India rely on these torrential summer rainstorms to irrigate their land • Large amount of India’s electricity is generated by water power provided by monsoon rains. Monsoons in India Rain Shadow • A rain shadow is a dry area on the mountainside facing away from the direction of the wind • The mountains block the passage of rain-producing weather systems, casting a “shadow” of dryness behind them • Warm, moist air rises through orographic lifting on the top of a mountain range or large mountain, where, due to decreasing atmospheric pressure with increasing altitude, it expands and cools reaching its dew point • At the dew point moisture condenses onto the mountain and precipitates on the top and windward side of the mountain • Typically, descending air also gets warmer down the leeward side of the mountain creating an arid region. Rain shadow/ orographic lifting Normal Conditions (El Nino, La Nina) • During normal conditions, easterly trade winds move water and air warmed by the sun toward the west (Walker circulation). • The ocean is generally around 24 inches higher in the western Pacific and water about 14 F warmer • The trade winds, in piling up water in the western Pacific, make a deep – 450 ft- warm layer in the west that pushes the thermocline down while it rises in the east • The shallow -90 ft- eastern thermocline allows the winds to pull up nutrient rich water from below, increasing fishing stocks. • The western side of equatorial pacific is characterized by warm, wet, low-pressure weather, as the collected moisture is released in the form of typhoons and thunderstorms. Normal Conditions (El Nino, La Nina) El Nino • When the air pressure patterns In the South Pacific reverse direction (the air pressure at Australia is higher than at Thaiti), the trades winds decrease in strength (or reverse). • The result is that the normal flow of water away from S America decreases and the ocean water piled up off the coast of S America. • This pushes the thermocline deeper and decreases the upwelling of nutrient-rich deep water which results in massive fish kills off the S American coast • With a deeper thermocline and decreased westward transport of water, the surface temp increases in the eastern Pacific • The net result is a shift of prevailing rain pattern from the normal western Pacific to central Pacific; rainfall is more common in the central pacific while the western pacific becomes dry El Nino El Nino- Global Effects La Nina • When trade winds that blow west across the tropical Pacific are stronger than normal leading to increased upwelling off S America and COOLER sea surface temperatures • Prevailing rain pattern also shifts farther west than normal • These winds pile up warm surface water in the western Pacific • Characterized by unusually cold ocean temps in eastern equatorial Pacific • Tends to bring opposite effects of El Nino to the US with wetter than normal conditions across the Pacific NW and both dryer and warmer condition in the southern states • Winter temps are warmer than normal in the SE US and cooler than normal in the NW • Increased temps in the SE lead to more hurricanes • La Nina is also responsible for heavier than normal monsoons in India and SE Asia. Global Change 10-15% of your APES Exam Stratospheric Ozone • Stratosphere contains 97% of Ozone • Most Ozone is formed over the tropics. However, slow circulation currents carry the majority of it to the poles, resulting in the thickest layers over the poles and the thinnest layers over the tropics • Formed in the stratosphere by the reaction of UV radiation striking an oxygen molecule and splitting it into two free radical Oxygens • That free molecule reacts with atmospheric ozone to form O3. • The reverse reaction also happens so generally these reactions balance each other out keeping the level of ozone fairly constant • O + O 2 O3 Ultraviolet Radiation • UVA- usually causes skin tanning. 1,000X less effective than UVB in producing skin redness but more of it reaches the surface than UBV. Many fruits, flowers seeds and patterns of bird plumage are only visible in UV light as well as the urine of some animals. • UVB- causes blistering sunburns and is associated with skin cancer • UVC- found only in the stratosphere and is responsible for creating Ozone. Causes of Ozone Depletion • Thinning of the Ozone layer was first discovered in 1985 • It occurs seasonally and due to human made compounds containing halogens (chlorine, bromine, fluorine or iodine) • Measurements indicate that ozone over the Antarctic has decreases about 60% since the late 1970s with an average loss of 3% per year. Causes Of Ozone Depletion • The main culprits are CFCs • First manufactured during the 1920s they are used as refrigerants (Freon), aerosol propellants, electrical part cleaning solvents and in the manufacture of foam products and insulation • By 1974, nearly 1 million tons of CFCs were produced per year • The largest source of CFCs to the atmosphere were from leaking AC units • The average time of CFCs in the atmosphere is 200 years. Causes of Ozone Depletion Causes of Ozone Depletion • One chlorine atom released from CFCs can destroy over 100,000 ozone molecules • Much destruction is from CFCs released many years ago as it takes 8 years for a CFC molecule to reach the ozone layer • Bromine, found in much smaller quantities than chlorine, is about 50X more effective in its effect on ozone depletion and is responsible for about 20% of the problem • Bromine is found in halons, found in fire extinguishers. Methyl Bromide is used fumigation and agricultures and is naturally released from phytoplankton and biomass burning Effects of Ozone Depletion • During the onset of the 1998 Antarctic spring, a hole 3X the size of Australia (over 3,500 miles in diameter) developed in the ozone layer over the South Pole. • Stratospheric Ozone protects life from harmful UV radiation. Harmful effects of increased UV radiation include: – – – – – Increases in skin cancer, sunburns and damage Increases in cataracts of the eye Reduction in crop production Deleterious effects to animals (they don’t wear sunscreen) Reduction in the growth of phytoplankton and cumulative effect on food webs – Cooling of the stratosphere – Reduction in immune system – Climate Change Reducing Ozone Depletion • Although most developed countries have phased out ozonedestroying chemicals, they are still legal in developing countries • 1. HCFC replaces chlorine with hydrogen. Unfortunately, it is still capable of destroying ozone but less effectively because it breaks down ozone more in the troposphere • 2. alternatives to halons can be used in fire extinguishers • 3. helium, ammonia, propane or butane can be used as a coolant. Helium-cooled refrigerators use 50% less electricity. • 4. Use a pump spray instead of aerosol sprays • 5. Comply with disposal of oil refrigerators and AC units via instructions from the Clean Air Act. Relevant Laws and Treaties • Montreal Protocol (1987): designed to protect the stratospheric ozone layer. Stipulated that production and consumption of compounds that deplete ozone in the stratosphere were to be phased out by 2000 • London (1990): Countries that signed Montreal Protocol met again in London and decided that a total phase-out of CFCs was necessary. They agreed this could happen by 2000 • Copenhagen (1992): Phase-out schedule for CFCs was accelerated, with the industrialized countries agreeing to stop production by 1996. This goal had already been prescribed in the US in 1990 by the amendments of the Clean Air Act. In 1994, Europe decided that a phase-out could be achieved in Europe by 1995 Greenhouse Gas Years in the Warming Atmosphere Potential CO2=1 Sources Carbon Dioxide (CO2) 100 1 Burning Oil, coal, plants, deforestation, cellular respiration Carbon Tetrachloride (CCl4) 45 1500 Cleaning Solvent CFC 15 (100 in Strat) 1000-8000 AC, Refrigerators, foam products, insulation Halons 65 6000 Fire Extinguishers HCHCs 10-400 500-2000 AC, Refrigerators, foam products, insulation HFCs 15-400 150-13000 AC, Refrigerators, foam products, insulation Methane (CH4) 15 25 Rice cultivation, production of coal, natural gas leaks Nitrous Oxide (N2O) 115 300 Burning fossil fuels, fertilizers, livestock wastes, plastic manufacturing Sulfur Hexafluoride (SF6) 3,200 24000 Electrical industry as a replacement for PCBs Troposphereic Variable 3000 Combustion of fossil fuels Human Sources of Greenhouse Gases Greenhouse Gases • Levels of greenhouse gases have increased by 25% since the industrial revolution • During the last 20 years, ¾ of all human-made CO2 was from burning fossil fuels • Energy related green house gases represent 82% of the US anthropogenic emissions • Although the carbon cycle takes up 6.1 billion metric tons of anthropogenic CO2 emissions, 3.2 billion metric tons are still added annually Impacts and Consequences of Global Warming • Acidification: The ocean can absorb CO2 but increased CO2 levels in the ocean lower the pH of the water causing it to be more acidic. This adversely affects corals, plankton, and reproduction rates • Forest fires: Boreal forest fires in N America used to average 2.5 million acres but now average about 7 million acres. This may also be because of forest management practices Impacts and Consequences of Global Warming • Air temps average 5-9 F warmer than they were before the Industrial Revolution • Historic increases in temp average less than 2 F per 1,000 years • Higher temps will result in higher amounts of rain due to higher rates of evaporation • Hurricanes of category 4/5 have risen from 20% in the 70s to 35% in the 90s • Precipitation due to hurricanes is up 7% in the US • More rainfall increases erosion which then leads to higher rates of desertification due to deforestation… this leads to loss in biodiversity from loss in habitats • El Nino and La Nina Patterns and their frequencies have also changed Impacts and Consequences of Global Warming Impacts and Consequences of Global Warming • Displacement of People: The UN estimates that bt 2050, 150 million people will need to relocate worldwide. This is because of effects of coastal flooding, shoreline erosion and agricultural disruption • Increases Health and Behavioral Effects: Higher temps result in a higher rate of heat-related deaths. Estimates indicate that a temp increase of just 2F will result in about 25,000 additional homicides in the US due to stress and resulting rage. Impacts and Consequences of Global Warming • Ecological Productivity: Satellite photos have shown that productivity in the N hemisphere has increased since 1982, BUT, biomass increases due to warmer temps reaches a certain point- the point where limiting factors of water and nutrients curb future productivity increases. In the tropics, plants increase productivity more so than trees (which are carbon sinks). With higher % of plants due to increase temps and CO2 concentrations, the rates of decomposition increase because the plants are shorter lived. As a results, more carbon enters the carbon cycle. Impacts and Consequences of Global Warming • Glacier Melting: Total surface area of glaciers worldwide has decreased 50% since the end of the 19th century. Temps in the Antarctic Southern Ocean rose 0.31 F between the 50s-80s. Glacier melting causes: landslides, flash floods, lake overflow and increased variation in water flows into ricers • Hindu Kush and Himalayan glacier melts are reliable water sources for many people in China, India and much of Asia. • Global warming initially increases water flow causing flooding and disease. Flow will then decrease as the glacier volume dwindles, resulting in drought. • Eventual decreases in glacial melt will also affect hydroelectric productions Impacts and Consequences of Global Warming • Increase in Disease: Rates of Malaria, cholera and other waterborne diseases will increase. Remediation and mitigation efforts will end up costing more • Increased Property Loss: Weather-related disasters have increased 3-fold since the 60s. Insurance payouts have increased 15-fold (adjusted for inflation) during the same time period. Much of this can be attributed to people moving to vulnerable coastal areas. Impacts and Consequences of Global Warming • Increase in Economic Development: Money that was designed to increase education, improve health care, reduce hunger and improve sanitation and fresh water supply will now go to mitigating the effects of climate change • Releases of Methane from Hydrates in Coastal Sediments: Methane hydrate is a form of water ice that contains methane within its crystal structures. Extremely large deposits of this resource have been discovered in ocean sediments. Impacts and Consequences of Global Warming • Loss of Biodiversity: Arctic fauna will be most affected. The food webs of polar bears that depend on ice flows, birds and marine mammals will be negatively impacted. Many refugee species have shifted their ranges toward the poles, averaging 4 miles per decade. Bird migrations are averaging over two days earlier per decade. Grasses have become established in Antarctica for the first time. Many species of dish and krill that require cooler waters will be negatively impacted. Decreased glacier melt will impact migratory fish, such as salmon, that need sufficient river flow Impacts and Consequences of Global Warming • Releases of Methane from Thawing Permafrost: would increase bacterial levels in the soil and eventually lead to higher releases of methane. Estimates of melting of permafrost peat bogs in Siberia could release as much as 70,000 million metric tons of methane in the next few decades • POSITIVE FEED BACK LOOP Impacts and Consequences of Global Warming • Rise in Sea Level: sea levels have risen 400 feet since the peak of the last ice age. From 3,000 years ago to the start of the industrial revolution, a rate of sea level rise averaged 0.1-0.2 mm per year. Since 1900, sea level has risen about 3 mm per year (over a 10-fold increase). As increase in global temperatures of 3F-8F is estimated to lead to an increase of 6-37 inched in seal level rise. If all the glaciers, ice caps and ice sheets melted on earth the sea level would rise 225 ft. – – – – – Increase coastal erosion Create higher storm surge flooding Increase loss of property and coastal habitats Cause losses in fish and shellfish catches Cause loss of cultural resources and values such as tourism and recreation – Cause losses in agriculture and aquaculture due to diminishing soil and water quality – Result in the intrusion of salt water into aquifers. Impacts and Consequences of Global Warming • Slowing or Shutdown of Thermohaline circulation: Melting of the glaciers in Greenland would shift the salt water- freshwater balance of the North Atlantic. This would result in a decrease of heavier saline waters sinking than in traditional ocean circulation patterns. This would have significant effects on the fishing industry. Localized cooling in the N Atlantic brought about through the reduction of thermohaline circulation currents would result in much colder temps in Great Britain and Scandinavia Reducing Climate Change • World carbon dioxide levels are expected to increase by 2% annually between 2001-2025. • Much of the increase in these emissions is expected to occur in the developing world (China and India) where emerging economies fuel economic development with fossil energy. • Developing countries emissions are expected to grow by 3% annually between 2001-2025 and will surpass emissions of industrialized countries by 2019 . • The US produces about 25% of global CO2 emissions by burning fossil fuels. • This is due to a robust economy and 85% of the US’s energy needs are met through burning fossil fuels. Reducing Climate Change • To stabilize the current global warming crisis would require: – A decrease in methane emissions by 8% – A decrease in Nitrous Oxide emissions by 50% – A decrease in carbon dioxide emissions by up to 80% Reducing Climate change 1. Increasing the efficiency of cars, this would decrease dependence on oil and other fossil fuels. Cars currently represent 25% of the CO2 emissions in the US 2. Use more energy efficient sources or move to renewable energy. 3. Finding chemical substitutes that don’t impact global warming and banning ones that do 4. Slow down the rate of deforestation and increase reforestation 5. Reduce dependence on inorganic, nitrogen-based fertilizers and substituting conservation tillage techniques 6. Support treaties, protocols and legislation that require a reduction in greenhouse gases