Envi Sci: Unit 4 & 9 Flashcards
What is the atmosphere made up of?
Permanent gases:
- Nitrogen: 78.1%
- Oxygen: 20.9%
Other permanent gases: argon, neon, helium, krypton, hydrogen
Variable gases (more or less depending on activities in specific locations)
- Water vapor: 0 to 4% (big amount)
- Carbon Dioxide: 0.035% (smaller amount)
- Methane: 0.0002% (smaller amount)
- Ozone: 0.000004% (small amount, we want it in 2nd layer not at ground level)
Troposphere
Immediately adjacent to the earth’s surface
Ranges in depth from 18 km over the equator to 8 km over the poles.
- Responsible for weather
- Convection currents result from warm, less dense air rising above more dense air
Tropopause: boundary that limits mixing between the troposphere & upper zones
Stratosphere
From tropopause up to about 50 km
- Has very little water vapor, but 1000X more ozone than the troposphere
- Ozone (O3) absorbs UV light🡪 warms upper part of stratosphere.
- O3 protects life on Earth since UV radiation damages living tissues.
- O3 is being depleted/broken by CFCs & other pollutants🡪 more UV radiation to Earth
~Low levels of O3 in the stratosphere DO NOT contribute to global warming
Weather
Short-lived, local patterns in temperature & precipitation due to circulation of the troposphere.
Climate
Long term patterns of temperature and precipitation.
- Influence on both: greenhouse effect, solar intensity & seasonal change, convection currents & circular patterns, etc.
Greenhouse effect
A natural process that traps heat from the sun in the Earth’s atmosphere.
- Not a bad thing, it is a natural process, it turns bad with humans overuse of fossil fuels, etc.
Solar Energy (Absorbed & Reflected)
Solar radiation forms:
- 8% ultraviolet (UV) rays (the ones that cause sunburn)
- 42% visible light (the EM spectrum we can see)
- 50% Infrared (IR) rays (the ones that give us heat).
Absorbed Solar Energy: Absorption of sunlight causes the molecules of the object or surface it strikes to vibrate faster, increasing its temperature.
- White color = higher albedo %
- Darker color = lower albedo %
Reflected Solar Energy: the portion of sunlight that bounces back from a surface on Earth, like land, water, or clouds, instead of being absorbed
Ocean circulation patterns
The result of differential heating, gravity, prevailing winds, the Coriolis effect, and the locations of continents.
Ocean Currents
Gyers: large ocean circ. patterns due to global wind
(clockwise in N hem, counterclockwise in S hem.)
Upwelling Zones: areas of ocean where winds blow warm surface water away from a land mass, drawing up colder, deeper water to replace it
- Brings O2 & nutrients to surface → productive fishing
ENSO: pattern of shifting atmospheric pressure & ocean currents in the pacific ocean between South America and Australia/Southeast Asia
- Oscillates, or shifts regularly from El nino (warmer, rannier) to La Nina (cooler, drier) conditions along coast of South America
El Niño
A naturally occurring climate pattern characterized by the warming of the ocean surface in the central & eastern tropical Pacific
Normal conditions:
- Trade winds push warm surface waters away from the coast of South America & promote the upwelling of water from the ocean bottom
-Dry conditions on west coast
El Nino conditions:
- Trade winds weaken or reverse direction, so warm waters build up along the west coast of Peru.
- Wetter conditions on west coast
La Nino conditions:
- Stronger than normal trade winds (W ← ← ← E)
- Increased upwelling off SA coast brings cooler than normal conditions, extra good fisheries
- Warmer & rainier than normal in Australia & SE Asia
Albedo
Levels of reflection of surfaces
- The warmer it gets -less ice and snow- the less albedo/reflection - the higher the temperatures - positive feedback loop
Global Warming
Long term heating of Earth’s surface observed since the pre-industrial period (between 1850 & 1900) due to human activities, primarily fossil fuel burning
Climate Change
Long-term change in the average weather patterns that have come to define Earth’s local, regional & global climates.
Greenhouse effect
Absorption of infrared radiation by atmospheric gases and reradiation of the energy back toward Earth.
The major greenhouse gases are:
- Water vapor (H2O)
- Carbon dioxide (CO2)
- Methane (CH4)
- Nitrous oxide (N2O)
- Chlorofluorocarbons (CFCs)
Natural processes:
- Volcanic eruptions: carbon dioxide (CO2)
- Decomposition & digestion: methane (CH4)
- Denitrification (conversion of nitrogen to atmosphere from soil): nitrous oxide (N20)
- Evaporation & evapotranspiration: water vapor (H2O)
Proxy Data
Help us measure different climate conditions from historical things
- Ice cores
- Tree rings
- Foraminifera -mine marine protists with hard shells
Effects of global climate change on the environment: Melting
Sea ice, glaciers (fresh water source) & permafrost
Permafrost covers 20% of Earth’s surface, can be up to a mile thick & will release CH4 as it thaws & decomposes
Effects of global climate change on the environment: Rising Sea Levels
- Melting of land ice (glaciers and ice sheets) Greenland & Antarctica contributes to volume of oceans
- Thermal expansion water warms it expands
- Has risen about 9 inches (about .25 m) since 1870 & could rise an additional 12-24 (or more) inches by 2100
- Damage coastal cities & coastal habitats
Changes in Weather Patterns
- As Earth warms, Hadley cells move from the equator towards the poles
- Tropics have expanded poleward by about 70 to 200 miles in each hemisphere over the period 1979-2009
- There is less movement of the jet stream & the mid-latitude winds
- Ocean gyre (currents) may shift
Climate Change: Impact on Oceans
- Critical in carbon cycle; regulates atmospheric carbon levels
- Ocean CO2 uptake slows atmospheric CO2 increase
- Ocean acidification:
- Increases ocean CO2
- More CO2 converted to carbonic acid
- pH dropped from 8.2 to 8.1
- Reduces carbonate ions for shell building
- Can dissolve shells and coral skeletons
- Temperature changes impact marine life:
- Affects metabolism, lifecycle, and behavior
- Cues reproduction in some species
- Determines sex in sea turtles and some fish
Wild plants and animals:
- Growing seasons for plants have changed
- Animals may be harmed if unable to adapt or relocate
- Corals are particularly sensitive:
-Coral bleaching due to high water temperatures- May lead to coral death
Humans:
- Potential relocation due to:
- Vulnerability to storms
- Coastal flooding
- Drought
- Increased spread of diseases (especially mosquito-borne)
- Economic consequences
- Expansion of tropical regions
International Level
Kyoto Protocol: An international agreement that sets a goal for global emissions of greenhouse gases from all industrialized countries to be reduced by 5.2 percent below their 1990 levels by 2012.
- Although the United States signed the original Kyoto Protocol, Congress never ratified the agreement
Paris Climate Agreement: A pledge by 195 countries to keep global warming less than 2°C above pre-industrial levels.
Reducing Emissions
- Switching to alternative energies (solar, wind, geothermal, nuclear, hydroelectric, biomass)
- Increasing Efficiencies Corporate Average Fuel Economy (CAFE) standards, green building design
- Carbon sequestration - removes CO2 from the atmosphere
- Promote formation of SOC (soil organic carbon) by no-till, manure, etc. or retiring agricultural land and allowing it to become pasture or forest
- Wetland restoration, urban forestry, reforestation
- Research into cost effective ways of capturing
- CO2 from the air, from coal-burning power stations, and from other emission sources.
- Captured CO2 would be compressed and pumped into abandoned oil wells or the deep ocean.
