Website Notes:

Section 1:

• Accumulated gasses are necessary for life on Earth
• The Atmosphere is mostly nitrogen (78%) and oxygen (21%) (the last 1% has carbon dioxide, water vapor, etc.)
  • Nitrogen and oxygen are important for life on Earth
• In earth’s early life, it was so hot that it was liquid (which caused the layers to form, like how iron sank)
  • Less dense material rose (like helium, hydrogen, nitrogen, argon, and carbon dioxide) and came out through volcanoes
    • This process was called Volcanic Outgassing.
• Gasses (once they left the surface of the Earth) rose and sank depending on the densities (because gas is a liquid)
  • Caused the layers of the atmosphere
    • Troposphere
    • Stratosphere
    • Mesosphere
    • Thermosphere
    • Exosphere
• Troposphere:
  • Lowest layer
  • We live in this layer
  • Greatest influence on Earth
  • Mostly composed of nitrogen, water vapor, and carbon dioxide
  • Water vapor condensed as Earth cooled, which cause clouds and rain (and eventually formed oceans)
  • Life began in these oceans
  • First RNA developed in the ocean
  • Grew into microbial bats
  • These grew evolved to cyanobacteria (green algae, first organism to photosynthesize)
  • Converted sunlight and carbon dioxide into chemical energy (which allowed the bacteria to grow), and produced oxygen as a byproduct
  • This oxygen caused the Oxygen Catastrophe b
  • Decrease in carbon dioxide occurred between 4-2.5 billion years ago, the introduction of oxygen occurred 2.5 billion years ago
  • Oxygen Catastrophe is proven through BIFs (banded iron formations), which is iron that was exposed to oxygen, which then rusted, causing red layers in rocks.
  • Air in the troposphere layer is mixed with global winds (which spread heat for the equator to the poles, and mix molecules to make the troposphere have a composition that is the same throughout)
  • 3-Celled Model shows the general global winds, but there are smalled local winds
  • Air over land that is heated has spread out molecules
    • This air rises and forms a center of low pressure
  • Air over land that is less heated has closer molecules
    • This air is more dense and stays on the surface, forming a center of high pressure
  • As air rises at low-pressure areas, air needs to replace it, which is taken from high pressure paces
  • The Coriolis Effect causes the air to curve into the low and out of the high
  • Air rises and cools in low pressure areas (condensing water vapor, forming of clouds)
  • These pressure systems are pushed by global winds
  • Low pressure centers between 30°-60°N/S pull warm air from tropics and cold from poles
    • Known as mid-latitude cyclones
    • Move from about southwest to northeast with westerly winds
  • Low pressure centers between 0°-30°N/S pull warm air in only and develop into tropical storms/hurricanes

Section 2:

• The sun causes Earths weather and climate
  • It provides energy that heats the earth unevenly
    • This causes high and low pressure in different places
      • This causes global winds and local pressure systems
• The sun uses nuclear fusion to produce energy
• The suns energy is called electromagnetic radiation (energy that travels in waves through empty space)
  • These waves are not always the same intensity
    • High-energy radiation: gamma waves
    • Low-energy radio waves (these are converted to sound waves)
  • The different types of energy are shown through wavelength
    • Wavelength is the distance between the peak to the next peak in a wave
• Human eyes can see wavelengths between 380-780 nanometers
  • Called visible light
• Temperature of an object determines the type of energy it produces
• The sun emits mostly visible light radiation (mostly within the green wavelength)
• The Earth emits energy within the infrared wavelength
  • We cannot see infrared light, however we can feel it as heat
• Energy brought into the atmosphere from the sun is mostly visible light
  • When it enters the troposphere, there are many paths it can take
    • It can be reflected or absorbed by the Earth, clouds, or atmosphere
      • The amount being reflected depends on a property named Albedo
        • Albedo is measured from 0-1
        • 0 means all energy is absorbed
        • 1 means all energy is reflected
      • Reflected energy goes back to space (doesn’t impact the temperature of Earth)
      • Absorbed energy heats the planet/atmosphere (depending where it was absorbed)
        • The Earth re-radiates energy in the Infrared Spectrum

This energy can either be reabsorbed by greenhouse gasses or released to space

• Carbon dioxide, water vapor, and methane are able to absorb and re-radiate infrared radiation
  • These are the three greenhouse gasses
  • Once these molecules absorb energy, they re-radiate it either back to Earth or to space
• Heat transfer within Earth’s system in known as Earth’s Energy Budget
  • Total Input - Total Output = Change in Storage
• More energy entering Earth’s systems than leaving means a higher temperature for Earth
  • Vice verse, less energy entering than leaving means a decreasing temperature

Section 5:

• The last ice age was 11,000 years ago
  • Since then global temp has fluctuated between 2 degF
    • Linked to volcanic eruptions, solar radiation differences, etc.
• Earth is heating up quickly
  • Reason for heating is change of composition in the atmosphere
    • Aka more carbon dioxide and greenhouse gases
      • Bc of Earth’s Carbon Cycle, which is the process of carbon being stored in and transferred between biosphere (living organisms), lithosphere (Earth material), atmosphere, and hydrosphere
        • This process can be slow or fast
        • Eg. process of calcium carbonate shell depositing in the ocean floor, eventually forming limestone takes a long time
        • Eg. process of trees using photosynthesis to transfer atmospheric carbon to biological carbon is quick
        • Many things have influenced the speed of the carbon cycle (ice ages, volcanic eruptions, plants)
      • A time period that was very influential to carbon was the carboniferous
• Carboniferous:
  • 365 mil years ago trees evolved.
  • Since trees absorb carbon dioxide and release oxygen, there was a steep decrease in carbon dioxide
  • Dead trees became coal because they were buried and compressed (decomposers had not evolved)
  • In the 18th century, humans mined and burned the coal
    • This led to an increase in CO₂
  • Compression of buried marine organisms formed natural gases and oil.
    • People burned these too which also increased the amount of CO₂
  • These fuels have been used to produce electricity
• Chemical energy becoming mechanical energy and electricity:
  • Suns energy comes to earth → molecules on earth absorb or radiate the energy → molecules absorbing energy are also photosynthetic organisms (like plants, which use that energy to grow) → animals eat those plants → the solar energy is now chemical potential energy
  • Animals use energy to grow, move muscles, digest food, etc.
    • Eg. animal uses that energy to push a boulder, which supplies energy to the bolder, which is not mechanical energy
  • Similar to the boulder example: burning fossil fuels, releasing chemical energy, and the heat is used to heat water and produce steam, and the steam turns a turbine, now the energy is mechanical energy.
    • Inside the turbine could be a generator that transforms the mechanical energy to electrical energy.
      • Mechanical energy moves a system of magnets and metal coils, producing a magnetic field, turning the energy into a voltage.
  • Other ways to produce electricity: renewable sources (wind, sun, waves, etc.)
    • These do not emit CO₂
• Impact of burning fossil fuels:
  • Fossil fuels are cheap
  • Burning fossil fuels take carbon that was in the geosphere and moves it to the atmosphere
  • Some countries burn a lot of fossil fuels for a new type of manufacturing, causing a large increase of CO_c (this started in last 18th century)
• As temp of Earth increases, local weather and climate systems also change
  • These changes are hard to predict
  • They affect different places differently
• As global temp incerases, sea temp increases.
  • Warm water takes more space than cold, making a bigger ocean
  • Ices melt, adding more water to the oceans
• Water cycles will change
  • Land will be drier, closing pore spaces that hold water
    • More runoff into oceans
  • Deltas and wetlands will disappear
• As global temp increases, poles will be warmer
  • Differences in temp cause global winds
  • Global winds cause local high and low-pressure centers
  • Slowing down the winds will cause longer storms, and longer dry periods
  • There will be an increased risk of flooding because precipitation will no longer infiltrate
• Thermohaline circulation is caused by sinking of cold, dense water
  • If water warms, their density will increase, having a slower sinking rate or possibly not even sink
  • The gulf stream is very important to climates of continents bordering the north atlantic
    • If thermohaline circulation stops, gurl stream will not be pulled as far North to replace sinking water
      • This will make Europe colder

Section 1: Earth’s Atmosphere

Volcanic Outgassing: As the Earth cools, less dense materials seep out onto Earth’s surface via: volcanic outgassing

• This forms an atmosphere rich in Carbon Dioxide and Nitrogen

Note: there is no oxygen that exists by itself yet

• First life: nitrogen-fixing bacteria (they do not need oxygen to survive)

Video Notes:

• Cyanobacteria released the first free-range oxygen into the atmosphere
• Oceans were full of one-celled organisms that did not need oxygen to survive
  • One of these (most likely living near the surface) adapted to have photosynthesis (cyanobacteria)
• After a few hundred years, there was more oxygen being released that it could leave, which killed off other animals because oxygen was toxic to them (Oxygen Catastrophe)
• The planet was a snowball for hundreds of years because there was an increase of oxygen, meaning less greenhouse gases, so the Earth did not retain the heat (which cooled the Earth)
• Endosymbiosis: two organisms, one living inside the other

Oxygen in the atmosphere:

• Photosynthetic life forms evolve (cyanobacteria)
• This bacteria takes carbon dioxide and releases oxygen
• This impacts the composition of the Earth drastically
• Proof for this: Banded Iron Formations (BIFs), Red Beds
  • Banded Iron Formations: layers in sedimentary rock (less oxygen environments)
  • Red Beds: oxygen creating rust on iron because of their reaction together (oxygen rich environments)

Tropopause: the border between the troposphere and the stratosphere

Stratopause: the border between the stratosphere and the mesosphere

Mesopause: the border between the mesosphere and the thermosphere

Thermopause: the border between the thermosphere and the exosphere

• The ozone layer prevents 99% of the suns ultraviolet light/rays from reaching us
  • It absorbs sunlight (ultraviolet light)
  • Ozone's chemical formula is O₃
• If somebody was thrown into the exosphere, since the molecules are so far apart and there are so few of them, they would die from freezing, even though the temperature is actually 200 degrees. This is because the little amount of molecules means less chance of heating your skin, which means you lose heat at a faster rate.

Air Pressure: the force exerted on a surface by the air above due to gravity

• Simple definition: The weight of air over an area

Equilibrium: when two opposing forces become balanced

Low Pressure:

• Rising air
• Clouds

High Pressure:

• Sinking air
• Clear skies

Movement of air:

• Air moves from areas of high pressure to areas of low pressure
• Nature wants balance
• Differences in pressure will want to balance out

Video Notes:

• A storms rotation is due to the coriolis effect
• At the center of a hurricane is a very low pressure center
• Southern hemisphere - storms spin around the eye in a clockwise direction
• Northern hemisphere - storms spin around the eye in a counter-clockwise direction
• Different atmospheric conditions lead to different conditions of storms

Section 2: Earth’s Energy Budget

Concept review:

• Heat and temperature ARE NOT THE SAME
  • Temperature: a measurement of the average kinetic energy (the motions) of each particle in an object
  • Thermal (Heat) Energy: the total amount of energy of all particles that make up an object
  • Example: A large glacier has a higher heat than a boiling pot (because it has more molecules), but a boiling pot has a higher temperature than a large glacier.

Heat vs. Temperature Comparison Chart:

Energy from the Sun:

• Nuclear fusion occurs inside the sun to generate energy
  • This energy is radiated through space to earth (in the span of 8 minutes) in the form of Electromagnetic Radiation

Radiation/waves:

• Radiation is heat (energy) through empty space
• Radiation travels as waves or photons
• Waves do not require molecules to spread
• Shorter waves carry more energy than longer ones

Electromagnetic Radiation (EMR):

• EMR is energy that travels in the form of waves through empty space.
• EMR travels at the speed of light through empty space
• Wavelengths between 380-720 nanometers, a human eye can see it
  • 380 - purple
  • 720 - red
• The wavelength of the energy determines what color the human eye will see
• If the light is a combination of many wavelengths, humans will see “white light”

EM Radiation Production:

• For EM radiation to be produced, an electron must first absorb energy
• The absorbed energy causes one or more electrons to jump from a lower shell to a higher shell
  • When the electron moves from a higher shell abc down to a lower shell, a photon (light particle) is produced that acts as both a particle and a wave (EM radiation)
• As electrons move up, energy is absorbed
• As electrons move down, energy is emitted
• Each atom has a unique amount of protons, neutrons, and electrons, meaning when energized, it produces a unique spectrum of EM radiation.
• Objects that nucleosynthesis occurs in (like stars) form a lot of atoms, therefore electrons jumping shells ??
  • Example: Our sun produces the colors of the rainbow (note: mostly green)
• The temperature of an object determines which types of EM Radiation are emitted
• Blackbody Radiation Curves: Temperatures of an object determines which types of EM Radiation are emitted
• Earth’s surface temp 288 k
  • Longer wavelength
  • Lower frequency
• Sun’s temperature is 5778 k
  • Shorter wavelength
  • Higher frequency
• Different molecules react differently to different types of energy

Greenhouse gases:

• Water vapor, nitrous oxide, Methane, and Carbon dioxide are the 4 main greenhouse gases
  • Carbon dioxide is most important?
• Greenhouse gases:
  • Interact with energy in the infrared spectrum
  • Absorb radiation coming from the Earth
  • Increase movement (temperature) for a time
  • Re-radiates infrared energy back down to Earth
• Gasses work together

How the Greenhouse Effect Works:

• Sunlight comes in (70% goes through to earth, 30% gets reflected by Earth’s atmosphere and surface like clouds, ice, rocks, etc.)
• Earth absorbs the energy
• After the sun goes down, Earth cools which allows it to releases energy
• Some of the released energy/heat is trapped inside the atmosphere (by greenhouse gases)
• Earth needs a certain amount of greenhouse gases to maintain its temperature, but human activities led to us having more than needed (meaning more heat is trapped → warmer Earth)
• CO2 absorbs infrared energy

Video Notes:

• Our atmosphere prevents us from having a large range of temperature
• Greenhouse gasses trap heat in the atmosphere
• Greenhouse gases absorbs 90% of Earth’s released heat
• Humans can manipulate the energy that Earth gives off

Mini Section: Climate Control Factors

Climate:

• the characteristic pattern or course of the weather that an area has over a long period of time
• The average weather in a place over many years (usually 30)
• Climate takes hundreds, thousands and even millions of years to change naturally

Weather: day to day events that happen in the atmosphere

Climatogram: a graph that shows the climate of a place

• How to read it:
  • Title: place
  • X axis: months (each letter is for a month)
  • Two y axis: one for temperature (line graph), one for precipitation (bar graph)

Climate Controls: conditions that determine the climate of an area, including but not limited to latitude, elevation, topography (shape of the land), and prevailing winds

• Control factors:
  • Latitude
    • Temperature is colder towards to poles
    • Latitude does not affect precipitation, but pressure belts do
  • Elevation (altitude)
    • Temperature is colder at higher elevations
    • Higher elevations have less moisture
  • Nearby water
    • Mild climates at coastal areas, and the opposite at inland areas
    • Large bodies mean more water vapor, so more likely to have precipitation
  • Ocean currents
    • Warm currents warm nearby coasts, cold currents cool nearby coasts
    • Some ocean currents cause fog
  • Topography
    • The leeward side (side with dry, descending air, usually dry) is warmer than the windward side of the mountain (usually green bc it gets the rain)
      • When the cloud rises, it is under less pressure bc there are fewer molecule, so it expands
    • Windward has more precipitation than leeward, which is called the rain shadow effect
  • Prevailing winds
    • If the winds bring warm currents (from warm regions), it will warm the climate, if they are bring cold currents (from cool regions), it will cool the climate.
    • If the winds bring moist air, there will be more precipitation, but if they bring dry air, there will be less.
  • Pressure belts
    • No affect on temperature
    • Low pressure belts have precipitation, high pressure belts have little precipitation
  • Seasonal shifts
    • Some areas have seasonal changes in temperature (summers vs winters)
    • Seasonal changes shift pressure belts
  • Vegetation
    • Affects how much insolation Earth’s surface absorbs and how quickly the surface heats or cools
    • Release water vapor to the air through transpiration

Section 4: Present Climate

Definitions

• Local Climate: an area’s long-term pattern of weather (temperature and precipitation)
  • For temperature we look at range and min-max temperatures
  • For precipitation we look at amount and type of precipitation
• Global Climate: Earth’s long-term pattern of temperature and precipitation
  • For temperature we look at range and min-max temperatures
  • For precipitation we look at amount and type of precipitation
• Biomes: (for our purposes) are areas with similar temperature and precipitation throughout (the local climate)

Info:

• Mid latitudes = temperate latitudes
• Low latitudes = tropical latitudes
• Polar latitudes = high latitudes

The nine biomes:

• Tropical rain forest: rising air, low pressure, lows of precipitation, near the equator, warm/tropical
  • Located near the equator
  • Average temps 25°C (high rainfall, so many trees) around 200~1,000 cm/yr (~78-390 in/yr)
  • Extra rainfall in this biome makes this area very biodiverse (lots of unique species)
  • Warm, usually near the equator
• Temperate Grassland:
  • 30°-60° N/S
  • Warm summers, cold winters (30°C, 0°C)
  • Moderate rainfall (grasses grows), 50-90 cm/yr (20-35 in/yr)
  • Rain not sufficient to support forests
  • Sufficient rain for grasses to dominate
  • Periodic wildfires/droughts prevent extensive vegetative growth (preventing more trees)
  • Temperature Range from -20°C to 30°C (-4°F-86°F)
• Desert:
  • At high pressure belts
  • Dry soils
  • Low rainfall (less than 25 cm/yr) (less that 10 in/yr)
  • Exist at higher pressure belts
    • By this def. Antarctica is a desert because it has low annual rainfall. It could also be an “ice cap” or Polar Biome
    • Several forms of desserts, but for our sake it is a place with low annual rainfall
• Savana:
  • Aka Tropical grassland
  • Tropical latitudes/regions
  • Moderate amount of precipitation = 50-127 cm/yr (20-50 in/yr)
    • Bc its in between low and high pressure ares (0°: low pressure, 30°N/S: high pressure)
• Regular fires during droughts prevent forest growth
• Biome of majority of world’s megafauna
• Slightly higher rainfall than Temperate Grasslands, but most of that rain falls in single season
• Temperature Range from 20°C-30°C (68°F-86°F)
• Chaparral:
  • Aka Mediterranean
  • 35°-40° N/S
  • Appears next to cold currents
  • Usually on the west side of the continent
  • A hot/dry biome that receives a bit more precipitation than a desert; about 25-43 cm/yr (10-17 in/yr)
  • Fires
  • Seasonal shirt between dry and wet (seasons)
    • IE: Los Angeles
  • Usually on West Coast of Continents
  • Mild & Wet Winters, Hot & Dry Summers
  • Created when cool, seawater meets with high temperature landmasses
  • Temperature range from 10-12°C (winter) to 30-40°C (summer) (~50°F to ~86°F-104°F)
• Coniferous Forest:
  • Aka Taiga, Boreal Forest
  • Places that are in this biome at lower latitudes have higher elevations
  • Home to evergreen (coniferous) trees
    • Trees evolved to be a darker color overall in order to absorb the maximum amount of energy
  • “Swampy, Moist Forest” - Taiga
  • Typically have long, cold winters and brief summers
  • Also may be called “Boral (Northern) Forest”
  • Annual Rainfall 30-85 cm/yr (12-33 in/yr)
  • Average Temperature: ~0°C (32°F)
• Temperate Deciduous Forest:
  • Deciduous: color changing
  • Forest: its gets a lot of rain
  • Temperate: mid latitudes
  • Near warm currents
  • Mid-latitude biome
  • Dense, mixed hardwood forests
  • Moderately High Rainfall 76-152 cm/yr (30-60 in/yr)
  • Average Temperature: ~10°C (~50°F)
• Tundra:
  • Aka Artic GRassland
  • Narrow range of low-lying vegetation
  • Above treeline and high moutain regions
    • Treeline: max altitude/latitude for trees to grow
  • Often characterized by permafrost (only rop meter or so is not frozen)
    • Permafrost: Frozen soil
  • Temperature Range depends on Seasons
  • Low Rainfall 25.4 cm/yr (~10 in/yr)
  • Winter: ~-34°C (-39°F)
  • Summer: ~3-13°C (37-54°C)
• Polar/High Mountain Ice
  • Characterized by alpine glaciers and very high altitudes
  • Mostly underlain by soil bedrock rather than soils
  • May also be called “Alpline” Biome
    • This is one of the few biomes tat can be dependent on Elevaton/Altitude of the region
  • Monthly Average temperature does not exceed 0°C (32°F)

Section 3: Past Climate

How to Manipulate Earth’s Energy Budget

• Changing the amount of greenhouse gases
• Changing what is on Earth (albedo)
  • Eg. more ice on Earth = colder Earth bc more is being reflected

Climate Proxies:

• Climate Proxies are preserved physical characteristics of the past that stand in for direct measurements that enable scientists to reconstruct the climatic conditions that prevailing during much of the Earth’s history

Ice Cores:

• Ice core records - deep ice cores, such as those from Lake Vostok, can be analyzed for trapped gases, stable isotope ratios, and pollen trapped within the layers to infer past climate
• Up to 800,000

Tree Rings:

• They can tell us the age of trees
• The thickness can be used to figure out fluctuations in temp/precip
  • Thick and light circles = summer, and dark and thin circles = winter. These two come together to mark one year
• Scars and burns indicate natural events (eg. fires)
• Up to 9,000

Sediment Cores:

• Sediment layers can indicate sedimentation rate through time
• Charcoal trapped in sediments can indicate past fire events
• Ripple marks and grain size can indicate characteristics of land when sediment was deposited hw
  • Ripple marks can show water direction and wind
• Remains of microorganisms and pollen within sediment can indicate changes in past climate since each species has a limited range of habitable conditions
• Oldest sedimentary rock in Greenland (3.9 bya)

Natural Causes of Climate Change:

• Changes in Greenhouse Gas Concentration
• Changes in solar output
  • The sun is 20-30% brighter than it used to be
  • More sunspots = more solar activity (aka more energy output by 0.1%)
  • Solar maxima = the peaks in a graph of years/# of sunspots (more solar activity/warmer temps)
  • Solar minima = the minimums in a graph of years/# of sunspots (less solar activity/cooler temps)
  • The sun usually has an 11-year cycle of mins and maxs in sunspots
• Changes in the distribution of continents
  • Continents have moved over the last million years
  • Plate tectonics and drift concentrated continents at higher latitudes allowing for more ice cover, reflecting more sunlight, and creating positive feedback to cause greater cooling.
    • Feedback loops definitions:
      • Positive feedback loop: a string of events where one leads to the next and the initial forcing is amplified.
        • Eg. temp increase → ice melts → Earth’s albedo decreases → more energy from sun being absorbed → temp increase (then it repeats)
      • Negative feedback loop: a string of events where one leads to the next and the initial forcing is diminished
        • Eg. temp increase → more rising air → increased cloud formation → albedo increases bc of cloud color → earth reflects more energy → temp decreases
  • Periods of mountain building increase snow-covered high elevation areas producing a similar snow-albedo positive feedback.
  • The position of continents, mountains, and oceans create complex changes in atmospheric (and oceanic circulation).
• Changes in Earth’s Orbit
  • Milankovitch Cycles:zv dxf
    • Eccentricity: How circular or elliptical the Earths orbit looks like
      • Takes about 100,000 years to go through the cycle of circle to oval and then back to circle
    • Axial tilt (obliquity)
      • Causes seasons
        • Increased tilt → more extreme seasons (hotter summer and colder winters)
      • Takes 41,000 years for a full cycle (max to min to max)
    • Earths Wobble (precession)
      • Def. the circular movement of where the north star points to
        • Currently pointing to polaris, but the opposite direction is ????
      • When combining this with eccentricity, it can change the durations of seasons and ?????
      • Affects where and when seasons happen
  • Kepler’s Laws of Planetary Motion:
    • The orbit of planets, including Earth are elliptical in shape with Sol at one focus of the ellipse
    • A line segment connecting Sol and the planet will sweep out equivalent areas in the same amount of time
      • Objects closer to Sol will tend to travel faster due to the force of gravity
        • “Slingshot effect”
    • Perihelion: point on the ellipse where the planet is the closest to the sun it can be
    • Aphelion: point on the ellipse where the planet is the furthest from the sun it can be
• Aerosols are emitted into the atmosphere, which reduce incoming radiation and have a new cooling effect on Earths surface
  • Aersols in the stratosphere take a longer time to settle to the earths surface
  • Starts with a cooling effect, then has a warming effect
  • Large volcanic eruptions are linked to short term cooling episodes
• Extinction of dinosaurs:
  • Astroid on Earth → dust and debris everywhere → reduction in sunlight → photosynthesis stops → food chain is broken
  • There is a layer in sediment called the K-T boundary, which separates the end of the Cretaceous period and the start of the Tertiary Period
    • Made of Iridium
• The Milankovitch Theory states that variations in Earth’s orbit causes climate to change through time
• According to this theory, changes in the shape of Earth’s orbit around the sun (eccentricity), variations in Earth’s axial tilt (obliquity), and the tendency for Earth to ‘Wobble’ with respect to the direction of its rotational axis (precession) affect climate
  • Eccentricity cycle = 100 k.y.
  • Obliquity Cycle = 41 k.y.
  • Precession of the Equinoxes = 19 and 23 k.y.

Section 5: Future Climate

Pointillism - painting technique made of many dots

• Distribution of carbon dioxide is due to winds
• Anthracite: High-quality coal
  • Takes a long time to form (millions of years)
• Bituminous Coal: Mid-quality coal
  • Second longest time to form (tens of thousands/hundreds of thousands of years to form
• Peat: Low-quality coal
  • Shortest time to form (tens of thousands to form)
• Non-renewable source - energy sources that are threatening to run out if we use it too much
• Renewable source - replaced in time and will not run out easily
• Fossil fuel - natural materials made from organisms over time