Earth's Environmental Spheres and Systems

• A discussion on Earth's Systems Overview

Four Environmental Spheres

• Lithosphere is the Earth's solid, rocky crust, containing both mineral particles and unconsolidated matter.
• Lithosphere covers the entire surface.
• Atmosphere is composed of five layers and primarily contains 79% nitrogen and less than 21% oxygen and affected by solar energy and Earth's rotation.
• Hydrosphere includes all forms of water like oceans, rivers, and glaciers with oceans holding 97% of Earth's water.
• Cryosphere is the frozen part of the hydrosphere, consisting of snow and ice.
• Biosphere encompasses all areas where living organisms exist, including all animal and plant life and most life exists within 3 meters below and 30 meters above ground, or in the top 200 meters of the ocean.

Earth as a System

• Earth as a system involves a collection of processes operating as a whole.
• Earth can be viewed as a closed system, where energy can enter or leave, but materials cannot.
• Example of a closed system is that Earth does not gain or lose significant mass.
• Open systems are those where both matter and energy can enter as inputs or leave as outputs.

Interconnected Systems and Feedback Loops

• Changes in one sphere impact other spheres.
• Volcanic eruptions can affect atmospheric composition.
• Positive feedback enhances ongoing changes, accelerating warming.
• CO2 emissions increasing global temperatures is an example of positive feedback.
• Negative feedback counteracts changes, stabilizing the system.
• Cloud cover reflecting sunlight to cool the Earth is an example of negative feedback.

Examples of Feedback Loops

• Arctic ice melting decreases albedo (reflectivity), which leads to further warming, an example of positive feedback.
• Deforestation and drought increase fire likelihood in the Amazon rainforest, which worsens the problem due to positive feedback.

Geographic Grid & Time Zones

• Latitude measures distance from the equator.
• Longitude has no natural baseline, using the Prime Meridian (Greenwich) as the standard reference.
• Time zones exist for standardized timekeeping.
• Coordinated Universal Time (UTC) is the standard reference for time.
• International Date Line (IDL) is the line where crossing it changes the calendar day.

Earth’s Movements & Seasons

• Rotation (daily spin) causes day/night cycles, influences local climate, and causes the Coriolis Effect.
• Revolution (orbit around the sun) takes approximately 365.25 days, with leap year adjustments.
• Perihelion, when Earth is closest to the Sun, occurs around January 3.
• Aphelion, when Earth is farthest from the Sun, occurs around July 4.
• Earth’s tilt is 23.5°, which dictates the occurance of longest and shortest days known as the solstices.
• Equinoxes result in equal day/night lengths.
• Seasonal variations are determined by the tilt and orbit.

Telling Time

• Standard Time is based on fixed time zones.
• Daylight Saving Time (DST) was introduced to conserve energy, it is not fully observed everywhere and mostly exist in mid-latitude, unnecessary in tropical regions.

Key summary points on Earth systems

• Constant interaction exists between all four of Earth's spheres
• Feedback loops can impact climate regulation
• Earth's movement impacts time, seasons, and environmental patterns.
• Time zones and DST help synchronize human activities with Earth's rotation.

Insolation & Temperature Summary

• Energy is the ability to do work, measured in joules (J).
• Heat refers to energy transfer due to temperature differences.
• Temperature measures the average kinetic energy of molecules.

Gravitational Potential and Kinetic Energy

• Gravitational potential energy is stored energy due to an object's height.
• Hydropower plants use falling water to generate electricity.
• Kinetic energy is energy in motion with water speeding through a dam turning turbines to generate power.
• Work is a force applied over a distance.
• Power is energy transfer per unit time, measured in watts.

Measuring Temperature

• Kelvin (K) is used in scientific contexts, and it has no negative values.
• Celsius (°C) is the international standard unit for measuring temperature.
• Fahrenheit (°F) is primarily used in the U.S.

Formulas

• °F = (°C × 1.8) + 32
• °C = (°F - 32) / 1.8

Solar Energy & Insolation

• Sun is Earth's primary energy source.
• Nuclear fusion, where hydrogen fuses into helium, creates the sun's energy.
• Energy travels via electromagnetic radiation.

Electromagnetic Spectrum

• Visible light makes up 47% of the solar spectrum.
• Ultraviolet (UV) radiation has short wavelengths with only about 8% reaching the Earth and can be partly blocked by the atmosphere.
• Infrared radiation makes up 45% of the spectrum and is felt as heat.

Radiation & Heat Transfer

• Radiation describes emission of energy from an object, and when objects takes in this emitting energy it is known as absorption.
• Dark surfaces absorb more energy than light surfaces.
• Reflection describes surfaces that repel solar energy.
• Albedo is the reflectivity of a surface.
• Snow has a high albedo, while forests have a low albedo.
• Scattering happens with redirection of solar radiation where it causes blue skies and red sunsets.

Warming & Cooling Processes

• Conduction transfers heat between molecules.
• Convection is vertical heat transfer
• Advection is horizontal heat transfer
• Latent heat describes heat exchange during phase changes.

Latitudinal & Seasonal Temperature Variations

• Angle of incidence determines how much solar energy a region receives and low latitudes receive an energy surplus.
• High latitudes experience energy deficit.

Land & Water Contrasts

• Land heats and cools faster than water because water has a higher heat capacity, increasing it's specific heat.
• Sunlight penetrates water but not land, water circulates heat, and land does not, and evaporative cooling occurs when water evaporates, cooling the surface.

Global Energy Transfer

• Atmospheric Circulation impacts energy through the movement of warm air poleward and cool air equatorward.
• The atmosphere accounts for 75-80% of horizontal energy transfer.

Ocean Circulation

• Ocean circulation is driven by wind and Earth’s rotation
• Warm currents move poleward and cold currents move equatorward.

Global Temperature Patterns

• Latitude, altitude, land vs. water, and ocean currents affect global temperature patterns.
• Isotherms are lines that connect equal temperatures.
• Temperature extremes occur more in continental interiors than in coastal regions.

Climate Change & Human Impact

• Since 1880, global temperatures have risen by 1.4°F.
• CO2 levels have increased from 280 ppm in 1750 to 417 ppm in 2021.
• The greenhouse effect is impacting climate, but excess greenhouse gases contributing to global warming.
• Methane (CH4) is 25 times more potent than CO2 over 100 years.
• Nitrous oxide (N2O) is 200 times more potent than CO2.
• CO2 absorption reduces ocean pH by 0.1 units
• Ocean acidity has increased by 30%

Key Takeaways

• Solar radiation impacts the climate
• Latitude, land/water contrast, and ocean currents shape the climate
• Heat transfer processes regulate temperature differences
• Human activities contribute to global warming

Introduction to the Atmosphere

• The atmosphere that surrounds Earth uniformly is held by gravity.
• Atmosphere extends up to 10,000 km, and 50% of its mass is below 6 km.
• Air mostly consists of 78% nitrogen and 21% oxygen.

Early Atmosphere Evolution

• Volcanic eruptions are thought to have released water vapor, CO2, and nitrogen around 4 billion years ago.
• Early life forms consumed CO2 and released oxygen via photosynthesis 3.5 billion years ago.
• CO2 was stored in sedimentary rocks over geologic time, and oxygen accumulated.

Modern Atmosphere Composition

• Permanent Gases (constant levels)
  • Nitrogen makes up 78% of the atmosphere, added by decay and volcanic activity, removed by biological processes.
  • Oxygen makes up 21% of the atmosphere and is essential for life.
  • Argon is less than 1% and has minimal impact on climate.
• Variable Gases (change over time)
  • Water vapor levels are most abundant in warm, moist areas.
  • Carbon dioxide absorbs heat, and a major increasing factor in global warming.
  • Ozone absorbs harmful UV radiation and is found in the ozone layer (15-48 km above Earth).
• Particulates (Aerosols)
  • Small solid/liquid particles in the air.
  • Imporant for cloud formation and radiation absorption.
  • Found in cities, deserts, volcanoes, and coastal regions.

Layers by Temperature

• Troposphere has a altitude between 0-18
  • Lowest layer where weather occurs.
  • Temperature decreases with altitude.
  • Most clouds and water vapor existing here.
• Stratosphere has a altitdue between 18-48 km
  • Ozone layer exists.
  • Temperature increases with altitude.
• The Mesosphere 48-80 km
  • Coldest layer important for studying long-term climate change.
• The thermosphere extends between 80-200km
  • Absorbs solar radiation, causing high temperatures.
  • Home to auroras and the space station.
• Exosphere above 200km
  • Gradual transition into outer space, has very little pressure
  • Pressure decreases with altitude

Pressure

• Air is compressed near the surface, making it denser.
• Measured in millibars (mb) (standard sea level pressure = 1013.25 mb).
• Higher temperatures reduce air density, creating low-pressure zones.

Weather vs Climate

• Weather is short-term atmospheric conditions (temperature, precipitation, wind).
• Climate: Long-term atmospheric patterns (measured over 30+ years).

Factors Influencing Climate

• Latitude: Determines sunlight received.
• Land vs. Water: Oceans regulate temperature, land heats/cools faster.
• Atmospheric Circulation: Moves warm/cool air globally.
• Ocean Currents: Transport heat across the globe.
• Altitude: Higher elevation = cooler temperatures.
• Topography: Mountains influence wind and precipitation.
• Human Activities: Urban heat islands and deforestation affect local climate.

Climate Classification (Köppen System)

• Climates are classified through tempreature and patterns A: Tropical (humid, hot year-round)
• B: Dry (deserts, evaporation exceeds precipitation)
• C: Temperate (humid mid-latitude, mild winters)
• D: Continental (humid mid-latitude, severe winters)
• E: Polar (cold year-round)

Climate Change & Global Warming

• Climate change is long-term shifts in temperature, pressure, and wind.
• Global warming is a recent rapid increase in Earth's average temperature with current data showing global temperatures have increased by 1.4°F since 1880.
• CO2 levels have risen from 280 ppm (1750) to 417 ppm (2021).
• Methane (CH4) is 25x stronger than CO2, mainly from agriculture.
• Nitrous oxide (N2O) is 200x stronger than CO2 from fertilizers.

Effects of Climate Change

• Rising sea levels.
• Changing precipitation patterns.
• More extreme weather events.
• Expanding deserts.

Key Forces Affecting Wind

1. Gravity: Keeps air from escaping into space.
2. Pressure Gradient Force: Air moves from high to low pressure, controlling wind speed.
3. Coriolis Effect: Earth's rotation deflects moving air.
   • Right in the Northern Hemisphere, left in the Southern Hemisphere.
4. Friction: Slows wind movement near Earth's surface.

Types of Winds

• Geostrophic winds exhibit balance between pressure gradient force and Coriolis effect, causing winds to move parallel to isobars in the upper atmosphere.
• Surface Winds: Affected by friction, moving diagonally across isobars.

Quick Takeaways

• A dynamic system driven by temperature, pressure, and gasses comprises Earth's atmosphere
• Climate is the long-term pattern and climate change is driven by human activity
• The Coriolis Effect impacts wind and ocean currents.
• Wind and pressure systems influence weather patterns globally.
• Climate change has been exacerbated by rising CO2 and methane levels

The Hydrosphere & Hydrologic Cycle

• The hydrosphere accounts as one of the four spheres and includes the movement of Earth water
• 99% of Earth's water is in storage (oceans, glaciers, groundwater).
• Hydrologic Cycle: The continuous movement of water between different storage areas.
• Evaporation: Water changes from liquid to vapor.
• Transpiration: Water leaves plants through their leaves.
• Condensation: Water vapor cools and changes to liquid.
• Precipitation: Water falls back to Earth as rain, snow, etc.
• Runoff/Infiltration: Water either runs off the surface or infiltrates into the ground.

Water Distribution on Earth

97.2% is saltwater and 2.8% is Freshwater

• Most freshwater is accounted in ice caps and glaciers

Surface Water & Runoff

• Runoff: Describes water that does not filtrate and runs back to the seas/rivers.
• Aquifers: Describe underground layers of rock storing groundwater.

Ocean Characteristics

• Ocean salt measures 3.5% on average.
• Ocean acidity rises due to climate change and CO2 absorption
• Ocean temperature is warmest near the equator with density increasing at low temperatures

Movement of Ocean Water

• Tides: Caused by the gravitational pull of the Moon and Sun. Current: -Surface currents occur from wind Influenced by Coriolis Effect Deep currents are driven by temperature and salinity differences
  • Waves: Created by wind or disturbances like earthquakes.

Cryosphere (Frozen Water)

The following are forms of Ice: 

• Permafrost: Permanently frozen water ground in cold regions. 
• Ice floe: Floating mass of ice.
• Ice shelf: Thick ice extending from land into the sea
• Icebergs are large chunks of ice that break off glaciers

Freshwater Resources

• Lakes are temporary: Many dry up over thousands of years.
• Human impact from climate change accelerating lakes Example: Aral Sea is now <10% of its area due to water diversion.
• Reservoirs are artificial lakes created by dams
• Reservoirs can be used for flood control and hydroelectric power, but come with the effects of habitat loss

Wetlands

• Wetlands are categorized either as Swamps or Marshes
• Wetlands provide help in controlling floods and wildlife

Rivers & Streams

• Drainage Basin: Land area drained by river
• Amazon River alone contributes 20% of the Rivers and Streams

Groundwater and Aquifers

• Groundwater and Aquifers are essential for potable water, and are derived from rainwater
• Overuse leads to "cones of depression", lowering the water table to the point where shallow wells are left high and dry
• Pollution affects this precious recource due to runoff from Human activities

Summary

• There is is a limited supply of freshwater, which being used faster than which it is being supplied.
• Climate Change is being impacted by both water scarcity.

Climate Regions & Understanding Climate summaries

• Köppen Climate Classification System relates climate using temperature, precipitation and other elements
• Climographs help classify and compare climate patterns

Major Climate Types

• Tropical Climates (Group A):
  • Tropical Wet (Af): Amazon areas tend to be warm, humid, and have year-round rain.
  • Tropical Savanna (Aw): displays seasonal rainfall due to ITCZ shifts
  • Tropical climates near the monsoon zone also show shifts in wind direction with heavy raining pattern.
• Dry Climates (Group B):
  • Subdesert zone that has high pressure and is very dry near coastal areas.
  • Dry area tend to found in rainshadow areas

Climate Change & Global Warming

• Climate change includes long term shifts, while global warming describes the long term rapid heating in the atmosphere
• Both have direct effects on the water, land and atmosphere as well biological entitites world-wide and a key feature of climate change is a shifting of wind and precipitation

Analyzing Climate projections

• Understanding past Climate and climate can be studied through tree rings and oxygen ratios Ice Cores are also a reliable way to see past data but can cost billions
• Causes of natural Climate include naturally through volcanic activity

Climate and the Human Factors

Factors relating to Humans:

• Greenhouse Gas Emissions that can result in feedback loops
• Temperature Rise by 0.78°C that happened in the last century
• Changing Patterns in Weather

Projecting Climate Change

• Climate has been projected to rise in the upcoming decades- resulting in impacts to land, and rising water levels ultimately affecting weather patterns and species

Steps on Addressing Climate Change

• Efforts have been done internatilonally to limit global warming and its effects
• Rising temperatures and melting ice has accelerated
• Future projections are show worsening effects due to ongoing climate change and pollution
• These issues will require necessary climate coopoeration to mitigate risks and political unrest

Overview of Earth's four environmental spheres: Lithosphere, Atmosphere, Hydrosphere, and Biosphere. Discusses Earth as a closed system where energy can enter or leave, but materials cannot. Covers the composition and characteristics of each sphere and their interactions.