🌱Intro to Environmental Systems Unit 2 – Earth Systems and Processes

Key Concepts and Terminology

• Earth systems science interdisciplinary field that studies the interactions and processes within and between Earth's spheres (geosphere, atmosphere, hydrosphere, biosphere)
• Geosphere solid Earth, including the crust, mantle, and core, as well as landforms and geological processes (plate tectonics, volcanism, erosion)
• Atmosphere gaseous layer surrounding Earth, composed primarily of nitrogen (78%) and oxygen (21%), with trace amounts of other gases (carbon dioxide, water vapor)
• Hydrosphere all water on Earth's surface, including oceans, lakes, rivers, groundwater, and water vapor in the atmosphere
• Biosphere all living organisms on Earth, including plants, animals, and microorganisms, as well as their habitats and interactions
• Biogeochemical cycles movement and exchange of matter (carbon, nitrogen, phosphorus) between the biosphere, geosphere, hydrosphere, and atmosphere
• Feedback loops mechanisms that amplify (positive feedback) or dampen (negative feedback) changes in Earth systems (albedo effect, greenhouse effect)
• Anthropocene proposed geological epoch characterized by significant human impact on Earth's systems and processes (climate change, land use changes, biodiversity loss)

Earth's Spheres and Their Interactions

• Earth's spheres are interconnected systems that exchange matter and energy through various processes and interactions
• Geosphere-atmosphere interactions include weathering, erosion, and volcanic eruptions, which affect atmospheric composition and climate (Mount Pinatubo eruption, 1991)
• Hydrosphere-atmosphere interactions involve the water cycle, with evaporation, transpiration, and precipitation transferring water between the two spheres (Amazon rainforest)
• Biosphere-atmosphere interactions include photosynthesis and respiration, which regulate atmospheric carbon dioxide levels and oxygen production (phytoplankton in oceans)
  • Photosynthesis removes carbon dioxide from the atmosphere and releases oxygen
  • Respiration consumes oxygen and releases carbon dioxide back into the atmosphere
• Geosphere-hydrosphere interactions involve the formation and alteration of landforms through processes like weathering, erosion, and deposition (Grand Canyon)
• Biosphere-geosphere interactions include soil formation, nutrient cycling, and the role of organisms in shaping landforms (coral reefs)
• Human activities, such as fossil fuel combustion, deforestation, and land use changes, significantly influence the interactions between Earth's spheres (urbanization, agriculture)

Geological Processes and Landforms

• Plate tectonics theory that explains the movement and interaction of Earth's lithospheric plates, driven by convection currents in the mantle
  • Divergent boundaries plates move apart, creating new oceanic crust (Mid-Atlantic Ridge)
  • Convergent boundaries plates collide, resulting in subduction, mountain building, and volcanic activity (Andes Mountains)
  • Transform boundaries plates slide past each other, causing earthquakes (San Andreas Fault)
• Volcanism process by which molten rock (magma) and gases are expelled from Earth's interior onto the surface (Yellowstone caldera)
• Earthquakes sudden release of energy in Earth's crust, caused by the movement of tectonic plates or volcanic activity (1906 San Francisco earthquake)
• Weathering breakdown of rocks and minerals at Earth's surface due to physical, chemical, or biological processes (exfoliation, oxidation)
• Erosion removal and transport of weathered material by agents such as water, wind, or ice (Nile River delta)
• Deposition settling of eroded material, leading to the formation of sedimentary rocks and landforms (sand dunes, deltas)
• Landforms distinctive features of Earth's surface, shaped by geological processes (mountains, valleys, plateaus, plains)

Atmospheric Composition and Dynamics

• Atmosphere is a mixture of gases held in place by Earth's gravity, with a vertical structure divided into layers based on temperature and composition
• Troposphere lowest layer of the atmosphere, where most weather phenomena occur (thunderstorms, hurricanes)
  • Contains approximately 75% of the atmosphere's mass and 99% of its water vapor
  • Temperature decreases with altitude at a rate of ~6.5°C/km (lapse rate)
• Stratosphere layer above the troposphere, characterized by a temperature inversion due to the absorption of UV radiation by the ozone layer
• Mesosphere layer above the stratosphere, where temperature decreases with altitude, reaching the coldest temperatures in the atmosphere (~-90°C)
• Thermosphere uppermost layer of the atmosphere, where temperature increases with altitude due to the absorption of high-energy solar radiation (aurora borealis)
• Atmospheric circulation large-scale movement of air, driven by uneven heating of Earth's surface and the Coriolis effect (trade winds, jet streams)
• Pressure gradient force difference in atmospheric pressure between two points, causing air to move from high to low pressure (sea breeze)
• Coriolis effect apparent deflection of moving objects (air, water) due to Earth's rotation (hurricane rotation)

Hydrosphere and Water Cycle

• Hydrosphere includes all water on Earth's surface, with oceans making up ~97% of the total volume
• Water cycle continuous movement of water through Earth's spheres, driven by solar energy and gravity (evaporation, condensation, precipitation)
  • Evaporation process by which liquid water transforms into water vapor, primarily from oceans and other water bodies (lake evaporation)
  • Transpiration release of water vapor from plants through stomata, contributing to atmospheric moisture (Amazon rainforest)
  • Condensation formation of liquid water droplets from water vapor, often resulting in clouds or fog (dew formation)
  • Precipitation falling of liquid water (rain) or solid water (snow, hail) from the atmosphere onto Earth's surface (monsoon rains)
• Groundwater water stored in soil and rock pores beneath Earth's surface, often accessed through wells or springs (Ogallala Aquifer)
• Runoff movement of water over land surfaces, contributing to streamflow and the formation of rivers and lakes (Mississippi River)
• Cryosphere portion of the hydrosphere that is frozen, including glaciers, ice caps, and sea ice (Antarctic ice sheet)
  • Glaciers and ice caps store ~69% of Earth's freshwater, playing a crucial role in regulating global sea levels and climate (Greenland ice sheet)

Biosphere and Ecosystems

• Biosphere encompasses all living organisms on Earth, as well as their habitats and interactions
• Ecosystems communities of living organisms interacting with each other and their non-living environment (Serengeti savanna)
  • Producers organisms that convert solar energy into chemical energy through photosynthesis, forming the base of food webs (phytoplankton, plants)
  • Consumers organisms that obtain energy by feeding on other organisms (herbivores, carnivores, omnivores)
  • Decomposers organisms that break down dead organic matter, recycling nutrients back into the ecosystem (fungi, bacteria)
• Biodiversity variety of life at all levels, from genes to species to ecosystems (tropical rainforests, coral reefs)
• Biomes large-scale ecosystems characterized by distinct climate patterns and vegetation types (tundra, desert, temperate forest)
• Ecological succession gradual process of change in species composition and community structure over time (primary succession on volcanic islands)
• Nutrient cycling movement and exchange of essential elements (carbon, nitrogen, phosphorus) through biotic and abiotic components of ecosystems (nitrogen fixation by legumes)
• Ecosystem services benefits that humans derive from ecosystems (pollination, water purification, carbon sequestration)

Climate Systems and Global Change

• Climate long-term average weather patterns in a given area, influenced by factors such as latitude, altitude, and proximity to water bodies
• Greenhouse effect warming of Earth's surface and lower atmosphere due to the absorption and re-emission of infrared radiation by greenhouse gases (carbon dioxide, methane, water vapor)
  • Greenhouse gases allow shortwave solar radiation to pass through the atmosphere but trap longwave infrared radiation emitted by Earth's surface
• Global warming observed increase in Earth's average surface temperature over the past century, primarily due to anthropogenic greenhouse gas emissions (burning of fossil fuels, deforestation)
• Climate change long-term shifts in temperature, precipitation, and other climate variables, often with significant impacts on ecosystems and human societies (sea level rise, more frequent extreme weather events)
• Carbon cycle movement and exchange of carbon through Earth's spheres, including the atmosphere, biosphere, hydrosphere, and geosphere (photosynthesis, respiration, fossil fuel combustion)
• Albedo effect reflection of solar radiation by Earth's surface, with high-albedo surfaces (snow, ice) reflecting more energy and low-albedo surfaces (oceans, forests) absorbing more energy
• Feedback loops mechanisms that amplify (positive feedback) or dampen (negative feedback) changes in climate systems (ice-albedo feedback, carbon cycle feedback)
• Mitigation efforts to reduce greenhouse gas emissions and minimize the impacts of climate change (renewable energy, energy efficiency, carbon pricing)

Human Impact on Earth Systems

• Anthropocene proposed geological epoch characterized by significant human influence on Earth's systems and processes
• Land use changes alteration of Earth's surface for human activities, such as agriculture, urbanization, and resource extraction (deforestation, urban sprawl)
  • Deforestation clearing of forests for timber, agriculture, or other land uses, leading to habitat loss, soil erosion, and carbon emissions (Amazon rainforest)
  • Urbanization growth and expansion of cities, resulting in land cover changes, increased energy consumption, and altered hydrological processes (urban heat island effect)
• Pollution introduction of harmful substances into the environment, often as a result of human activities (air pollution, water pollution, plastic pollution)
  • Air pollution presence of harmful substances in the atmosphere, such as particulate matter, ozone, and nitrogen oxides, often from fossil fuel combustion and industrial activities (Beijing smog)
  • Water pollution contamination of water bodies by chemicals, nutrients, or pathogens, often from agricultural runoff, sewage, or industrial discharges (Gulf of Mexico dead zone)
• Biodiversity loss decline in the variety of life at all levels, often due to habitat destruction, overexploitation, invasive species, and climate change (sixth mass extinction)
• Overexploitation unsustainable use of natural resources, such as overfishing, overhunting, or groundwater depletion (collapse of Atlantic cod fisheries)
• Invasive species non-native organisms that establish and spread in new environments, often outcompeting native species and altering ecosystem functions (kudzu vine in the southeastern United States)
• Ecological footprint measure of human demand on Earth's ecosystems, expressed in terms of the area of biologically productive land and water required to support a population's resource consumption and waste assimilation
• Sustainability meeting the needs of the present without compromising the ability of future generations to meet their own needs, often through the responsible use of resources and minimizing environmental impacts (renewable energy, sustainable agriculture)