Earth Systems Science Major

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About the Major

The Earth Systems Science major prepares students to understand and solve critical challenges facing our environment including:

  • Climate change
  • Water and soil pollution
  • Conservation of biological diversity
  • Management of natural resources.

The major is highly interdisciplinary, integrating the study of fundamental physical, chemical, and biological processes that shape our environment with practical applications to real-world problems. Core courses within the major provide students with a firm foundation in the fundamentals of chemistry, biology, hydrology, ecology and Earth sciences, while upper division elective courses allow students the flexibility to pursue a variety of topics related to Earth and environmental systems.

This major emphasizes an integrated approach to Earth Systems Science, incorporating field studies, laboratory experiments and computations. Coursework in the social sciences exposes students to the political, economic and societal implications of human interactions with the environment and to the challenges of environmental sustainability.

There has never been a better time to study Earth Systems Science. In addition to interdisciplinary and flexible coursework, students have opportunities for internships, summer jobs, and research experiences through the UC Merced Sierra Nevada Research Institute and partnerships with Yosemite and Sequoia/Kings Canyon National Parks, the U.S. Forest Service, and other agencies. The location of UC Merced in the San Joaquin Valley near the Sierra Nevada offers a diverse real-world laboratory for studying the natural environment and how it is affected by human activity. From local opportunities in the Sierra Nevada Mountains and San Joaquin Valley to protect endangered species and sustainably manage soil, water, and ecological resources, to state and national opportunities to shape informed policies for preventing and adapting to climate change, environmental professionals with science backgrounds are increasingly in demand.

The Program

Unique aspects of the Earth Systems Science major are its breadth and flexibility, and coursework that emphasizes the application of fundamental science concepts to current environmental challenges. Lower division coursework emphasizes foundation courses in physical, chemical and biological sciences, and mathematics, with a choice of a lower division elective science course. Upper division requirements consist of five core courses that provide students with a balance of key concepts in Earth Systems Science, and exposure to environmental science and policy. In the upper division, students choose three elective courses to tailor their program to their individual interests.

Many courses in the program contain laboratory, field, or computer-based components. An upper division seminar highlights the latest research in interdisciplinary Earth Systems Science. General education coursework in communications and economics prepares majors to apply their quantitative science skills in the job market or in further studies at the graduate level. Students participate in research, internship, or service learning activities with faculty as part of their undergraduate studies.

Learning Outcomes

Upon graduating, students from the Earth Systems Science B.S. program will have achieved the following learning outcomes:

  1. Foundational knowledge of physics, chemistry, biology, and mathematics related to Earth systems that supports a working knowledge of basic research methodologies, data analysis, and interpretation for a variety of Earth-related data.
  2. Knowledge of major concepts, theoretical principles, experimental findings, and areas of study related to Earth systems science, and comprehension of the interactions between natural Earth systems and human economic, political, and social systems.
  3. An ability to employ critical thinking, quantitative and numerical analyses, and hypothesis-driven methods of scientific inquiry in the formulation of research questions, experimental design, application and use of laboratory and field instrumentation, and analysis and interpretation of data related to Earth systems.
  4. Effective written and oral communication skills, especially the ability to transmit complex technical information.
  5. An ability to work effectively individually and in teams in classroom, laboratory, and field settings.

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Graduates of this major will have a strong background in the theory and application of Earth Systems Science, and the ability to apply their knowledge to diverse subjects. They will be well prepared for either graduate studies or jobs in the areas of environmental conservation, ecosystem and natural resource management and science, and aspects of agricultural sciences. Additionally, Earth Systems Science is an excellent foundation for professional careers in law, policy and administration that involve the environmental sciences.

This major responds to the need to prepare a future workforce with both foundational science training and practical ability to solve and manage complex environmental problems and sustainable resources in an increasingly interdisciplinary and interconnected world.

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In addition to adhering to the UC Merced and School of Natural Sciences requirements, the additional requirements that must be met to receive the B.S. in Earth Systems Science at UC Merced are:

Earth Systems Science Requirements [65-57 units]

The Earth Systems Science program consists of a minimum of 14 courses (6 lower division and 8 upper division plus a seminar course) designed to give all students a common foundation of core knowledge specific to the discipline.

Lower Division Major Requirements [42-44 Units]

  • One Earth Systems Science lower division course [4 units]
  • General Chemistry I (CHEM 002) or Honors General Chemistry I (CHEM 002H) [4 units]
  • Computer Science (MATH 015, CSE 005, or CSE 020) [2-4 units]
  • General Chemistry II (CHEM 010) or Honors General Chemistry II (CHEM 010H) [4 units]
  • Calculus I (MATH 011 or MATH 021) [4 units]
  • Calculus II (MATH 012 or MATH 021) [4 units]
  • Probability and Statistics(MATH 018, MATH 032, or ENVE 105) [4 units]
  • Introductory Physics I (PHYS 008/008H or PHYS 018) [4 units]
  • Introductory Physics II (PHYS 009.009H or 019)
  • Two additional science or engineering courses* [6-8 units]

*Relevant courses outside of Natural Sciences or Engineering by approval

Upper Division Major Requirements [30-33 units]

  • Environmental Chemistry (ESS 100) [4 units]
  • Hydrology and Climate (ESS 110) [4 units]
  • Introduction to Ecological and Environmental Microbiology (ESS 120) [4 units]
  • Fundamentals of Ecology (BIO/ESS 148) [4 units]
  • Environmental Science and Policy (ESS 141) or equivalent course (by approval) [4 units]
  • Three elective courses in ESS or related fields [9-12 units]
  • Undergraduate Seminar (ESS 190) [1 unit]

Additional Degree Requirements [10-13 units]

  • Economics of the Environment and Public Policy (ECON 120) or Intermediate Microeconomic Theory (ECON 100) or Engineering Economic Analysis(ENGR 155) [3-4 units]
  • Two upper division electives in Natural Sciences or Engineering* [6-8 units]
  • Research (ESS 095 or ESS 195) and/or Service Learning (ENGR 097 or ENGR 197) [1-3 units]

*Relevant courses outside of Natural Sciences or Engineering by approval.

Upper Division Elective Courses in ESS or Related Fields

Elective courses in the major can be selected from among upper division ESS courses (3 or 4 units) or from related courses offered in other areas, such as Biology (BIO), Environmental Engineering (ENVE), Engineering (ENGR), geography (GEOG), and management (MGMT). A list of approved courses offered each semester is available in the Natural Sciences office. Example elective courses include:

  • ESS 103: Geochemistry of Earth Systems [3.0 units]
  • ESS 105: Biogeochemistry [3.0 units]
  • ESS 112: Subsurface Hydrology [4.0 units]
  • ESS 124: Terrestrial Ecosystem Ecology [3.0 units]
  • ESS 125: Microbial Ecology [4.0 units]
  • ESS 129: Paleoecology [3.0 units]
  • ESS 132: Applied Climatology [3.0 units]
  • ESS 147: Astrobiology [4.0 units]
  • ESS 149: Conservation Biology [4.0 units]
  • ESS 170: Fundamentals of Soil Science [3.0 units] and
  • ESS 170L: Soil Science Laboratory [1.0 unit]
  • ECON 120: Economics of the Environment and Public Policy [4.0 units]
  • ENGR 180: Spatial Analysis and Modeling [4.0 units]
  • ENVE 114: Mountain Hydrology of the Western United States [3.0 units]
  • ENVE 118: Global Change [4.0 units]
  • ENVE 140: Water Resources Planning and Management [3.0 units]
  • ENVE 152: Remote Sensing of the Environment [4.0 units]
  • BIO 140: Genetics [4.0 units]
  • BIO 141: Evolution [4.0 units]

Transfer Students

Transfer students who wish to major in Earth Systems Science should complete one year of calculus, one year of physics, one year of general chemistry, and two to three semesters of general biology, organic chemistry, or Earth or environmental science courses. Students should consult the online student-transfer information system at

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ESS 001: Introduction to Earth Systems Science [4]

An introduction to basic principles of earth systems for non-science majors and prospective majors.  A multidisciplinary approach that draws from geology, chemistry, physics and biology to understand how the earth functions as a complex system and the role and impact of human beings on earth systems.

ESS 002: Sustainability Science [4]

This course explores the scientific basis for a rigorous definition of the concept of sustainability and its implementation in society. Using “back-of-the-envelope” style calculations it explains major magnitudes and trends of environmental impacts and sustainable activities. It will also employ assignments and discussions that encourage communication across disciplinary barriers.   [Syllabus]

ESS 005: Introduction to Biological Earth Systems [4]

An introduction to basic principles of earth systems for non-science majors and prospective majors. A multidisciplinary approach that draws from geology, chemistry, physics and biology to understand how the earth functions as a complex system and the role and impact of human beings on earth systems. An introduction to basic principles of coupled biological and earth systems for non-science majors and prospective majors. An interdisciplinary approach that combines concepts from biology and earth science to understand how the Earth functions as a biological incubator, the origin and evolution of molecular life, the rise of complex biological and ecological earth systems, human impacts and the sustainable Earth.  

ESS 010: Earth Resources and Society [4]

We are users and changers of our planet. This course discusses the materials and resources our planet supplies to societies, and the environmental consequences that result from consumption. We will examine the origin and use of food, water, energy, and mineral resources, and consider challenges to management and sustainability.

ESS 012: Geology of California [4]

Introduction to the geology of California for non-science majors. A tour of the major geologic features of our state, its geologic hazards and its natural earth resources in the context of basic plate tectonics and earth science principles.  

ESS 020: Fundamentals of Earth Processes [4]

Fundamentals of earth science with focus on terrestrial, marine and atmospheric systems through time; surface geological processes (plate tectonics, lithosphere cycling, weathering, erosion, sedimentation, landscape and soil formation); material and heat transport in atmosphere-ocean-lithosphere systems; paleoclimatic and paleoenvironmental dynamics and their relation to tectonic processes. (ESS 001, ESS 005, BIO 001 or CHEM 002) and (MATH 021 or ICP 001A).  [Syllabus]

ESS 025: Introduction to Ecosystem Science [4]

Fundamentals of ecosystem science; organization, function and development of ecological systems; energy and mass flow; biogeochemical cycling; biodiversity, population dynamics, and sustainability (Lab). Prerequisite: (ESS 1 or ESS 5, or BIO 1) and ICP or [(Math 11 or 21) and (PHYS 8 or 18)].  

ESS 034: Introduction to Marine Science

An introduction to biological, chemical and physical oceanography, marine geomorphology and their synthesis in the study of marine life; also including relationships with atmospheric, freshwater and terrestrial systems. Areas of emphasis include ecosystems (from the deep sea to saltwater ponds), the integrated coastal zone, resource management and global change. Normal Letter Grade only.  

ESS 040: Air Quality, Air Resources and Environmental Health [4]

A survey of principles and issues related to air quality and resources from global to regional scales, including evolution of the earth’s atmosphere, urban smog formation, visibility, acid rain, stratospheric and tropospheric ozone, effects of meteorology on air pollution, air pollution transport across political boundaries and health effects of exposure to air pollution.  

ESS 050: Ecosystems of California [4]

An introduction to ecological principles and processes through the examination of California?s varied ecosystems; discussion of native and invasive species, land use, human impacts and biodiversity; two Saturday field trips to a variety of California habitats.  [Syllabus]

ESS 060: Global Environmental Change [4]

History, causes and consequences of anthropogenic and natural changes in the atmosphere, oceans and terrestrial ecosystems; geologic evidence for glacial cycles and climate changes, modern marine and atmosphere circulation, greenhouse gases, deforestation and species extinctions and human population growth and impacts on climate and resources.  

ESS 070: Soil Foundations of Terrestrial Ecosystems [4]

Examines the physical, chemical and biological properties of soils that influence terrestrial and freshwater ecosystems. Topics include processes that control soil formation, evolution, development, and chemical properties. Particular emphasis is placed on the quantitative descriptions of energy nutrient and contaminant fluxes into, out of and through soils. Prerequisite: (ESS 001 or BIO 001) and CHEM 002.  [Syllabus]

ESS 90X: Freshman Seminar [1]

Examination of a topic in earth systems science. Pass/No Pass grading only.

ESS 095: Lower Division Undergraduate Research [1 - 5]

Supervised research. Permission of instructor required. May be repeated for credit.  

ESS 098: Lower Division Directed Group Study [1 - 5]

Permission of instructor required. Pass/No Pass grading only. May be repeated for credit.  

ESS 099: Lower Division Individual Study [1 - 5]

Permission of instructor required. Pass/No Pass grading only. May be repeated for credit.  

ESS 100: Environmental Chemistry [4]

Chemical principles of Earth and environmental systems focusing on environmental processes in water, soil and air. Emphasis on acid-based chemistry, aqueous speciation, mineral and gas solubility, oxidation and reduction and isotopes. Prerequisite: CHEM 010 and (MATH 022, ICP 001B or PHYS 008).  [Syllabus]

ESS 102: Chemical Processes in the Soil Environment [3]

Thermodynamics and kinetics of chemical process in soil systems. Topics include the formation and identification of common minerals, adsorption/desorption, precipitation/dissolution and electrochemical reactions in soils. Prerequisite: ENVE 100 or ESS 100. Normal Letter Grade only.  

ESS 103: Geochemistry of Earth Systems [3]

Quantitative analysis of earth systems using principles of thermodynamics, kinetics and isotope geochemistry; solution-mineral equilibrium and phase relations; equilibrium and reactive transport approaches to modeling geochemical processes at ambient and elevated temperatures. Prerequisite: ENVE 100 or ESS 100.  Letter Grade only.  [Syllabus]

ESS 104: Organic Geochemistry [3]

Focus on organic chemical reactions in soils and sedimentary environments. Topics include the formation and weathering of natural organic matter and reactions of natural organic matter with pollutants. Prerequisite: ENVE 100 or ESS 100. Letter Grade only.  

ESS 105: Biogeochemistry [3]

Movement, storage, and transformation of elements in the atmosphere, biosphere, hydrosphere, lithosphere, and pedosphere, with an emphasis on nutrients, human impacts, and global change. Prerequisite: ENVE 100 or ESS 100 and ENVE 110 or ESS 110.  

ESS 106: Instrumental Methods in Environmental Systems [3]

Instrumental analytical methods and quantitative analysis applied to the study of environmental materials, including inorganic, organic, and biological substances. Prerequisite: ENVE 100, ESS 100 or CHEM 010.  

ESS 108: Surface and Colloid Chemistry of Earth Materials [3]

Surface, colloid and interfacial chemistry related to soil, environmental and microbial applications; properties, energetics and reactivity of surfaces and interfaces of Earth materials; the role of mineral surfaces in promoting and catalyzing chemical phenomena at phase boundaries. Prerequisite: ENVE 100 or ESS 100. Letter grade only.  

ESS 109: Inorganic Chemistry of Earth’s Materials [3]

Chemical principles, structure and bonding of minerals and Earth materials, including crystallography (symmetry, space groups, group theory), coordination chemistry, bonding models (valence bond, crystal field and MO theories) and electronic and magnetic properties. Prerequisite: ENVE 100, ESS 100, or CHEM 010.  

ESS 110: Hydrology and Climate [4]

Basics of the hydrological cycle and the global climate system. Fundamentals of surface water hydrology, hydrometeorology, evaporation, precipitation, statistical and probabilistic methods, unit hydrograph and flood routing. Prerequisite: ENVE 20 or ESS 20.  [Syllabus]

ESS 112: Subsurface Hydrology [4]

Hydrologic and geologic factors controlling the occurrence and use of groundwater on regional and local scales. Physical, mathematical, geologic and engineering concepts fundamental to subsurface hydrologic processes. Introduction to ground-water flow and transport modeling, with emphasis on model construction and simulation. Prerequisites: ENVE 110.  [Syllabus]

ESS 120: Introduction to Ecological and Environmental Microbiology [4]

Fundamentals of microbiology in ecological and environmental systems, including the distribution of microbial diversity throughout terrestrial, ‘extreme,’ and marine environments; microbial control of global biogeochemical cycles; and environmental services provided by microorganisms. Both classical and contemporary biochemical, molecular, and genomic approaches to microbial physiology, metabolism, and ecology will be discussed. Prerequisite: CHEM 010 and (ESS 001, ESS 005, ENVE 020, or permission of the instructor).

ESS 124: Terrestrial Ecosystem Ecology [4]

Ecosystem ecology is the study of interactions between organisms and their environment. Focus on energy, water and nutrient flows through the living (plants, animals, microbes) and nonliving (soils, atmosphere) components of ecosystems. Examines both natural and human-modified terrestrial ecosystems. Prerequisite: Junior standing and (BIO 148 or ESS 025). Letter grade only.  [Syllabus]

ESS 125: Microbial Ecology [4]

Advanced course in microbiological systems and techniques. Prerequisite: ESS 120. Letter Grade only.  

ESS 126: Environmental Genomics [4]

Introduction to the principles and methods of genomics as applied to the understanding of ecosystems. Topics include population genetics, adaptation to environmental change and genomic analysis of environmental microbial communities; experimental and computational methods relevant to environmental genomics. Prerequisite: BIO 141 or ESS 120. Letter Grade only.  

ESS 128: Theoretical Ecology [4]

Advanced course on the application of theoretical and quantitative methods for the analysis and interpretation of populations, communities and ecosystems. Prerequisite:  (MATH 12 or 22 or MATH 30); BIO 145.

ESS 131: Atmospheric Chemistry and Physics [4]

Chemistry and physics of the troposphere and stratosphere, including atmospheric aerosols. Prerequisite: CHEM 008, PHYS 009 and (ESS 020 or ENVE 020).  

ESS 132: Applied Climatology [3]

Spatial and temporal patterns in climate and their association with land surface characteristics and processes. Methods for exploiting these for hypothesis testing, modeling and forecasting.Applications include seasonal forecasting, ecological modeling and analysis of processes such as flooding and wildfire. Prerequisite: ENVE 110 or ESS 110, or consent of instructor.  

ESS 133: Flora of California

This course introduces students to the plant diversity of California. It consists of lectures, discussions, and field trips. The field trips focus on plant identification in the foothills of the Central Sierra Nevada and help illustrate concepts presented in lecture such as endemism, plant/soil interactions, and vegetation types. Prerequisite: BIO001 or ESS001 or BIO148 or ESS050.  [Syllabus]

ESS 134: Air Pollution and Resources [3]

Chemistry and physics of atmospheric pollutants, urban air pollution, visibility, mitigation and resource economics. Prerequisite: ESS 100 or ENVE 100.  

ESS 141: Environmental Science Policy [4]

In depth-analysis of environmental case studies. Focus on science critical to policy development and implementation, the policy-making process, and policy outcomes. Special emphasis on interaction between scientific information and policy-making. Example topics include Western water resources, biodiversity conservation, and global warming. Emphasis on written and oral communication and critical analysis. Prerequisite: Lower division ESS, ENVE, BIS, ECON, POLI, or PUBP course; and WRI10; or consent of instructor.  [Syllabus]

ESS 147: Astrobiology [4]

Astrobiology refers to the study of the origin and evolution of life in the cosmos. It is an integrative, multidisciplinary field that includes areas of biology, astronomy, geology, chemistry and physics. Students in the class face some of the most fundamental topics addressed by science today such as who we are, where we came from, and where we might go. We cover three main themes: How did life begin and evolve? Does life exist elsewhere in the universe? What is life’s future on Earth and beyond? Prerequisite: CORE 001 and (BIO 001, BIO 005, PHYS 006, CHEM 002 or ESS 001), or consent of instructor. Letter grade only.

ESS 148: Fundamentals of Ecology [4]

Introduction to the principles of ecology at population, community, ecosystem, landscape, and global scales. Prerequisites: BIO 1 or BIO 5 or ESS 1 or ESS 5 or permission of the instructor.  [Syllabus]

ESS 149: Conservation Biology [4]

Detailed examination of the evolutionary, ecological, management, and policy issues related to the conservation of ecosystems, species, and genetic diversity. Theory and practical aspects of biological conservation are presented, with special reference to case studies from California. Prerequisite: BIO 001 and (MATH 018 or MATH 032). BIO 148 recommended. Letter grade only.

ESS 150: Geomorphology and Surface Processes

Observation and analysis of earth surface processes and the development of landforms and landscape. The interaction between surficial processes and tectonic, biologic, hydrologic, climatic and atmospheric processes. Evaluation of environmental hazards and engineering solutions. Prerequisite: ESS 20 or ENVE 20.  

ESS 170: Fundamentals of Soil Science [3]

ESS 170/ES 270 examines the soil as a natural resource and soils as ecosystems. Soil science explores the major physical, chemical, and biological properties of soils, and fundamental processes that regulate interaction of the terrestrial biosphere with other components of the earth system.  Prerequisite:  Chem 2 and (BIO 1 or ESS 1).  [Syllabus]

ESS 180: Field Methods in Earth Systems [4]

Field techniques in chemistry, hydrology, geology, ecology and microbiology, emphasizing principles of measurement, observation and interpretation; integration of diverse data sets. Prerequisite: CHEM 10 and (MATH 12 or 22) and (Phys 8 or 18).  

ESS 190: Undergraduate Seminar [1]

Weekly seminar of current topics in earth and environmental systems. Prerequisite: Junior standing. Pass/No Pass grading only.  

ESS 192: Topics in Environmental Systems [1 - 6]

Treatment of a special topic or theme in Environmental Systems. Prerequisite: Junior standing or consent of instructor. May be repeated for credit with different topics.  

ESS 195: Upper Division Undergraduate Research [1 - 5]

Supervised research. Permission of instructor required. May be repeated for credit.  

ESS 198: Upper Division Directed Group Study [1 - 5]

Permission of instructor required. Pass/No Pass grading only. May be repeated for credit.  

ES 199: Upper Division Individual Study [1-5]

Prerequisite: Junior standing. Permission of instructor required. Pass/No Pass grading only. May be repeated for credit.

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Assessment Plan

We will use the following tools to assess learning outcomes of the program:

  • Review of random samples of student coursework in required courses
  • Review of student samples of laboratory and field reports in courses with those components
  • Exit interviews with graduating seniors
  • Review of relevant data gathered the University Graduating Senior Survey

The information gathered during student assessment will be reviewed by ESS faculty (with help from the Center for Research on Teaching Excellence) and used to revise program requirements, or communicated directly to course instructors if specific gaps are identified. Assessment information will be used to make program or curriculum changes to improve student learning outcomes and to enhance the student experience.

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