Earth Sciences and Environmental Sustainability, Doctor of Philosophy

School of Earth and Sustainability

College of the Environment, Forestry, and Natural Sciences

This Doctoral program will prepare you to be part of a growing industry of leaders, scientists, and engineers addressing issues of climate change, water scarcity, natural resource demand, and environmental sustainability in the Southwest, United States, and the global community.

  • Available Emphasis Areas:
  • Climate and Environmental Change - Emphasis
  • Earth Systems - Emphasis
  • Ecology, Evolution and Conservation Biology - Emphasis
  • Engineering Sustainable Systems - Emphasis
  • Environment and Society - Emphasis

  • To receive a Doctor of Philosophy Degree (PhD) at Northern Arizona University, you must complete a planned group of courses, from one or more disciplines, ranging from at least 60 - 109 units of graduate-level courses. Most plans require research, a dissertation, and comprehensive exams. All plans have residency requirements regarding time spent on the Flagstaff campus engaged in full-time study.

    The full policy can be viewed here.

In addition to University Requirements:

Minimum Units for Completion 60
Additional Admission Requirements Required
Dissertation Dissertation is required.
Comprehensive Exam Comprehensive Exam is required.
Oral Defense Oral Defense is required.
Research Individualized research is required.
Emphasis Required

An emphasis is required for this degree.

Purpose Statement

The Interdisciplinary PhD Program in Earth Sciences & Environmental Sustainability (ESES) brings together students and faculty from across the University. Many ESES topics address questions that can inform decisions and solutions related to environmental issues made by governments, business and society.
ESES students produce discipline-specific science and engineering of the highest quality. They strive to integrate different disciplines from the natural sciences, social sciences and engineering to build, connect and communicate knowledge to increase the broader impacts of their research.
ESES students study how planet Earth is changing due to natural phenomena and human activities over spatial and temporal scales. They observe, explain, understand, and project trends in earth, environmental, and societal systems, and investigate the drivers and processes that shape natural and social worlds and the interactions between them.
Student Learning Outcomes

ESES students will select one of the following three emphasis areas, based upon their background and the work they will complete toward their dissertation:
Earth Systems

This emphasis will prepare you to pursue research and educational opportunities that:

  • Advance cutting-edge research in the Earth sciences.
  • Increase knowledge in the critical areas for society of energy, natural resources, water, and natural hazards.
  • Apply this knowledge in areas that bridge the geosciences with physics, chemistry, engineering, and biology.
This emphasis area will train and educate leaders in rapidly growing industries and academic fields such as natural resources and energy, and in government agencies that require PhD-level researchers to inform policy decisions on some of the greatest problems facing society.

Climate and Environmental Change
This emphasis is designed to develop research and educational skills that:
  • Advance new understandings of natural climate variability,
  • Improve projections of climate change and its impacts on ecosystems and their hydrological and geological underpinnings
  • Inform policy decisions about how best to manage natural resources under changing climate and related environmental stresses.
This emphasis often combines the long-term perspective from geological archives with process-oriented investigations of today, with the goal of integrating a field-based understanding of natural systems into predictive models to support sustainable resource management in the face of climate change.
Engineering Sustainable Systems
The goals of this emphasis are to develop research and educational skills that:
  • Advance engineering analysis and applications relevant to sustainable development,
  • Improve the efficiency and effectiveness of engineering processes, products, and education
  • Understand and apply their knowledge in the sustainability contexts of economic viability, environmental compatibility and sustainability, societal impacts and policy development and implications.
This emphasis is designed for engineers who are interested in understanding the economic, societal and environmental implications of engineering systems. It provides a strong background in engineering enhanced by understanding future sustainability of our environment, and will prepare you for careers in academia, industry, and governmental organizations.

Ecology, Evolution and Conservation Biology

This emphasis is designed to develop research and educational skills that:
  • Advance the frontiers of understanding of ecological and evolutionary processes.
  • Synthesize applied, empirical, or experimental work from multiple disciplines to confront
  • Integrative challenges at the cutting edge of applied and basic research.
  • Apply ecological, evolutionary, and conservation theory to conservation challenges, incorporating the human dimensions of sustainable management and policy.
This emphasis will train and educate leaders in areas of research and application at the cutting edge of conservation and sustainability professions, including basic research, management
decision-making, sustainable policy development, and applied conservation.
Environment and Society

This emphasis is designed to develop research and educational skills that:
  • Advance knowledge in social theory and environmental policy related to sustainability.
  • Conduct cutting-edge interdisciplinary research at the nexus of the natural and social sciences.
  • Apply this knowledge in decision making for sustainable resource management and socio-economic policies.
This emphasis will prepare leaders in the areas of natural resources management, community engagement, the non-profit/NGO sector, academia, and in government agencies that require PhD-level researchers to inform management and policy decisions that address some of the greatest environmental problems facing society today.

Additional Admission Requirements
  • Individual program admission requirements over and above admission to NAU are required.

  • The NAU graduate online application is required for all programs. Admission to many graduate programs is on a competitive basis, and programs may have higher standards than those established by the Graduate College.

    Admission requirements include the following:

    • Transcripts.
    • Undergraduate degree from a regionally accredited institution with a 3.0 GPA on a 4.0 scale ("A" = 4.0), or the equivalent.

    Visit the NAU Graduate Admissions website for additional information about graduate school application deadlines, eligibility for study, and admissions policies.

    Ready to apply? Begin your application now.

    International applicants have additional admission requirements. Please see the International Graduate Admissions Policy.

    • GRE® revised General Test
    • Three letters of recommendation
    • A writing sample
    • A personal statement or essay
    • Resume or curriculum vitae
Doctoral Requirements
  • This Doctoral degree requires 60 units distributed as follows:

    • Common Courses: 7 units
    • Graduate Seminar:  2 units
    • Professional Experience:  6 units
    • Research Methods Courses: 3 units
    • Select an Emphasis: 27 units
      • Climate and Environmental Change Emphasis
      • Earth Systems Emphasis
      • Ecology, Evolution and Conservation Biology Emphasis
      • Engineering Sustainable Systems Emphasis
      • Environment and Society Emphasis
    • Dissertation: 15 units

    Take the following 60 units, with a minimum GPA of 3.0:

    • ENV 555 (3 units)
    • EES 605, EES 606 (2 units)
    • ESE 698 School of Earth and Sustainability Seminar Series (2 units)
    • 698 Graduate Seminar course from any unit (2 units)
    • Professional experience: Any experience that significantly broadens knowledge and skills, and advances the student’s career objectives. The requirement can be satisfied through regular course work or through individualized study that expands the student’s skills in an area outside his/her dissertation but in a professional area related to his/her career goals, or research experiences within the context of the dissertation.  See an advisor. (6 units)
    • Research methods course.  In consultation with your advisor, select any graduate-level course with significant content in statistics and/or science/engineering research methods (3 units).

    Emphasis Requirements (27 units):
    Select courses specific to an area of emphasis and dissertation topic, with at least 3 units in the area of emphasis chosen with approval of the student's dissertation committee.

      • Climate And Environmental Change Emphasis
        • Graduate-level courses with EES, ENV, BIO or FOR prefixes, or other courses that focus on climate or environmental change
      • Earth Systems Emphasis
        • Graduate-level courses with GLG prefix, or other courses that focus on earth systems.
      • Engineering Sustainable Systems Emphasis
        • Graduate-level courses with CENE or ME prefixes, or other courses that focus on engineering sustainable systems
      • Environment and Society Emphasis
        • Graduate-level courses with ECO, EES, ENV, FOR, POS, SOC or SUS prefixes, or other courses that focus on economic, political and social theories and practices related to environmental sustainability
  • You may have no more than 6 units of 400-level courses. These 400-level courses cannot have been used to satisfy the requirements for any previous degree program(s). You must get your dissertation committee's approval for any courses taken outside of NAU.

  • Be aware that some courses may have prerequisites that you must also successfully complete. For prerequisite information, click on the course or see your advisor.

  • In addition:

    • EES 799, for the research, writing, and oral defense of an approved dissertation. You can only count 15 units of dissertation credit toward your degree; however, you may end up taking additional units because you must enroll for it each term while you're working on your dissertation. (15 units)
    In choosing courses, please be aware that:
    • Your dissertation committee must approve all of your courses.


    In addition to completing 45 units of coursework, you must demonstrate your independence, research skill, and experience in a discipline within earth sciences and environmental sustainability by choosing a problem and research area in consultation with your dissertation committee and then satisfactorily completing a dissertation.

    Your dissertation research meets our standards when it is soundly based in the theoretical context of the subject, proceeds with a sound design that gives due attention to statistical adequacy, and concludes with findings and inferences set forth within an appropriate theoretical context. Your dissertation must demonstrate that you have mastered your field of specialization, carried out independent scholarly work, and contributed significant new knowledge. You must pass an oral defense of your dissertation.


    We also require that you demonstrate written and oral communication skills in English at a level that will allow you to effectively communicate your ideas and knowledge to a wide range of audiences. Part of this demonstration involves comprehensive oral exams by the end of your 4th semester designed to establish your competence in a breadth and depth of subjects within your emphasis area and the larger field of earth sciences and environmental sustainability.


    NAU policy for PhD programs includes a research competency requirement that must be satisfied before a student can be admitted to candidacy. This interdisciplinary doctoral program recognizes ENV 555, EES 605, and EES 606, plus one graduate level course with significant content in statistics and/or science/engineering research methods, as meeting this requirement.