Pages (10 results)
TopHarte Lab: Ecology & Global Change
Ecology and global change are the primary topics of research in the Harte Lab. Among the goals are: to characterize ecological feedbacks to climate change, to predict effects of global change on biodiversity, and to develop fundamental theory that predicts the structure of ecosystems across spatial scales.
Renewable & Appropriate Energy Laboratory (RAEL)
RAEL is engaged in projects to develop the science, technology, policy needs and to foster engagements that explore the future of energy, specifically the transition to a low-cabon, environmentally, socially, and economically sustainable energy system.
Affiliated Faculty
ERG has a small core faculty but a much larger group of affiliated faculty. Affiliated faculty are based in other departments on campus or at the Lawrence Berkeley National Laboratory, ... Continue Reading »
Courses
All Course Offerings Please note: This is a full list of ERG course offerings; not all courses are offered each term. For current course offerings, please refer to the online ... Continue Reading »
Give to ERG
Your donation to ERG provides critical funding and academic opportunities for our graduate students. ERG has a 50-year history of outstanding research, teaching, policy advice and scholar-activism. ERG has researched ... Continue Reading »
Faculty by Primary Interest
Areas of Interest Climate ChangeEcologyEnergyGovernanceWaterInternational Climate Change ERG CORE David Anthoff David Anthoff is an environmental economist who studies climate change and environmental policy. He co-develops the integrated assessment model ... Continue Reading »
Master’s Degree Curriculum Requirements (MA or MS)
The purpose of the ERG Master’s program is to educate the next generation of interdisciplinary leaders. Specifically, students are taught the range of methods and subjects they should be able ... Continue Reading »
Sustainability Summer Minor and Certificate
The Minor and Certificate in Sustainability provides a comprehensive understanding of the most pressing issues facing the world today. ERG’s Minor/Certificate program offers a practical and relevant interdisciplinary approach at ... Continue Reading »
Summer Instructors
The Energy and Resources Group summer instructors understand the complex and interdisciplinary nature of sustainability. All have significant experience teaching and/or professional experience in the subject areas of their courses. ... Continue Reading »
Undergraduate Minor in Energy and Resources
The Minor in Energy and Resources offers undergraduates basic knowledge and skills to address issues arising from the interaction of social, economic, political, technical, and environmental factors shaping our world. ... Continue Reading »
Faculty (4 results)
TopMeg Mills-Novoa
Assistant Professor
Meg Mills-Novoa is a human-environment geographer who researches the enduring impacts of climate change adaptation projects. She is jointly appointed to the Energy and Resources Group and the Department of Environmental Science, Policy, and Management.
- climate change adaptation
- critical development studies
- Deforestation
- Latin America
- participatory mixed methods
- political ecology of global change
- water justice
Margaret Torn
Adjunct Professor
The focus of my work is carbon and nutrient cycling in terrestrial ecosystems and trace-gas flux between soil and atmosphere. I conduct research on soil carbon, global change, and the impacts of human activities on ecosystem processes.
Daniel M. Kammen
Professor
Daniel Kammen is the Distinguished Professor of Energy with appointments in the Energy and Resources Group, The Goldman School of Public Policy, and the Department of Nuclear Engineering at the University of California, Berkeley.
- Africa
- Asia
- Energy Access
- Energy for Community Development
- Energy Supply
- Energy Transmission
- Latin America
- Life-cycle Impacts of Transportation
- Low-carbon Energy Systems
- Smart Grid
John Harte
Professor of the Graduate School
John Harte is a physicist turned ecologist. His research interests span ecological field research, the theory of complex systems, and policy analysis. Current interests include applying insights from information theory to the analysis of complex ecosystems and empirical investigation of climate-ecosystem feedback dynamics.
Students (2 results)
TopNicholas Depsky
MS, PhD
Drought in Central America: Past Patterns and Future Projections (MS ’19) Nick’s primary research focus is on the impacts of climate change on human migration and displacement. Specific focus areas ... Continue Reading »
Lisa Rennels
MS, PhD
Sobol Sensitivity Analysis for Integrated Assessment Models: Supporting Result Characterization (MS ’19) Lisa is interested in using computer science to explore issues related to the economic impacts of climate change, ... Continue Reading »
Alumni (22 results)
TopSamira Siddique
MS, PhD
Development for the Stateless: the Displacement-Development Nexus and Implications for the Future (MS ’19) Samira Siddique is a PhD candidate and National Science Foundation Graduate Research Fellow in the Energy ... Continue Reading »
- Climate change justice
- critical development studies
- Cultural memory
- Displacement infrastructure
- Forced migration and refugee studies
- Postcolonial theory
Adam Hanbury-Brown
MS, PhD
Predicting the future of forests under global change: the critical role of the regeneration process (PhD ’22) Adam is a PhD focused on ecosystem modeling and remote sensing. His research ... Continue Reading »
- Agriculture
- climate
- Earth System Models
- ecology
- Forest Regeneration
- Movement Ecology
- remote sensing
- Vegetation Dynamics
- Wildlife Ecology
Monkgogi Otlhogile
MA
Monkgogi (who goes by MK) was born and raised in Botswana and recently graduated cum laude with her BA from Scripps College in Environment, Economics, and Politics. Personally, MK has ... Continue Reading »
Scott Saleska
PhD
Global Climate Change and Ecosystem Carbon Storage: An Experimental Investigation of Ecologically-Mediated Feedbacks to Climate in Montane Meadows (’98 Ph.D.)
- ecology of environmental systems (eg. global climate)
- environmental impact of nuclear energy and nuclear weapons production
- how to implement and practice "public interest science"
- modeling life-cycle environmental impacts of human activities
- social justice and environmental sustainability
Chalotorn Kansuntisukmongkol
PhD
Irreversibility and Learning in the Context of Global Climate Change (’04 PhD)
Carla Peterman
PhD
State-Level Regulations Effectiveness in Addressing Global Climate Change and Promoting Solar Energy Deployment (PhD ’17)
Priyanka Mohanty
MS
What are the Best Practices for Rapid and Just Energy Transition? (MS ’22) Priyanka earned her Masters of Science with the Energy and Resources Group. At ERG, she works on ... Continue Reading »
- China
- climate
- development
- economics
- environmental justice
- Green New Deal
- India
- Indonesia
- Low-Carbon Transport
Luke Sherman
MPP, MS
Increasing the spatial resolution of the Human Development Index using satellite imagery (MS ’22) Luke’s research aims to encourage the use of innovative technology and management systems in order to ... Continue Reading »
Alana Siegner
MA, PhD
Alana Siegner received her B.A. from Tufts University in Environmental Science and International Relations, and served as an AmeriCorps National Teaching Fellow in Boston for two years after graduating from ... Continue Reading »
- climate change education
- environmental education
- Food Justice
- Sustainable food systems
- urban agroecology
Catherine Ledna
MS, PhD
Modeling Adaption to Sea Level Rise Under Uncertainty (MS ’19) Catherine received a BA in Economics from Dartmouth College, with a minor in Environmental Studies. Prior to coming to ERG, ... Continue Reading »
Joseph Rand
MS
Environmental, Economic, and Social Trade-Offs of Hydropower Relicensing (MS ’16) Joseph is interested in the social, environmental, and economic trade-offs in energy development, and in particular the social conflicts arising ... Continue Reading »
Sophie Major
MA, PhD
Sophie Major is an interdisciplinary PhD candidate, studying and researching across the disciplines of political theory, environmental politics, and Indigenous studies. Their dissertation examines the marginalization of Indigenous people and ... Continue Reading »
- Contemporary Political Theory
- Decolonial Theory and Research Methods
- environmental justice
- History of Political Thought
- Indigenous Studies
- public policy
Ian Bolliger
MS, PhD
Monitoring and Projecting the Impacts of Climate Change with Emerging Environmental Datasets and Machine Learning (PhD ’20) Ian works to provide decision-makers with quantitative, high-resolution projections of the socioeconomic impacts ... Continue Reading »
- climate
- economics
- energy
- Global Policy Laboratory
- health impacts of climate change
- machine learning
- remote sensing
- spatial statistics
- tropical cyclones
- water
Alana Siegner
MA, PhD
Growing Environmental Literacy: On Small-Scale Farms, in the Urban Agroecosystem, and in School Garden Classrooms (PhD ’20) Alana Siegner graduated from Tufts University in 2012 with a double major in ... Continue Reading »
Jim Williams
MS, PhD
M.S. 1986 – A Vehicular Power Plant Application of the Monolithic Solid Oxide Fuel Cell Ph.D. 1995 – Fan-Lizhi’s Big Bang: Science and Politics in Mao’s China ERG alumnus Jim Williams, now ... Continue Reading »
- acid rain
- Arctic haze
- China
- comparative religion
- cosmology
- dissidents and outlaws
- economic globalization and cultural survival
- fuel-cell powered vehicles
- global change
- over the last ten years: speech synthesizers
- science and politics
- the theory and practice of Utopia
Ann Kinzig
PhD
ALUMNI SPOTLIGHT Ann Kinzig Ph.D. ’94 Professor in the School of Life Sciences at Arizona State University Perhaps more than most alumni, Ann Kinzig’s intellectual path has traversed ERG’s interdisciplinary ... Continue Reading »
Amber Kerr
PhD
Drought resilience of maize-legume agroforestry systems in Malawi (PhD ’12) Amber Kerr is an agricultural ecologist focusing on climate change impacts and adaptation. She has studied nutrient cycling in California ... Continue Reading »
Jalel Sager
MA, PhD
Formerly a freelance writer and founding director of the Vietnam Green Building Council (2007-2009), Jalel remains a board member and international coordinator for Green Cities Fund (its NGO parent). In ... Continue Reading »
Morgan Levy
MS, PhD
Morgan’s research focuses on hydrology and water resources, the effects of land use and climate change on human health and the environment, human-environmental system dynamics, and environmental data science. Her ... Continue Reading »
- Agriculture
- climate
- climate change
- climate change adaptation
- eco-hydrology
- environmental data science
- environmental health science
- geographic information systems
- hydroclimatology
- hydrology
- irrigation
- water
- water resources management
Kripa Jagannathan
MS, PhD
Ready-to-use? Bridging the Climate Science Usability Gap for Adaptation (PhD ’19) Kripa’s research interests are in the field of climate change adaptation and climate-resilient planning. Her PhD focuses on improving ... Continue Reading »
- Adaptation
- Agriculture
- Carbon markets
- climate change
- climate-resilient planning
- co-production of knowledge
- science usability
- stakeholder engagement
- water
Zoë Chafe
MPH, MS, PhD
Dr. Chafe works at the intersections of public health, air pollution, climate change, and energy use. She holds a PhD from the Energy and Resources Group (ERG), as well as ... Continue Reading »
- climate
- climate change and public health
- co-benefits (ancillary benefits) of climate change mitigation
- development
- energy
- energy transitions and impacts on air pollution
- heating and cooking with solid fuels
- household energy policy options
- Household energy use trends
- short-lived greenhouse pollutants
Nate Aden
MS, PhD
Taking the Man Out of Manufacturing: Drivers and Components of Industrial Sector Low-Carbon Transformation (PhD ’17) Nate Aden completed his PhD at the Energy and Resources Group at UC Berkeley and is ... Continue Reading »
News (49 results)
TopERG’s Anthoff and Alum Errickson Promote Utilitarian Approach to Global Climate Policy
September 27, 2021
ERG Professor David Anthoff and Frank Errickson, PhD '20, ERG, recently published in Nature Climate Change, proposing a practical way of measuring how different nations should reduce carbon emissions in order to maximize well being in the world. (Photo by Stuart Rankin)
New Research from Alumnus Errickson Connects Animal-based Foods with High Climate Costs
May 4, 2021
ERG alumnus Frank Errickson recently published research on Nature, "Animal-based foods have high social and climate costs", quantifying the climate costs of animal-based agricultural greenhouse gas emissions at a regional level.
ERG Dan Kammen on What the Biden-Harris Victory Means For COVID-19 & Climate Change
November 16, 2020
ERG professor Dan Kammen recently published an op-ed on the Daily Californian, discussing the powerful impact the Biden-Harris victory has on addressing the issues of COVID-19 and climate change. Kammen further states that the new leadership's energy and climate platform can be a game-changer for achieving social and climate justice. "Science, social justice and both domestic and global partnerships to address climate change are now back on the agenda in the United States," Kammen writes. "More than any one specific action, the commitment Biden has already shown to a science-driven administration is critically important domestically and worldwide."
ERG Alumnus Zeke Hausfather on the Best and Worst Scenarios of Global Warming
July 30, 2020
In a recent article for The Guardian, ERG Alumnus Zeke Hausfather speaks on climate predictions and adjusting forecasts for global warming — including the best and worst case scenarios.
ERG Professor Kueppers’ Research on Climate-Threatened Forests Published in Science
June 5, 2020
ERG Professor Lara Kueppers recently co-authored a research paper titled "Pervasive shifts in forest dynamics in a changing world". The research focuses on how global warming negatively impacts forests around the world, "resulting in shorter and younger trees with broad impacts on global ecosystems." Furthermore, the paper was picked up on various media sources, including Forbes, Science, Berkeley Lab, and others.
ERG Zeke Hausfather Warns Normalizing “Worst Case” Climate Change
February 10, 2020
In a recent article published by Nature, ERG Alumnus Zeke Hausfather suggests that using a more-realistic baselines for emissions would make for better policy in fighting global warming.
Dan Kammen and Researchers Urge More Aggressive Action Against Climate Change
December 12, 2019
In a new study done by ERG's Dan Kammen and a team of researchers, analysis shows that global warming crisis is worse than previously thought. However, their research also shows how it is completely possible for countries to achieve an increased and sustainable rate of decarbonisation through more aggressive policies against climate change.
ERG Alum Zeke Hausfather Cited by NY Times Regarding Global Warming
July 10, 2019
Recent ERG Alumnus, Zeke Hausfather (PhD '19) was quoted in the New York Times last week, with two correspondents reaching out to the climate change expert for commentary.
ERG Student Zeke Hausfather Maps Global Warming
October 4, 2018
“Climate change is often communicated by looking at the global average temperature. But a global average might not mean much to the average person. How the climate is likely to ... Continue Reading »
Energy New ERG Courses Focus on Data
June 26, 2018
The Energy and Resources Group has announced two new courses this fall addressing current, timely topics in energy and environment. Registration is open.
Food Security Why Climate Change
May 16, 2018
Last month, the Nanaimo and Area Land Trust co-hosted a world-class symposium on water stewardship in a changing climate. Canadian water expert and professor Bob Sandford spoke about “The Hard ... Continue Reading »
Transportation Emissions in Mexico City – How Big Data is Driving Change
March 8, 2018
Mexico City is one of the most congested cities in the world, and it’s taking a toll on the health of its citizens and the environment. Sergio Castellanos, a postdoctoral ... Continue Reading »
Climate Change Slowing Down Wind Turbines? Kammen Weighs In
December 12, 2017
With global temperatures increasing, researchers analyze the effects of temperature differences on wind patterns. Multiple studies confirm the possibility of wind resources declining across the Northern Hemisphere, reducing the energy ... Continue Reading »
Dan Kammen Discusses Climate Change Initiative Being Developed by California Universities
August 20, 2017
In a recent Nature article, ERG Professor Dan Kammen comments on the potential establishment of a California-based climate change research institute. The proposal is backed by all University of California ... Continue Reading »
including ERG International Team
July 5, 2017
“The fossil-free economy is already profitable.”
No Pause in Global Warming Says ERG Grad Student Hausfather NOAA Was Right
January 11, 2017
A controversial paper published two years ago that concluded there was no detectable slowdown in ocean warming over the previous 15 years — widely known as the “global warming hiatus” — has now been confirmed using independent data in research led by researchers from UC Berkeley and Berkeley Earth.
Kammen from COP22: Is Trump’s victory game over for climate?
November 10, 2016
Donald Trump, who has described global warming a "hoax", said in May he would "cancel" the climate-rescue Paris Agreement if elected leader of the free world.
Kammen: Panelists Consider Potential of Nuclear Power As Climate Change Solution
May 6, 2016
ERG professor Dan Kammen spoke on a Cornell University panel on the potential of nuclear power to address global climate change.
ERG Professor Dan Kammen Speaks at Climate Change Symposium
April 19, 2016
ERG professor Dan Kammen participated in a Climate Change Symposium on Friday, April 15, at a Modesto Area Partners in Science (MAPS) lecture.
One grad student’s story: from English lit to global climate talks
December 7, 2015
ERG grad student Valeri Vasquez will be at the COP21, acting as a counselor to the co-chair of the United Nations climate negotiations, Daniel Reifsnyder. She has been advising on the mediation and negotiations among the 195 national parties to the U.N. Framework Convention on Climate Change.
ERG at the Paris Climate Talks
December 1, 2015
The 2015 United Nations Climate Change Conference in Paris has begun and will continue until December 11th. Energy and Resources Group faculty, students and alumni will be playing an active role at the conference and the many peripheral activities.
23-year experiment finds surprising global warming impacts
February 11, 2015
Professor John Harte and team's paper on results of a 23-year ecosystem experiment in Rocky Mountain meadowlands featured in Guardian.
RAEL at UN Climate Summit
September 26, 2014
SWITCH model selected as a "Project to Watch" by the UN's Big Data Climate Challenge.
Upcoming Certificate Course on Economic Impact of Climate and Energy Policy
August 13, 2014
3-day certificate course Oct 3-5, offering a practical perspective on the economic effects of climate and energy policy.
Kammen on UC Climate Advisory Group
June 9, 2014
UC President forms Global Climate Leadership Council including UC professors and climate experts.
Kammen and Hausfather of ERG Respond to Withdrawal from Paris Agreement
June 22, 2017
ERG Professor Dan Kammen and graduate student Zeke Hausfather respond to President Trump's decision to withdraw from the Paris climate agreement
ERG’s Energy Research Featured in Multiple News Outlets
May 25, 2016
“Research at the Renewable and Appropriate Energy Laboratory [ERG Professor Daniel Kammen’s lab] at the University of California Berkeley highlights that while cities currently contribute to global climate change by ... Continue Reading »
ERG students win United Nations award
November 13, 2013
Jalel Sager (PhD candidate) and Austin Cappon (Minor) head to Nairobi, Kenya to pick up UN prize for a sustainable energy development project in Vietnam.
and Solutions Easier ERG’s John Harte: Risks of Warming Greater
July 1, 2022
ERG’s John Harte was recently featured in an Environmental Health News article discussing the tremendous risks of global warming, and how the solutions to address this crisis could be simpler ... Continue Reading »
ERG’s Dan Kammen on How Decreased CO2 Emissions Shape the Future of Electric Vehicles
November 19, 2020
In a recent Sustainability Times article, ERG professor Dan Kammen explains how pandemic lockdowns resulted in historic drops in our CO2 emissions. Additionally, Kammen's previous study on how exactly COVID-19 lowered said Co2 emissions was featured in a Berkeley News article, arguing that a move towards greater usage of electric-powered vehicles would "reduce the major greenhouse gas responsible for climate change and global warming". "The greatest reduction of emissions was observed in the ground transportation sector. Largely because of working from home restrictions, transport CO2 emissions decreased by 40% worldwide,” Kammen stated. Read how the pandemic lockdowns decreased Co2 emissions here, and what this means for the future usage of electric vehicles here.
ERG PhD Student Nancy Freitas Featured in New Webinar Series “Midday Science Cafe”
September 16, 2020
In the new virtual series "Midday Science Cafe" hosted by Science at Cal, ERG PhD student Nancy Freitas will be speaking in the upcoming episode, "Climate Change Solutions: Managing the Global Carbon Cycle". The event will be taking place on Thursday, September 17th, 12pm – 1:30pm. Freitas will be discussing "how quantifying carbon dioxide and methane emissions released from deep lake sediments in the Arctic can improve Earth system models, advancing the quality of climate model projections."
CNN Interviews Kammen on COVID-19 and Pollution Levels
April 16, 2020
ERG professor Dan Kammen was recently featured in a CNN interview discussing the effects of COVID-19 on pollution levels around the world.
Scientific American Cites ERG Alumnus Jones on How Coronavirus Impacts CO2 Emissions
March 17, 2020
ERG alumnus Christopher Jones was recently cited in both Scientific American and Global News articles. In both articles, he discusses how Coronavirus is effecting global carbon emissions and the general environment.
ERG student Hausfather in Science: Oceans are warming even faster than previously thought
January 16, 2019
“If you want to see where global warming is happening, look in our oceans,” said Zeke Hausfather, a graduate student in the Energy and Resources Group at UC Berkeley and co-author of the paper. “Ocean heating is a very important indicator of climate change, and we have robust evidence that it is warming more rapidly than we thought.”
Carbon Loopholes: Report by ERG Student Cecilia Springer in New York Times
September 6, 2018
In an article examining the costs of carbon pollution "outsourcing" this week, The New York Times featured a report co-authored by ERG student Cecilia Springer.
The Fundamentals of a Clean(er) Economy – Dan Kammen
April 25, 2018
ERG Chair Dan Kammen wrote an Op-Ed piece for the Daily Californian this week, outlining the stark global reality of climate change in 2018 and the need for collective action. ... Continue Reading »
Zeke Hausfather Cited by the Washington Post on 2017’s Concerning Temperatures
January 25, 2018
Recently, scientists from NASA and the National Oceanic and Atmospheric Administration reported that 2017 was among the warmest years in history. While the two agencies approach global temperature measurements differently, both ... Continue Reading »
ERG Student Jose Daniel Lara Joins UC’s Carbon Neutrality Initiative as a 2017 Fellow
September 19, 2017
Jose Daniel Lara was recently selected to represent UC Berkeley as a fellow for the University of California’s Carbon Neutrality Initiative (CNI). Jose will foster communication about UC-wide goals to ... Continue Reading »
ERG graduate student Hausfather in LA Times
May 10, 2017
ERG doctoral student Zeke Hausfather comments in this LA Times article on a newly published analysis that reconciles different climate change data sets and confirms dominant human influence in long-term warming.
ERG Alum Receives Microsoft Grant for Ugandan Micro-grid Systems
June 27, 2016
New Sun Road is a California technology company directed by ERGie Jalel Sager (MS’11 , PhD’15). They are committed to implementing solutions to climate change and global energy poverty, provide ... Continue Reading »
ERG Alum Dr. Peter Gleick on Arctic Warming
March 1, 2016
ERG Alum Dr. Peter Gleick warns about catastrophic artic warming.
ERG Summer Courses Available
February 28, 2016
ERG is offering four of its most popular courses this summer! Enroll Today!
BOOK: Applying Anthropology and Physics to Sustainability
March 30, 2015
New book by Dove and Kammen released this week.
A unique moment in history for “sustainable energy for all”
March 26, 2015
ERG team study showing how off-grid power can improve equality in energy access published in Nature Climate Change. Interview with lead author Peter Alstone.
UC Berkeley Ranks 1st in the World for Environment
October 29, 2014
Subject-specific rankings from US New & World Report are based on academic research performance in those subjects.
Profs. Leach & Ray Launch UN Gender Equality Report
October 24, 2014
Dr. Isha Ray at UN Headquarters discussing report on gender equality.
Obama’s Carbon Rules Bring Urban Flooding Closer to Home
June 17, 2014
"It seems as if after years of feet dragging the United States is finally willing to walk its climate talk," Dr. Malini Ranganathan (MS'05, PhD'10), Assistant Professor at American University.
Holdren Sets New Course for US Energy
March 20, 2014
President Obama's top science advisor and ERG Co-founder, John Holdren, is confident that America's next energy plan "will make a difference."
50% of U.S. household carbon footprint Suburban sprawl
January 8, 2014
Chris Jones (ERG PhD) and Prof. Dan Kammen point out that U.S. households are responsible for about 20% of annual worldwide greenhouse gas emissions, which are driving climate change.
Topics (4 results)
TopNina Zheng
MS
Urbanizing China: Residential Energy Implications and the Role for Energy Efficiency Standards (MS, ’09)
- energy and economic development in china
- global climate change
- renewable energy and energy efficiency policymaking and implementation
- technology transfer and adoption in developing countries
M. Rebecca Shaw
PhD
Ecosystem and Plant Community Consequences of Climate Warming in a High-Altitude Meadow (’97 PhD)
Omar Masera
MS, PhD
Sustainable Energy Scenarios for Rural Mexico: An Integrated Evaluation Framework for Cooking Stoves (’90 M.S.) Socioeconomic and Environmental Implications of Fuelwood Use Dynamics and Fuel Switching in Rural Mexico (’95 ... Continue Reading »
- biomass and bioenergy technological change in rural areas
- efficient use of energy in the residential sector
- energy and agriculture
- global climate change
- rural integrated energy systems in the third world
Paul Baer
PhD
Justifying Climate Policy Choices: New Approaches to Uncertainty, Risk & Equity (’05 PhD) Deceased
- carbon cycling
- democratic participation in environmental decision making
- ecological economics
- equity and sustainability
- global climate change
- modeling