Brian C O''Neill
Biographic Data
| ID | 324204 |
|---|---|
| NAME | Brian C O''Neill |
| GIVEN NAMES | Brian C |
| FAMILY NAME | O''Neill |
| SIGNATURE | NEILL B C O |
| AFFILIATIONS | NSF National Center for Atmospheric Research |
| ORCID | 0000-0001-7505-8897 |
| VERIFIED | Yes |
| TOTAL WORKS | 45 |
| TOTAL CITATIONS | 700 |
| AUTHOR COUNT | 45 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1997 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 7 |
Implications of climate change impacts for emission and land use scenario development
Scenarios of future emissions and land use produced by Integrated Assessment Models (IAMs) have traditionally been developed without accounting for how climate change impacts could affect the emissions and land use trajectories themselves. This omission risks skewing our assessments of the plausible range of future emission pathways and associated Earth system changes. Beyond the salience for emission scenario development, a better integrated rep…
Long-term decarbonization impacts on residential energy security across income groups and US states
The impact of a transition to a net-zero economy on the residential energy sector across diverse income groups in the US remains uncertain. Here, we employ an integrated human-Earth system model, incorporating an expanded set of ten income groups in the residential energy sector, to examine the distributional impacts of long-term decarbonization scenarios on residential energy security at the state level through 2050. We use multiple metrics of e…
A conceptual framework for residential energy security in the context of clean energy transitions
Divergent urban land trajectories under alternative population projections within the Shared Socioeconomic Pathways
Population change is a main driver behind global environmental change, including urban land expansion. In future scenario modeling, assumptions regarding how populations will change locally, despite identical global constraints of Shared Socioeconomic Pathways (SSPs), can have dramatic effects on subsequent regional urbanization. Using a spatial modeling experiment at high resolution (1 km), this study compared how two alternative US population p…
Envisioning a future with climate change
Non-parametric projections of national income distribution consistent with the Shared Socioeconomic Pathways
Understanding and projecting income distributions within countries and regions is important to understanding consumption trends and the distributional consequences of climate impacts and responses. Several global, country-level projections of income distribution are available but most project only the Gini coefficient (a summary statistic of the distribution) or utilize the Gini along with the assumption of a lognormal distribution. We test the l…
Non-parametric projections of the net-income distribution for all U.S. states for the Shared Socioeconomic Pathways
Income distributions are a growing area of interest in the examination of equity impacts brought on by climate change and its responses. Such impacts are especially important at subnational levels, but projections of income distributions at these levels are scarce. Here, we project U.S. state-level income distributions for the Shared Socioeconomic Pathways (SSPs). We apply a non-parametric approach, specifically a recently developed principal com…
The importance of reclassification to understanding urban growth: A demographic decomposition of the United States, 1990–2010
An improved understanding of reclassification as a sociodemographic component of urban growth is important for urban planning and sustainable development. However, empirical assessments of the effect of reclassification on urban population dynamics are lacking, especially in countries in the later stage of the urban transition. Using recently available data on spatial reclassification of rural and urban land areas and population, and adopting mul…
A framework for complex climate change risk assessment
Real-world experience underscores the complexity of interactions among multiple drivers of climate change risk and of how multiple risks compound or cascade. However, a holistic framework for assessing such complex climate change risks has not yet been achieved. Clarity is needed regarding the interactions that generate risk, including the role of adaptation and mitigation responses. In this perspective, we present a framework for three categorie…
Mapping global urban land for the 21st century with data-driven simulations and Shared Socioeconomic Pathways
Urban land expansion is one of the most visible, irreversible, and rapid types of land cover/land use change in contemporary human history, and is a key driver for many environmental and societal changes across scales. Yet spatial projections of how much and where it may occur are often limited to short-term futures and small geographic areas. Here we produce a first empirically-grounded set of global, spatial urban land projections over the 21st…
Population scenarios for U.S. states consistent with shared socioeconomic pathways
There is a growing demand for subnational population projections for informing potential demographic influences on many aspects of society and the environment at the scale at which interactions occur and actions are taken. Existing US subnational population projections have not fully accounted for regional variations of demographic rates and therefore under-estimate the uncertainties in and heterogeneity of population trends. We present a first s…
The effect of education on determinants of climate change risks
A spatial population downscaling model for integrated human-environment analysis in the United States
Spatial population models are important to inform understanding of historical demographic development patterns and to project possible future changes, especially for use in anticipating environmental interactions
Empirically based spatial projections of US population age structure consistent with the shared socioeconomic pathways
Spatially-explicit population projections by age are increasingly needed for understanding bilateral human–environment interactions. Conventional demographic methods for projecting age structure experience substantial challenges at small spatial scales. In search of a potentially better-performing alternative, we develop an empirically based spatial model of population age structure and test its application in projecting US population age structu…
The use of the Community Earth System Model in human dimensions climate research and applications
Earth system models (ESMs) are the primary tool used to understand and project changes to the climate system. ESM projections underpin analyses of human dimensions of the climate issue, yet little is known about how ESMs are used in human dimensions research. Such foundational information is necessary for future critical assessments of ESMs. We review applications of a leading ESM, the National Center for Atmospheric Research (NCAR) Community Ear…
Economic and biophysical impacts on agriculture under 1.5 °C and 2 °C warming
The goal of limiting global mean warming to well below 2 °C, and possibly to 1.5 °C, emerged in the Paris Agreement, motivated by the belief that achieving these targets 'would significantly reduce the risks and impacts of climate change'. Understanding the climate impacts of relatively low levels of warming, in particular whether there are substantial benefits to reducing emissions to limit warming to 1.5 °C rather than 2 °C, is important for in…
Determinants of Urban Growth during Demographic and Mobility Transitions: Evidence from India, Mexico, and the US
IPCC reasons for concern regarding climate change risks
The Shared Socio-economic Pathways: Trajectories for human development and global environmental change
The Scenario Model Intercomparison Project (ScenarioMIP) for CMIP6
Projections of future climate change play a fundamental role in improving understanding of the climate system as well as characterizing societal risks and response options. The Scenario Model Intercomparison Project (ScenarioMIP) is the primary activity within Phase 6 of the Coupled Model Intercomparison Project (CMIP6) that will provide multi-model climate projections based on alternative scenarios of future emissions and land use changes produc…
Spatially explicit global population scenarios consistent with the Shared Socioeconomic Pathways
Here we report that the projected size and spatial distribution of the future population are important drivers of global change and key determinants of exposure and vulnerability to hazards. Spatial demographic projections are widely used as inputs to spatial projections of land use, energy use, and emissions, as well as to assessments of the impacts of extreme events, sea level rise, and other climate-related outcomes. To date, however, there ar…
The Shared Socioeconomic Pathways and their energy, land use, and greenhouse gas emissions implications: An overview
This paper presents the overview of the Shared Socioeconomic Pathways (SSPs) and their energy, land use, and emissions implications. The SSPs are part of a new scenario framework, established by the climate change research community in order to facilitate the integrated analysis of future climate impacts, vulnerabilities, adaptation, and mitigation. The pathways were developed over the last years as a joint community effort and describe plausible…
Sensitivity of regional climate to global temperature and forcing
The sensitivity of regional climate to global average radiative forcing and temperature change is important for setting global climate policy targets and designing scenarios. Setting effective policy targets requires an understanding of the consequences exceeding them, even by small amounts, and the effective design of sets of scenarios requires the knowledge of how different emissions, concentrations, or forcing need to be in order to produce su…
Global urbanization projections for the Shared Socioeconomic Pathways
The roads ahead: Narratives for shared socioeconomic pathways describing world futures in the 21st century
The Shared Socioeconomic Pathways and their energy, land use, and greenhouse gas emissions implications: An overview
This paper presents the overview of the Shared Socioeconomic Pathways (SSPs) and their energy, land use, and emissions implications. The SSPs are part of a new scenario framework, established by the climate change research community in order to facilitate the integrated analysis of future climate impacts, vulnerabilities, adaptation, and mitigation. The pathways were developed over the last years as a joint community effort and describe plausible…
The roads ahead: Narratives for shared socioeconomic pathways describing world futures in the 21st century
Global urbanization projections for the Shared Socioeconomic Pathways
The need for and use of socio-economic scenarios for climate change analysis: A new approach based on shared socio-economic pathways
The Shared Socio-economic Pathways: Trajectories for human development and global environmental change
Determinants of Urban Growth during Demographic and Mobility Transitions: Evidence from India, Mexico, and the US
Anthropogenic Drivers of Ecosystem Change: An Overview
Nelson, G. C., E. Bennett, A. A. Berhe, K. Cassman, R. DeFries, T. Dietz, A. Dobermann, A. Dobson, A. Janetos, M. Levy, D. Marco, N. Nakicenovic, B. O Neill, R. Norgaard, G. Petschel-Held, D. Ojima, P. Pingali, R. Watson, and M. Zurek. 2006. Anthropogenic drivers of ecosystem change: an overview. Ecology and Society 11(2): 29
Enhancing engagement between the population, environment, and climate research communities: The shared socio-economic pathway process
Demographers have much to contribute to climate change science. This paper describes a new framework being developed by the climate research community that holds potential as an organizing tool for population-climate scholarship, as well as being useful for identifying demographic research gaps within the climate change field. The shared socio-economic pathways (SSPs) represent plausible alternative trends in the evolution of social and natural s…
A Guide to Global Population Projections
Interdisciplinary studies that draw on long-term, global population projections often make limited use of projection results, due at least in part to the historically opaque nature of the projection process. We present a guide to such projections aimed
The effect of education on determinants of climate change risks
Impacts of Demographic Trends on US Household Size and Structure
We use a household projection model to construct future scenarios for the United States designed to reflect a wide but plausible range of outcomes, including a new set of scenarios for union formation and dissolution rates based on past trends, experience in other countries, and current theory. The period covered is from 2000 to 2100. We find that the percentage of people living in households headed by the elderly may climb from 11 percent in 200…
The importance of reclassification to understanding urban growth: A demographic decomposition of the United States, 1990–2010
An improved understanding of reclassification as a sociodemographic component of urban growth is important for urban planning and sustainable development. However, empirical assessments of the effect of reclassification on urban population dynamics are lacking, especially in countries in the later stage of the urban transition. Using recently available data on spatial reclassification of rural and urban land areas and population, and adopting mul…
The Long-Term Effect of the Timing of Fertility Decline on Population Size
Existing long-range population projections imply that the timing of the fertility transition has a relatively unimportant effect on long-term population size when compared with the impact of the level at which fertility is assumed eventually to stabilize. However, this note shows that the effect of the timing of fertility decline is a function of the eventual fertility rate: the lower the eventual fertility rate, the greater the effect of the tim…
Cairo and climate change: A win–win opportunity
Population and global warming with and without CO2 targets
A spatial population downscaling model for integrated human-environment analysis in the United States
Spatial population models are important to inform understanding of historical demographic development patterns and to project possible future changes, especially for use in anticipating environmental interactions
Population and global warming with and without CO2 targets
The Long-Term Effect of the Timing of Fertility Decline on Population Size
Existing long-range population projections imply that the timing of the fertility transition has a relatively unimportant effect on long-term population size when compared with the impact of the level at which fertility is assumed eventually to stabilize. However, this note shows that the effect of the timing of fertility decline is a function of the eventual fertility rate: the lower the eventual fertility rate, the greater the effect of the tim…
Cairo and climate change: A win–win opportunity
A Guide to Global Population Projections
Interdisciplinary studies that draw on long-term, global population projections often make limited use of projection results, due at least in part to the historically opaque nature of the projection process. We present a guide to such projections aimed
Population Scenarios Based on Probabilistic Projections: An Application for the Millennium Ecosystem Assessment
Learning and climate change
Learning – i.e., the acquisition of new information that leads to changes in our assessment of uncertainty – plays a prominent role in the international climate policy debate. For example, the view that we should postpone actions until we know more continues to be influential. The latest work on learning and climate change includes new theoretical models, better informed simulations of how learning affects the optimal timing of emissions reductio…
Anthropogenic Drivers of Ecosystem Change: An Overview
Nelson, G. C., E. Bennett, A. A. Berhe, K. Cassman, R. DeFries, T. Dietz, A. Dobermann, A. Dobson, A. Janetos, M. Levy, D. Marco, N. Nakicenovic, B. O Neill, R. Norgaard, G. Petschel-Held, D. Ojima, P. Pingali, R. Watson, and M. Zurek. 2006. Anthropogenic drivers of ecosystem change: an overview. Ecology and Society 11(2): 29
Impacts of Demographic Trends on US Household Size and Structure
We use a household projection model to construct future scenarios for the United States designed to reflect a wide but plausible range of outcomes, including a new set of scenarios for union formation and dissolution rates based on past trends, experience in other countries, and current theory. The period covered is from 2000 to 2100. We find that the percentage of people living in households headed by the elderly may climb from 11 percent in 200…
Learning from global emissions scenarios
Scenarios of global greenhouse gas emissions have played a key role in climate change analysis for over twenty years. Currently, several research communities are organizing to undertake a new round of scenario development in the lead-up to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). To help inform this process, we assess a number of past efforts to develop and learn from sets of global greenhouse gas emiss…
Where next with global environmental scenarios
Scenarios have become a standard tool in the portfolio of techniques that scientists and policy-makers use to envision and plan for the future. Defined as plausible, challenging and relevant stories about how the future might unfold that integrate quantitative models with qualitative assessments of social and political trends, scenarios are a central component in assessment processes for a range of global issues, including climate change, biodive…
Gas hydrates: Entrance to a methane age or climate threat
Climate change is projected to negatively impact biophysical agricultural productivity in much of the world. Actions taken to reduce greenhouse gas emissions and mitigate future climate changes, are thus of central importance for agricultural production. Climate impacts are, however, not unidirectional; some crops in some regions (primarily higher latitudes) are projected to benefit, particularly if increased atmospheric carbon dioxide is assumed…
Global demographic trends and future carbon emissions
Substantial changes in population size, age structure, and urbanization are expected in many parts of the world this century. Although such changes can affect energy use and greenhouse gas emissions, emissions scenario analyses have either left them out or treated them in a fragmentary or overly simplified manner. We carry out a comprehensive assessment of the implications of demographic change for global emissions of carbon dioxide. Using an ene…
The response of the climate system to very high greenhouse gas emission scenarios
Well informed decisions on climate policy necessitate simulation of the climate system for a sufficiently wide range of emissions scenarios. While recent literature has been devoted to low emissions futures, the potential for very high emissions has not been thoroughly explored. We specify two illustrative emissions scenarios that are significantly higher than the A1FI scenario, the highest scenario considered in past IPCC reports, and simulate t…
A comprehensive view on climate change: Coupling of earth system and integrated assessment models
There are several reasons to strengthen the cooperation between the integrated assessment (IA) and earth system (ES) modeling teams in order to better understand the joint development of environmental and human systems. This cooperation can take many different forms, ranging from information exchange between research communities to fully coupled modeling approaches. Here, we discuss the strengths and weaknesses of different approaches and try to …
A unifying framework for metrics for aggregating the climate effect of different emissions
Multi-gas approaches to climate change policies require a metric establishing equivalences among emissions of various species. Climate scientists and economists have proposed four kinds of such metrics and debated their relative merits. We present a unifying framework that clarifies the relationships among them. We show, as have previous authors, that the global warming potential (GWP), used in international law to compare emissions of greenhouse…
The need for and use of socio-economic scenarios for climate change analysis: A new approach based on shared socio-economic pathways
Historically grounded spatial population projections for the continental United States
Large-scale spatial population projections are of growing importance to the global change community. Spatial settlement patterns are a key determinant of vulnerability to climate-related hazards as well as to land-use and its consequences for habitat, energy use, and emissions of greenhouse gases and air pollutants. Few projections exist of spatial distribution at national or larger scales, and while recent efforts improve on earlier approaches t…
A new scenario framework for Climate Change Research: Scenario matrix architecture
This paper describes the scenario matrix architecture that underlies a framework for developing new scenarios for climate change research. The matrix architecture facilitates addressing key questions related to current climate research and policy-making: identifying the effectiveness of different adaptation and mitigation strategies (in terms of their costs, risks and other consequences) and the possible trade-offs and synergies. The two main axe…
A new scenario framework for climate change research: The concept of shared socioeconomic pathways
The new scenario framework for climate change research envisions combining pathways of future radiative forcing and their associated climate changes with alternative pathways of socioeconomic development in order to carry out research on climate change impacts, adaptation, and mitigation. Here we propose a conceptual framework for how to define and develop a set of Shared Socioeconomic Pathways (SSPs) for use within the scenario framework. We def…
Enhancing engagement between the population, environment, and climate research communities: The shared socio-economic pathway process
Demographers have much to contribute to climate change science. This paper describes a new framework being developed by the climate research community that holds potential as an organizing tool for population-climate scholarship, as well as being useful for identifying demographic research gaps within the climate change field. The shared socio-economic pathways (SSPs) represent plausible alternative trends in the evolution of social and natural s…
Sensitivity of regional climate to global temperature and forcing
The sensitivity of regional climate to global average radiative forcing and temperature change is important for setting global climate policy targets and designing scenarios. Setting effective policy targets requires an understanding of the consequences exceeding them, even by small amounts, and the effective design of sets of scenarios requires the knowledge of how different emissions, concentrations, or forcing need to be in order to produce su…
Global urbanization projections for the Shared Socioeconomic Pathways
The roads ahead: Narratives for shared socioeconomic pathways describing world futures in the 21st century
The Scenario Model Intercomparison Project (ScenarioMIP) for CMIP6
Projections of future climate change play a fundamental role in improving understanding of the climate system as well as characterizing societal risks and response options. The Scenario Model Intercomparison Project (ScenarioMIP) is the primary activity within Phase 6 of the Coupled Model Intercomparison Project (CMIP6) that will provide multi-model climate projections based on alternative scenarios of future emissions and land use changes produc…
Spatially explicit global population scenarios consistent with the Shared Socioeconomic Pathways
Here we report that the projected size and spatial distribution of the future population are important drivers of global change and key determinants of exposure and vulnerability to hazards. Spatial demographic projections are widely used as inputs to spatial projections of land use, energy use, and emissions, as well as to assessments of the impacts of extreme events, sea level rise, and other climate-related outcomes. To date, however, there ar…
Climate change (29 works) · Environmental Science (29 works) · Geography (25 works) · Economics (21 works) · Ecology (20 works) · Environmental resource management (20 works) · Population (19 works) · Climate Change Policy and Economics (17 works) · Computer Science (14 works) · demographic modeling and climate adaptation (13 works)