Most recent 40 articles: MIT - Global Change -Publications
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Contribution of double-cropped maize ethanol in Brazil to sustainable development - MIT - Global Change -Publications (Sep 4) |
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Sep 4 · Abstract: Sustainable energy and food production can include double-cropping where two crops are produced sequentially on land required for one crop to maximize resource use. In Brazil, this system involves maize being planted as a second crop following soybean to generate ethanol, thus allowing for combined food–energy production. However, the impacts of such production systems on several sustainable development goals (SDG) and associated indirect land-use changes have not yet fully been explored.
We evaluate the fast-expanding food–energy system of double-cropped maize ethanol in the Central-West region of Brazil with respect to SDG impacts, combining life-cycle ... Read more ...
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Spatially Resolved Temperature Response Functions to CO2 Emissions - MIT - Global Change -Publications (Jul 9) |
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Jul 9 · Carbon dioxide (CO2) emissions affect local temperature; quantifying that local response is important for learning about the earth system, the impacts of mitigation, and adaptation needs. We assume the climate system can be represented as a time-dependent linear system, diagnosing Green's Functions for the spatial temperature response to CO2 emissions based on CMIP6 earth system models. This allows us to emulate the linear component of the temperature response to CO2. This approach is sufficient to capture the spatial temperature response of CMIP6 experiments within one standard deviation of the multimodel spread across most regions, though accuracy is lower in the Southern Ocean ... Read more ...
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Machine Learning Driven Sensitivity Analysis of E3SM Land Model Parameters for Wetland Methane Emissions - MIT - Global Change -Publications (Jul 1) |
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Jul 1 · Key Points • Identified five key sensitive parameters for methane emissions using the Sobol sensitivity analysis method. • Parameters linked to production and diffusion present the highest sensitivities despite apparent seasonal variation. • Fourteen out of nineteen model parameters exert negligible influence on methane emissions.
Plain Language Summary Methane is a critical greenhouse gas, and wetlands are the largest natural source of it. Accurately predicting methane emissions from wetlands is key to tackling climate change. But these predictions, made through computer models, are seldom spot-on. Why? Because there are many factors in the models that lead to uncertain ... Read more ...
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Rising Perfluorocyclobutane (PFC-318, cC4F8) Emissions in China from 2011 to 2020 Inferred from Atmospheric Observations - MIT - Global Change -Publications (Jun 20) |
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Jun 20 · Abstract: Global atmospheric emissions of perfluorocyclobutane (c-C4F8, PFC-318), a potent greenhouse gas, have increased rapidly in recent years.
Combining atmospheric observations made at nine Chinese sites with a Lagrangian dispersion model-based Bayesian inversion technique, we show that PFC-318 emissions in China grew by approximately 70% from 2011 to 2020, rising from 0.65 (0.54-0.72) Gg year-1 in 2011 to 1.12 (1.05-1.19) Gg year-1 in 2020. The PFC-318 emission increase from China played a substantial role in the overall increase in global emissions during the study period, contributing 58% to the global total emission increase. This growth predominantly originated in ... Read more ...
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Substantial increase in perfluorocarbons CF4 (PFC-14) and C2F6 (PFC-116) emissions in China - MIT - Global Change -Publications (Jun 20) |
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Jun 20 · Abstract: The perfluorocarbons tetrafluoromethane (CF4, PFC-14) and hexafluoroethane (C2F6, PFC-116) are potent greenhouse gases with near-permanent atmospheric lifetimes relative to human timescales, and global warming potentials thousands of times that of CO2.
Using long-term atmospheric observations from a Chinese network and an inverse modelling approach (top-down method), we determined that CF4 emissions in China increased from 4.7 (4.2-5.0, 68% uncertainty interval) Gg yr-1 in 2012 to 8.3 (7.7-8.9) Gg yr-1 in 2021, and C2F6 emissions in China increased from 0.74 (0.66-0.80) Gg yr-1 in 2011 to 1.32 (1.24-1.40) Gg yr-1 in 2021, both increasing by approximately 78%. ... Read more ...
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Climate and Air Quality Impact of Using Ammonia as an Alternative Shipping Fuel - MIT - Global Change -Publications (Jun 11) |
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Jun 11 · Abstract: As carbon-free fuel, ammonia has been proposed as an alternative fuel to facilitate maritime decarbonization. Deployment of ammonia-powered ships is proposed as soon as 2024. However, NOx, NH3 and N2O from ammonia combustion could impact air quality and climate. In this study, we assess whether and under what conditions switching to ammonia fuel might affect climate and air quality. We use a bottom–up approach combining ammonia engine experiment results and ship track data to estimate global tailpipe NOx, NH3 and N2O emissions from ammonia-powered ships with two possible engine technologies (NH3–H2 (high NOx, low NH3 emissions) vs pure NH3 (low NOx, very high NH3 ... Read more ...
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Mutual Reinforcement of Land-based Carbon Dioxide Removal and International Emissions Trading in Deep Decarbonization Scenarios - MIT - Global Change -Publications (Jun 5) |
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Jun 5 · Abstract: Carbon dioxide removal (CDR) technologies and international emissions trading are both widely represented in climate change mitigation scenarios, but the interplay among them has not been closely examined.
By systematically varying key policy and technology assumptions in a global energy-economic model, we find that CDR and international emissions trading are mutually reinforcing in deep decarbonization scenarios.
This occurs because CDR potential is not evenly distributed geographically, allowing trade to unlock this potential, and because trading in a net-zero emissions world requires negative emissions, allowing CDR to enable trade. Since carbon prices ... Read more ...
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Drivers and implications of alternative routes to fuels decarbonization in net-zero energy systems - MIT - Global Change -Publications (May 10) |
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May 10 · Abstract: Energy transition scenarios are characterized by increasing electrification and improving efficiency of energy end uses, rapid decarbonization of the electric power sector, and deployment of carbon dioxide removal (CDR) technologies to offset remaining emissions. Although hydrocarbon fuels typically decline in such scenarios, significant volumes remain in many scenarios even at the time of net-zero emissions. While scenarios rely on different approaches for decarbonizing remaining fuels, the underlying drivers for these differences are unclear.
Here we develop several illustrative net-zero systems in a simple structural energy model and show that, for a given set of ... Read more ...
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A Framework for Multisector Scenarios of Outcomes for Well-Being and Resilience - MIT - Global Change -Publications (Apr 29) |
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Apr 29 · Abstract: Shared community scenarios of societal and environmental system changes have underpinned a broad range of research and assessment studies over the past several decades. These scenarios have largely aimed to address specific questions within broad issue areas like climate change or biodiversity and generally provided information on the drivers of change. The consequences of those drivers, such as impacts on society and policy responses, have tended to be left to the research community to investigate, using scenarios of drivers as inputs to their studies, producing projections of a disparate set of relevant output metrics. While this approach has had many benefits, it has ... Read more ...
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How do winter-time extratropical cyclones change in the future over South Africa? - MIT - Global Change -Publications (Apr 5) |
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Apr 5 · Abstract: Extratropical cyclones (ETCs) in South Africa usually occur during the winter (June to August), specifically influencing the Western Cape, causing extreme rain and strong winds.
We investigate future changes in these winter-time ETCs using the simulations from three CORDEX-CORE Africa models. Each of these models was driven by three Coupled Model Intercomparison Project phase 5 (CMIP5) General Circulation Models (GCMs), resulting in nine sets of simulations. The simulations are from 1970-2100, with scenarios starting from 2006. We identified the cyclone tracks using the Hodges tracking algorithm, which used 6-hourly relative vorticity data at 850 hPa level. We chose ... Read more ...
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Sensitivity Analysis and Uncertainty Quantification of E3SM Methane model using Machine Learning - MIT - Global Change -Publications (Apr 5) |
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Apr 5 · Abstract: Methane (CH4) is the second most important greenhouse gas after carbon dioxide, accounting for 16-25% of atmospheric warming to date. However, large uncertainty exists in methane emissions estimates using biogeochemistry models. This uncertainty arises largely because CH4 dynamics depend on multiple physical, biological, and chemical processes and a large number of uncertain model parameters. Sensitivity analysis (SA) can help not only identify important parameters for methane emission, but also achieve reduced biases and uncertainties in future projections.
In this study, SA is performed for the pre-selected critical parameters of methane biogeochemistry module ... Read more ...
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Machine learning based parameter sensitivity of regional climate models - a case study of the WRF model for heat extremes over Southeast Australia - MIT - Global Change -Publications (Apr 4) |
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Apr 4 · Abstract: Heatwaves and bushfires cause substantial impacts on society and ecosystems across the globe. Accurate information of heat extremes is needed to support the development of actionable mitigation and adaptation strategies. Regional climate models are commonly used to better understand the dynamics of these events. These models have very large input parameter sets, and the parameters within the physics schemes substantially influence the model's performance. However, parameter sensitivity analysis (SA) of regional models for heat extremes is largely unexplored.
Here, we focus on the southeast Australian region, one of the global hotspots of heat extremes. In southeast ... Read more ...
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Multiple biotic interactions establish phytoplankton community structure across environmental gradients - MIT - Global Change -Publications (Mar 25) |
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Mar 25 · Abstract: The combination of taxa and size classes of phytoplankton that coexist at any location affects the structure of the marine food web and the magnitude of carbon fluxes to the deep ocean. But what controls the patterns of this community structure across environmental gradients remains unclear.
Here, we focus on the North East Pacific Transition Zone, a ~?10° region of latitude straddling warm, nutrient-poor subtropical and cold, nutrient-rich subpolar gyres. Data from three cruises to the region revealed intricate patterns of phytoplankton community structure: poleward increases in the number of cell size classes; increasing biomass of picoeukaryotes and diatoms; ... Read more ...
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Deforestation as an anthropogenic driver of mercury pollution. - MIT - Global Change -Publications (Mar 12, 2024) |
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Mar 12, 2024 · Abstract: Deforestation reduces the capacity of the terrestrial biosphere to take up toxic pollutant mercury (Hg) and enhances the release of secondary Hg from soils. The consequences of deforestation for Hg cycling are not currently considered by anthropogenic emission inventories or specifically addressed under the global Minamata Convention on Mercury.
Using global Hg modeling constrained by field observations, we estimate that net Hg fluxes to the atmosphere due to deforestation are 217 Mg year–1 (95% confidence interval (CI): 134–1650 Mg year–1) for 2015, approximately 10% of global primary anthropogenic emissions. If deforestation of the Amazon rainforest continues at ... Read more ...
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Sustained growth of sulfur hexafluoride emissions in China inferred from atmospheric observations - MIT - Global Change -Publications (Mar 08, 2024) |
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Mar 08, 2024 · Abstract: Sulfur hexafluoride (SF6) is a potent greenhouse gas. Here we use long-term atmospheric observations to determine SF6 emissions from China between 2011 and 2021, which are used to evaluate the Chinese national SF6 emission inventory and to better understand the global SF6 budget. SF6 emissions in China substantially increased from 2.6 (2.3-2.7, 68% uncertainty)?Gg?yr-1 in 2011 to 5.1 (4.8-5.4)?Gg?yr-1 in 2021.
The increase from China is larger than the global total emissions rise, implying that it has offset falling emissions from other countries. Emissions in the less-populated western regions of China, which have potentially not been well quantified in previous ... Read more ...
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Assessing Compounding Climate-Related Stresses and Development Pathways on the Power Sector in the Central U.S. - MIT - Global Change -Publications (Mar 04, 2024) |
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Mar 04, 2024 · Abstract: Future configurations of the power system in the central region of the U.S. are dependent on relative costs of alternative power generation technologies, energy and environmental policies, and multiple climate-induced stresses. Higher demand in the summer months combined with compounding supply shocks in several power generation technologies can potentially cause a “perfect storm” leading to failure of the power system. Potential future climate stress must be incorporated in investment decisions and energy system planning and operation.
We assess how projected future climate impacts on the power system would affect alternative pathways for the electricity sector ... Read more ...
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Corn, Soybeans and Winter Wheat Water Requirements over the Contiguous United States between 2013 and 2021: The Application of the SEBALIGEE v2 Global Model - MIT - Global Change -Publications (Jan 11, 2024) |
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Jan 11, 2024 · Abstract: The open-source fully-automated Surface Energy Balance Algorithm for Land-Improved (SEBALI) Google Earth Engine (SEBALIGEE) estimates 30-m actual evapotranspiration (ET) at a monthly rate, a much needed parameter in many hydrological and agricultural applications. An improved version of the basin-based SEBALIGEE v1 is proposed in this paper.
The improvement of SEBALIGEE v1, named v2, focuses primarily on adding advanced machine learning approaches which have enabled us to implement SEBALIGEE over any scale application and enhance its performance. More particularly, an evaluation of the monthly ET estimated from the new algorithm across several fluxnet sites in the ... Read more ...
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Net greenhouse gas balance in U.S. croplands: How can soils be part of the climate solution? - MIT - Global Change -Publications (Jan 11, 2024) |
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Jan 11, 2024 · Abstract: Agricultural soils play a dual role in regulating the Earth's climate by releasing or sequestering carbon dioxide (CO2) in soil organic carbon (SOC) and emitting non-CO2 greenhouse gases (GHGs) such as nitrous oxide (N2O) and methane (CH4). To understand how agricultural soils can play a role in climate solutions requires a comprehensive assessment of net soil GHG balance (i.e., sum of SOC-sequestered CO2 and non-CO2 GHG emissions) and the underlying controls. Herein, we used a model-data integration approach to understand and quantify how natural and anthropogenic factors have affected the magnitude and spatiotemporal variations of the net soil GHG balance in U.S. ... Read more ...
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Phytoplankton thermal trait parameterization alters community structure and biogeochemical processes in a modeled ocean - MIT - Global Change -Publications (Jan 01, 2024) |
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Jan 01, 2024 · Abstract: Phytoplankton exhibit diverse physiological responses to temperature which influence their fitness in the environment and consequently alter their community structure. Here, we explored the sensitivity of phytoplankton community structure to thermal response parameterization in a modelled marine phytoplankton community. Using published empirical data, we evaluated the maximum thermal growth rates (µmax) and temperature coefficients (Q10; the rate at which growth scales with temperature) of six key Phytoplankton Functional Types (PFTs): coccolithophores, cyanobacteria, diatoms, diazotrophs, dinoflagellates, and green algae. Following three well-documented methods, PFTs were ... Read more ...
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Equity implications of net-zero emissions: A multi-model analysis of energy expenditures across income classes under economy-wide deep decarbonization policies - MIT - Global Change -Publications (Dec 16, 2023) |
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Dec 16, 2023 · Abstract: With companies, states, and countries targeting net-zero emissions around midcentury, there are questions about how these targets alter household welfare and finances, including distributional effects across income groups. This paper examines the distributional dimensions of technology transitions and net-zero policies with a focus on welfare impacts across household incomes. The analysis uses a model intercomparison with a range of energy-economy models using harmonized policy scenarios reaching economy-wide, net-zero CO2 emissions across the United States in 2050. We employ a novel linking approach that connects output from detailed energy system models with survey ... Read more ...
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Deploying direct air capture at scale: how close to reality? - MIT - Global Change -Publications (Dec 14, 2023) |
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Dec 14, 2023 · Abstract: The role of negative emissions in achieving deep decarbonization targets has been demonstrated through Integrated Assessment Models (IAMs). While many studies have focused on bioenergy with carbon capture and storage (BECCS), relatively little attention has been given to direct air capture (DAC) in IAMs beyond assessing the role of low-cost DAC with carbon storage (DACCS). In this study, we employ an economywide model to more fully explore the potential role of DAC, considering the full range of cost estimates ($180-$1,000/tCO2), DAC units supplied by either dedicated renewables or grid electricity, and both the storage of captured CO2 (DACCS) or its utilization (DACCU) to ... Read more ...
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Mitigating Emissions in the Global Steel Industry: Representing CCS and Hydrogen Technologies in Integrated Assessment Modeling - MIT - Global Change -Publications (Dec 14, 2023) |
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Dec 14, 2023 · Abstract: We conduct a techno-economic assessment of two low-emissions steel production technologies and evaluate their deployment in emissions mitigation scenarios utilizing the MIT Economic Projection and Policy Analysis (EPPA) model. Specifically, we assess direct reduced iron-electric arc furnace with carbon capture and storage (DRI-EAF with CCS) and H2-based direct reduced iron-electric arc furnace (H2 DRI-EAF) which utilizes low carbon hydrogen to reduce CO2 emissions.
Our techno-economic analysis based on the current state of technologies found that DRI-EAF with CCS increased costs ~7% relative to the conventional steel technology. H2 DRI-EAF increased costs by ~18% ... Read more ...
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Phytoplankton thermal trait parameterization alters community structure and biogeochemical processes in a modeled ocean - MIT - Global Change -Publications (Dec 11, 2023) |
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Dec 11, 2023 · Abstract: Phytoplankton exhibit diverse physiological responses to temperature which influence their fitness in the environment and consequently alter their community structure. Here, we explored the sensitivity of phytoplankton community structure to thermal response parameterization in a modelled marine phytoplankton community. Using published empirical data, we evaluated the maximum thermal growth rates (µmax) and temperature coefficients (Q10; the rate at which growth scales with temperature) of six key Phytoplankton Functional Types (PFTs): coccolithophores, cyanobacteria, diatoms, diazotrophs, dinoflagellates, and green algae. Following three well-documented methods, PFTs were ... Read more ...
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Power sector impacts of the Inflation Reduction Act of 2022 - MIT - Global Change -Publications (Nov 30, 2023) |
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Nov 30, 2023 · Abstract: The Inflation Reduction Act (IRA) is regarded as the most prominent piece of federal climate legislation in the U.S. thus far. This paper investigates potential impacts of IRA on the power sector, which is the focus of many core IRA provisions. We summarize a multi-model comparison of IRA to identify robust findings and variation in power sector investments, emissions, and costs across 11 models of the U.S. energy system and electricity sector.
Our results project that IRA incentives accelerate the deployment of low-emitting capacity, increasing average annual additions by up to 3.2 times current levels through 2035. CO2 emissions reductions from electricity ... Read more ...
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Compounding uncertainties in economic and population growth 1 increase tail risks for relevant outcomes across sectors - MIT - Global Change -Publications (Nov 29, 2023) |
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Nov 29, 2023 · Abstract: Understanding the long-term effects of population and GDP changes requires a multisectoral and regional understanding of the coupled human-Earth system, as the long-term evolution of this coupled system is influenced by human decisions and the Earth system. This study investigates the impact of compounding economic and population growth uncertainties on long-term multisectoral outcomes. We use the Global Change Analysis Model (GCAM) to explore the influence of compounding and feedback between future GDP and population growth on four key sectors: final energy consumption, water withdrawal, staple food prices, and CO2 emissions.
The results show that uncertainties in ... Read more ...
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A Large Ensemble Global Dataset for Climate Impact Assessments - MIT - Global Change -Publications (Oct 31, 2023) |
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Oct 31, 2023 · Abstract: We present a self-consistent, large ensemble, high-resolution global dataset of long-term future climate, which accounts for the uncertainty in climate system response to anthropogenic emissions of greenhouse gases and in geographical patterns of climate change. The dataset is developed by applying an integrated spatial disaggregation (SD) - bias-correction (BC) method to climate projections from the MIT Integrated Global System Modeling (IGSM) framework. Four emissions scenarios are considered that represent energy and environmental policies and commitments of potential future pathways, namely, Reference, Paris Forever, Paris 2°C and Paris 1.5°C. The dataset contains nine ... Read more ...
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A comparative analysis of the efficiency, timing, and permanence of carbon dioxide removal (CDR) pathways (Invited) - MIT - Global Change -Publications (Oct 10, 2023) |
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Oct 10, 2023 · Most emission scenarios consistent with the Paris Agreement target of limiting global warming to 1.5°C include net negative CO2 emissions in the second half of this century, i.e. CO2 removal (CDR) from the atmosphere exceeds CO2 emissions. These pathways differ significantly with regards to their: a) CDR efficiency - the net CO2 removal; b) timing - the potential for net CO2 removal occurring at the right time to meet the net-zero targets; and c) permanence - the net CO2 removal from the atmosphere for a sufficiently long length of time.
Here, we adapted the MONET framework to compare the CDR efficiency, timing, and permanence of a non-exhaustive portfolio of archetypal CDR ... Read more ...
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Anthropogenic emissions of chlorine-containing very short-lived halogenated substances in China - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Abstract: Unregulated very short-lived halogenated substances (VSLSs) are playing an increasingly important role in global stratospheric ozone depletion as emissions of long-lived ozone-depleting substances such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) decline due to the controls of the Montreal Protocol on Substances that Deplete the Ozone Layer. The impacts of VSLSs on the stratospheric ozone layer could be more significant when their emissions are from regions with strong convective pathways from the surface to the stratosphere, such as occur in East and South Asia, compared to other regions.
Dichloromethane (CH2Cl2) and chloroform (CHCl3) are the ... Read more ...
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Global-ocean carbon and biogeochemical response to input from rivers and coastal wetlands - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Abstract: Large amounts of terrestrial carbon and nutrients are routed to the ocean through the Land-Ocean Aquatic Continuum (LOAC). Once in coastal waters, these terrestrial inputs impact ocean carbon chemistry. Lateral carbon export from rivers has been estimated to be responsible for global-ocean outgassing of roughly 0.45 Pg C yr-1. However, the biogeochemical pathway for this outgassing has not yet been quantified. In this study, we have carried out a set of model sensitivity experiments, in which we introduce terrestrial carbon and nutrients in the ECCO-Darwin global-ocean biogeochemistry state estimate. We compute daily riverine export by combining the GlobalNEWS2.0 watershed ... Read more ...
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Incorporating Below Ground City Textures into Urban Flood Modeling for Enhanced Flood Prediction and Risk Assessment: A Case Study of the MIT CAMPUS - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Pluvial (rain-driven) flooding poses a significant threat to urban areas worldwide, necessitating accurate flood prediction for effective flood risk adaptation and damage mitigation. This research explores the impact of incorporating below ground city textures, such as basements, garages, and tunnels, into urban flood models on the extent and propagation of surface and subsurface flooding and damages. A high-resolution 1&2D Rain On Mesh (ROM) hydrodynamic flood model for the city of Cambridge was developed. The model integrated various layers of geospatial data and the city's DEM. An extended version of the model, the Basement Model, applies an approach to incorporate below ground ... Read more ...
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Long-term Comparison of NOAA and AGAGE Non-CO2 Trace Gas Observations at Common Sites - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Abstract: The Advanced Global Atmospheric Gases Experiment (AGAGE) program and the National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Laboratory (GML) maintain some of the longest measurement records of the atmospheric abundances of ozone-depleting substances (ODSs) and their substitutes, many of which are strong greenhouse gases (GHGs). Several records extend back more than 40 years, and fittingly, Walt Komhyr was involved in the early halocarbon measurements at NOAA in the mid-1970s. For the past 20+ years, comparisons of ozone-depleting substances and non-CO2 greenhouse gas measurements have been carried out and reviewed by project participants for more than ... Read more ...
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Maximizing Air Quality Benefits of Organizational Climate Action: Evidence from Electricity Purchase and Personnel Business Travel - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Abstract: Organizational decisions to mitigate climate change are often focused solely on reducing greenhouse gas emissions, but also can have multiple sustainability-related impacts. A substantial area of impact from reducing greenhouse gases relates to air quality, where reductions in fossil fuel use can cause health damages locally and regionally. While much research has quantified the air quality benefits of large-scale strategies to reduce greenhouse gas emissions, information about the different impacts of organizational Scope 1–3 emissions on air quality is lacking. We use data from two universities and one multinational corporation based in the northeast U.S. to examine the ... Read more ...
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Modeling Impacts of Wildfires on Soil Thermal and Hydrological and Carbon Dynamics in Northern High Latitudes - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Abstract: Wildfires significantly affect vegetation, soil thermal and hydrological as well as carbon dynamics. This study uses a process-based biogeochemistry modeling framework that is incorporated with land surface energy balance, soil thermal and hydrological dynamics and their effects on carbon and nitrogen cycling to simulate these dynamics and carbon budget in northern high latitudes. Here we present our model results on North American boreal forests from 1986 to 2020 using satellite-derived burn severity data. We find that fires remove ecosystem carbon through combustion emissions and reduce net ecosystem production, making the ecosystem lose 3.5 Pg C during 1986-2020 and ... Read more ...
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On the Influence of Ocean Sinks and Hydroxyl Radical Changes on Estimated Lifetimes and Emissions of Halogenated Greenhouse Gases - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Abstract: Halogenated greenhouse gases (such as HCFCs, HFCs, PFCs, and SF6) have global warming potentials thousands to tens of thousands of times greater than carbon dioxide on a per kilogram basis. Estimating the emissions of these gases on a global scale is challenging since direct measurements are unavailable. Instead, they are inferred using measured global atmospheric concentrations and knowledge of their lifetimes. The ocean uptake for halogenated species can impact their lifetimes, but this process has been assumed to be largely negligible in the past. Further, reaction with hydroxyl radicals (OH) is a major atmospheric loss pathway for HCFCs and HFCs. Emission estimations ... Read more ...
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On the Influence of Ocean Sinks and Hydroxyl Radical Changes on Estimated Lifetimes and Emissions of Halogenated Greenhouse Gases - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Abstract: Halogenated greenhouse gases (such as HCFCs, HFCs, PFCs, and SF6) have global warming potentials thousands to tens of thousands of times greater than carbon dioxide on a per kilogram basis. Estimating the emissions of these gases on a global scale is challenging since direct measurements are unavailable. Instead, they are inferred using measured global atmospheric concentrations and knowledge of their lifetimes. The ocean uptake for halogenated species can impact their lifetimes, but this process has been assumed to be largely negligible in the past. Further, reaction with hydroxyl radicals (OH) is a major atmospheric loss pathway for HCFCs and HFCs. Emission estimations ... Read more ...
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Potential Impacts On Ozone And Climate From A Fleet Of Supersonic Aircraft Under Different Adoption Projections - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Abstract: With renewed interest in commercial supersonic transport (SST) aircraft due to increased demand for air travel, the environmental impacts on ozone and climate from proposed supersonic fleets need to be analyzed. In this study we have examined two such proposed fleets developed by MIT, flying at Mach 1.6 with a cruise ceiling at 17 km and representing either high or low economic growth. The high scenario burns 43.1 Tg of fuel with 0.39 Tg NOx and 0.14 Tg BC emission whereas the numbers for the low scenario are 9.6 Tg, 0.008 Tg and 0.03 Tg respectively. The UIUC analyses was done using the global climate chemistry model CESM2 – WACCM6 with model top ~140km with comprehensive ... Read more ...
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Practical Steps for Achieving Equity in Water Resources System Planning: Lesotho Irrigation Investment under Climate Change - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Abstract: In recent years, researchers have begun to propose methods to assess distributive justice under climate change and within adaptation policies. Literature calls for a systematic approach for incorporating distributive justice in water resources planning, and clear guidelines on how best to include such an approach in standard project development and decision-making frameworks. So far, there are inadequate illustrative examples of how this is done in practice, and little connection has been made to financial evaluation and decision metrics commonly used by stakeholders. While stakeholders and decision makers rely on the outcome of financial assessment methods such as Cost ... Read more ...
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Urban Flood Modeling: The Influence of surface run-off modeling and Geospecificity in estimating Flood Extent and Propagation - MIT - Global Change -Publications (Oct 06, 2023) |
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Oct 06, 2023 · Catchment-based surface runoff models underestimate the duration and extent of flooding as compared to models that incorporate of rain-on-mesh surface runoff modeling in urban drainage analysis. This underestimation of flood extent and duration leads to underestimation of the expected damages and impacts on lifespan of urban infrastructure. Case studies of Cambridge, Massachusetts and Cleveland, Ohio are presented.
Strzepek, K.M. and K. Boukin
Abstract
Spatial results of the ROM simulations, see Figure 1, revealed for a range of design storms flood extents 7-9.5 times greater and depths 1.2-7 times deeper across the city during peak flooding, as compared to the ... Read more ...
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Logs or permits? Forestry land use decisions in an emissions trading scheme - MIT - Global Change -Publications (Sep 26, 2023) |
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Sep 26, 2023 · Abstract: Negative carbon emissions options are required to meet long-term climate goals in many countries. One way to incentivize these options is by paying farmers for carbon sequestered by forests through an emissions trading scheme (ETS). New Zealand has a comprehensive ETS, which includes incentives for farmers to plant permanent exotic forests.
When there is forestry land use change, the results indicate that the responsiveness of land owners to the carbon price has a measured impact on carbon sequestration. For example, under the fastest land use change scenario, carbon sequestration reaches 29.93 Mt CO2e by 2050 compared to 23.41 Mt CO2e in the no land use change ... Read more ...
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Overlooked Long-Term Atmospheric Chemical Feedbacks Alter the Impact of Solar Geoengineering: Implications for Tropospheric Oxidative Capacity - MIT - Global Change -Publications (Sep 21, 2023) |
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Sep 21, 2023 · Authors' Summary: Solar geoengineering is a proposed set of technologies to help lessen the impacts of climate change by reducing the amount of sunlight received by the Earth. Stratospheric aerosol injection is a method of solar geoengineering that reduces sunlight by increasing the amount of aerosol particles in the stratosphere, a process which can also cause stratospheric ozone depletion. Nearly all studies of stratospheric aerosol injection have focused exclusively on the direct impacts of increased stratospheric aerosol on climate. However, changes in sunlight also alter the rates of chemical reactions throughout the atmosphere, changing the concentrations of greenhouse gases ... Read more ...
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