For more than 20 years, the work of academic climate scientists and those at groups like the Union of Concerned Scientists has been to analyze, synthesize, and convey the projected and, in recent years, current impacts of climate change. In the earlier years, these impacts were still largely imperceptible and pathways for solving the problem seemed wide and flexible. A key objective of climate science communication during those years was to establish the legitimacy of our work, which faced tremendous public and policy maker scrutiny, as a simultaneous barrage of well-coordinated disinformation had led to unusual skepticism of the science. Now we are clearly seeing the impacts of one degree Celsius of warming, the current and projected climate impacts themselves have grown, and the solutions pathways have become narrow and steep. While the climate context has changed for the worse over those 20 years, scientists have largely soldiered on with the same reticent communication. Visible climate change impacts and alarming projections for future change have far outpaced the growth in experts’ ability to reach people and inspire them to act with urgency. At UCS, we have consciously and deliberately begun to change the tenor of our climate communications in response to the increasingly dire results our own analyses have generated and against a backdrop of accumulating and similarly dire science. In our most recent work on extreme heat, particularly in introducing and concluding our results, we have embraced starkly visceral and impassioned language because, as scientists, we see how dangerous the future looks, how serious this moment is in the arc of climate change, and our own moral obligation to communicate it. In this presentation, we will examine the communications space our climate scientists at UCS—as well as those at other institutions—have leaned into. As sentient humans who see an emergency measured not just by data points in charts and graphs but by the faces of those whose homes have flooded, whose loved ones have lost their lives during heat waves, or whose livelihoods are no longer viable, we can’t “tell it like it is” without letting go of reticence and objectivity. The words we choose may be perceived as dangerous, but they are not as dangerous as the world we are ushering in. The house is objectively on fire. It’s time to shout.

We present our results on the second year of TOTO-Cheyenne (TGFs On Top Of Cheyenne), a continuing collaboration of the US Air Force Academy and the Naval Research Laboratory. The project’s goal is to study the ionizing radiation as lightning strikes near the antenna farm on the top of Cheyenne Mountain, near Colorado Springs CO. Thunderstorms and accompanying lightning produce ionizing radiation on time scales from milliseconds to minutes. This radiation includes terrestrial gamma-ray flashes, hard X-rays from stepped leaders, gamma-ray glows, and thunderstorm ground enhancements. Recent measurements indicate that getting up close and personal with the storms might produce more details about the complex processes inside. The US Rocky Mountains offer the opportunity to do just that by getting closer to the charge layers. This year’s experiment (starting in May 2019 and continuing to October 2019) involved the setup of a high speed camera at the Air Force Academy facing south to watch Cheyenne Mountain plus the reinstallation of a small gamma-ray and X-ray detection system (NaI and plastic scintillators) on the mountain. This year has proven to be a very active storm year. As of 20 July, there were already 25 strikes within 2 km of the detector (compared to 1 strike during the summer 2018).

We explore the effects of changing heating parameters in closed coronal loops on the intensity of Atmospheric Imaging Assembly (AIA) observations. Using EBTEL (Enthalpy-Based Thermal Evolution of Loops) hydrodynamic simulations, we produce realizations of coronal loops with a series of heating events randomly drawn from a power law distribution. We repeat this procedure for multiple loop lengths, heating intensities, and characteristic heating frequencies to investigate how each of these parameters individually and in combination influences observable loop properties. We generate AIA intensities from the corona and transition region for each realization. The variations within and between models generated with these different parameters illustrate the sensitivity of narrowband imaging to the details of coronal heating. Using insights from this analysis, we generate images of observed coronal active regions using the GX Simulator SSW IDL package and interpret the causes of discrepancies between the models and observations.

Assessing the extent and impact of past extreme weather events within cities can help identify vulnerabilities, map potential solutions, and prevent future calamities. Modern urban environments are particularly vulnerable to hydrological extremes due to high population densities, expansive impermeable surfaces, more intense precipitation extremes, and infrastructure designed for a now obsolete climate. Intense rainfall in urban environments can lead to impacts ranging from nuisance flooding to overloading of sewage and drainage systems to neighborhood inundation. In the flood-prone city of Chicago, storm waters are contained in a network of tunnels and reservoirs until treated and released to the waterways. Management decisions for a 600 km^2 metropolitan area are made based on precipitation data collected at just 9 gauge sites. Here, we combine high-resolution radar-derived precipitation data with urban-scale hydrological models to improve our understanding of water flow, advance stormwater management practices, and potentially mitigate flood risks. Proximity of the NEXRAD system to Chicago allows us to improve the spatial resolution of rainfall estimates to 500m, which will be used to produce neighborhood-scale rainfall hindcasts. Different dual-polarimetric radar-rainfall retrieval methods, e.g., rainfall from reflectivity, attenuation, specific differential phase, and differential reflectivity will be examined to determine the most accurate representation of rainfall estimates. This suite of rainfall estimates will be used to derive catchment-level precipitation, and serve as input in a coupled hydrological-hydraulic MetroFlow model. To verify the utility of our radar precipitation data, we examine an April 2013 event that delivered a record-breaking 7 inches of rain in 2 days in some areas. We compare our highly-resolved precipitation-driven hydrological model predictions with those made using the 9 gauge stations. This research is conducted under the premise that hydrological extremes are expected to be exacerbated by climate change. Understanding drivers of urban flooding using high-resolution precipitation data and models can be used to improve resiliency-focused infrastructure design in Chicago neighborhoods.

Soft x-ray and EUV radiation from the Sun is absorbed by and ionizes the atmosphere, creating both the ionosphere and thermosphere. Temporal changes in irradiance energy and spectral distribution can have profound impacts on the ionosphere, impacting technologies such as satellite drag and radio communication. Because of this, it is necessary to estimate and predict changes in Solar EUV spectral irradiance. Ideally, this would be done by direct measurement but the high cost of solar EUV spectrographs makes this prohibitively expensive. Instead, scientists must use data driven models to predict the solar spectrum for a given irradiance measurement. In this study, we further develop the Synthetic Reference Spectral Irradiance Model (SynRef). The SynRef model, which uses broadband EUV irradiance data from the MAVEN EUVM at Mars, was created to mirror the SORCE XPS model which uses data from the TIMED SEE instrument and the SORCE XPS instrument at Earth. Both models superpose theoretical Active Region and Quiet Sun spectra generated by CHIANTI to match daily measured irradiance data, and output a modeled solar EUV spectrum for that day. We use the broadband EUVM measurements to estimate Active Region temperature. This will allow us to select from a library of AR reference spectra with different temperatures. We also investigate how the prevalence of solar minimum coronal holes affects our measurements and how to account for them. We present this updated SynRef model to more accurately characterize the Solar EUV and soft x-ray spectra.

NASA’s Capacity Building Program (CBP) works to empower communities around the globe to use Earth observation data and products in their decision making. Working through program and element activities, CBP developed a theoretical framework for engagement focused around user needs which identifies the appropriate path for engagement based on geography, discipline, data needs and availability, depth of support required, partnerships involved, length of engagement, and desired outcomes. These decision factors would determine which CBP element would take on the effort – ARSET, DEVELOP, or SERVIR, and which approach would be implemented – trainings or co-development. Each approach offers participants different benefits and leads to outcomes that fall on a spectrum from increased awareness to sustained use of Earth observations. However, implementation of this framework across multiple programs with differing constraints has been challenging. This presentation will highlight the CBP framework and its user-centric approach, capacity building methods and incentives, metrics and tracking indicators, challenges, and lessons learned.

Climate and carbon cycling during the Eocene were complex, as inferred from records of stable isotopes and carbonate accumulation in marine sediment sections. Following a now well-documented early Eocene interval characterized by extreme global warmth and numerous short-term C-cycle perturbations documented in many sediment sections across the world, the ‘warmhouse’ climate state of the middle-late Eocene remains far less studied. In particular, the middle Eocene was punctuated by an event of significant global warming and seafloor carbonate dissolution (Middle Eocene Climate Optimum or MECO, ca. ~40.5 Ma). Over the last decade, studies from multiple sites in the Atlantic have suggested another abrupt and transient (and potentially a hyperthermal) warming event seemingly associated with a C-cycle perturbation at ~41.5 Ma, referred to as the Late Lutetian Thermal Maximum (LLTM). While both MECO and LLTM punctuate the post-EECO long-term cooling, their isotopic expression and duration are fundamentally different. At present, a dearth of continuous middle Eocene chemostratigraphic records limits our understanding of warming events like MECO and especially, the global extent of the LLTM. In this study, we develop an isotope stratigraphy of Lutetian-Bartonian age sediments from three different sites in the southwest Pacific region, two of which were drilled during IODP Expedition 371 in the Tasman Sea and a third that derives from field work in New Caledonia. We identify long-term changes in carbon and oxygen isotope records, possibly related to 405 Ky eccentricity cycles, and identify the stratigraphic expression of the LLTM and MECO. These new middle Eocene chemostratigraphic records from the southwest Pacific help to establish the global nature and relevance of multiple warming events that occurred during the ‘warmhouse’ climatic conditions of middle Eocene and highlight the utility of sedimentary carbon isotopes as a tool for chemostratigraphy and deciphering causes of past global changes.

The thermal and chemical structure of the middle atmosphere is determined by molecules of air absorbing high-energy, solar, ultraviolet radiation. The dominant photochemical reaction for forming the stratosphere is dissociation of a molecule of oxygen into two atoms of oxygen. When a molecule is dissociated, the two pieces fly apart at high velocity. Temperature of air is directly proportional to the average velocity of all its molecules and atoms squared. Thus, photochemical dissociation converts bond energy efficiently and completely into air temperature. A molecule of oxygen is dissociated by absorbing ultraviolet-C radiation with frequencies around 1237 terahertz, energies around 5.1 electronvolts. Since oxygen makes up 20.95% of Earth’s atmosphere, there is ample oxygen to absorb all solar ultraviolet-C of appropriate frequencies that reaches the stratosphere, keeping the stratopause 30 to 40 oC warmer than the tropopause. Thus, the stratosphere forms an “electric” blanket warming Earth—electric in the sense that the thermal energy comes from a distant source, Sun, not from the body under the blanket, Earth. The second most important photochemical reaction in the stratosphere is dissociation of ozone by ultraviolet-B radiation with frequencies around 967 terahertz, energies around 4.0 electronvolts. While ozone concentrations, even in the ozone layer, are less than 10 parts per million, ozone is continually being formed and dissociated in the endless ozone-oxygen cycle, absorbing most solar ultraviolet-B radiation. When atoms of chlorine reach the lower stratosphere especially in winter, ozone concentrations that normally increase in winter can be depleted. One atom of chlorine, under the right conditions, can destroy 100,000 molecules of ozone. Depletion of the ozone layer allows more ultraviolet-B radiation than normal to reach Earth. Ultraviolet-B radiation is observed to cause sunburn, cataracts, skin cancer and mutations. It also dissociates ground-level ozone pollution, warming air in populated regions and penetrates oceans more than one hundred meters, very efficiently increasing ocean heat content as observed. Because of the ozone-oxygen cycle, where there are increased concentrations of ozone in the atmosphere, there is increased temperature. Sudden stratospheric warmings of 30-40 oC within days are typically associated with high concentrations of ozone and occur most frequently at altitudes of 30-50 km where dissociation of oxygen and ozone are most efficient. In 1798, Sir Benjamin Thompson proposed the mechanical theory of heat generated by friction when boring canon. This mechanical theory evolved into two fundamental assumptions: 1) heat is a flux of thermal energy measured in watts per square meter and 2) the greater the amount of flux absorbed, the hotter the body will become. Note that this approach never addresses the issue of what heat or thermal energy are, physically. (Complete abstract in poster file.)

The US National Center for Atmospheric Research (NCAR) has published several large datasets in the Amazon Web Services (AWS) cloud, thanks to support from the NCAR “Science at Scale” project, the AWS Open Data Sponsorship program, and the Amazon Sustainability Data Initiative. In each case we selected a subset comprising the most useful variables from the original data, and converted that subset from NetCDF to Zarr before publication. The Zarr format supports the same data model as netCDF and is well suited to object storage and distributed computing in the cloud using the Pangeo libraries in Python. Each dataset has an accompanying Intake-ESM catalog to facilitate data discovery and reading via Xarray, and each also has a sample Jupyter Notebook to illustrate how to access and analyze the data. Egress for these data are free, but users are encouraged to bring their compute to the data. The datasets currently published are: Community Earth System Model Large Ensemble (CESM LENS): https://doi.org/10.26024/wt24-5j82 North American Coordinated Regional Downscaling Experiment (NA-CORDEX): https://doi.org/10.26024/9xkm-fp8 CESM version 2 Large Ensemble (CESM2-LE): https://doi.org/10.26024/y48t-q717 Data Assimilation Research Testbed (DART) Reanalysis: https://doi.org/10.26024/sprq-2d04 This paper will provide information about the datasets and summarize lessons learned from the data conversion and publication.

Electric field measurements are necessary to understand thunderstorm evolution and lightning initiation. However, most existing measurements are made with single instruments carried by weather balloons. It is difficult to interpret such data since a change in observed electric field could be due either to motion of the instrument or charging/discharging currents. In order to decouple these behaviors, it is necessary to make simultaneous measurements at multiple locations. To avoid the complexity of multiple balloon launches, we describe a single balloon instrument with multiple, independent dropsondes to be released at desired time intervals. The dropsondes are designed to rotate and be self stabilizing, enabling them to measure electric fields as they fall. The dropsondes are lightweight, robust, and low-cost, and include a preamplifier, GPS receiver, search coil and accelerometer for orientation sensing, microcontroller, and a telemetry system to transmit data to a ground station. Prototype instruments have been drop-tested to demonstrate aerodynamic stability and rotation and have been calibrated for electric field measurement. A balloon payload set to release a set of such dropsondes via hot-wire release mechanisms can thus accomplish the goal of multi-point measurements of thunderstorm electrical structures.

The investigation of the Ora Ignimbrite (~275 Ma) helps further our understanding of how vast amounts (>1,000 km3) of melt are generated, stored, and erupted from the shallow crust. As the last eruptive product of a slab rollback ignimbrite flareup that lasted for 10 Ma, Ora’s glacially incised outcrops tower over 1,300 m above Bolzano, Italy. Two key outcrops, early-erupted intracaldera vitrophyre and late-erupted outflow vitrophyre, provide well-preserved, glass-bearing juvenile material. Petrographic optical and electronic (back-scattered electron) analysis was used to document the textural features of minerals and glass. Glass and mineral major-element compositions were obtained using Energy-Dispersive X-ray (EDX) analysis on a Scanning Electron Microscope (SEM). Glass with low Na/high K concentrations and A/CNK ratios > 1.1 was deemed altered. Intracaldera vitrophyre contains two distinct fiamma types: very coarse-grained, crystal-rich (VCCR) and fine-grained (FG) fiamme. Glass in VCCR fiamme is homogeneous high-silica rhyolite (76.5-77.5 wt. % SiO2; normalized anhydrous) with low K2O values (3-3.5 wt. %). The FG fiamme have a broader SiO2 range (75-78 wt. % and 72-78 wt. %) and higher K2O values (3-4.5 wt. %). Outflow vitrophyre has medium-grained (MG) and fine-grained, crystal-poor (FGCP) fiamme. The MG fiamme have homogeneous high-silica rhyolite glass (76-78 wt. % SiO2) with lower K2O (2-3 wt. %). Glass in three FGCP fiamma form compositional continua from 68-78 wt. %, 67-79 wt. %, and 72-78 wt. % SiO2, and K2O varies substantially (0.5-3.5 wt. %). These results demonstrate mingling and mixing and suggest that multiple melt-rich zones contributed to the erupting magma. We propose that at least four separate magma bodies contributed to the Ora eruption. Each one evolved independently, leading to variable amounts of magma mingling and mixing. These results illuminate the subsurface architecture of a large silicic system during the final episodes of an ignimbrite flareup.

The percentage of Geoscience students, faculty, and professionals from historically under-represented minority (URM) groups has been largely unchanged for two decades and remains significantly below general population trends. Diversifying Geosciences, and developing an equitable culture in the discipline requires faculty members (irrespective of race/ethnicity) to engage actively in JEDI (Justice-Diversity-Equity-Inclusion) efforts. Previous studies that focused broadly on faculty experiences in academia indicate that restructuring of existing faculty evaluation frameworks to better value JEDI work may help more URM faculty, researchers and students feel valued, thus enhancing diversity at all academic levels. However, such efforts may not be significantly valued in many Geoscience departments. To better understand faculty perspectives and motivations related to JEDI work, including the effects of faculty evaluation systems on behaviors, we are interviewing a range of faculty members across the US. Preliminary interviews suggest <50% of faculty in the Geoscience departments are actively involved in JEDI work and those who are, are more likely to be women and/or early career professionals. To aid to this data collection process, we will also be conducting a nation-wide survey of Geoscience faculty to better understand the value of JEDI activities in current faculty assessment (evaluations/promotion/tenure/raise etc.) frameworks, and identify potential barriers in engaging more faculty in meaningful DEI work. Using data from the interviews and survey results, we aim to develop example evaluation and reward structures that explicitly value JEDI work that can be adopted/adapted by other Geoscience departments, and to produce webinars focused on helping faculty leaders explicitly value JEDI efforts within hiring and evaluation systems.

The unusually cold springtime Arctic stratospheres of 2011, 2016 and 2020 generated substantial Polar Stratospheric Clouds (PSCs) activity and a significant ozone hole. These events were accompanied by an unusual presence of precipitating liquid clouds in the high Arctic. Satellite lidar measurements helped to identify a possible mechanistic link between tropospheric cloud formation and the PSCs. The synoptic meteorological context provided by the ERA 5 reanalysis was instrumental in the identification of potential liquid-precipitation formation scenarios related to atmospheric rivers.

Balancing socio-ecological systems among competing water demands is a difficult and complex task. Traditional approaches based on limited, linear growth optimization strategies overseen by command/control have partially failed to account for the inherent unpredictability and irreducible uncertainty affecting most water systems due to climate change. Governments and managers are increasingly faced with understanding driving-factors of major change processes affecting multifunctional systems. In the last decades, the shift to address the integrated management of water resources from a technocratic “top-down” to a more integrated “bottom-up” and participatory approach was motivated by the awareness that water challenges require integrated solutions and a socially legitimate planning process. Assuming water flows as physical, social, political, and symbolic matters, it is necessary to entwining these domains in specific configurations, in which key stakeholders and decision-makers could directly interact through social-learning. The literature on integrated water resources management highlights two important factors to achieve this goal: to deepen stakeholders’ perception and to ensure their participation as a mechanism of co-production of knowledge. Stakeholder Analysis and Governance Modelling approaches are providing useful knowledge about how to integrate social-learning in water management, making the invisible, visible. The first one aims to identify and categorize stakeholders according to competing water demands, while the second one determines interactions, synergies, overlapping discourses, expectations, and influences between stakeholders, including power-relationships. The HydroSocial Cycle (HSC) analysis combines both approaches as a framework to reinforce integrated water management by focusing on stakeholder analysis and collaborative governance. This method considers that water and society are (re)making each other so the nature and competing objectives of stakeholders involved in complex water systems may affect its sustainability and management. Using data collected from a qualitative questionnaire and applying descriptive statistics and matrices, the HSC deepens on interests, expectations, and power-influence relationships between stakeholders by addressing six main issues affecting decision-making processes: relevance, representativeness, recognition, performance, knowledge, and collaboration. The aim of this contribution is to outline this method from both theory and practice perspective by highlighting the benefits of including social sciences approaches in transdisciplinary research collaborations when testing water management strategies affecting competing and dynamic water systems.

Climate change tends to be addressed by accurate statistics and modelling, but it is generally perceived abstractly, being considered a distant psychological risk in which impacts and effects are spatially and temporally differentiated. In other words, people’s attitude towards climate change is that it will impact other individuals and communities that are geographically, temporally, and even generationally removed from themselves. However, due to the hybrid nature of climate change as both a physical and social phenomenon, individuals are not ‘blank slates’ receiving information and facing climate change. Many have argued that deepening personal experience could be the first step for reducing individual and community psychological distance of climate change while increasing the potential for behavior change. Considering that agriculture affects and is affected by climate change in several ways, farmers can provide first-hand observations of climate change impacts and testing different adaptation options. This contribution provides an overview of the intellectual structure of farmers’ behavior on climate change awareness, perceived risks, and adaptation capacity. A portfolio of 108 survey studies published in the last decade was selected for a comprehensive analysis. Exploratory variables such as farmers’ socio-demographic characteristics, level of climate change awareness, major perceived impacts, and adaptation measures, parameters, and barriers have been reported. In addition to the bibliographic analysis, the first results from a survey conducted in different irrigation systems in northern Italy will be tested to identify(dis)similar trends in farmers’ behavior. The identification of not only farmers’ behavior gaps but also their causing reasons will contribute to focus attention on most concerning issues and provide more accurate bottom-up knowledge to managers and decision-makers.

Coronal holes (CH) are dark areas in EUV images that are generally associated with open magnetic field regions on the Sun. CHs detected over the entire Sun can be used to estimate the open magnetic flux in the heliosphere by overlaying them on magnetic field measurements. Making accurate estimates is difficult due to many factors, including limited instrument coverage, uncertainties in the observations, and challenges in reliable detection of CH boundaries. One such CH detection challenge stems from the fact that EUV line-of-sight observations essentially flatten the three-dimensional structure in the low corona, which can cause nearby bright structures to obstruct CHs. Here we introduce a mitigation strategy for avoiding the effects of CH obscuration. Using a global thermodynamic MHD model of the corona, we first generate synthetic EUV images for a multitude of observer locations (chosen to mimic the view of SDO over the solar rotation) and combine them into a full-Sun synoptic EUV map. A CH map is then extracted using an established detection algorithm. The resulting open flux estimates are computed and compared to the model’s true open flux. The mitigation strategy (called “minimum intensity disk merge (MIDM)”) is applied by changing the way multiple EUV disk images are combined. Instead of using central strips, full disk images are used by taking the minimum intensity in all overlapping regions. This allows any CH area observed at any vantage point to be seen in the final map. We compare the resulting open flux and CH areas to those using the standard synoptic method. We apply the MIDM method to SDO AIA 193 observational data for the same rotation, and the resulting EUV and CH maps (with corresponding open flux estimates) are compared. Issues such as CH evolution over the rotation, and synchronizing the effective EUV image height to the height of the magnetic field values are discussed.

The widespread presence of meteoric smoke particles (MSPs) within a distinct class of stratospheric aerosol particles has become clear from in-situ measurements in the Arctic, Antarctic and at mid-latitudes. We apply an adapted version of the interactive stratosphere aerosol configuration of the composition-climate model UM-UKCA, to predict the global distribution of meteoric-sulphuric particles nucleated heterogeneously on MSP cores. We compare the UM-UKCA results to new MSP-sulphuric simulations with the European stratosphere-troposphere chemistry-aerosol modelling system IFS-CB05-BASCOE-GLOMAP. The simulations show a strong seasonal cycle in meteoric-sulphuric particle abundance results from the winter-time source of MSPs transported down into the stratosphere in the polar vortex. Coagulation during downward transport sees high latitude MSP concentrations reduce from ~500 per cm3 at 40km to ~20 per cm3 at 25km, the uppermost extent of the stratospheric aerosol particle layer (the Junge layer). Once within the Junge layer’s supersaturated environment, meteoric-sulphuric particles form readily on the MSP cores, growing to 50-70nm dry-diameter (Dp) at 20-25km. Further inter-particle coagulation between these non-volatile particles reduces their number to 1-5 per cc at 15-20km, particle sizes there larger, at Dp ~100nm. The model predicts meteoric-sulphurics in high-latitude winter comprise >90% of Dp > 10nm particles above 25km, reducing to ~40% at 20km, and ~10% at 15km. These non-volatile particle fractions are slightly less than measured from high-altitude aircraft in the lowermost Arctic stratosphere (Curtius et al., 2005; Weigel et al., 2014), and consistent with mid-latitude aircraft measurements of lower stratospheric aerosol composition (Murphy et al., 1998), total particle concentrations also matching in-situ balloon measurements from Wyoming (Campbell and Deshler, 2014). The MSP-sulphuric interactions also improve agreement with SAGE-II observed stratospheric aerosol extinction in the quiescent 1998-2002 period. Simulations with a factor-8-elevated MSP input form more Dp>10nm meteoric-sulphurics, but the increased number sees fewer growing to Dp ~100nm, the increased MSPs reducing the stratospheric aerosol layer’s light extinction.

Basalt carbonation has gained traction as a key technology for avoiding the worst consequences of human-driven climate change. However, our understanding of this method’s promise is likely inflated by the specialized conditions used in many of the most well-known laboratory studies and demonstration projects. For technological, hydrogeologic, and energetic simplicity, many basalt CO2 storage projects will likely inject supercritical, not dissolved, CO2. Thus, fluids in these systems are likely to have low alkalinity and low pH, in contrast to many experimental and demonstration studies. Here, we present a series of geochemical models that explore the dependence of carbon mineralization efficiency on alkalinity and therefore pH at conditions relevant to these proposed operations. We modelled the interaction of basalt with CO2 enriched, seawater-derived aquifer fluid with varying initial alkalinities at 60°C using a custom thermodynamic database incorporating updated thermodynamic data for relevant primary and secondary minerals. The results reinforce the notion that alkalinity is an important driver for carbonate precipitation, ultimately because carbonate minerals are up to an order of magnitude more soluble at pH <5 than they are at pH >6. Alkalinity increases of 5 to 10% proportionally increase carbonate precipitation in the models. Our results thus demonstrate that the elevated alkalinity found in many of the most well-known basalt carbonation studies yield disproportionately high rates of carbon mineralization, which, in turn, frames basalt carbonation as an extremely rapid and exceptionally effective CO2 storage method. Although supercritical CO2 injection operations such as those we explore here are likely to achieve high fractions of CO2 mineralization over their lifetimes, this will likely take considerably longer and potentially be ultimately less effective, due to sluggish rates of CO2 dissolution and alkalinity generation.