Braggy Bio

This research biography was written in 2023 by a colleague is kindly helping to promote my work 

David Keith is a scientist and technology innovator who plays a central role in both carbon removal and solar geoengineering research, among the most important emerging areas of climate technology and science. Deep scientific analysis and practical technological innovation on critical topics has allowed Keith to make an impact on both fundamental discovery and deployed solutions. 

In carbon removal, Keith was among the first to realize that biomass energy combined with CCS (BECCS) enables negative emissions. He developed methods to increase the security of stored CO₂ and led the technical and commercial development of a direct air capture of CO₂ (DAC) technology that is the closest to large-scale deployment at the million ton per year scale.   

In solar geoengineering, Keith is arguably the world’s most influential researcher. 

Keith is an applied physicist working at the intersection of climate science, energy technology, and public policy. Keith’s gift for applied technologies was evident in graduate school when he developed the first interferometer for atoms, a long-sought prize in experimental physics.  

Beyond applied science, Keith is known for policy analysis that avoids prescriptive claims in favor of quantitative analyses that take uncertainty seriously, with outputs ranging from an influential 1995 elicitation of expert judgments about climate sensitivity to a study critiquing overconfident assertions on battery storage for grid decarbonization. Keith’s outlook has been steadfastly analytical and skeptical. The depth of Keith’s policy analytic expertise was demonstrated by his appointment as full tenured faculty at Harvard’s Kennedy School, an unusual appointment for a scholar who trained in the sciences. His recent work is exemplified in the first integrated assessment model to dynamically incorporate carbon removal and solar geoengineering producing the first analytical version of John Shepherd’s “Napkin Diagram”, and in a taxonomy of concerns about solar geoengineering in Science Magazine’s influential Policy Forum. 

Keith’s thought leadership is demonstrated by early work on initially obscure topics—biomass with carbon capture, direct air capture of CO₂, and solar geoengineering—that have now risen to the top of the climate agenda. In 2023 The University of Chicago launched a Climate Systems Engineering initiative with Keith as director. The initiative illustrates how these topics are maturing into a coherent research field. It is distinct in that it started a wide-ranging faculty consultative process that led to a strategic choice by university leadership to pursue coordinated research with a commitment to ten faculty hires, the first commitment of this magnitude by a major research university.   

Beginning with a 1998 Policy Forum, Keith was an early leader in quantitative, policy-relevant technology assessment of carbon capture and storage (CCS) and carbon removal. Keith supervised the first Ph.D. on BECCS developing a new method for integrating capture and gasification, and he was the first to address the land-use impacts of BECCS, more than a decade before concerns about its environmental impacts became common. 

Professor Keith’s policy analysis of carbon removal and CCS includes the first analysis of carbon removal within an optimal climate policy framework that incorporates uncertainty. His analysis of CO₂ options for regulating storage integrity helped shape development of the EPA’s regulation of sequestration wells. As the crosscutting lead author for the IPCC special report on CCS, Keith’s expert judgment survey produced the “likely more than 99% for 1000 years” leakage estimate that is the most cited conclusion of that pivotal report. His technical work on CO₂ storage includes a novel method for engineering subsurface reservoirs to minimize leakage risk by accelerating CO₂ dissolution, and development of analytical tools to estimate the in-reservoir convection mixing timescale from the Rayleigh number.  

Starting as a skeptic of direct air capture of CO₂ (DAC), Keith’s efforts to estimate the cost of DAC by developing a low-risk process design led him to found Carbon Engineering (CE) in 2009. Keith led the company for its first half-decade and led the development of CE’s low-cost, low-energy, air-liquid contactor technology. He led early efforts to develop electrochemical recovery pathways that may now supplant CE’s original calcium cycle technology. Committed to open sources of analyzable information, his 2018 paper was the first to provide engineering and economic details of a DAC system under commercial development and is the Journal’s most downloaded paper. DAC opens a pathway to synthetic solar fuels, or “Carbon Neutral Hydrocarbons” as Keith called them in an influential 2008 article. The development of practical DAC is a pivotal technical enabler of net-zero carbon emissions and with large scale industrial engagement and scaling is a technical achievement of historical proportions.  

CE is now one of two companies leading world-wide efforts to commercialize DAC, now widely accepted internationally as a critical component of limiting atmospheric CO₂ levels. As of fall 2023, CE has over 160 employees and 100 active patent applications. CE is being purchased by Oxy at a valuation of 1.6 $bn US in the first major DAC venture transaction. The 500,000 ton-CO₂/year plant now being constructed is over 10 times larger than the largest plant being constructed by CE’s competitors and is, by far, the largest commitment of capital to DAC globally; and Oxy has announced plans to build up to 30 million tons per year of carbon removal for pure storage (not oil recovery) all with CE’s technology. 

Keith has played a transformative role in the study of solar geoengineering providing the first definitive technical work to address several important questions. Thus, he conducted the first quantitative analysis of the regional inequality of solar geoengineering impacts, and provided the first systematic demonstration that feedback-control could manage uncertainty in the climate response to solar geoengineering. Keith’s early work showing that regional inequality of climate impacts resulting from solar geoengineering was overstated, has been confirmed with state-of-the-art models and by the geoengineering model inter-comparison study (GeoMIP).  

Keith has developed technical innovations that may improve the standard idea of injecting SO₂. These include use of accumulation-mode aerosols to limit the amount of sulphur needed for a given level of radiative forcing, now confirmed in a formal multi-model intercomparison, and development of a route for making SO₃ in situ. Keith has also proposed reactive solid aerosols such as CaCO₃ that simultaneously provide radiative forcing and help restore the ozone layer; plus proposed methods to alter the spectral distribution of radiative forcing to simultaneously restore temperature and precipitation. Keith has also invented a novel class of self-levitated particles, now demonstrated by Bargatin a decade later. Keith’s development of new methods for effecting stratospheric aerosols is transformative, as prior research was dominated by analysis of volcanic stratospheric sulphur injection which, though an important analog, provides a limited basis to assess impact of deliberate artificial aerosol injection.  

Keith argues that careful application of existing models is necessary, but insufficient, to improve understanding of the risk and efficacy of solar geoengineering, and that some uncertainties can only be reduced experimentally. Keith’s group has led the development of plans for an in situ stratospheric experiment, the Stratospheric Controlled Perturbation Experiment (SCoPEx).  

Keith has advanced the quantitative social science of solar geoengineering by incorporating an empirical parametrization of geoengineering’s efficacy and risks into an integrated assessment model. His social science work includes the first large-scale survey of public perception, a novel two-threshold system for governance that combines a deployment moratorium with a pathway for regulating small-scale research and a taxonomy of risks. 

Beyond his own technical work, Keith has been a leader in building the community working on solar geoengineering and its governance. Keith, for example, recruited many leading researchers (e.g. MacMartin and Parson) into the field, two of his solar geoengineering PhD advisees now have tenured positions (Ricke and Moreno-Cruz). Keith led the creation of an early and influential set of summer schools starting in Heidelberg in 2010, led the application for a Gordon Research Conference (GRC) on solar geoengineering, and led Harvard’s Solar Geoengineering Research Program. Finally, Keith was the first researcher to write a book on solar geoengineering for non-specialists.  

In 2004, Keith led a NCAR-Princeton-GFDL team in the first climate model study of the climatic impacts of large-scale wind power. Wind turbine parameterizations developed by Keith’s team are now part of standard modelling tools such as NCAR’s WRF. His most recent work provides the first large-scale observational estimates of areal wind power density, which both confirm theoretical estimates and show that common wind-energy resource estimates are incorrect. Keith’s recent work also provides the first quantitative comparison between warming at windfarms observed using satellite data and model-based estimates of such warming. The agreement between observations and models suggests that wind power’s climate impacts, while small, should not be neglected.  

David Keith’s technical prowess and thought leadership is evident in his pioneering work on BECCS and DAC, now widely seen as the two most prominent large-scale carbon removal technologies. His work with Carbon Engineering is transformative and world leading. His early work on wind power’s climate impacts anticipated key issues now validated by observations. Finally, Keith is arguably the single most influential scholar working on solar geoengineering today. David Keith has produced a published body of highly acclaimed technical literature, policy papers, and actual technological solutions that is unparalleled in importance and application at the intersection of climate science, energy technology, and public policy. The rising importance of solar geoengineering and carbon removal are marked by their recognition by the Global Overshoot Commission, an effort that Keith helped launch, and which is, by far, the highest-level political body to examine these topics.