
David DenkenbergerUniversity of Canterbury | UC · Department of Mechanical Engineering
David Denkenberger
PhD, Building Systems Program
About
129
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4,308
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Introduction
Additional affiliations
August 2005 - August 2010
Position
- Global Catastrophic Risks
Position
- Heat exchangers
Education
August 2005 - July 2010
August 2002 - July 2005
August 1997 - May 2002
Publications
Publications (129)
Following global catastrophic infrastructure loss (GCIL), traditional electricity networks would be unavailable, necessitating alternative solutions to sustain critical services, such as decentralized electricity generation from wood gas. This study explores the feasibility of using modified light duty vehicles to self-sustain electricity generatio...
Mass labor shortages in a catastrophic pandemic could pose a significant risk to the continuity of vital sectors, severely restricting the ability of countries to provide food, water, and other basic needs to their populations. In this study, we investigate vital sector preparedness by using Monte Carlo simulations to estimate the availability of a...
Nuclear war poses catastrophic risks not only through its immediate effects and potential nuclear winter, but also through the disruption of industrial production on which modern civilization depends. In this study we estimate the reduction in global industrial output following a US-Russia nuclear war, as well as a more limited India-Pakistan excha...
To combat global warming, energy systems are transitioning to generation from renewable sources, such as wind and solar, which are sensitive to climate conditions. While their output is expected to be little affected by global warming, wind, and solar electricity generation could be affected by more drastic climatic changes, such as abrupt sunlight...
In the eventuality of a major volcanic eruption or nuclear war, particles would accumulate in the stratosphere and reduce sunlight, potentially altering climate conditions severely and decreasing crop yields. Mass starvation could be prevented with the help of resilient foods, such as transforming natural gas into protein, wood into sugar, and relo...
After a major nuclear war, volcanic eruption or asteroid or comet impact that causes an abrupt sunlight reduction scenario, agricultural yields would plummet. We analyzed a nuclear winter scenario involving the injection of 150 Tg of soot in the stratosphere using a linear optimization model with and without global food trade. We investigated the e...
Global catastrophic threats to the food system upon which human society depends are numerous. A nuclear war or volcanic eruption could collapse agricultural yields by inhibiting crop growth. Nuclear electromagnetic pulses or extreme pandemics could disrupt industry and mass-scale food supply by unprecedented levels. Global food storage is limited....
This anthology brings together a diversity of key texts in the emerging field of Existential Risk Studies. It serves to complement the previous volume The Era of Global Risk: An Introduction to Existential Risk Studies by providing open access to original research and insights in this rapidly evolving field. At its heart, this book highlights the o...
An event such as a large volcanic eruption, nuclear winter or asteroid/comet impact has the potential to seriously reduce incoming sunlight, impacting both the global climate and conventional crop yields. This could have catastrophic impacts on human nutrition, unless the food system can adapt. One possible answer is seaweed, where growth is projec...
Global catastrophic infrastructure loss (GCIL) would disrupt energy supply networks, prohibiting heating in houses reliant on electricity or piped natural gas. Cold climates would require alternative heating methods, as space heating is critical to survival. This work assesses the viability of converting household appliances to wood-burning stoves,...
The food supply chain's heavy reliance on electricity poses significant vulnerabilities in the event of prolonged and widespread power disruptions. This study introduces a system-dynamics model that integrates five critical infrastructures—electric grid, liquid fossil fuels, Internet, transportation, and human workforce—to evaluate the resilience o...
The food supply chain’s heavy reliance on electricity poses significant vulnerabilities in the event of prolonged and widespread power disruptions. This study introduces a system-dynamics model that integrates five critical infrastructures—electric grid, liquid fossil fuels, Internet, transportation, and human workforce—to evaluate the resilience o...
To combat global warming, energy systems are transitioning to generation from renewable sources, such as wind and solar, which are sensitive to climate conditions. While their output is expected to be little affected by global warming, wind and solar electricity generation could be affected by more drastic climatic changes, such as abrupt sunlight...
Earthworms are a resilient group of species thriving in varied habitats through feeding on decaying organic matter, and are therefore predicted to survive an abrupt sunlight reduction scenario, e.g., a nuclear winter. In this study, the feasibility and cost-effectiveness of foraging earthworms to reduce global famine in such a scenario with or with...
Una guerra nuclear, una erupción volcánica, o el impacto de un asteroide o cometa pueden reducir la cantidad de luz solar que alcanza la superficie terrestre, de la que depende el sistema alimentario global. Los rendimientos agrícolas caerían debido a la disminución de temperaturas y precipitaciones, lo que se define como un Escenario de Reducción...
The global food trade system is resilient to minor disruptions but vulnerable to major ones. Major shocks can arise from global catastrophic risks, such as abrupt sunlight reduction scenarios (e.g., nuclear war) or global catastrophic infrastructure loss (e.g., due to severe geomagnetic storms or a global pandemic). We use a network model to examin...
It is crucial to increase the resilience of the global food production and distribution systems against the growing concerns relating to factors that could cause global catastrophic infrastructure losses, such as nuclear war or a worldwide pandemic. Currently, such an event would result in the global loss of industry, including the ability to drill...
A variety of events such as high-altitude electromagnetic pulses, extreme solar storms, and coordinated cyber attacks could result in a catastrophic loss of infrastructure on a continental or global scale. The lengthy repair of critical infrastructure creates a need for alternative fuels such as wood gas. Wood gas is produced by heating wood in a l...
After a major nuclear war, volcanic eruption or asteroid or comet impact that causes an abrupt sunlight reduction scenario, agricultural yields would plummet. We analyzed a nuclear winter scenario involving the injection of 150 Tg of soot in the stratosphere using a linear optimization model with and without global food trade. We investigated the e...
Earthworms are a resilient group of species that thrive in a variety of habitats through feeding on decaying organic matter, and are therefore predicted to survive an abrupt sunlight reduction scenario, such as a nuclear winter. In this study, the feasibility and cost-effectiveness of foraging earthworms to reduce global famine following a reductio...
Background: The growing human population requires consistent access to nutritious and sustainable food to thrive. To this end, non-agricultural, closed-environment food production methods can complement agriculture while increasing the resilience of the global food system to climate shocks and other risks such as biological, environmental, and trad...
An abrupt sunlight-reducing scenario (ASRS) is an example of an event nations should be prepared for, as it can trigger several interconnected catastrophes with long-lasting effects. A possible scenario is a nuclear winter triggered by a nuclear war, in which the burning of cities releases soot that accumulates in the stratosphere, reducing the sun...
Abrupt sunlight reduction scenarios such as a nuclear winter caused by the burning of cities in a nuclear war, an asteroid/comet impact or an eruption of a large volcano inject large amounts of particles in the atmosphere, which limit sunlight. This could decimate agriculture as it is practiced today. We therefore need resilient food sources for su...
Modern civilization relies on a complex, globally interconnected industrial agriculture system to produce food. Its unprecedented yields hinge on external inputs like machinery, fertilizers, and pesticides, rendering it vulnerable to disruptions in production and international trade. Such a disruption could be caused by large-scale damage to the el...
Background: Potential resilient foods which help reduce hunger are converting the ~998 million tons of agricultural residue generated each year into human edible food. Although it is possible to extract Leaf Protein Concentrate (LPC) from agricultural residues, it is not widely practiced because both toxicity and yields of the protein concentrates...
Modern civilization relies on a complex, globally interconnected industrial agriculture system to produce food. Its unprecedented yields hinge on external inputs like machinery, fertilizers, and pesticides, rendering it vulnerable to disruptions in production and international trade. Such a disruption could be caused by large scale damage to the el...
In the event of an abrupt sunlight reduction scenario, there is a time window that occurs between when food stores would likely run out for many countries (~6 months or less) and ~1 year when resilient foods are scaled up. A promising temporary resilient food is leaf protein concentrate (LPC). Although it is possible to extract LPC from tree biomas...
African countries have been severely affected by food insecurity such that 54% of the population (73 million people) are acutely food insecure, in crisis or worse. Recent work has found technical potential for feeding humanity during global catastrophes using leaves as stop-gap alternative foods. To determine the potential for adopting agricultural...
In order to prepare in case of an Abrupt Sunlight Reduction Scenario (ASRS), it is necessary to understand the threats and vulnerabilities of the agri-food system and the current ecosystem of risk management in Argentina.
Through research, modeling, and interviews, the RCG team, in collaboration with ALLFED, has produced a report titled "Food Secu...
Abrupt sunlight reduction scenarios such as a nuclear winter caused by the burning of cities in a nuclear war, an asteroid/comet impact or an eruption of a large volcano inject large amounts of particles in the atmosphere, which limit sunlight. This could decimate agriculture as it is practiced today. We therefore need resilient food sources for su...
In the event of an abrupt sunlight reduction scenario there is a time window that occurs between when food stores would likely run out for many countries (~6 months or less) and ~1 year when resilient foods are scaled up. A promising temporary resilient food is leaf protein concentrate (LPC). Although it is possible to extract LPC from tree biomass...
The current food method in space is launching prepackaged food which is costly and unsustainable. Alternatives include growing crops and microalgae single cell protein (SCP) using artificial light photosynthesis, which are energy inefficient. Prepackaged food and microalgae food were compared to microbial electrosynthesis of acetic acid (MES-AA). S...
Global catastrophes such as a supervolcanic eruption, asteroid impact, or nuclear winter could cause global agricultural collapse due to reduced sunlight reaching the Earth’s surface. The human civilization’s food production system is unprepared to respond to such events, but methane single cell protein (SCP) could be a key part of the solution. Cu...
In this paper, the experimental performance of a “V” type solar still coupled with a hybrid solar concentrator (HSC) and Heat exchanger (HX) are presented. A high yield, inexpensive solar desalination system is constructed almost entirely from salvaged components. Even though it requires a mild maintenance, the necessary skills of operation are rud...
Solar energy-driven evaporation-based freshwater production is one of the sustainable ways to purify contaminated/salty water. Recent advances in solar absorbers’ assemblies, design modifications, and integrations with heating sources improved the rate of freshwater productivity. However, the type of feed water affects the evaporation rate in a sol...
Global agricultural catastrophes, which include nuclear winter and abrupt climate change, could have long-term consequences on humanity such as the collapse and nonrecovery of civilization. Using Monte Carlo (probabilistic) models, we analyze the long-term cost-effectiveness of resilient foods (alternative foods) - roughly those independent of sunl...
Abrupt sunlight reduction scenarios (ASRS) following catastrophic events, such as a nuclear war, a large volcanic eruption or an asteroid strike, could prompt global agricultural collapse. There are low-cost foods that could be made available in an ASRS: resilient foods. Nutritionally adequate combinations of these resilient foods are investigated...
Solar desalination is one of the green energy processes to treat saline water and wastewater. Solar evaporation systems, formally solar stills, have been widely used to evaporate water to purify it. However, the evaporation rate in solar stills is typically low due to incoming energy used to heat the entire bulk water. In order to minimize the bulk...
Extreme solar storms, high-altitude electromagnetic pulses, and coordinated cyber attacks could disrupt regional/global electricity. Since electricity basically drives industry, industrial civilization could collapse without it. This could cause anthropological civilization (cities) to collapse, from which humanity might not recover, having long-te...
Recyclable food technologies are essential for long-term manned space missions. This research compares customary and alternative space foods to non-biological synthesis (NBS) systems using recycled CO2. Using electrochemical conversion of CO2 as a starting point, different carbohydrate synthesis routes are reviewed. Sugars and glycerol are consider...
Producing sugar from lignocellulosic biomass is a promising resilient food solution to counter the near-total global failure of food production due to the agricultural collapse that would likely follow an abrupt sunlight reduction catastrophe such as a nuclear winter, a supervolcanic eruption, or a large asteroid or comet impact.
This study examine...
Human civilization’s food production system is unprepared for global catastrophic risks (GCRs). catastrophes capable of abruptly transforming global climate such as supervolcanic eruption, asteroid/comet impact or nuclear winter, which could completely collapse the agricultural system. Responding by producing resilient foods requiring little to no...
A finite difference model of a heat exchanger (HX) considered maldistribution, axial conduction, heat leak, and the edge effect, all of which are needed to model a high effectiveness HX. An HX prototype was developed, and channel height data were obtained using a computerized tomography (CT) scan from previous work along with experimental results....
Due to the ready availability of tree leaves in many geographies, the alternative food of leaf concentrate currently has the potential to alleviate hunger in over 800 million people. It is therefore potentially highly impactful to determine the edibility of leaf concentrates, which are in the same regions as the world's most undernourished populati...
Global agricultural catastrophes, which include nuclear winter and abrupt climate change, could have long-term consequences on humanity such as the collapse and nonrecovery of civilization. Using Monte Carlo (probabilistic) models, we analyze the long-term cost-effectiveness of resilient foods (alternative foods) - roughly those independent of sunl...
Modern civilisation depends on many different sectors functioning well and concurrently to run smoothly. This includes the energy sector, the transport sector, and the information technology sector. As such, the consequences can be catastrophic if these sectors were to fail due to some form of power outage or disaster. Possible causes include a hig...
A sun-blocking global catastrophic risk (GCR) such as a nuclear winter could completely collapse the agricultural system. Producing alternative foods through methods requiring little to no sunlight has been identified as a cost-effective response to these types of GCRs. This preliminary techno-economic assessment evaluates the potential of acetic a...
To safeguard against meat supply shortages during pandemics or other catastrophes, this study analyzed the potential to provide the average household’s entire protein consumption using either soybean production or distributed meat production at the household level in the U.S. with: (1) pasture-fed rabbits, (2) pellet and hay-fed rabbits, or (3) pel...
To safeguard against meat supply shortages during pandemics or other catastrophes, this study analyzed the potential to provide the average household’s entire protein consumption using either soybean production or distributed meat production at the household level in the U.S. with: 1) pasture-fed rabbits, 2) pellet and hay-fed rabbits, or 3) pellet...
The cost of launching food into space is very high. An alternative is to make food during missions using methods such as artificial light photosynthesis, greenhouse, nonbiological synthesis of food, electric bacteria, and hydrogen oxidizing bacteria (HOB). This study compares prepackaged food, artificial light microalgae, and HOB. The dominant fact...
Solar energy is a sustainable energy source with many applications. Desalination of ocean/wastewater with solar energy has attracted considerable interest worldwide. However, solar desalination is a slow process with poor efficiency. In order to improve performance, highly efficient photothermal absorbers have been introduced. The main objective of...
A catastrophe such as supervolcanic eruption, asteroid impact or nuclear winter could reduce global food production by 10% or more. Human civilization’s food production system is unprepared to respond to such an event, and current preparedness centers around food stockpiles, an excessively expensive solution given that a global catastrophic risk (G...
Solar energy is one of the most powerful sources for many sustainable applications. Recently, efficient water distillation has attracted significant attention. The fresh water productivity depends on how efficiently the system harvests the incoming solar energy and converts it into useful heat. In the present work, nano-coated absorber plates (NCAP...
The present investigation elucidates the effect of different absorbing materials in the single slope solar still (SSSS). The said absorbing materials are Polyvinyl Alcohol (PVA) sponges, pebbles, spherical clay balls (SCB) and CuO nano-coated absorber plates (CuO-NCAP). The experiment has been conducted in the following ways: (i) SSSS with PVA spon...
Human civilization's food production system is currently unprepared for catastrophes that would reduce global food production by 10% or more, such as nuclear winter, supervolcanic eruptions or asteroid impacts. Alternative foods that do not require much or any sunlight have been proposed as a more cost-effective solution than increasing food stockp...
Channels not receiving the same amount of flow (flow maldistribution) is an important effectiveness loss for high effectiveness heat exchangers. This paper develops a finite difference model of a counter flow heat exchanger. It reproduced the simple NTU result for two channels exactly. For more than two channels, there is an edge effect, and the mo...
A classification of the global catastrophic risks of AI is presented, along with a comprehensive list of previously identified risks. This classification allows the identification of several new risks. We show that at each level of AI’s intelligence power, separate types of possible catastrophes dominate. Our classification demonstrates that the fi...