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Charles Hall

SUNY: College of Environmental Science and Forestry, Environmental and Forest Biology, Faculty Member

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I received my Ph.D. in Systems Ecology under Howard Odum at UNC in 1970. I have been professor at Cornell University, Univ. Montana and SUNY College of Environmental Science and Forestry. I am now very active as Professor Emeritus in Western Montana, and author or editor of 14 books and some 300 scholarly articles. I have been awarded the Hubbert-Simmons Prize for Energy Education by ASPO, and the Lifetime Achievement Award from the International Society of BioPhysical Economics. I am probably best known for his development of the concept of EROI, or energy return on investment, and have contributed a lot to the development of BioPhysical Economics.

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Noel B. Salazar

KU Leuven

Queen's University Belfast

University of Central Florida

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University of North Carolina at Greensboro

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University of Copenhagen

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Université du Québec à Rimouski

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Papers by Charles Hall

Energía, economía y cambio climático: ecuación insoluble

... nsayos Energía, economía y cambio climático: ecuación insoluble 77 puede hablar siquiera de “... more

Erratum to “Forecasting the limits to the availability and diversity of global conventional oil supply” [Energy (2004) 1673–1696]

Energy, Jul 1, 2005

John L. Hallock Jr.*, Pradeep J. Tharakan, Charles A.S. Hall, Michael Jefferson, Wei Wu Departmen... more John L. Hallock Jr.*, Pradeep J. Tharakan, Charles A.S. Hall, Michael Jefferson, Wei Wu Department of Environmental and Forest Biology, Graduate Program in Environmental Sciences, State University of New York, College of Environmental Science and Forestry (SUNY ESF), 320 Illick Hall, 1 Forestry Drive, Syracuse, NY 13210, USA Department of Forest and Natural Resources Management, SUNY ESF, 342 Illick Hall, 1 Forestry Drive, Syracuse, NY 13210, USA Maxwell School of Citizenship and Public Affairs, Syracuse University, 200 Eggers Hall, Syracuse, NY 13244, USA Global Energy and Environmental Consultants, The Old Stables, Felmersham, Bedfordshire, MK43 7HJ, UK

A Hero for Our Time

BioScience

Further Review of Jarvis and King by C. Hall

Universal rules of life: metabolic rates, biological times and the equal fitness paradigm

Here we develop and extend the equal fitness paradigm (EFP) of (Brown et al. 2018) as an importan... more Here we develop and extend the equal fitness paradigm (EFP) of (Brown et al. 2018) as an important step in developing and testing a synthetic theory of ecology and evolution based on energy and metabolism. The EFP states that all species are equally fit at steady state, because all species allocate the same quantity of energy, ∼22.4 kJ/g/generation to production of offspring. On the one hand, the EFP may seem tautological, because equal fitness across species is necessary for the origin and persistence of biodiversity. On the other hand, the EFP reflects universal laws of life: how biological metabolism – the uptake, transformation and allocation of energy – links ecological and evolutionary patterns and processes across levels of organization: from the structure and function of individual organisms, to the life history and dynamics of populations, to the coevolution of species in ecosystems. The physics and biology of metabolism have simultaneously facilitated the origin and mainte...

Equal fitness paradigm explained by a trade-off between generation time and energy production rate

Nature ecology & evolution, Jan 8, 2018

Most plant, animal and microbial species of widely varying body size and lifestyle are nearly equ... more Most plant, animal and microbial species of widely varying body size and lifestyle are nearly equally fit as evidenced by their coexistence and persistence through millions of years. All organisms compete for a limited supply of organic chemical energy, derived mostly from photosynthesis, to invest in the two components of fitness: survival and production. All organisms are mortal because molecular and cellular damage accumulates over the lifetime; life persists only because parents produce offspring. We call this the equal fitness paradigm. The equal fitness paradigm occurs because: (1) there is a trade-off between generation time and productive power, which have equal-but-opposite scalings with body size and temperature; smaller and warmer organisms have shorter lifespans but produce biomass at higher rates than larger and colder organisms; (2) the energy content of biomass is essentially constant, ~22.4 kJ g-1 dry body weight; and (3) the fraction of biomass production incorporat...

EROI of Global Energy Resources: Status, Trends and Social Implications

All forms of economic production and exchange involve the transformation of materials, which in t... more All forms of economic production and exchange involve the transformation of materials, which in turn requires energy. Until recently cheap and seemingly limitless fossil energy has allowed many to ignore the important contributions from the biophysical world to the economic process and potential limits to growth. The report that follows, commissioned by the United Kingdom’s Department for International Development (DFID) and developed by the State University of New York College of Environmental Science and Forestry (SUNY-ESF) and Next Generation Energy Initiative (NGEI), examines the energy used by modern economies over time. This work centers on assessing the relation of energy costs of modern day society and its connection to the quality of human life. A focus of this report is energy return on investment (EROI) and some important characteristics of our major energy sources over time. We find the EROI for each major fossil fuel resource (except coal) has declined substantially ove...

Energy Return on Investment (EROI), Liquid Fuel Production, and Consequences for Wildlife

Peak Oil, Economic Growth, and Wildlife Conservation, 2014

Current liquid-fuel supplies in the United States are derived primarily from relatively inexpensi... more Current liquid-fuel supplies in the United States are derived primarily from relatively inexpensive fossil fuels. The low cost and widespread availability of petroleum has, over the last 150 years, facilitated enormous growth in the U.S. and global economies, in their respective human populations and resource consumption, and in their attendant impacts on ecosystems worldwide. Concerns are growing, however, as to whether alternative fuel sources can fill the void left by future declines in the supply of this inexpensive and energy-rich resource, concepts expressed in phrases such as “Peak Oil,” “end of cheap oil,” and “second half of the age of oil.”

Increased biotic metabolism of the biosphere inferred from observed data and models

Science in China Series B: Chemistry, 2000

A 35 year record of production and respiration in the Northern Hemisphere bas been derived from m... more A 35 year record of production and respiration in the Northern Hemisphere bas been derived from monthly records of atmospheric concentration, fossil fuel combustion, and oceanic absorption of carbon dioxide using a method developed by Hall et al. The original conclusion of Hall et al. that there was no significant change in biotic metabolism, is confirmed by measuring both production and respiration from 1958 to 1972. But the analysis of the subsequent record shows that both production and respiration have been enhanced since the early 1970s by some large scale global change, probably of human origin. Our results also show that high-latitude regions in the Northern Hemisphere are changing more than regions further south. Nevertheless, the ratio of production to respiration (P/R) remains unchanged during the time period examined. Thus, no argument can be made for net carbon storage of or release from the biosphere from this analysis, although the turnover rate of the biosphere appears to be enhanced.

Energy Returns on Ethanol Production

Science, 2006

Energy and the U.S. Economy: A Biophysical Perspective

Science, 1984

Spatial and seasonal dynamics of surface soil carbon in the Luquillo Experimental Forest, Puerto Rico

Ecological Modelling, 2002

We developed a spatially-explicit version of the CENTURY soil model to characterize the storage a... more We developed a spatially-explicit version of the CENTURY soil model to characterize the storage and flux of soil organic carbon (SOC, 0-30 cm depth) in the Luquillo Experimental Forest (LEF), Puerto Rico as a function of climate, vegetation, and soils. The model was driven by monthly estimates of average air temperature, precipitation, and potential evapotranspiration (PET), which in turn were simulated as a function of elevation, slope, and aspect using a spatially-explicit and validated model (TOPOCLIM) of solar insolation/microclimate in mountainous areas. We simulated forest gross primary productivity (GPP) and distribution of above-and below-ground biomass production using a forest productivity model (TOPOPROD). Output from TOPOCLIM and TOPOPROD models was used to run the CENTURY soil model for 1200 months under current climate conditions and in response to potential global warming. We validated our version of CENTURY soil model using 69 soil samples taken throughout the LEF. Simulated SOC storage agrees reasonably well with the observed storage (R 2 = 0.71). The simulated SOC storage in the top 30 cm within the LEF is highly variable, ranging from approximately 20-230 Mg/ha. The rates of decomposition were especially sensitive to changes in elevation. Carbon release rates due to decomposition were close to carbon assimilation rates and ranged from 0.6-0.96 Mg/ha per year at high elevations to 1.2-1.68 Mg/ha per year at lower elevations. Our simulations indicated that differences in elevation affect decomposition and SOC content primarily by changing microclimate. Finally, we found that a projected warming of 2.0°C is likely to result in losses of SOC in the lower and higher elevation, but increased storage in the middle elevations in the LEF.

Nitrogen and phosphorus budgets for a tropical watershed impacted by agricultural land use: Guayas, Ecuador

Biogeochemistry, 2006

Large-scale changes in land use are occurring in many tropical regions, with significant impacts ... more Large-scale changes in land use are occurring in many tropical regions, with significant impacts on nitrogen and phosphorus biogeochemistry. In this study we examine the relationships between land use, anthropogenic nutrient inputs, and riverine nutrient exports in a major agricultural watershed of the Pacific coast of South America, the Guayas River basin of Ecuador. We present comprehensive nutrient budgets for nitrogen (N) and phosphorous (P) for the Guayas River basin and 10 sub-watersheds. We quantify the four major anthropogenic nutrient fluxes into and out of the region: N and P fertilizer application, N fixation by leguminous crops, net import/export of N and P in agricultural products (food and feed), and atmospheric deposition. We also estimate inputs of N from biological N fixation in forests and of P from weathering sources in soils and bedrock. The sum of these sources represents net inputs of N and P to each watershed region. Overall, synthetic fertilizers are the largest input to the Guayas Basin for N (53%) and P (57%), and the largest outputs are N and P in crops. Losses of N and P in river export account for 14-38% of total N and P inputs, and there is significant accumulation of N and P, or unmeasured forms of N and P export, in most of the sub-basins. Nutrient balances are indicative of the sustainability of land use practices in a region, where a negative balance of N or P indicates nutrient depletion and subsequent loss of soil fertility, yield, and economic viability. Although the nutrient balance of the entire Guayas Basin is positive, there are negative or near zero balances in two sub-watersheds with extensive banana, coffee and permanent crops. In these basins, degradation of soil quality may be occurring due to these net nutrient losses. Our data show that nutrients are leaving the basin primarily as export crops, with riverine losses of nutrients smaller than crop exports. Nonetheless, there is a direct relationship between nutrient inputs and river outputs, suggesting that agricultural management practices in the basin may have direct impacts on N and P delivery to the highly productive Guayas estuary.

Modeling the spatial pattern of land-use change with GEOMOD2: application and validation for Costa Rica

Agriculture, Ecosystems & Environment, 2001

The objective of this paper is to simulate the location of land-use change, specifically forest d... more The objective of this paper is to simulate the location of land-use change, specifically forest disturbance, in Costa Rica over several decades. This paper presents a GIS-based model, GEOMOD2, which quantifies factors associated with land-use, and simulates the spatial pattern of land-use forward and backward in time. GEOMOD2 reads rasterized maps of land-use and other biogeophysical attributes to determine empirically the attributes of land that humans tend to use. Then GEOMOD2 uses the patterns of those biogeophysical attributes to simulate the spatial pattern of land-use change. GEOMOD2 can select locations for land-use change according to any of three decision rules based on (1) nearest neighbors, (2) stratification by political sub-region, and/or (3) the pattern of biogeophysical attributes. GEOMOD2 simulates the progressive loss of closed-canopy forest in Costa Rica for 1940, 1961 and 1983, which are the years for which maps of land-use are available. Also, GEOMOD2 extrapolates the pattern of land-use to the year 2010. When GEOMOD2 extrapolates land-use change over several decades, it is able to classify correctly between 84 and 86% of the grid cells, for two categories: forest versus non-forest. Over various simulation runs, Kappa ranges from 0.34 to 0.53. The model's ability to predict the location of disturbance is best when the model is driven by the location of biogeophysical characteristics, most importantly lifezones.

Diminished resources, energy scarcity and climate change: unsustainable future development

WIT Transactions on State of the Art in Science and Engineering, 2013

No substitute for petroleum has yet been developed that can deliver energy at the scale, quality,... more No substitute for petroleum has yet been developed that can deliver energy at the scale, quality, or within the time frame required to replace decreasing availability. Most alternative energy sources provide much less energy than petroleum and do not have its high energy density. The interplay among shrinking resources, energy scarcity, economic crisis, and climate change will be diffi cult to solve. The biggest challenge is to articulate different aspects of an equation of energy, economics, and climate change that strive for a sustainable solution, at least within the current societal context. This is not simply a problem of physical dimensions but involves deeper social, economic, and policy aspects. The continued use of fossil fuels leads to increasing concentrations of greenhouse gases in the atmosphere that leads to more climate disasters. An increasing energy scarcity will limit the energy intensive global economy as it currently operates. It is unlikely that economics solely can effectively address these problems since most economic models are based on incomplete information and largely ignore the biophysical basis of the biosphere. The economics of the future should be taught from a biophysical perspective that respects the limits to the natural world, rather than the unending growth of neoclassical market theories.

Current concepts of eco-economy and biophysical economics: towards sustainability of the Gulf of Mexico coastal zone

WIT Transactions on State of the Art in Science and Engineering, 2013

Sustainable development of the coastal zone is a complex topic involving social, economic, bio-ph... more Sustainable development of the coastal zone is a complex topic involving social, economic, bio-physical, ecological, and legal components. Nevertheless such complex topics must be explained in a relatively simple way to avoid incorrect analysis in studies by students and decisions by policymakers. In general, the usual procedure is to set up social versus economic versus market pressures, which are always on the table, during discussions of coastal zone management to reduce impacts to a level that does not induce any further environmental catastrophes. In fact we need a more integrated approach where each component is fairly represented. Our study case is the Gulf of Mexico where coastal resources in both Mexico and the United States are Gulf-dependent; i.e. just four economic sectors, oil and natural gas, fi sheries, port-shipping, and tourism are values at over 120 billion U.S. dollars annually. This means 16% of Gross Domestic Product by the USA and 13% of GDP by Mexico. This productive value is not static but is constantly changing due to several factors, most directly the market value of the resources themselves. While human-made capital is increasingly abundant (guided by market signals), it is the natural products and ecosystem services from the Gulf that are increasingly scarce, and natural capital, not human-derived capital, that is fast becoming the limiting factor.

Article Energy Return on Investment for Norwegian Oil and Gas

Norwegian oil and gas fields are relatively new and of high quality, which has led, during recent... more Norwegian oil and gas fields are relatively new and of high quality, which has led, during recent decades, to very high profitability both financially and in terms of energy production. One useful measure for profitability is Energy Return on Investment, EROI. Our analysis shows that EROI for Norwegian petroleum production ranged from 44:1 in the early 1990s to a maximum of 59:1 in 1996, to about 40:1 in the latter half of the last decade. To compare globally, only very few, if any, resources show such favorable EROI values as those found in the Norwegian oil and gas sector. However, the declining trend in recent years is most likely due to ageing of the fields whereas varying drilling intensity might have a smaller impact on the net energy gain of the fields. We expect the EROI of Norwegian oil and gas production to deteriorate further as the fields become older. More energy-intensive production techniques will gain in importance.

Energy Return on Investment

Energy and the Wealth of Nations, 2011

Article Time Series EROI for Canadian Oil and Gas

Modern economies are dependent on fossil energy, yet as conventional resources are depleted, an i... more Modern economies are dependent on fossil energy, yet as conventional resources are depleted, an increasing fraction of that energy is coming from unconventional resources such as tar sands. These resources usually require more energy for extraction and upgrading, leaving a smaller fraction available to society, and at a higher cost. Here we present a calculation of the energy return on investment (EROI) for all Canadian oil and gas (including tar sands) over the period 1990-2008, and also for tar sands alone (1994-2008). We used energy production and energy use data from Statistics Canada's Material and Energy Flow Accounts (MEFA). We were able to quantify both direct and indirect energy use, the latter from Statistics Canada's energy input-output model. We found that since the mid-1990s, total energy used (invested) in the Canadian oil and gas sector increased about 63%, while the energy production (return) increased only 18%, resulting in a decrease in total EROI from roughly 16:1 to 11:1. We also found (although with less certainty) that the EROI for tar sands alone has fluctuated around 4:1 since 1994, with only a slight increasing trend. Finally, we analyzed underlying factors possibly influencing these trends.

The 50th Anniversary of The Limits to Growth: Does It Have Relevance for Today’s Energy Issues?

Energies

The Limits to Growth was a remarkable, and remarkably influential, model, book and concept publis... more The Limits to Growth was a remarkable, and remarkably influential, model, book and concept published 50 years ago this year. Its importance is that it used, for essentially the first time, a quantitative systems approach and a computer model to question the dominant paradigm for most of society: growth. Initially, many events, and especially the oil crisis of the 1970s, seemed to support the idea that the limits were close. Many economists argued quite the opposite, and the later relaxation of the oil crisis (and decline in gasoline prices) seemed to support the economists’ position. Many argued that the model had failed, but a careful examination of model behavior vs. global and many national data sets assessed by a number of researchers suggests that the model’s predictions (even if they had not been meant for such a specific task) were still remarkably accurate to date. While the massive changes predicted by the model have not yet come to pass globally, they are clearly occurring...

Energía, economía y cambio climático: ecuación insoluble

... nsayos Energía, economía y cambio climático: ecuación insoluble 77 puede hablar siquiera de “... more

Erratum to “Forecasting the limits to the availability and diversity of global conventional oil supply” [Energy (2004) 1673–1696]

Energy, Jul 1, 2005

John L. Hallock Jr.*, Pradeep J. Tharakan, Charles A.S. Hall, Michael Jefferson, Wei Wu Departmen... more John L. Hallock Jr.*, Pradeep J. Tharakan, Charles A.S. Hall, Michael Jefferson, Wei Wu Department of Environmental and Forest Biology, Graduate Program in Environmental Sciences, State University of New York, College of Environmental Science and Forestry (SUNY ESF), 320 Illick Hall, 1 Forestry Drive, Syracuse, NY 13210, USA Department of Forest and Natural Resources Management, SUNY ESF, 342 Illick Hall, 1 Forestry Drive, Syracuse, NY 13210, USA Maxwell School of Citizenship and Public Affairs, Syracuse University, 200 Eggers Hall, Syracuse, NY 13244, USA Global Energy and Environmental Consultants, The Old Stables, Felmersham, Bedfordshire, MK43 7HJ, UK

A Hero for Our Time

BioScience

Further Review of Jarvis and King by C. Hall

Universal rules of life: metabolic rates, biological times and the equal fitness paradigm

Here we develop and extend the equal fitness paradigm (EFP) of (Brown et al. 2018) as an importan... more Here we develop and extend the equal fitness paradigm (EFP) of (Brown et al. 2018) as an important step in developing and testing a synthetic theory of ecology and evolution based on energy and metabolism. The EFP states that all species are equally fit at steady state, because all species allocate the same quantity of energy, ∼22.4 kJ/g/generation to production of offspring. On the one hand, the EFP may seem tautological, because equal fitness across species is necessary for the origin and persistence of biodiversity. On the other hand, the EFP reflects universal laws of life: how biological metabolism – the uptake, transformation and allocation of energy – links ecological and evolutionary patterns and processes across levels of organization: from the structure and function of individual organisms, to the life history and dynamics of populations, to the coevolution of species in ecosystems. The physics and biology of metabolism have simultaneously facilitated the origin and mainte...

Equal fitness paradigm explained by a trade-off between generation time and energy production rate

Nature ecology & evolution, Jan 8, 2018

Most plant, animal and microbial species of widely varying body size and lifestyle are nearly equ... more Most plant, animal and microbial species of widely varying body size and lifestyle are nearly equally fit as evidenced by their coexistence and persistence through millions of years. All organisms compete for a limited supply of organic chemical energy, derived mostly from photosynthesis, to invest in the two components of fitness: survival and production. All organisms are mortal because molecular and cellular damage accumulates over the lifetime; life persists only because parents produce offspring. We call this the equal fitness paradigm. The equal fitness paradigm occurs because: (1) there is a trade-off between generation time and productive power, which have equal-but-opposite scalings with body size and temperature; smaller and warmer organisms have shorter lifespans but produce biomass at higher rates than larger and colder organisms; (2) the energy content of biomass is essentially constant, ~22.4 kJ g-1 dry body weight; and (3) the fraction of biomass production incorporat...

EROI of Global Energy Resources: Status, Trends and Social Implications

All forms of economic production and exchange involve the transformation of materials, which in t... more All forms of economic production and exchange involve the transformation of materials, which in turn requires energy. Until recently cheap and seemingly limitless fossil energy has allowed many to ignore the important contributions from the biophysical world to the economic process and potential limits to growth. The report that follows, commissioned by the United Kingdom’s Department for International Development (DFID) and developed by the State University of New York College of Environmental Science and Forestry (SUNY-ESF) and Next Generation Energy Initiative (NGEI), examines the energy used by modern economies over time. This work centers on assessing the relation of energy costs of modern day society and its connection to the quality of human life. A focus of this report is energy return on investment (EROI) and some important characteristics of our major energy sources over time. We find the EROI for each major fossil fuel resource (except coal) has declined substantially ove...

Energy Return on Investment (EROI), Liquid Fuel Production, and Consequences for Wildlife

Peak Oil, Economic Growth, and Wildlife Conservation, 2014

Current liquid-fuel supplies in the United States are derived primarily from relatively inexpensi... more Current liquid-fuel supplies in the United States are derived primarily from relatively inexpensive fossil fuels. The low cost and widespread availability of petroleum has, over the last 150 years, facilitated enormous growth in the U.S. and global economies, in their respective human populations and resource consumption, and in their attendant impacts on ecosystems worldwide. Concerns are growing, however, as to whether alternative fuel sources can fill the void left by future declines in the supply of this inexpensive and energy-rich resource, concepts expressed in phrases such as “Peak Oil,” “end of cheap oil,” and “second half of the age of oil.”

Increased biotic metabolism of the biosphere inferred from observed data and models

Science in China Series B: Chemistry, 2000

A 35 year record of production and respiration in the Northern Hemisphere bas been derived from m... more A 35 year record of production and respiration in the Northern Hemisphere bas been derived from monthly records of atmospheric concentration, fossil fuel combustion, and oceanic absorption of carbon dioxide using a method developed by Hall et al. The original conclusion of Hall et al. that there was no significant change in biotic metabolism, is confirmed by measuring both production and respiration from 1958 to 1972. But the analysis of the subsequent record shows that both production and respiration have been enhanced since the early 1970s by some large scale global change, probably of human origin. Our results also show that high-latitude regions in the Northern Hemisphere are changing more than regions further south. Nevertheless, the ratio of production to respiration (P/R) remains unchanged during the time period examined. Thus, no argument can be made for net carbon storage of or release from the biosphere from this analysis, although the turnover rate of the biosphere appears to be enhanced.

Energy Returns on Ethanol Production

Science, 2006

Energy and the U.S. Economy: A Biophysical Perspective

Science, 1984

Spatial and seasonal dynamics of surface soil carbon in the Luquillo Experimental Forest, Puerto Rico

Ecological Modelling, 2002

We developed a spatially-explicit version of the CENTURY soil model to characterize the storage a... more We developed a spatially-explicit version of the CENTURY soil model to characterize the storage and flux of soil organic carbon (SOC, 0-30 cm depth) in the Luquillo Experimental Forest (LEF), Puerto Rico as a function of climate, vegetation, and soils. The model was driven by monthly estimates of average air temperature, precipitation, and potential evapotranspiration (PET), which in turn were simulated as a function of elevation, slope, and aspect using a spatially-explicit and validated model (TOPOCLIM) of solar insolation/microclimate in mountainous areas. We simulated forest gross primary productivity (GPP) and distribution of above-and below-ground biomass production using a forest productivity model (TOPOPROD). Output from TOPOCLIM and TOPOPROD models was used to run the CENTURY soil model for 1200 months under current climate conditions and in response to potential global warming. We validated our version of CENTURY soil model using 69 soil samples taken throughout the LEF. Simulated SOC storage agrees reasonably well with the observed storage (R 2 = 0.71). The simulated SOC storage in the top 30 cm within the LEF is highly variable, ranging from approximately 20-230 Mg/ha. The rates of decomposition were especially sensitive to changes in elevation. Carbon release rates due to decomposition were close to carbon assimilation rates and ranged from 0.6-0.96 Mg/ha per year at high elevations to 1.2-1.68 Mg/ha per year at lower elevations. Our simulations indicated that differences in elevation affect decomposition and SOC content primarily by changing microclimate. Finally, we found that a projected warming of 2.0°C is likely to result in losses of SOC in the lower and higher elevation, but increased storage in the middle elevations in the LEF.

Nitrogen and phosphorus budgets for a tropical watershed impacted by agricultural land use: Guayas, Ecuador

Biogeochemistry, 2006

Large-scale changes in land use are occurring in many tropical regions, with significant impacts ... more Large-scale changes in land use are occurring in many tropical regions, with significant impacts on nitrogen and phosphorus biogeochemistry. In this study we examine the relationships between land use, anthropogenic nutrient inputs, and riverine nutrient exports in a major agricultural watershed of the Pacific coast of South America, the Guayas River basin of Ecuador. We present comprehensive nutrient budgets for nitrogen (N) and phosphorous (P) for the Guayas River basin and 10 sub-watersheds. We quantify the four major anthropogenic nutrient fluxes into and out of the region: N and P fertilizer application, N fixation by leguminous crops, net import/export of N and P in agricultural products (food and feed), and atmospheric deposition. We also estimate inputs of N from biological N fixation in forests and of P from weathering sources in soils and bedrock. The sum of these sources represents net inputs of N and P to each watershed region. Overall, synthetic fertilizers are the largest input to the Guayas Basin for N (53%) and P (57%), and the largest outputs are N and P in crops. Losses of N and P in river export account for 14-38% of total N and P inputs, and there is significant accumulation of N and P, or unmeasured forms of N and P export, in most of the sub-basins. Nutrient balances are indicative of the sustainability of land use practices in a region, where a negative balance of N or P indicates nutrient depletion and subsequent loss of soil fertility, yield, and economic viability. Although the nutrient balance of the entire Guayas Basin is positive, there are negative or near zero balances in two sub-watersheds with extensive banana, coffee and permanent crops. In these basins, degradation of soil quality may be occurring due to these net nutrient losses. Our data show that nutrients are leaving the basin primarily as export crops, with riverine losses of nutrients smaller than crop exports. Nonetheless, there is a direct relationship between nutrient inputs and river outputs, suggesting that agricultural management practices in the basin may have direct impacts on N and P delivery to the highly productive Guayas estuary.

Modeling the spatial pattern of land-use change with GEOMOD2: application and validation for Costa Rica

Agriculture, Ecosystems & Environment, 2001

The objective of this paper is to simulate the location of land-use change, specifically forest d... more The objective of this paper is to simulate the location of land-use change, specifically forest disturbance, in Costa Rica over several decades. This paper presents a GIS-based model, GEOMOD2, which quantifies factors associated with land-use, and simulates the spatial pattern of land-use forward and backward in time. GEOMOD2 reads rasterized maps of land-use and other biogeophysical attributes to determine empirically the attributes of land that humans tend to use. Then GEOMOD2 uses the patterns of those biogeophysical attributes to simulate the spatial pattern of land-use change. GEOMOD2 can select locations for land-use change according to any of three decision rules based on (1) nearest neighbors, (2) stratification by political sub-region, and/or (3) the pattern of biogeophysical attributes. GEOMOD2 simulates the progressive loss of closed-canopy forest in Costa Rica for 1940, 1961 and 1983, which are the years for which maps of land-use are available. Also, GEOMOD2 extrapolates the pattern of land-use to the year 2010. When GEOMOD2 extrapolates land-use change over several decades, it is able to classify correctly between 84 and 86% of the grid cells, for two categories: forest versus non-forest. Over various simulation runs, Kappa ranges from 0.34 to 0.53. The model's ability to predict the location of disturbance is best when the model is driven by the location of biogeophysical characteristics, most importantly lifezones.

Diminished resources, energy scarcity and climate change: unsustainable future development

WIT Transactions on State of the Art in Science and Engineering, 2013

No substitute for petroleum has yet been developed that can deliver energy at the scale, quality,... more No substitute for petroleum has yet been developed that can deliver energy at the scale, quality, or within the time frame required to replace decreasing availability. Most alternative energy sources provide much less energy than petroleum and do not have its high energy density. The interplay among shrinking resources, energy scarcity, economic crisis, and climate change will be diffi cult to solve. The biggest challenge is to articulate different aspects of an equation of energy, economics, and climate change that strive for a sustainable solution, at least within the current societal context. This is not simply a problem of physical dimensions but involves deeper social, economic, and policy aspects. The continued use of fossil fuels leads to increasing concentrations of greenhouse gases in the atmosphere that leads to more climate disasters. An increasing energy scarcity will limit the energy intensive global economy as it currently operates. It is unlikely that economics solely can effectively address these problems since most economic models are based on incomplete information and largely ignore the biophysical basis of the biosphere. The economics of the future should be taught from a biophysical perspective that respects the limits to the natural world, rather than the unending growth of neoclassical market theories.

Current concepts of eco-economy and biophysical economics: towards sustainability of the Gulf of Mexico coastal zone

WIT Transactions on State of the Art in Science and Engineering, 2013

Sustainable development of the coastal zone is a complex topic involving social, economic, bio-ph... more Sustainable development of the coastal zone is a complex topic involving social, economic, bio-physical, ecological, and legal components. Nevertheless such complex topics must be explained in a relatively simple way to avoid incorrect analysis in studies by students and decisions by policymakers. In general, the usual procedure is to set up social versus economic versus market pressures, which are always on the table, during discussions of coastal zone management to reduce impacts to a level that does not induce any further environmental catastrophes. In fact we need a more integrated approach where each component is fairly represented. Our study case is the Gulf of Mexico where coastal resources in both Mexico and the United States are Gulf-dependent; i.e. just four economic sectors, oil and natural gas, fi sheries, port-shipping, and tourism are values at over 120 billion U.S. dollars annually. This means 16% of Gross Domestic Product by the USA and 13% of GDP by Mexico. This productive value is not static but is constantly changing due to several factors, most directly the market value of the resources themselves. While human-made capital is increasingly abundant (guided by market signals), it is the natural products and ecosystem services from the Gulf that are increasingly scarce, and natural capital, not human-derived capital, that is fast becoming the limiting factor.

Article Energy Return on Investment for Norwegian Oil and Gas

Norwegian oil and gas fields are relatively new and of high quality, which has led, during recent... more Norwegian oil and gas fields are relatively new and of high quality, which has led, during recent decades, to very high profitability both financially and in terms of energy production. One useful measure for profitability is Energy Return on Investment, EROI. Our analysis shows that EROI for Norwegian petroleum production ranged from 44:1 in the early 1990s to a maximum of 59:1 in 1996, to about 40:1 in the latter half of the last decade. To compare globally, only very few, if any, resources show such favorable EROI values as those found in the Norwegian oil and gas sector. However, the declining trend in recent years is most likely due to ageing of the fields whereas varying drilling intensity might have a smaller impact on the net energy gain of the fields. We expect the EROI of Norwegian oil and gas production to deteriorate further as the fields become older. More energy-intensive production techniques will gain in importance.

Energy Return on Investment

Energy and the Wealth of Nations, 2011

Article Time Series EROI for Canadian Oil and Gas

Modern economies are dependent on fossil energy, yet as conventional resources are depleted, an i... more Modern economies are dependent on fossil energy, yet as conventional resources are depleted, an increasing fraction of that energy is coming from unconventional resources such as tar sands. These resources usually require more energy for extraction and upgrading, leaving a smaller fraction available to society, and at a higher cost. Here we present a calculation of the energy return on investment (EROI) for all Canadian oil and gas (including tar sands) over the period 1990-2008, and also for tar sands alone (1994-2008). We used energy production and energy use data from Statistics Canada's Material and Energy Flow Accounts (MEFA). We were able to quantify both direct and indirect energy use, the latter from Statistics Canada's energy input-output model. We found that since the mid-1990s, total energy used (invested) in the Canadian oil and gas sector increased about 63%, while the energy production (return) increased only 18%, resulting in a decrease in total EROI from roughly 16:1 to 11:1. We also found (although with less certainty) that the EROI for tar sands alone has fluctuated around 4:1 since 1994, with only a slight increasing trend. Finally, we analyzed underlying factors possibly influencing these trends.

The 50th Anniversary of The Limits to Growth: Does It Have Relevance for Today’s Energy Issues?

Energies

The Limits to Growth was a remarkable, and remarkably influential, model, book and concept publis... more The Limits to Growth was a remarkable, and remarkably influential, model, book and concept published 50 years ago this year. Its importance is that it used, for essentially the first time, a quantitative systems approach and a computer model to question the dominant paradigm for most of society: growth. Initially, many events, and especially the oil crisis of the 1970s, seemed to support the idea that the limits were close. Many economists argued quite the opposite, and the later relaxation of the oil crisis (and decline in gasoline prices) seemed to support the economists’ position. Many argued that the model had failed, but a careful examination of model behavior vs. global and many national data sets assessed by a number of researchers suggests that the model’s predictions (even if they had not been meant for such a specific task) were still remarkably accurate to date. While the massive changes predicted by the model have not yet come to pass globally, they are clearly occurring...