Metric Tons Of Carbon Research Articles

Global agriculture and carbon trade-offs.

Feeding a growing and increasingly affluent world will require expanded agricultural production, which may require converting grasslands and forests into cropland. Such conversions can reduce carbon storage, habitat provision, and other ecosystem services, presenting difficult societal trade-offs. In this paper, we use spatially explicit data on agricultural productivity and carbon storage in a global analysis to find where agricultural extensification should occur to meet growing demand while minimizing carbon emissions from land use change. Selective extensification saves ∼ 6 billion metric tons of carbon compared with a business-as-usual approach, with a value of approximately $1 trillion (2012 US dollars) using recent estimates of the social cost of carbon. This type of spatially explicit geospatial analysis can be expanded to include other ecosystem services and other industries to analyze how to minimize conflicts between economic development and environmental sustainability.

A Reply to Parenti

Our friend and MR author Christian Parenti misunderstood our brief comments ("Notes from the Editors," MR, November 2013) on his article in the summer issue of Dissent. We did not challenge the science of climate change, which tells us that carbon emissions must cease before one trillion metric tons of carbon have been emitted—a tipping point that will be reached in about 2040 under business as usual. There is no question that the fossil-fuel industry must go. In fact the reality that the world is confronted by a planetary emergency with respect to climate change (and the global ecological problem as a whole) and that the critical threshold will likely be approached by around 2040 (or even sooner) under capitalist economics as usual, is one that has been insisted upon by Monthly Review for twenty years.This article can also be found at the Monthly Review website, where most recent articles are published in full.Click here to purchase a PDF version of this article at the Monthly Review website.

Reducing carbon footprint in cement material making: Characterizing costs of conserved energy and reduced carbon emissions

Abstract Adoption of energy efficient technologies is an important strategy to reduce demand for fossil fuels and carbon footprint in cement making. We characterized the costs of energy savings and carbon-emission reduction from applying energy efficiency technologies in cement-making plants in the United States in three historical years. Final energy savings resulting from efficiency measures identified in this study were estimated as 82 PJ, 125 PJ, and 95 PJ in 1994, 2004, and 2010, respectively; equivalent to approximately 20%, 25%, and 31% of the sector's annual final energy use. The associated carbon-emission reduction was 2.1 million metric tons of carbon (MtC), 3.3 MtC, and 2.5 MtC in 1994, 2004, and 2010, respectively. Using the concepts of cost of conserved energy (CCE) and cost of carbon-emission reduction (CCR), we estimated that cost effective measures contributed to final energy savings in the range of 15–25% of the sector's annual energy use, and carbon-emission reduction equals to 8–12% of the sector's annual carbon emissions. This study also points out the importance of future monitoring effort to track efficiency measure implementation for the industrial sector, and the need for an improved market for energy efficiency and reduced carbon footprint.

Deep Chlorophyll Maximum in Western Equatorial Atlantic - How does it Interact with Islands Slopes and Seamounts?

This paper investigates the dynamics of the deep chlorophyll maximu m layer (DCM L) along the Fernando de Noronha Ridge in the oligotrophic western equatorial Atlantic off northeast Brazil. M ixing processes between water masses above and below the thermocline may occur in a scale of tens of meters around the 24.5 to 25.5 isopycnals, where photoau- totrophs are concentrate at the bottom of the euphotic zone. The primary production at the DCM L can provide 210 (±170) metric tons of Carbon per day to the benthic community at the Rocas atoll. The behavior of isopycnals in deeper and strongly stratified waters suggest that internal waves may imp rove primary production, by lift ing the deeper and nutrient-rich South Atlantic Central Water upwards and carrying the autotrophs to brighter depths.

Assessing carbon storage in western U.S. ecosystems

Western U.S. ecosystems have the capacity to sequester about 91 million metric tons of carbon per year, according to a report released 5 December by the Department of the Interior. Entitled “Baseline and Projected Future Carbon Storage and Greenhouse‐Gas Fluxes in Ecosystems of the Western United States” and written by U.S. Geological Survey (USGS) scientists, the report came out of a congressionally mandated study. It examines how much carbon can be stored naturally through biological activity in various ecosystems, including forests, grasslands, and wetlands, in the western United States, from the Rocky Mountains to the Pacific.

Modeling challenges for predicting hydrologic response to degrading permafrost

The fate of the approximately 1,700 billion metric tons of carbon (Tarnocai et al. 2009) currently frozen in permafrost affected regions of the Arctic and subarctic is highly uncertain (IPCC 2007), primarily because of the potential for topographic evolution and resulting drainage network reorganization as permafrost degrades and massive ground ice contained in ice-rich permafrost soils melts. Computer modeling is a key tool in untangling these complex feedbacks to understand the evolution of the Arctic and subarctic landscapes and the potential feedbacks with the global climate system. Some of the challenges associated with modeling the hydrologic system in and around degrading permafrost are discussed in this essay. Modeling requirements depend very strongly on the spatial resolution of the model. Two different classes can be identified, depending on whether microtopography is explicitly resolved or incorporated into the model through a subgrid parameterization. The focus here is on the computational challenges associated with microtopography-resolving models using hydrologic response of polygon mires as an example. In such microtopography-resolving models, horizontal grid spacing on the order of 0.25mwould typically be required. Although highand low-centered ice wedge polygons have been identified as important controls on Arctic surface hydrology (e.g. Liljedahl et al. 2012) and evolution from lowto highcentered polygon landscapes is expected as Arctic temperatures increase (Jorgenson et al. 2006), as far as we are aware, there is no existing computer code that represents the full range of processes required to model the co-evolution of surface topography, active layer, and permafrost at the microtopography-resolving scale. For microtopography-resolving models of hydrology in permafrost landscapes, it is convenient to partition the large number of coupled processes into four critical sets: subsurface thermal/hydrology, surface thermal processes, mechanical deformation, and overland flow processes. However, it is important to recognize that the partitioning is somewhat arbitrary and that multiple tightly coupled processes exist within each set.

Dispatches

Dispatches

Detecting regional anthropogenic trends in ocean acidification against natural variability

Since the beginning of the Industrial Revolution humans have released ~500 billion metric tons of carbon to the atmosphere through fossil-fuel burning, cement production and land-use changes1, 2. About 30% has been taken up by the oceans3. The oceanic uptake of carbon dioxide leads to changes in marine carbonate chemistry resulting in a decrease of seawater pH and carbonate ion concentration, commonly referred to as ocean acidification. Ocean acidification is considered a major threat to calcifying organisms4, 5, 6. Detecting its magnitude and impacts on regional scales requires accurate knowledge of the level of natural variability of surface ocean carbonate ion concentrations on seasonal to annual timescales and beyond. Ocean observations are severely limited with respect to providing reliable estimates of the signal-to-noise ratio of human-induced trends in carbonate chemistry against natural factors. Using three Earth system models we show that the current anthropogenic trend in ocean acidification already exceeds the level of natural variability by up to 30 times on regional scales. Furthermore, it is demonstrated that the current rates of ocean acidification at monitoring sites in the Atlantic and Pacific oceans exceed those experienced during the last glacial termination by two orders of magnitude.

Coastal Ocean Last Glacial Maximum to 2100 CO2-Carbonic Acid-Carbonate System: A Modeling Approach

Using coupled terrestrial and coastal zone models, we investigated the impacts of deglaciation and anthropogenic inputs on the CO2–H2O–CaCO3 system in global coastal ocean waters from the Last Glacial Maximum (LGM: 18,000 year BP) to the year 2100. With rising sea level and atmospheric CO2, the carbonate system of coastal ocean water changed significantly. We find that 6 × 1012 metric tons of carbon were emitted from the coastal ocean, growing due to the sea level rise, from the LGM to late preindustrial time (1700 AD) because of net heterotrophy and calcification processes. This carbon came to reside in the atmosphere and in the growing vegetation on land and in uptake of atmospheric CO2 through the weathering of rocks on land. It appears that carbonate accumulation, mainly, but not exclusively, in coral reefs from the LGM to late preindustrial time could account for about 24 ppmv of the 100 ppmv rise in atmospheric CO2, lending some support to the “coral reef hypothesis”. In addition, the global coastal ocean is now, or soon will be, a sink of atmospheric CO2. The temperature rise of 4–5°C since the LGM led to increased weathering rates of inorganic and organic materials on land and enhanced riverine fluxes of total C, N, and P to the coastal ocean of 68%, 108%, and 97%, respectively, from the LGM to late preindustrial time. During the Anthropocene, these trends have been exacerbated owing to rising atmospheric CO2, due to fossil fuel combustion and land-use practices, other human activities, and rising global temperatures. River fluxes of total reactive C, N, and P are projected to increase from late preindustrial time to the year 2100 by 150%, 380%, and 257%, respectively, modifying significantly the behavior of these element cycles in the coastal ocean, particularly in proximal environments. Despite the fact that the global shoal water carbonate mass has grown extensively since the LGM, the pHT (pH values on the total proton scale) of global coastal waters has decreased from ~8.35 to ~8.18 and the carbonate ion concentration declined by ~19% from the LGM to late preindustrial time. The latter represents a rate of decline of about 0.028 μmol CO3 2− per decade. In comparison, the decrease in coastal water pHT from the year 1900 to 2000 was about 8.18–8.08 and is projected to decrease further from about 8.08 to 7.85 between 2000 and 2100, according to the IS92a business-as-usual scenario of CO2 emissions. Over these 200 years, the carbonate ion concentration will fall by ~120 μmol kg−1 or 6 μmol kg−1 per decade. This decadal rate of decline of the carbonate ion concentration in the Anthropocene is 214 times the average rate of decline for the entire Holocene. Hence, when viewed against the millennial to several millennial timescale of geologic change in the coastal ocean marine carbon system, one can easily appreciate why ocean acidification is the “other CO2 problem”.

The air we breathe: three vital respiratory gases and the red blood cell: oxygen, nitric oxide, and carbon dioxide

Three vital respiratory gases-oxygen (O(2)), nitric oxide (NO), and carbon dioxide (CO(2))-intersect at the level of the human red blood cell (RBC). In addition to hemoglobin (Hb)'s central role in O(2) transport, interaction of Hb with the Band 3 metabolon balances RBC energy flow. 2,3-Diphosphoglycerate enhances O(2) transport across the placenta and plays an important role in regulating RBC plasticity. NO is a key mediator of hypoxic vasodilation, but the precise role of RBC Hb remains controversial. In addition to established theories that depend on RBC uptake, delivery, and discharge of NO or its metabolites, an alternative hypothesis based on RBC permeability is suggested. NO depletion by free Hb may account for several clinical features seen during intravascular hemolysis or during deliberate infusion of Hb solutions used as RBC substitutes. CO(2) released by tissues triggers oxygen release through a series of well-coordinated reactions centered on the Band 3 metabolon. While RBC carbonic anhydrase and the Band 3 anion exchanger are central to this process, there is surprisingly little research on the kinetics of CO(2) clearance by transfusion. The three RBC gases are directly related to the three principal gases of Earth's atmosphere. Human fossil fuel consumption dumps 90 million metric tons of carbon into the atmosphere annually. Increasing CO(2) levels are linked to global warming, melting Arctic ice, rising sea levels, and climate instability. Just as individual cells depend on balance of the three vital gases, so too will their balance determine survival of life on Earth.

Carbon monoxide apparent quantum yields and photoproduction in the Tyne estuary

Abstract. Carbon monoxide (CO) apparent quantum yields (AQYs) are reported for a suite of riverine, estuarine and sea water samples, spanning a range of coloured dissolved organic matter (CDOM) sources, diagenetic histories, and concentrations (absorption coefficients). CO AQYs were highest for high CDOM riverine samples and almost an order of magnitude lower for low CDOM coastal seawater samples. CO AQYs were between 47 and 80% lower at the mouth of the estuary than at its head. Whereas, a conservative mixing model predicted only 8 to 14% decreases in CO AQYs between the head and mouth of the estuary, indicating that a highly photoreactive pool of terrestrial CDOM is lost during estuarine transit. The CDOM absorption coefficient (a) at 412 nm was identified as a good proxy for CO AQYs (linear regression r2 > 0.8; n = 12) at all CO AQY wavelengths studied (285, 295, 305, 325, 345, 365, and 423 nm) and across environments (high CDOM river, low CDOM river, estuary and coastal sea). These regressions are presented as empirical proxies suitable for the remote sensing of CO AQYs in natural waters, including open ocean water, and were used to estimate CO AQY spectra and CO photoproduction in the Tyne estuary based upon annually averaged estuarine CDOM absorption data. A minimum estimate of annual CO production was determined assuming that only light absorbed by CDOM leads to the formation of CO and a maximum limit was estimated assuming that all light entering the water column is absorbed by CO producing photoreactants (i.e. that particles are also photoreactive). In this way, annual CO photoproduction in the Tyne was estimated to be between 0.99 and 3.57 metric tons of carbon per year, or 0.004 to 0.014% of riverine dissolved organic carbon (DOC) inputs to the estuary. Extrapolation of CO photoproduction rates to estimate total DOC photomineralisation indicate that less than 1% of DOC inputs are removed via photochemical processes during transit through the Tyne estuary.

Land Use Effects on Sample Size Requirements for Soil Organic Carbon Stock Estimations

Soil organic carbon (SOC) stock (in metric tons of carbon per hectare) is calculated from SOC concentration (in grams per kilogram) and soil bulk density (ρb; in grams per cubic centimeter). Temporal changes in SOC stock are used to calculate terrestrial carbon sequestration rates used in global climate change models. The inherent variability in soil properties like SOC and ρb means that larger sample sizes may be needed to accurately determine SOC stocks. Our objective was to calculate the minimum sample size required to detect changes in ρb, SOC, and SOC stock for two land uses. Surface soils (0-5 cm) from two reclaimed mine soils and two managed hay fields in northern West Virginia were intensively sampled (60-74 samples each). Mean SOC and SOC stock values were larger in the hay fields (40 g/kg, 29 Mg ha−1) than in the mine soils (20 g/kg, 20 Mg ha−1), but ρb was larger in reclaimed mine soils (1.4 g cm−3) than in hay field soils (1.2 g cm−3). The ρb variance was larger in mine soils than that in hay field soils, but field variances for a given land use were similar (0.09 and 0.11 [g cm−3]2 in mine soils; 0.02 and 0.03 [g cm−3]2 in hay field soils). The variances in SOC concentration and SOC stock were not related to land use and were not similar within a land use. As a result, the minimum number of samples required to detect a change in ρb, SOC, and SOC stock was a site-specific property and cannot be assumed a priori.

CUANTIFICACIÓN DE CARBONO EN LA BIOMASA AEREA DE CAFÉ (<i>Coffea arábica</i> L.) CON SOMBRA, EN LA COMARCA PALO DE SOMBRERO, JINOTEGA, NICARAGUA

Los sistemas agroforestales son potenciales sumideros dedióxido de carbono, contribuyendo así a mitigar el calentamientode la tierra por efecto de las emisiones de C02. El propósitode la presente investigación, es cuantificar carbono orgánicoalmacenado en sistema de café. Esta investigación se desarrollóen la hacienda Santa Maura, Jinotega., altitud 1000-1250 msnm,temperatura promedio de 19 a 23°C, suelos del tipo molisol. Seidentificaron tres tipologías de cafeto de estudio que se diferencianpor su variedad, edad y densidad de establecimiento. Se realizó unmuestreo sistemático, intensidad del 2 %. La unidad de muestreofue una parcela circular de 250 m², en cada parcela de muestreose tomó un árbol de eje central, procediendo a inventariar eidentificar las especies de árboles y cafeto. Se midieron la alturatotal, altura fuste limpio, diámetro a la altura del pecho del quemuestrea, pesos húmedo y seco de los diferente componentes. Enlos depósitos aéreos de cafetos y especies de sombra, se estimó labiomasa y contenido de carbono. En la tipología dos se encontróel mayor promedio de C almacenado con 19.86 tonelada métricasde carbono por hectárea (tMC ha-1), seguido del tipo tres, con11.12 tMC ha-1 y por último, el tipo uno con 5.5 tMC ha-1. Ladiferencia de contenido de C entre tipología, está directamenteligado a la densidad, especie de árbol de sombra, edad y manejode la plantación.Palabras clave: Almacenamiento de carbono; servicioambiental.DOI: 10.5377/calera.v9i12.4

Respiration controls the unexpected seasonal pattern of carbon flux in an Asian tropical rain forest

Tropical rain forests play important roles in the global carbon cycle. We report a six-year eddy covariance carbon flux campaign in a primary tropical seasonal rain forest in southwest China. An unexpected seasonal pattern of net ecosystem carbon exchange was detected, with carbon lost during the rainy season and stored in the dry season. Strong seasonality of ecosystem respiration was suggested to primarily account for this seasonal pattern. The annual net uptake of CO 2 by the forest varied from 0.98 to 2.35 metric tons of carbon per hectare between 2003 and 2008. 6-year averaged sink strength was 1.68 metric tons of carbon per hectare.

A Case Study of Carbon Sequestration Potential of Land Use Policies Favoring Re-growth and Long-term Protection of Temperate Forests

There is a traditional view suggesting forests remove carbon dioxide from the atmosphere (Pregitzer & Euskirchen, 2004), but they cease to serve as a carbon sink as they fully mature (Odum, 1969). Recent modeling of old-growth forests indicate they continue to serve as a “net sink” of carbon even after maturity (Carey, Sala, & Callaway, 2001; Zhou, 2006), sequestering an average of 2.4 +/- 0.8 tC ha-1 yr-1 (tC = metric tons of carbon; ha = hectare; yr =year), identifying a ratio of heterotrophic respiration (Rh) to net primary production (NPP) of approximately 0.65 +/- 0.02 (Luyssaert, 2008). These figures show the strongest correlation amongst temperate forest regions. Two calculations are made using the carbon sequestration average. One is made identifying the amount of carbon sequestered through a small-scale land protection organization, showing a net carbon sequestration of approximately 224 metric tons of carbon per year. The other is based on the amount of land required to offset current anthropogenic emissions of carbon in the global carbon budget, showing approximately 235 million hectares of new forest growth would be required to offset current global anthropogenic emissions. One implication of these calculations is the traditional assumption of carbon neutrality increasing with age (Magnani, 2007) is incorrect, suggesting re-growing forests may be a favored policy choice for continued carbon sequestration.

A carbon sequestration strategy involving temperate fruit crops in the trans-Himalayan region

SummaryA current major concern is increasing levels of atmospheric CO2 which may be responsible for global warming or climate change. Fruit tree orchards have received attention in recent years by virtue of their potential to act as carbon pools. The trans-Himalayan valley (i.e., the Nubra Valley) at an altitude of 3,048 m, is covered by > 60,000 temperate fruit trees. The focus of this paper is on the potential of these fruit-yielding trees as a means of carbon sequestration in the Nubra Valley. The valley produces approx. 4,650 metric tonnes (MT) of apricot, apple, walnut, mulberry, grape, and plum fruit. It was observed that the total biomass of the temperate fruit trees (i.e., apricot, apple, and walnut) in the area surveyed was 40,000 MT dry weight (DW). Thus, 22,300 MT of carbon has been sequestered by these fruit species. This study revealed that the cultivation of temperate fruit crops species such as apricot, apple, and walnut could be exploited more efficiently for carbon sequestration which subsequently helps in mitigating global CO2 levels and restoring degraded land in these cold, arid areas by improving soil organic carbon (SOC) contents. These results concluded, in part, that growing biomass to sequester carbon is a beneficial grow-and-store process for sustainable development.

Household actions can provide a behavioral wedge to rapidly reduce US carbon emissions

Most climate change policy attention has been addressed to long-term options, such as inducing new, low-carbon energy technologies and creating cap-and-trade regimes for emissions. We use a behavioral approach to examine the reasonably achievable potential for near-term reductions by altered adoption and use of available technologies in US homes and nonbusiness travel. We estimate the plasticity of 17 household action types in 5 behaviorally distinct categories by use of data on the most effective documented interventions that do not involve new regulatory measures. These interventions vary by type of action and typically combine several policy tools and strong social marketing. National implementation could save an estimated 123 million metric tons of carbon per year in year 10, which is 20% of household direct emissions or 7.4% of US national emissions, with little or no reduction in household well-being. The potential of household action deserves increased policy attention. Future analyses of this potential should incorporate behavioral as well as economic and engineering elements.

The optimal choice of residue management, crop rotations, and cost of carbon sequestration: empirical results in the Midwest US

This study investigates the cost of soil carbon sequestration in the Midwest US. The model addresses several missing components in earlier analyses: the link between the residue level choice and carbon payments, crop rotations, carbon loss when shifting from conservation to conventional tillage and the spatial pattern of carbon sequestration across different soil types. The results suggest that for $100 per metric ton of carbon, 1.5 million metric tons of carbon could be sequestered per year on the 19.9 million hectares of cropland in the study region. These estimates suggest less carbon potential than existing studies because the opportunity costs associated with conservation tillage are fairly high. Annual carbon rental payments are found to be more efficient, as expected, but for smaller programs, per hectare rental payments are not substantially more costly.

Greenhouse gas emissions in Hawaiʻi: Household and visitor expenditure analysis

Abstract This paper focuses on petroleum use and greenhouse gas emissions associated with economic activities in Hawai‘i. Data on economic activity, petroleum consumption by type (gasoline, diesel, aviation fuel, residual, propane), and emissions factors are compiled and analyzed. In the baseline year 1997, emissions are estimated to total approximately 23.2 million metric tons of carbon, 181 thousand metric tons of nitrous oxide, and 31 thousand metric tons of methane in terms of carbon-equivalent global warming potential over a 100-year horizon. Air transportation, electricity, and other transportation are the key economic activity responsible for GHG emissions associated with fossil fuel use. More than 22% of total emissions are attributed to visitor expenditures. On a per person per annum basis, emission rates generated by visitor demand are estimated to be higher than that of residents by a factor of 4.3 for carbon, 3.2 for methane, and 4.8 for nitrous oxide.

Biochar: Carbon Mitigation from the Ground Up

As multibillion-dollar projects intended to sequester carbon dioxide (CO2) in deep geologic storage continue to seek financial support, the fertile black soils in the Amazon basin suggest a cheaper, lower-tech route toward the same destination. Scattered patches of dark, charcoal-rich soil known as terra preta (Portuguese for “black earth”) are the inspiration for an international effort to explore how burying biomass-derived charcoal, or “biochar,” could boost soil fertility and transfer a sizeable amount from the atmosphere into safe storage in of CO2 topsoil. Although burial of biochar is just beginning to be tested in long-term, field-scale trials, studies of Amazonian terra preta show that charcoal can lock up carbon in the soil for centuries and improve soil fertility. Charcoal is made by heating wood or other organic material with a limited supply of oxygen (a process termed “pyrolysis”). The products of the pyrolysis process vary by the raw material used, burning time, and temperature, but in principle, volatile hydrocarbons and most of the oxygen and hydrogen in the biomass are burned or driven off, leaving carbon-enriched black solids with a structure that resists chemical and microbial degradation. Christoph Steiner, a research scientist at the University of Georgia, says the difference between charcoal and biochar lies primarily in the end use. “Charcoal is a fuel, and biochar has a nonfuel use that makes carbon sequestration feasible,” he explains. “Otherwise there is no difference between charcoal carbon and biochar carbon.” Charcoal is traditionally made by burning wood in pits or temporary structures, but modern pyrolysis equipment greatly reduces the air pollution associated with this practice. Gases emitted from pyrolysis can be captured to generate valuable products instead of being released as smoke. Some of the by-products can be condensed into “bio-oil,” a liquid that can be upgraded to fuels including biodiesel and synthesis gas. A portion of the noncondensable fraction is burned to heat the pyrolysis chamber, and the rest can provide heat or fuel an electric generator. Pyrolysis equipment now being developed at several public and private institutions typically operate at 350–700°C. In Golden, Colorado, Biochar Engineering Corporation is building portable $50,000 pyrolyzers that researchers will use to produce 1–2 tons of biochar per week. Company CEO Jim Fournier says the firm is planning larger units that could be trucked into position. Biomass is expensive to transport, he says, so pyrolysis units located near the source of the biomass are preferable to larger, centrally located facilities, even when the units reach commercial scale.