Bassu, S., Brisson, N., Durand, J. - L., Boote, K., Lizaso, J., Jones, J. W., et al. (2014). How do various maize crop models vary in their responses to climate change factors? Glob Change Biol, 20(7), 2301–2320.
Abstract: Potential consequences of climate change on crop production can be studied using mechanistic crop simulation models. While a broad variety of maize simulation models exist, it is not known whether different models diverge on grain yield responses to changes in climatic factors, or whether they agree in their general trends related to phenology, growth, and yield. With the goal of analyzing the sensitivity of simulated yields to changes in temperature and atmospheric carbon dioxide concentrations [CO2], we present the largest maize crop model intercomparison to date, including 23 different models. These models were evaluated for four locations representing a wide range of maize production conditions in the world: Lusignan (France), Ames (USA), Rio Verde (Brazil) and Morogoro (Tanzania). While individual models differed considerably in absolute yield simulation at the four sites, an ensemble of a minimum number of models was able to simulate absolute yields accurately at the four sites even with low data for calibration, thus suggesting that using an ensemble of models has merit. Temperature increase had strong negative influence on modeled yield response of roughly −0.5 Mg ha−1 per °C. Doubling [CO2] from 360 to 720 μmol mol−1 increased grain yield by 7.5% on average across models and the sites. That would therefore make temperature the main factor altering maize yields at the end of this century. Furthermore, there was a large uncertainty in the yield response to [CO2] among models. Model responses to temperature and [CO2] did not differ whether models were simulated with low calibration information or, simulated with high level of calibration information.
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Brown, T. - R. W., Low-Decarie, E., Pillsbury, R. W., Fox, G. A., & Scott, K. M. (2017). The effects of elevated atmospheric CO2 on freshwater periphyton in a temperate stream. Hydrobiologia, 794(1), 333–346.
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Corbett, J. E., Tfaily, M. M., Burdige, D. J., Cooper, W. T., Glaser, P. H., & Chanton, J. P. (2013). Partitioning pathways of CO2 production in peatlands with stable carbon isotopes. Biogeochemistry, 114(1-3), 327–340.
Abstract: Although methanogenic pathways generally produce equimolar amounts of carbon dioxide and methane, CO2 concentrations are often reported to be higher than CH4 concentrations in both field and laboratory incubation studies of peat decomposition. In field settings, higher pore water concentrations of CO2 may result from the loss of methane by: (1) ebullition due to the low solubility of methane in pore water and (2) vascular-plant transport. Higher CO2 concentrations may also be caused by: (1) production of additional CO2 by high-molecular weight (HMW) organic matter (OM) fermentation and/or (2) respiration from non-methanogenic pathways. In this study of a peatland where advection and transverse dispersion were the dominant pore water solute transport mechanisms, an isotope-mass balance approach was used to determine the proportions of CO2 formed from non-fractionating OM respiration and HMW fermentation relative to CO2 production from methanogenesis. This approach also allowed us to estimate the loss of CH4 from the belowground system. The pathways of CO2 production varied with depth and surface vegetation type. In a Carex-dominated fen, methane production initially produced 40 % of the total CO2 and then increased to 90-100 % with increasing depth. In a Sphagnum-dominated bog, methanogenesis resulted in 60 % of total CO2 production which increased to 100 % at depth. Both bogs and fens showed 85-100 % of methane loss from pore waters. Our results indicate that the isotopic composition of dissolved CO2 is a powerful indicator to allow partitioning of the processes affecting peat remineralization and methane production.
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Cuyler, E. E., & Byrne, R. H. (2018). Spectrophotometric calibration procedures to enable calibration-free measurements of seawater calcium carbonate saturation states. Analytica Chimica Acta, 1020, 95–103.
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Ducker, J. A., Holmes, C. D., Keenan, T. F., Fares, S., Goldstein, A. H., Mammarella, I., et al. (2018). Synthetic ozone deposition and stomatal uptake at flux tower sites. Biogeosciences, 15(17), 5395–5413.
Abstract: We develop and evaluate a method to estimate O-3 deposition and stomatal O-3 uptake across networks of eddy covariance flux tower sites where O-3 concentrations and O-3 fluxes have not been measured. The method combines standard micrometeorological flux measurements, which constrain O-3 deposition velocity and stomatal conductance, with a gridded dataset of observed surface O-3 concentrations. Measurement errors are propagated through all calculations to quantify O-3 flux uncertainties. We evaluate the method at three sites with O(3 )flux measurements: Harvard Forest, Blodgett Forest, and Hyytiala Forest. The method reproduces 83 % or more of the variability in daily stomatal uptake at these sites with modest mean bias (21 % or less). At least 95 % of daily average values agree with measurements within a factor of 2 and, according to the error analysis, the residual differences from measured O-3 fluxes are consistent with the uncertainty in the underlying measurements.
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Griscom, B., Ellis, P., & Putz, F. E. (2014). Carbon emissions performance of commercial logging in East Kalimantan, Indonesia. Glob Change Biol, 20(3), 923–937.
Abstract: Adoption of reduced-impact logging (RIL) methods could reduce CO2 emissions by 30–50% across at least 20% of
remaining tropical forests. We developed two cost effective and robust indices for comparing the climate benefits
(reduced CO2 emissions) due to RIL. The indices correct for variability in the volume of commercial timber among
concessions. We determined that a correction for variability in terrain slope was not needed. We found that conces-
sions certified by the Forest Stewardship Council (FSC, N = 3), when compared with noncertified concessions
(N = 6), did not have lower overall CO2 emissions from logging activity (felling, skidding, and hauling). On the other
hand, FSC certified concessions did have lower emissions from one type of logging impact (skidding), and we found
evidence of a range of improved practices using other field metrics. One explanation of these results may be that FSC
criteria and indicators, and associated RIL practices, were not designed to achieve overall emissions reductions. Also,
commonly used field metrics are not reliable proxies for overall logging emissions performance. Furthermore, the
simple distinction between certified and noncertified concessions does not fully represent the complex history of
investments in improved logging practices. To clarify the relationship between RIL and emissions reductions, we pro-
pose the more explicit term ‘RIL-C’ to refer to the subset of RIL practices that can be defined by quantified thresholds
and that result in measurable emissions reductions. If tropical forest certification is to be linked with CO2 emissions
reductions, certification standards need to explicitly require RIL-C practices.
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Heinemann, A. B., Maia, A. D., Dourado-Neto, D., Ingram, K. T., & Hoogenboom, C. (2006). Soybean (Glycine max (L.) Merr.) growth and development response to CO2 enrichment under different temperature regimes. European Journal of Agronomy, , 52–61.
Abstract: The carbon dioxide (CO2) concentration of the global atmosphere has increased during the last decades. This increase is expected to impact the diurnal variation in temperature as well as the occurrence of extreme temperatures. This potentially could affect crop production through changes in growth and development that will ultimately impact yield. The objective of this study was to evaluate the effect of CO2 and its interaction with temperature on growth and development of soybean (Glycine max (L.) Merr., cv. Stonewall). The experiment was conducted in controlled environment chambers at the Georgia Envirotron under three different temperatures and two CO2 regimes. The day/night air temperatures were maintained at 20/15, 25/20 and 30/25 degrees C, while the CO2 levels were maintained at 400 and 700 ppm, resulting in six different treatments. Plants were grown under a constant irradiance of 850 mu moles m(-2) s(-1) and a day length of 12 h; a non-limiting supply of water and mineral nutrients were provided. Five growth analyses were conducted at the critical development stages V4, R3, R5, R6 and R8. No differences in start of flowering were observed as a function of the CO2 level, except for the temperature regime 25/20 degrees C, where flowering for the elevated CO2 level occurred 2 days earlier than for the ambient CO2 level. For aboveground biomass, an increase in the CO2 level caused a more vigorous growth at lower temperatures. An increase in temperature also decreased seed weight, mainly due to a reduction in seed size. For all temperature combinations, final seed weight was higher for the elevated CO, level. This study showed that controlled environment chambers can be excellent facilities for conducting a detailed growth analysis to study the impact on the interactive effect of changes in temperature and CO2 on soybean growth and final yield. (c) 2005 Elsevier B.V. All rights reserved.
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Hertzberg, J. E., Lund, D. C., Schmittner, A., & Skrivanek, A. L. (2016). Evidence for a biological pump driver of atmospheric CO2 rise during Heinrich Stadial 1. Geophys. Res. Lett., 43(23), 12,242–12,251.
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Hoadley, K. D., Pettay, D. T., Dodge, D., & Warner, M. E. (2016). Contrasting physiological plasticity in response to environmental stress within different cnidarians and their respective symbionts. Coral Reefs, 35(2), 529–542.
Abstract: Given concerns surrounding coral bleaching and ocean acidification, there is renewed interest in characterizing the physiological differences across the multiple host-algal symbiont combinations commonly found on coral reefs. Elevated temperature and CO2 were used to compare physiological responses within the scleractinian corals Montipora hirsuta (Symbiodinium C15) and Pocillopora damicornis (Symbiodinium D1), as well as the corallimorph (a non-calcifying anthozoan closely related to scleractinians) Discosoma nummiforme (Symbiodinium C3). Several physiological proxies were affected more by temperature than CO2, including photochemistry, algal number and cellular chlorophyll a. Marked differences in symbiont number, chlorophyll and volume contributed to distinctive patterns of chlorophyll absorption among these animals. In contrast, carbon fixation either did not change or increased under elevated temperature. Also, the rate of photosynthetically fixed carbon translocated to each host did not change, and the percent of carbon translocated to the host increased in the corallimorph. Comparing all data revealed a significant negative correlation between photosynthetic rate and symbiont density that corroborates previous hypotheses about carbon limitation in these symbioses. The ratio of symbiont-normalized photosynthetic rate relative to the rate of symbiont-normalized carbon translocation (P:T) was compared in these organisms as well as the anemone, Exaiptasia pallida hosting Symbiodinium minutum, and revealed a P:T close to unity (D. nummiforme) to a range of 2.0-4.5, with the lowest carbon translocation in the sea anemone. Major differences in the thermal responses across these organisms provide further evidence of a range of acclimation potential and physiological plasticity that highlights the need for continued study of these symbioses across a larger group of host taxa.
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Ishtiaq, K. S., & Abdul-Aziz, O. I. (2015). Relative Linkages of Canopy-Level CO2 Fluxes with the Climatic and Environmental Variables for US Deciduous Forests. Environmental Management, 55(4), 943–960.
Abstract: We used a simple, systematic data-analytics approach to determine the relative linkages of different climate and environmental variables with the canopy-level, half-hourly CO2 fluxes of US deciduous forests. Multivariate pattern recognition techniques of principal component and factor analyses were utilized to classify and group climatic, environmental, and ecological variables based on their similarity as drivers, examining their interrelation patterns at different sites. Explanatory partial least squares regression models were developed to estimate the relative linkages of CO2 fluxes with the climatic and environmental variables. Three biophysical process components adequately described the system-data variances. The ‘radiation-energy’ component had the strongest linkage with CO2 fluxes, whereas the ‘aerodynamic’ and ‘temperature-hydrology’ components were low to moderately linked with the carbon fluxes. On average, the ‘radiation-energy’ component showed 5 and 8 times stronger carbon flux linkages than that of the ‘temperature-hydrology’ and ‘aerodynamic’ components, respectively. The similarity of observed patterns among different study sites (representing gradients in climate, canopy heights and soil-formations) indicates that the findings are potentially transferable to other deciduous forests. The similarities also highlight the scope of developing parsimonious data-driven models to predict the potential sequestration of ecosystem carbon under a changing climate and environment. The presented data-analytics provides an objective, empirical foundation to obtain crucial mechanistic insights; complementing process-based model building with a warranted complexity. Model efficiency and accuracy (R 2 = 0.55–0.81; ratio of root-mean-square error to the observed standard deviations, RSR = 0.44–0.67) reiterate the usefulness of multivariate analytics models for gap-filling of instantaneous flux data.
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Liu, C., Huang, S., Xu, P., & Peng, Z. -ren. (2018). Exploring an integrated urban carbon dioxide (CO[sub:2]) emission model and mitigation plan for new cities. Environment and Planning B: Urban Analytics and City Science, 45(5), 821–841.
Abstract: Mitigating carbon emission efforts in urban planning and design phase have become increasingly popular due to climate change. However, it is difficult to verify whether the carbon mitigation target could be achieved for a new city in the absence of quantitative analysis methods. About 100 new cities have emerged every year in the past decades, yet few of them employed low carbon strategies within proper prediction methods. In response, this paper offers an integrated analysis method of assessment and mitigation for urban carbon dioxide (CO2) of new cities. Building sector, transportation sector, and green land sector are considered as urban CO2 sources and sink. Life cycle analysis was employed in building sector to estimate its emissions. Based on the current and predicted emission data, a mitigation goal was then set and allocated efficiently through different sectors. To elaborate on this process, a case study of Shanghai Lingang New City was presented. The urban low carbon roadmap was planned and a variety of recommendations concerning policy were offered to assist the local government and policy makers in order to achieve the low carbon development goal as well.
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Liu, Z., Macpherson,, Groves, C., Martin, J. B., Yuan, D., & Zeng, S. (2018). Large and active CO2 uptake by coupled carbonate weathering. Earth-Science Reviews, 182, 42–49.
Abstract: Carbonate mineral weathering coupled with aquatic photosynthesis on the continents, herein termed coupled carbonate weathering (CCW), represents a current atmospheric CO2 sink of about 0.5 Pg C/a. Because silicate mineral weathering has been considered the primary geological CO2 sink, CCW's role in the present carbon cycle has been neglected. However, CCW may be helping to offset anthropogenic atmospheric CO2 increases as carbonate minerals weather more rapidly than silicates. Here we provide an overview of atmospheric CO2 uptake by CCW and its impact on global carbon cycling. This overview shows that CCW is linked to climate and land-use change through changes in the water cycle and water-born carbon fluxes. Projections of future changes in carbon cycling should therefore include CCW as linked to the global water cycle and land-use change.
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Macreadie, P. I., Macreadie PI, Anton, A., Anton A, Raven, J. A., Raven JA, et al. (2019). The future of Blue Carbon science. Nat Commun, 10, 3998.
Abstract: The term Blue Carbon (BC) was first coined a decade ago to describe the disproportionately large contribution of coastal vegetated ecosystems to global carbon sequestration. The role of BC in climate change mitigation and adaptation has now reached international prominence. To help prioritise future research, we assembled leading experts in the field to agree upon the top-ten pending questions in BC science. Understanding how climate change affects carbon accumulation in mature BC ecosystems and during their restoration was a high priority. Controversial questions included the role of carbonate and macroalgae in BC cycling, and the degree to which greenhouse gases are released following disturbance of BC ecosystems. Scientists seek improved precision of the extent of BC ecosystems; techniques to determine BC provenance; understanding of the factors that influence sequestration in BC ecosystems, with the corresponding value of BC; and the management actions that are effective in enhancing this value. Overall this overview provides a comprehensive road map for the coming decades on future research in BC science.
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Malone, S. L., Barr, J., Fuentes, J. D., Oberbauer, S. F., Staudhammer, C. L., Gaiser, E. E., et al. (2016). Sensitivity to Low-Temperature Events: Implications for CO2 Dynamics in Subtropical Coastal Ecosystems. Wetlands, 36(5), 957–967.
Abstract: We analyzed the ecosystem effects of low-temperature events (< 5 A degrees C) over 4 years (2009-2012) in subtropical short and long hydroperiod freshwater marsh and mangrove forests within Everglades National Park. To evaluate changes in ecosystem productivity, we measured temporal patterns of CO2 and the normalized difference vegetation index over the study period. Both water levels and distance from the coast influenced the ecosystem response to low-temperature events. Photosynthetic capacity, or the maximum CO2 uptake rate, and sensitivity to low-temperature events were much higher in mangrove forest than in freshwater marsh ecosystems. During low-temperature events photosynthetic capacity was enhanced in freshwater marsh while it declined in mangrove forests, and respiration rates declined across Everglades ecosystems. While the long hydroperiod freshwater marsh gained 0.26 g CO2 m(-2) during low-temperature events, the mangrove forest had the greatest C lost (7.11 g CO2 m(-2) low-temperature event(-1)) followed by the short hydroperiod freshwater marsh (0.37 g CO2 m(-2) low-temperature event(-1)). Results suggest that shifts in the frequency and intensity of weather anomalies with climate change can alter C assimilation rates in Everglades ecosystems through effects on the photosynthetic capacity of existing species, which might lead to changes in species composition and ecosystem productivity in the future.
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McCoy, S. J., McCoy SJ, Santillan-Sarmiento, A., Santillan-Sarmiento A, Brown, M. T., Brown MT, et al. (2019). Photosynthetic Responses of Turf-forming Red Macroalgae to High CO2 Conditions. J Phycol, .
Abstract: Seaweeds are important components of near-shore ecosystems as primary producers, foundation species, and biogeochemical engineers. Seaweed communities are likely to alter under predicted climate change scenarios. We tested the physiological responses of three perennial, turf-building, intertidal rhodophytes, Mastocarpus stellatus, Osmundea pinnatifida, and the calcified Ellisolandia elongata, to elevated pCO2 over 6 weeks. Responses varied between these three species. E. elongata was strongly affected by high pCO2 , whereas non-calcified species were not. Elevated pCO2 did not induce consistent responses of photosynthesis and respiration across these three species. While baseline photophysiology differed significantly between species, we found few clear effects of elevated pCO2 on this aspect of macroalgal physiology. We found effects of within-species variation in elevated pCO2 response in M. stellatus, but not in the other species. Overall, our data confirm the sensitivity of calcified macroalgae to elevated pCO2 , but we found no evidence suggesting that elevated pCO2 conditions will have a strong positive or negative impact on photosynthetic parameters in non-calcified macroalgae.
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Misra, B. B., & Chen, S. (2015). Advances in understanding CO2 responsive plant metabolomes in the era of climate change. Metabolomics, 11(6), 1478–1491.
Abstract: Anthropogenic climate change due to increased CO2 emission poses a major threat to global crop productivity, food quality, and security. Numerous studies, mostly classical, have predicted the effects of increased CO2 levels on environmental temperature and water balance, and on the life cycle, biomass, photosynthesis, leaf carbon/nitrogen ratio, and stomatal distribution in various plant species. With the advent of high-throughput tools for studying plant-CO2 responsiveness, it is now possible to obtain a metabolome-level view of the effect of climate change on plants. In this review, we examine the plant CO2-responsive primary and secondary metabolism, isoprene emission, in the presence of other stressors, and the advancement in state-of the art research methods that will facilitate future metabolomic studies.
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Muradov, N. (2017). Low to near-zero CO 2 production of hydrogen from fossil fuels: Status and perspectives. International Journal of Hydrogen Energy, 42(20), 14058–14088.
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O'Leary, G. J., Christy, B., Nuttall, J., Huth, N., Cammarano, D., Stöckle, C., et al. (2015). Response of wheat growth, grain yield and water use to elevated CO2 under a Free Air CO2 Enrichment (FACE) experiment and modelling in a semi-arid environment. Glob Change Biol, 21(7), 2670–2686.
Abstract: The response of wheat crops to elevated CO2 (eCO2) was measured and modelled with the Australian Grains Free-Air CO2 Enrichment experiment, located at Horsham, Australia. Treatments included CO2 by water, N and temperature. The location represents a semi-arid environment with a seasonal VPD of around 0.5 kPa. Over three years the observed mean biomass at anthesis and grain yield ranged from 4200 to 10200 kg ha−1 and 1600 to 3900 kg ha−1, respectively over various sowing times and irrigation regimes. The mean observed response to daytime eCO2 (from 365 to 550 μmol mol−1 CO2) was relatively consistent for biomass at stem elongation and at anthesis, LAI at anthesis and grain yield with 21%, 23%, 21% and 26%, respectively. Seasonal water use was decreased from 320 to 301 mm (P=0.10) by eCO2, increasing water use efficiency for biomass and yield, 36% and 31%, respectively. The performance of six models (APSIM-WHEAT, APSIM-NWHEAT, CAT, CROPSYST, OLEARY-CONNOR and SALUS) in simulating crop responses to eCO2 were similar and within or close to the experimental error for accumulated biomass, yield and water use response, despite some variations in early growth and LAI. The primary mechanism of biomass accumulation via radiation use efficiency (RUE) or transpiration efficiency (TE) was not critical to define the overall response to eCO2. However, under irrigation the effect of late sowing on response to eCO2 to biomass accumulation at DC65 was substantial in the observed data (~40%), but the simulated response was smaller, ranging from 17% to 28%. Simulated response from all six models under no water or nitrogen stress showed similar response to eCO2 under irrigation, but the differences compared to the dryland treatment were small. Further experimental work on the interactive effects of eCO2, water and temperature are required to resolve these model discrepancies.
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Pau, S., Okamoto, D. K., Calderon, O., & Wright, S. J. (2018). Long-term increases in tropical flowering activity across growth forms in response to rising CO2 and climate change. Global Change Biology, 24(5), 2105–2116.
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Raymundo, R., Asseng, S., Prassad, R., Kleinwechter, U., Concha, J., Condori, B., et al. (2017). Performance of the SUBSTOR-potato model across contrasting growing conditions. Field Crops Research, 202, 57–76.
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