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1.
G. Cornelis van Kooten 《Climatic change》2009,95(3-4):449-463
Biological activities that sequester carbon create CO2 offset credits that could obviate the need for reductions in fossil fuel use. Credits are earned by storing carbon in terrestrial ecosystems and wood products, although CO2 emissions are also mitigated by delaying deforestation, which accounts for one-quarter of anthropogenic CO2 emissions. However, non-permanent carbon offsets from biological activities are difficult to compare with each other and with emissions reduction because they differ in how long they prevent CO2 from entering the atmosphere. This is the duration problem. It results in uncertainty and makes it hard to determine the legitimacy of biological activities in mitigating climate change. Measuring, verifying and monitoring the carbon sequestered in sinks greatly increases transaction costs and leads to rent seeking by sellers of dubious sink credits. While biological sink activities undoubtedly help mitigate climate change and should not be neglected, it is shown that there are limits to the substitutability between temporary offset credits from these activities and emissions reduction, and that this has implications for carbon trading. A possible solution to inherent incommensurability between temporary and permanent credits is also suggested. 相似文献
2.
Alejandro Caparrós 《Climatic change》2009,96(3):421-441
We set out a dynamic model to investigate optimal time paths of emissions, carbon stocks and carbon sequestration by land
conversion, allowing for non-instantaneous carbon sequestration. Previous research in a dynamic general equilibrium framework,
assuming instantaneous carbon sequestration, has shown that land conversion should take place as soon as possible. On the
contrary, previous research within a partial equilibrium framework has shown that, with increasing carbon prices, it is optimal
to delay carbon sequestration through land conversion. We show that land use change alternatives, e.g. reforestation, have
to be used as soon as possible before the singular path is reached, i.e. the unique trajectory that brings the system to the
steady-state. We also show that faster increasing carbon prices can induce a reduction in the rate of reforestation, and that
this may take place after an initial phase of increased reforestations or even immediately, depending upon the shape of the
increase in carbon prices. Finally, we show that the type of species used is relevant and that the land conversion rate gets
smaller the longer it takes the trees to grow. We analyze four different carbon accounting methods, describing the conditions
that make them efficient and discussing the comparative advantages of each of them. 相似文献
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Soil carbon sequestration 总被引：1，自引：0，他引：1
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The voluntary carbon market allows participants to go beyond regulatory carbon offsetting. Recent developments have improved the transparency and credibility of voluntary carbon trading, and forest carbon credit transactions constitute more than half of trade volume. Its workings, however, have not been sufficiently explored in the literature. This study analyses the characteristics of forest carbon credit transactions in the voluntary carbon market using frequency analysis and logistic regression analysis. The results reveal that the co-benefits of forest carbon projects are an important factor influencing carbon credit transactions. From the higher transaction ratio of credits from CCB Standards-labelled projects and projects using co-benefit-oriented standards, it can be inferred that credits with potential for co-benefits (e.g. fostered corporate social responsibility, social cohesion of local communities and voluntary leadership, and positive environmental impacts) are preferred to those focusing exclusively on emission reduction in the voluntary carbon market. The findings of this study suggest that developing co-benefits is important for strengthening the market competitiveness of forest carbon credits in the voluntary carbon market. Additionally, unlike the compliance carbon market, in the voluntary carbon market stringent carbon standards do not always guarantee credit transaction performance.
POLICY RELEVANCE
After UNFCCC COP-21, the global society agreed to acknowledge various forms of international carbon crediting mechanisms, and noted the significance of greenhouse gas emissions reduction for sustainable development and environmental integrity through the Paris Agreement. Moreover, the agreement encouraged both REDD+ activities in developing countries and supports from developed countries. Additionally, co-benefits of forest carbon projects are important for credit transaction in the global voluntary carbon market. Under the new climate regime, co-benefits of forest carbon projects are expected to gain attention in the carbon market. To promote the social, economic, and environmental co-benefits of forest carbon projects, the introduction of an objective co-benefit assessment and certification system should be reviewed at the national level. 相似文献
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To find out the secular and seasonal trends of the 13C value and CO2 concentration in the surface air and the determination of the 13C in the atmospheric CO2 collected at Tsukuba Science City was carried out during the period from July 1981 to October 1983. The monthly average of the 13C value of CO2 in the surface air collected at 1400 LMT ranged from -7.52 to \s-8.45 with an average of -7.96±0.25 and the CO2 concentration in the air varied from 334.5 l 1-1 to 359 l 1-1 with an average of 347.2±6.3 l 1-1. The 13C value is high in summer and low in winter and is negatively correlated with the CO2 concentration. In general, the relationship between the 13C and the CO2 concentration is explainable by a simple mixing model of two different constant carbon isotopic species but the relationship does not always follow the model. The correlation between the 13C value and the CO2 concentration is low during the plant growth season and high at other times. The observed negative deviation of the 13C value from the simple mixing model in the plant growth season is partly due to the isotopic fractionation process which takes place in the land biota. 相似文献
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The challenge of reversing rising atmospheric CO2 concentrations is growing with the continued expansion of CO2-emitting energy infrastructure throughout the world and with the lack of coordinated, effective measures to manage and reduce
emissions. Given this situation, it is prudent for society to explore all potential carbon management options, including those
with seemingly low probability for success. Recent initiatives for advancing and enhancing carbon storage options have focused
primarily on the physical trapping of CO2 in underground geologic formations and on the biological uptake of CO2; less attention has been given to approaches that rely primarily on geochemical reactions that enhance transformation of
CO2 gas into dissolved or solid phase carbon by liberating cations to neutralize carbonic acid. This paper provides a structured
review of the technical status of these geochemical approaches, and also presents a simple framework for assessing the potential
and limitations of various proposed geochemical approaches to assist prioritizing future research in this area. Despite major
limitations, geochemical approaches have unique potential to contribute to CO2 reductions in ways that neither physical nor biological carbon storage can by allowing for the direct removal of CO2 from the atmosphere with minimal requirements for integrating with existing infrastructure. Recognizing the severity and
urgency of the need for carbon management options, we argue for an increase in research activity related to geochemical approaches
to carbon management. 相似文献
10.
Frederick van der Ploeg 《Climatic change》2018,147(1-2):47-59
Cumulative emissions drive peak global warming and determine the carbon budget needed to keep temperature below 2 or 1.5 °C. This safe carbon budget is low if uncertainty about the transient climate response is high and risk tolerance (willingness to accept risk of overshooting the temperature target) is low. Together with energy costs, this budget determines the optimal carbon price and how quickly fossil fuel is abated and replaced by renewable energy. This price is the sum of the present discounted value of all future losses in aggregate production due to emitting one ton of carbon today plus the cost of peak warming that rises over time to reflect the increasing scarcity of carbon as temperature approaches its upper limit. If policy makers ignore production losses, the carbon price rises more rapidly. If they ignore the peak temperature constraint, the carbon price rises less rapidly. The alternative of adjusting damages upwards to factor in the peak warming constraint leads initially to a higher carbon price which rises less rapidly. 相似文献
11.
L. H. Allen Jr. 《Boundary-Layer Meteorology》1975,8(1):39-79
Model predictions of CO2 concentrations downwind from a line source were calibrated using experimental data. Agreement between the model and experimental data was improved by adjusting for wind direction meander and cup anemometer overshoot. The model predictions showed that by using a negative exponential wind speed profile within the crop canopy, predictions were closer to observed CO2 concentration profiles than when experimentally-observed wind speed profiles, which were constant with height in the lower canopy, were used. This finding suggests that much of the lower canopy airflow was not direct mass flow in the downwind direction. Eddy diffusivity profiles which showed a within-canopy local minimum resulted in arestriction in the predicted loss of CO2 out of the canopy system. Two-dimensional plots of predicted null vertical flux and CO2 concentration portrayed vividly the turbulent diffusion and mass flow transport of CO2 from the line source. 相似文献
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John M. DeCicco 《Climatic change》2012,111(3-4):627-640
Public policy supports biofuels for their benefits to agricultural economies, energy security and the environment. The environmental rationale is premised on greenhouse gas (GHG, “carbon”) emissions reduction, which is a matter of contention. This issue is challenging to resolve because of critical but difficult-to-verify assumptions in lifecycle analysis (LCA), limits of available data and disputes about system boundaries. Although LCA has been the presumptive basis of climate policy for fuels, careful consideration indicates that it is inappropriate for defining regulations. This paper proposes a method using annual basis carbon (ABC) accounting to track the stocks and flows of carbon and other relevant GHGs throughout fuel supply chains. Such an approach makes fuel and feedstock production facilities the focus of accounting while treating the CO2 emissions from fuel end-use at face value regardless of the origin of the fuel carbon (bio- or fossil). Integrated into cap-and-trade policy and including provisions for mitigating indirect land-use change impacts, also evaluated on an annual basis, an ABC approach would provide a sound carbon management framework for the transportation fuels sector. 相似文献
14.
Land-use, land-use change and forestry (LULUCF) activities will play an important role in global climate change mitigation. Many carbon schemes require the delivery of both climate and rural development benefits by mitigation activities conducted in developing countries. Agroforestry is a LULUCF activity that is gaining attention because of its potential to deliver climate benefits as well as rural development benefits to smallholders. There is hope that agroforestry can deliver co-benefits for climate and development; however experience with early projects suggests co-benefits are difficult to achieve in practice. We review the literature on agroforestry, participatory rural development, tree-based carbon projects and co-benefit carbon projects to look at how recommended project characteristics align when trying to generate different types of benefits. We conclude that there is considerable tension inherent in designing co-benefit smallholder agroforestry projects. We suggest that designing projects to seek ancillary benefits rather than co-benefits may help to reduce this tension. 相似文献
15.
Mechanisms controlling soil carbon turnover and their potential application for enhancing carbon sequestration 总被引：6，自引：0，他引：6
In addition to increasing plant C inputs, strategies for enhancing soil C sequestration include reducing C turnover and increasing
its residence time in soils. Two major mechanisms, (bio)chemical alteration and physicochemical protection, stabilize soil organic C (SOC) and thereby control its turnover. With (bio)chemical alteration, SOC is transformed by biotic
and abiotic processes to chemical forms that are more resistant to decomposition and, in some cases, more easily retained
by sorption to soil solids. With physicochemical protection, biochemical attack of SOC is inhibited by organomineral interactions
at molecular to millimeter scales. Stabilization of otherwise decomposable SOC can occur via sorption to mineral and organic
soil surfaces, occlusion within aggregates, and deposition in pores or other locations inaccessible to decomposers and extracellular
enzymes. Soil structure is a master integrating variable that both controls and indicates the SOC stabilization status of
a soil. One potential option for reducing SOC turnover and enhancing sequestration, is to modify the soil physicochemical
environment to favor the activities of fungi. Specific practices that could accomplish this include manipulating the quality
of plant C inputs, planting perennial species, minimizing tillage and other disturbances, maintaining a near-neutral soil
pH and adequate amounts of exchangeable base cations (particularly calcium), ensuring adequate drainage, and minimizing erosion.
In some soils, amendment with micro- and mesoporous sorbents that have a high specific surface – such as fly ash or charcoal
– can be beneficial.
All authors contributed equally to this article. 相似文献
16.
Empirical investigations have indicated that projections of future atmospheric carbon dioxide concentrations of a quality
quite adequate for practical questions regarding the environmental threat of anthropogenic carbon dioxide emissions and its
relationship to energy use policy could be made with the simple assumption that a constant fraction of these emissions would
be retained by the atmosphere. By analysis of the structural behavior of equations describing the transfer of carbon and carbon
dioxide between their several reservoirs we have been able to demonstrate that this characteristic can be explained to result
from approximately linear behavior and exponentially growing carbon dioxide release rates, combined with fitting of carbon
cycle model parameters to the last twenty years of observed atmospheric carbon dioxide growth.
These conclusions are independent of the details of carbon cycle model structure for projections up to 100 years into the
future as long as the growth in atmospheric carbon dioxide release rates is sufficiently high, of the order of 1.5% per annum
or more, as referenced to p re-industrial (steady state) conditions. At low rates of growth, when the longer response times
of the carbon cycling system become important, for most energy use projections the resultant CO2 induced climate changes are small and the uncertainties in predicted atmospheric carbon dioxide level are thus not important.
A possible exception to this condition occurs for scenarios of future fossil fuel use rates designed to avoid atmospheric
CO2 levels exceeding a chosen threshold. In this instance details of carbon cycle model structure could significantly affect
conclusions that might be drawn concerning future energy use policies; however, it is possible that such a result stems from
inappropriate specification of a criterion for an environmental threat, rather than from inherent inadequacy of current carbon
cycle models.
Recent carbon cycle model developments postulate transfer processes of carbon into the deep ocean, large carbon storage reservoir
at rates much higher than in the models we have analysed. If the existence of such mechanisms is confirmed, and they are found
to be sufficiently rapid and large, some of our conclusions regarding the use of the constant fractional retention assumption
may have to be modified.
Currently at the Gas Research Institute, 8600 West Bryn, Mawr Ave., Chicago, IL 60631, U.S.A. 相似文献
17.
T. M. L. Wigley 《Climatic change》1983,5(4):315-320
Recent indirect data and direct measurements from ice cores point towards a ‘pre-industrial’ CO2 level of around 260–270 ppmv, considerably below the commonly assumed value of 290 ppmv. Early measurements from the southern
hemisphere tend to favour the lower value. 相似文献
18.
The oxidation of carbon disulphide has been studied under conditions which are likely to pertain in the atmosphere. The quantum yield for direct photo-oxidation of CS2 in air at 1 atm pressure, using near UV radiation was 0.012, with OCS as a major product. The rate coefficient (k 1) for the reaction of OH with CS2, was determined from measurements of OCS formation in the near UV photolysis of HONO?CS2?O2?N2 mixtures. k 1 was dependent on oxygen concentration rising from ≤4×10-14 cm3 molecule-1 s-1 at O2≤15 Torr to (2.0±1.0)×10-12 cm3 molecule-1 s-1 at 1 atm air and 300 K. Equimolar amounts of carbonyl sulphide and sulphur dioxide were the major reaction products. The concentration of carbon disulphide in the ambient atmosphere was measured and the concentration to be expected in the background atmosphere was estimated. Rate and concentration data were used to show that carbon disulphide oxidation represents a major source for atmospheric carbonyl sulphide. It can also serve as an alternate source for atmospheric sulphur dioxide in addition to that produced from hydrogen sulphide and dimethyl sulphide. A consideration of atmospheric concentrations and rate data for these trace sulphur gases suggests that the natural sulphur budget is much smaller than the yearly amounts of sulphur dioxide emitted from anthropogenic sources. 相似文献
19.
In this article the problem of credible commitment in carbon policy is discussed. Investors favour long-term predictability of the policy, but without any external enforcement mechanisms a commitment made by a government can be withdrawn, leading to scepticism and lack of credibility. This results in increased market risks and investment hold-up. Regulatory uncertainty stems from (i) strategic interactions between government and firms, (ii) potential learning about climate damage and abatement cost and (iii) political volatility. Although commitment to future policy encourages private investment, it also imposes costs in the form of reduced flexibility to accommodate new information or preferences. The article reviews devices that may help policy makers raise the level of commitment while also leaving some room for flexible adjustments. In particular, legislation of a long-term governance framework, delegation to an independent carbon agency and securitization of investors' stakes in emission markets offer palliative approaches. 相似文献
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