Outside the Cap: Opportunities and Limitations of Greenhouse Gas Offsets

Explains the role of carbon offsets in providing flexibility and containing costs in a cap-and-trade program to limit greenhouse gas emissions. Recommends rigorous quantification, verification, and enforcement criteria to ensure the caps' integrity

A Tale of Two Writing Centers in Namibia: Lessons for Us All

The pivotal role of writing centers in improving the quality of academic writing has been well documented by research.  Although writing centers are commonplace in many countries, it appears that none existed prior to 2008 between South Africa and the Sahara. This article reports on the writer's assignment to start one in Namibia. The expectations of the challenges in this task, centering on training staff and tutors and acquiring resources, did not resemble the realities experienced, involving infrastructure, matrix management, hierarchy, and bureaucracy. Various paradigms for deconstructing these experiences, such as post-colonialism, culture clash, and ‘contact zone’ theory, all only partially explain the challenges encountered. These experiences in Namibia provide a case study of the politics of collaboration involved in implementing a writing center, and a microcosm of the challenges one might face anywhere. This account is thus 'glocal'; that is, locally derived but with global applications. Eleven specific guidelines can assist anyone contemplating a similar administrative assignment.

Methods that equate temporary carbon storage with permanent CO2 emission reductions lead to false claims on temperature alignment

AbstractThere has been renewed interest in equating temporary carbon storage with permanent CO2 emission reductions, both within corporate GHG inventories and for carbon offset accounting. Proposed methods discount future emissions, such that carbon stored temporarily can be accounted for as (some fraction of) a permanent reduction in emissions. These approaches are problematic as long-term temperature change is primarily caused by cumulative CO2 emissions and delayed emissions accumulate in the atmosphere the same as any other emission of CO2. This perspective article uses illustrative examples to show how discounting future emissions results in false temperature alignment and net zero claims. We recommend that emissions and removals should be reported without discounting to ensure that GHG accounts accurately reflect contribution to cumulative emissions. There is value in temporarily storing carbon, e.g. it can reduce peak warming and buy time to implement permanent mitigation measures, but it cannot be treated as equivalent to permanent mitigation, and alternative approaches should be used to convey the value of temporary storage

Lessons learned from the first round of applications by carbon-offsetting programs for eligibility under CORSIA

In 2016, the International Civil Aviation Organization (ICAO) adopted the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). The scheme requires participating airline operators to purchase carbon offset credits to compensate for the increase in their carbon dioxide emissions from international flights above 2019/2020 levels. This paper synthesizes key lessons learned from an assessment of the first 14 applications of carbon-offsetting programs for eligibility under CORSIA, focussing on five out of eight eligibility criteria established by ICAO. The evaluation shows that the degree to which the applicants satisfy the ICAO requirements differs substantially. Some applicants hardly meet any of the requirements and may not even be considered carbon-offsetting programs. However, there are also notable differences in relation to specific criteria. With regard to ensuring additionality and establishing baselines, key shortcomings are that many programmes apply approaches that do not guarantee environmental integrity of the generated credits. Not all programs regularly reassess whether their approaches are still appropriate in the light of new circumstances, such as lower costs of renewable energy technologies, and programs may still need to update their approaches for assessing additionality and establishing baselines in the light of the new context of the Paris Agreement. Some programs also do not require an independent third-party assessment of baseline methodologies. Most programs do not yet have procedures in place or planned for avoiding double counting between CORSIA and nationally determined contributions (NDCs) under the Paris Agreement. However, a few programs are in the process of implementing detailed procedures, based on voluntary Guidelines developed by a multistakeholder group. To address non-permanence, most programs use "buffer" approaches. The duration for which non-permanence is ensured, the avoidance of moral hazard risks of intentional reversals, and the "capitalization" of buffers vary considerably among programs. The Clean Development Mechanism's provisions to address non-permanence were in principle robust but do no longer work, given that the Kyoto Protocol will not have a third commitment period. Lastly, only two programs have a process in place which requires the assessment of environmental and social risks, the adoption of safeguards, and the monitoring and reporting on risks. The paper also identifies several cross-cutting issues. First, we recommend that ICAO only approve programs as eligible for CORSIA once programs have amended their standards and procedures to fulfil all criteria. Second, the evaluation identified that ICAO still needs to clarify several matters that are not explicitly addressed in current criteria, such as what global warming potentials programs should use to convert non-CO2 emissions into CO2 equivalents; whether offset credits will be eligible if the host country does not participate in the Paris Agreement; with what type of international mitigation targets double counting must be avoided; and the treatment of emission reductions not covered by NDCs. Clear international rules on these matters would greatly facilitate the approval of programs and the implementation of CORSIA. Third, we recommend that ICAO adopts a transparent procedure for the initial approval, ongoing supervision, re-approval, suspension and termination of eligibility of programs. This procedure could also address the insufficient level of information in current applications, by requiring programs to provide more detailed information. Lastly, we recommend that the Parties to the Paris Agreement include specific provisions in the international rules on Article 6 for how countries should account for offset credits used under CORSIA

Kenniseconomie vraagt actieve houding

De beoogde kenniseconomie vergt niet alleen investeringen, maar vooral een meer ondernemende, verantwoordelijke houding van iedere burger, aldus Thijs Boekhoff, Paul Iske en Mathieu Weggeman

The use of small angle neutron scattering with contrast matching and variable adsorbate partial pressures in the study of porosity in activated carbons

The porosity of a typical activated carbon is investigated with small angle neutron scattering (SANS), using the contrast matching technique, by changing the hydrogen/deuterium content of the absorbed liquid (toluene) to extract the carbon density at different scattering vector (Q) values and by measuring the p/p0 dependence of the SANS, using fully deuterated toluene. The contrast matching data shows that the apparent density is Q-dependent, either because of pores opening near the carbon surface during the activation processor or changes in D-toluene density in nanoscale pores. For each p/p0 value, evaluation of the Porod Invariant yields the fraction of empty pores. Hence, comparison with the adsorption isotherm shows that the fully dry powder undergoes densification when liquid is added. An algebraic function is developed to fit the SANS signal at each p/p0 value hence yielding the effective Kelvin radii of the liquid surfaces as a function of p/p0. These values, when compared with the Kelvin Equation, show that the resultant surface tension value is accurate for the larger pores but tends to increase for small (nanoscale) pores. The resultant pore size distribution is less model-dependent than for the traditional methods of analyzing the adsorption isotherms

Detection of the delayed condensation effect and determination of its impact on the accuracy of gas adsorption pore size distributions

Macroscopic, highly disordered, mesoporous materials present a continuing challenge for accurate pore structure characterization. The typical macroscopic variation in local average pore space descriptors means that methods capable of delivering statistically representative characterizations are required. Gas adsorption is a representative but indirect method, normally requiring assumptions about the correct model for data analysis. In this work we present a novel method to both expand the range, and obtain greater accuracy, for the information obtained from the main boundary adsorption isotherms by using a combination of data obtained for two adsorptives, namely nitrogen and argon, both before and after mercury porosimetry. The method makes use of the fact that nitrogen and argon apparently ‘see’ a different pore geometry following mercury entrapment, with argon, relatively, ‘ignoring’ new metal surfaces produced by mercury porosimetry. The new method permits the study of network and pore–pore co-operative effects during adsorption that substantially affect the accuracy of the characteristic parameters, such as modal pore size, obtained for disordered materials. These effects have been explicitly quantified, for a typical sol-gel silica catalyst support material as a case study. The technique allowed the large discrepancies between modal pore sizes obtained from standard gas adsorption and mercury thermoporometry methods to be attributed to the network-based delayed condensation effect, rather than spinodal adsorption. Once the network-based delayed condensation effect had been accounted for, the simple cylindrical pore model and macroscopic thermodynamic Kelvin-Cohan equation were then found sufficient to accurately describe adsorption in the material studied, rather than needing a more complex microscopic theory. Hence, for disordered mesoporous solids, a proper account of inter-pore interactions is more important than that of intra-pore adsorbate density distribution, to obtain accurate pore size distributions

Mesoporosity changes from cambium to mature tension wood: a new step toward the understanding of maturation stress generation in trees

International audienceIn order to progress in the understanding of mechanical stress generation, the mesoporosity of the cell wall and its changes during maturation of poplar (Populus deltoides x P. nigra) tension wood (TW) and opposite wood (OW) were measured by nitrogen adsorption–desorption. Variations in the thickness of the gelatinous layer (G-layer) were also measured to clarify whether the mesoporosity change simultaneously with the deposition of the G-layer in TW. Results show that mesoporous structures of TW and OW were very similar in early development stages before the deposition of G-layers. With the formation of the S2 layer in OW and the G-layer in TW, the mesopore volume decreased steeply before lignification. However, in TW only, the decrease in mesopore volume occurred together with the pore shape change and a progressive increase in pore size. The different patterns observed in TW revealed that pores from G-layers appear with a different shape compared to those of the compound middle lamella, and their size increases duringthe maturation process until stabilising in mature wood. This observation strongly supports the hypothesis of the swelling of the G-layer matrix during maturation as the origin of maturation stress in poplar tension wood