Bioenergy is a critical element in many national and international climate change mitigation efforts, including as a carbon dioxide removal strategy combined with the capture and durable geological storage of flue gas emissions (BECCS). However, divergent results on the effectiveness of bioenergy as a climate change mitigation measure are reported in the scientific literature. Climate impacts of bioenergy depend on case-specific factors, primarily biophysical features of the biomass production system, and the design and efficiency of conversion and capture processes. Estimates of climate impacts are also strongly affected by methodological choices and assumptions, and much of the divergence between studies derives from differences in the assumed alternate use of the land or feedstock, the alternate energy source and the system boundaries applied. We present a methodology to support robust estimates of the climate change effects of bioenergy systems, updating the standard methodology developed by the International Energy Agency's Technology Collaboration Program on Bioenergy. We provide guidance on the key choices including the reference land use and energy system that bioenergy is assumed to displace, spatial and temporal system boundaries, co-product handling, climate forcers considered, metrics applied and time horizon of impact assessment. Researchers should consider the whole bioenergy system including all life cycle stages, and choose system boundaries, reference systems and treatment of co-products that are consistent with the intended application of the results. The assessment should be normalised to a functional unit that can be compared with other systems delivering an equivalent quantity of the same function. All significant climate forcers should be included, and climate effects should be quantified using appropriate impact assessment methods that distinguish the impact of time. Consistency in methodology and interpretation will facilitate comparison between studies of different bioenergy systems.

In this article, we explore patterns of R-2 across data sets to reveal a fundamental equivalence. If any set of bivariate data is rotated, the R-2 value changes and defines a curve as a function of the rotation angle theta. We show that for any data set whose rotated R-2 curve has the same maximum value, the entire curve is identical up to a shift in the rotation angle. We also find that a recently introduced measure of linearity, Q(2), provides a definitive relation between these data sets, with equal Q(2) values resulting in identically rotated R-2 curves. Finally, we also show that we can consider R-2 as the combination of two components, the linearity of the data and a rotation angle. While rotating data or axes for non spatial data loses the specific meaning of the variables, these results may provide additional understanding of the relationships within the data and can reveal similarities between data sets, the role of sensitivity in correlation, and the nature of correlation itself.

With emerging issues of global climate change, it is clear that there is value in controlling the amount of carbon dioxide in the atmosphere. Managing the release or uptake of carbon by forests is an important opportunity to yield reductions in atmospheric CO2, and this includes managing the amount of harvested forest carbon that is stored in harvested wood products (HWP). To evaluate the contribution of forest carbon to climate change, we need to evaluate how much carbon is released to the atmosphere, when it is released, how long the released C remains in the atmosphere, and our preference for the timing and amplitude of climate change. When forest is harvested, the subsequent amount of carbon in the atmosphere depends on the processes and efficiency of harvest, the life times of the forest products, and the treatment of forest products at the end of their useful lifetime. This paper assembles extensive US data on the fractions of forest carbon that are released to the atmosphere during the processing of a forest harvest and the production and life expectancy of harvested wood products (HWP). Using a model of the global carbon cycle and an illustrated treatment of time preference, we calculate the relative cost of different forest management scenarios in terms of the ton years of CO2 in the atmosphere. We show that delaying the emission of one ton of C as CO2 for 1 year yields a reduction of 41.74 ton years of carbon in the atmosphere when integrated to infinite time and using a low time preference of 1

Abstract The simple linear regression model and the associated goodness-of-fit measure, the coefficient of determination, R 2, are only appropriate when all measurement errors are associated with the measurement of the data in the dependent variable. When measurement errors are assumed in both variables, a Deming regression can be used; however, there is no associated R 2-type measure for this specific type of regression. In this paper, we propose a measure, which utilizes the minimum percentage improvement of the Deming regression over either the horizontal or the vertical line through the centroid of the data. We investigate some properties of this measure and its relation to R 2. We also consider other candidate methodologies for a generalized R 2 measure for a Deming regression model and investigate strengths and weaknesses of each as a way of beginning the conversation about which measure is the best and for which applications it is most suited.

Third Week of June, and: Carrying Memory Eric Marland (bio) Third Week of June When I was younger, my parents took us on tripsAdventures more likeCaving, canoeing, skiing, climbingSome turned into real adventuresSome just for us But one stands outAnd I keep going backThird week of June, my father would sayI heard it is getting close, my father would sayRhododendron I have been on mountain tops before and sinceDifferent mountains, east, west, other countriesThis one is differentIs it my history, a tie to my family?Third week of June Loaded up in a big blue vanIt was a two-hour drive at the timeIt doesn't seem so far these daysMaybe the drive made it feel more an adventureRoan Mountain We would start at Carver's GapHike up the hillside, running, laughingI remember few of the detailsMy father likes the flowers, all in bloomNot for me Peaceful, even with the wind blowingA cold wind, but a warmth of belongingHundred-mile views, but still groundedRolling mountains and treesA connection [End Page 21] But times are changing, the winds changeI go as often as I canWork and life keep me tied upBut out on the mountain it all comes backA mental resetting Some change is good, expectedBut it is not just me changingThe second week of June now mostlyThe damp winds seep throughMore turbulent somehow This year I plan to go backI will take my family, an adventureSecond week of June, it's getting closeI want to go backTo go back [End Page 22] Carrying Memory Through the park they walk side by side, slowly, down a pathBundled in bulky coats, they trace a well-worn routeBowed forward, they lean in to support each otherHands held together, hanging down like a weight They held hands when they met,a nervous novelty They held hands on the beach,in pursuit of synchrony They held hands after the first time,a bit of wonder and uncertainty They held hands when he asked,with anticipation and hope They held hands during the birth,a dichotomy of pain and joy They held hands with news of promotion,in a shared celebration They held hands when one was sick,a connection without words They held hands …Just because Through the park they walk side by side, slowly, down the pathBundled in bulky coats, they trace a well-worn routeBowed forward, they lean in to support each otherHands bound in memory, hanging down like a weight [End Page 23] Eric Marland Dr. eric marland is a professor at Appalachian State University and loves working at the boundaries between disciplines. He engages in interdisciplinary work with collaborators across many disciplines and recently began co-teaching a class in communicating science. Copyright © 2023 University of North Dakota

Estimates of global and national emissions of carbon dioxide (CO 2 ) are important for scientific understanding and public policy on global climate change. Estimates published annually often see revisions of estimates from previous years. Revisions of data on CO 2 emissions reflect revisions of the energy data from which CO 2 emissions are estimated. Learning is taking place as missing values are compiled, estimated values are revised, and data management systems are updated. Revisions are a frequent feature of the database. Revisions are widespread among countries, commodities, and transactions. We have examined 11 annual reports of the United Nations Energy Statistics Database (those published from 2010 to 2020) to see in the detailed statistics what values are being changed and what are the magnitudes and patterns of change. They are most common in recent years, among developed countries, and among data on liquid fuels. Revisions are generally small and there are no indications of systematic manipulation or bias. Revisions of specific numbers are believed to represent improvements in accuracy but lack of revisions does not point toward accuracy. This examination of revisions does not permit by itself a quantitative estimate of the data uncertainty but it does suggest that the estimates of global and national totals of CO 2 emissions are generally consistent and that both absolute values and trends are reliable over time and sufficiently accurate for scientific understanding and public policy.

Widespread concern about the risks of global climate change is increasingly focused on the urgent need for action (IPCC, 2018; IPCC, 2021), and natural climate solutions are a critical component of global strategies to achieve low temperature targets (e.g. Griscom et al. 2017, Roe et al. 2019). Yet to date, the full potential of natural systems to store carbon has not been leveraged because policy-makers have required long-term contracts to compensate for permanence concerns, and these long-term contracts substantially raise costs and limit deployment. In this paper, we lay out the rationale that our time preference for early action embedded in the Global Warming Potentials (GWP) leads to the conclusion that multiple tons of short-term storage of carbon in ecosystem stocks can be considered to have equal value – as measured by the social cost of carbon -- as 1 ton of carbon sequestered permanently. This equivalence can be used to quantify the value of short-term carbon storage, thereby removing one of the most significant barriers to participation in the carbon market and enabling the full climate mitigation potential of the land sector to be realized.

The scientific literature contains contrasting findings about the climate effects of forest bioenergy, partly due to the wide diversity of bioenergy systems and associated contexts, but also due to differences in assessment methods. The climate effects of bioenergy must be accurately assessed to inform policy-making, but the complexity of bioenergy systems and associated land, industry and energy systems raises challenges for assessment. We examine misconceptions about climate effects of forest bioenergy and discuss important considerations in assessing these effects and devising measures to incentivize sustainable bioenergy as a component of climate policy. The temporal and spatial system boundary and the reference (counterfactual) scenarios are key methodology choices that strongly influence results. Focussing on carbon balances of individual forest stands and comparing emissions at the point of combustion neglect system-level interactions that influence the climate effects of forest bioenergy. We highlight the need for a systems approach, in assessing options and developing policy for forest bioenergy that: (1) considers the whole life cycle of bioenergy systems, including effects of the associated forest management and harvesting on landscape carbon balances; (2) identifies how forest bioenergy can best be deployed to support energy system transformation required to achieve climate goals; and (3) incentivizes those forest bioenergy systems that augment the mitigation value of the forest sector as a whole. Emphasis on short-term emissions reduction targets can lead to decisions that make medium- to long-term climate goals more difficult to achieve. The most important climate change mitigation measure is the transformation of energy, industry and transport systems so that fossil carbon remains underground. Narrow perspectives obscure the significant role that bioenergy can play by displacing fossil fuels now, and supporting energy system transition. Greater transparency and consistency is needed in greenhouse gas reporting and accounting related to bioenergy.

Background Although there is broad agreement that negative carbon emissions may be required in order to meet the global climate change targets specified in the Paris Agreement and that carbon sequestration in the terrestrial biosphere can be an important contributor, there are important accounting issues that often discourage forest carbon sequestration projects. The legislation establishing the California forest offset program, for example, requires that offsets be “real, additional, quantifiable, permanent, verifiable, and enforceable”. While these are all clearly desirable attributes, their implementation has been a great challenge in balancing complexity, expense, and risk. Most forest offset protocols carry similar accounting objectives, but often with different details, (e.g. Richards and Huebner in Carbon Manag 3(4):393–410, 2012 and Galik et al. in Mitig Adapt Strateg Glob Change 14:677–690, 2009). The result is that the complexity, expense, and risk of participation discourage participation and make it more difficult to achieve climate mitigation goals. We focus on the requirements for accounting and permanence to illustrate that current requirements disproportionately disadvantage small landowners. Results The simplified 1040EZ filing system for U.S. income taxes may provide insight for a protocol model that balances reward, effort, and risk, while still achieving the overall objectives of standardized offset protocols. In this paper, we present initial ideas and lay the groundwork behind a “2050EZ” protocol for forest carbon sequestration as a complement to existing protocols. Conclusion The Paris Agreement states that “Parties should take action to conserve and enhance, as appropriate, sinks and reservoirs of greenhouse gases.” The Paris Agreement also refers to issues such as equity, sustainable development, and other non-carbon benefits. The challenge is to provide incentives for maintaining and increasing the amount of carbon sequestered in the biosphere. Monitoring and verification of carbon storage need to be sufficient to demonstrate sequestration from the atmosphere while providing clear incentives and simple accounting approaches that encourage participation by diverse participants, including small land holders.

Carbon dioxide (CO2) emissions from U.S. power plants are independently reported by the U.S. Energy Information Administration (EIA) and the Clean Air Markets Division (CAMD) within the U.S. Environmental Protection Agency (EPA). Differences between the CAMD and EIA emission tallies show that the amount of CO2 produced by an individual power plant is less certain than might be imagined or desired. These differences are attributed to systematic error and random measurement error. Random error cannot be retroactively corrected, whereas systematic error can be corrected where relevant data are available. Accordingly, this study identified and, where possible, corrected systematic error affecting the CAMD and EIA CO2 emission tallies for 1065 power plants that emitted more than 25,000 tons of CO2 during 2013. The EIA tallies were corrected by accounting for emission factor error, acid-gas sorbent consumption, and combustion of biogenic fuel. The CAMD tallies were likewise corrected by accounting for unreported unit emissions. It was not possible to objectively correct systematic error affecting about 11% of the power plants, and subjective corrections were not attempted. At these plants, the CAMD and EIA emission tallies sometimes differed by more than 20% due to missing unit error, plant identification error, temporal measurement error, or inferred reporting error. Comparisons of the CAMD and EIA emission tallies before and after correction for systematic error show the effectiveness of these corrections. The comparisons also show the persistence of random measurement error. Implications: Understanding the uncertainty of CO2 emission tallies for USA power plants might inform emission inventories, atmospheric flow models or inversions, and emission reduction policies. Knowing the cause and size of measurement errors that contribute to this uncertainty might also help to identify ways to improve the measurement methods and reporting protocols that these CO2 emission tallies are based on.

A crucial aspect of constructing a gridded model of anthropogenic fossil fuel CO2 (FFCO2) emissions involves careful consideration of uncertainty. Both the spatial resolution of the emissions estimates (grid scale) and the selection of proxy data to represent the spatial distribution of emissions, plus the quality of data on point sources of emissions, have important impacts on uncertainty. In earlier papers, we explored the uncertainties associated with grid selection and the available data on large point sources. In this work CO2 emissions data are spatially distributed using population density as the selected proxy, using three different treatments of large point sources, and with five levels of grid resolution (1(o), 2(o), 3(o), 4(o), and 5(o)). The methods of calculating uncertainty associated with grid size, proxy selection, and reported point-source emissions data are presented, with particular attention being drawn to grid size selection. We find that as the resolution becomes coarser, relative uncertainty (total uncertainty as a percentage of total emissions) at the grid cell level decreases. Relative uncertainty in most grid cells decreases as the portion of emissions attributed to specific point sources increases. Good data on large point sources is very important for spatially explicit emissions inventories.

In the forest offset program, sequestration of carbon from the atmosphere has quite a number of factors that are uncertain or pose a risk. The uncertainty among the different factors can vary by region or by project. The uncertainty can also be reduced using a variety of strategies. The risks may be different under a variety of circumstances and may be reduced by one of several actions.

There are many ideas presented in this document but here we highlight some of the major points. There is much still to be learned for implementing a forest offset program and what works for one market is likely to be emulated or adapted in other markets. Goldstein and Nayland (2015) note that “there are a few key compliance carbon-pricing policies to watch” and “California represents the most certain source of demand for forest carbon in the next few years.” Challenges that are met can be modified and improved in other markets and in new iterations of existing markets. A key objective is to maintain fungibility among markets and between emissions and offsets (Lee et al. 2013).

A key component of California's cap-and-trade program is the use of carbon offsets as compliance instruments for reducing statewide GHG emissions. Under this program, offsets are tradable credits representing real, verifiable, quantifiable, enforceable, permanent, and additional reductions or removals of GHG emissions. This paper focuses on the permanence and additionality standards for offset credits as defined and operationalized in California's Compliance Offset Protocol for U.S. Forest Projects. Drawing on a review of the protocol, interviews, current offset projects, and existing literature, we discuss how additionality and permanence standards relate to project participation and overall program effectiveness. Specifically, we provide an overview of offset credits as compliance instruments in California's cap-and-trade program, the timeline for a forest offset project, and the factors shaping participation in offset projects. We then discuss the implications of permanence and additionality at both the project and program levels. Largely consistent with previous work, we find that stringent standards for permanent and additional project activities can present barriers to participation, but also, that there may be a trade-off between project quality and quantity (i.e. levels of participation) when considering overall program effectiveness. We summarize what this implies for California's forest offset program and provide suggestions for improvements in light of potential program diffusion and policy learning.

Carbon offset programs, such as that overseen by the California Air Resources Board (CA ARB), have emerged as a strategy for climate change mitigation. Offset projects sequestering carbon earn credits that can be traded on the Cap-and-Trade market to compensate for carbon emissions. The carbon stock embodied in harvested wood products can make up a substantial portion of the sequestered carbon in forest offset projects. In this paper we investigate the sensitivity of the calculations for the number of credits allocated to a forest offset project in the California system. We also examine how alternative models for the decay of harvested wood products might better reflect the dynamics of both the lifetime and cascade chain progression of the products and how this might change the amount of credits earned. The results suggest improved data collection and refinement in methodology would help to improve accuracy and reduce uncertainty in a large and important carbon stock. We conclude with offering suggestions on how an understanding of the dependence of harvested wood product stocks on life cycle parameters might affect the economics of offset programs and assist targeted mitigation efforts.