•Global forest sector model intercomparison of 81 future pathway scenarios.•Socioeconomic drivers have strongly influence forest sector model estimates.•Global forests could sequester 1.2–5.8 ...GtCO2e/yr over the next century.•Improved management can increase carbon and harvests without expanding forest area.•Climate policy assessments could better represent forest markets and management dynamics.
Deforestation has contributed significantly to net greenhouse gas emissions, but slowing deforestation, regrowing forests and other ecosystem processes have made forests a net sink. Deforestation will still influence future carbon fluxes, but the role of forest growth through aging, management, and other silvicultural inputs on future carbon fluxes are critically important but not always recognized by bookkeeping and integrated assessment models. When projecting the future, it is vital to capture how management processes affect carbon storage in ecosystems and wood products.This study uses multiple global forest sector models to project forest carbon impacts across 81 shared socioeconomic (SSP) and climate mitigation pathway scenarios. We illustrate the importance of modeling management decisions in existing forests in response to changing demands for land resources, wood products and carbon. Although the models vary in key attributes, there is general agreement across a majority of scenarios that the global forest sector could remain a carbon sink in the future, sequestering 1.2–5.8 GtCO2e/yr over the next century. Carbon fluxes in the baseline scenarios that exclude climate mitigation policy ranged from −0.8 to 4.9 GtCO2e/yr, highlighting the strong influence of SSPs on forest sector model estimates. Improved forest management can jointly increase carbon stocks and harvests without expanding forest area, suggesting that carbon fluxes from managed forests systems deserve more careful consideration by the climate policy community.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
•Numerous policies globally could increase the demand for wood-based bioenergy.•Biomass energy demand growth can drive forest resource investment/management.•Global market reallocation and trade ...adjustments are also important considerations.•Projected changes in forest management globally show carbon beneficial outcomes.
Several previous studies have evaluated the potential greenhouse gas (GHG) benefits of forest biomass energy relative to fossil fuel equivalents over different spatial scales and time frames and applying a variety of methodologies. This paper contributes to this literature through an analysis of multiple projected sources of biomass demand growth in different regions of the world using a detailed intertemporal optimization model of the global forest sector. Given the range of current policies incentivizing bioenergy expansion globally, evaluating the combined global implications of regional bioenergy expansion efforts is critical for understanding the extent to which renewable energy supplied from forest biomass can contribute to various policy goals (including GHG emissions mitigation). Unlike previous studies that have been more regionally focused, this study provides a global perspective, illustrating how large potential demand increases for forest biomass in one or multiple regions can alter future forest management trends, markets, and forest carbon sequestration in key timber supply regions. Results show that potential near term (2015–2030) biomass demand growth in the U.S., Europe, and elsewhere can drive forest resource investment at the intensive and extensive margins, resulting in a net increase in forest carbon stocks for most regions of the world. When the reallocation of biomass away from traditional pulp and sawtimber markets is accounted for, net forest carbon sequestration increases (that stored on the land and in wood products) by 9.4 billion tons CO2 over the near term and 15.4 billion tons CO2 by 2095. Even if most of the increased forest biomass demand arises from one region (e.g., Europe) due to a particularly strong promotion of forest bioenergy expansion, changes in forest management globally in anticipation of this demand increase could result in carbon beneficial outcomes that can be shared by most regions.
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GEOZS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SBCE, UM, UPUK
In this study we implement the global partial equilibrium model GLOBIOM, which has been used extensively in the past: 1) to analyze the effects of biofuel policies on total GHG emissions balance ...(Havlík et al. 2011; Frank et al. forthcoming; and Mosnier et al. 2012); 2) to assess the mitigation potential of reduced emissions from deforestation (Böttcher et al. 2012); and 3) to investigate future global challenges in the sector in general (Schneider et al. 2011). The model specifically allows feed requirements to be defined in physical units for each production system. Hence, the substitution of feed crops for grass can be explicitly modeled as a switch from one system to another. To assess the effects of crop yield growth, we first simulate future scenarios with varying crop yield assumptions, and we compare their effects on the structure of production systems, cropland and grassland expansion, and GHG emissions. In a second step, we compare the resulting emission reductions with the efforts that would be needed under mitigation policies without crop yield growth, and discuss their implications for policy-making. Reprinted by permission of the American Agricultural Economics Association
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BFBNIB, FZAB, GIS, IJS, INZLJ, IZUM, KILJ, NLZOH, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZRSKP
Background
Wood products continue to store carbon sequestered in forests after harvest and therefore play an important role in the total carbon storage associated with the forest sector. Trade-offs ...between carbon sequestration/storage in wood product pools and managed forest systems exist, and in order for forest sector carbon modeling to be meaningful, it must link wood product carbon with the specific forest system from which the products originate and have the ability to incorporate in situ and ex situ carbon synchronously over time.
Results
This study uses elements of a life cycle assessment approach, tracing carbon from US southern pine timber harvests to emission, to create a decision support tool that practitioners can use to inform policy design around land- and bioproduct-based mitigation strategies. We estimate that wood products from annual loblolly and shortleaf pine timber harvests across the southern US store 29.7 MtC in the year they enter the market, and 11.4 MtC remain stored after 120 years. We estimate fossil fuel emissions from the procurement, transportation, and manufacturing of these wood products to be 43.3 MtCO
2
e year
−1
. We found that composite logs, used to manufacture oriented strand board (OSB), were the most efficient log type for storing carbon, storing around 1.8 times as much carbon as saw logs per tonne of log over 120 years.
Conclusions
Results from our analysis suggest that adjusting rotation length based on individual site productivity, reducing methane emissions from landfills, and extending the storage of carbon in key products, such as corrugated boxes, through longer lifespans, higher recycling rates, and less landfill decomposition could result in significant carbon gains. Our results also highlight the benefits of high site productivity to store more carbon in both in situ and ex situ pools and suggest that shorter rotations could be used to optimize carbon storage on sites when productivity is high.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The United States has recently set ambitious national goals for greenhouse gas (GHG) reductions over the coming decades. A portion of these reductions are based on expected sequestration and storage ...contributions from land use, land use change, and forestry (LULUCF). Significant uncertainty exists in future forest markets and thus the potential LULUCF contribution to US GHG reduction goals. This study seeks to inform the discussion by modeling US forest GHG accounts per different simulated demand scenarios across a grid of over 130,000 USDA Forest Service Forest Inventory and Analysis (FIA) forestland plots over the conterminous United States. This spatially disaggregated future supply is based on empirical yield functions for log volume, biomass and carbon. Demand data is based on a spatial database of over 2300 forest product manufacturing facilities representing 11 intermediate and 13 final solid and pulpwood products. Transportation costs are derived from fuel prices and the locations of FIA plot from which a log is harvested and mill or port destination. Trade between mills in intermediate products such as sawmill residues or planer shavings is also captured within the model formulation. The resulting partial spatial equilibrium model of the US forest sector is solved annually for the period 2015–2035 with demand shifted by energy prices and macroeconomic indicators from the US EIA's Annual Energy Outlook for a Reference, Low Economic Growth, and High Economic Growth case. For each macroeconomic scenario simulated, figures showing historic and scenario-specific live tree carnon emissions and sequestration are generated. Maps of the spatial allocation of both forest harvesting and related carbon fluxes are presented at the National level and detail is given for both regions and ownerships.
•Uncertainty exists in contributions of Land Use land Use Change and Forestry (LULUCF) to future U.S. GHG national accounting.•This uncertainty is driven in part by the contribution of macroeconomic conditions to LULUCF emissions and/or sequestration.•We project 2014–2035 live tree carbon via a spatially explicit model of the U.S. forest sector for 3 macroeconomic scenarios.•The model shows that underlying macroeconomic conditions are a key driver of future LULUCF GHG emission and/or sequestration.•A consistent finding across scenarios is that U.S. will continue to sequester carbon but at a decreasing rate.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
Many countries have taken on ambitious but potentially costly renewable energy development goals to combat climate change. The government of Guatemala has introduced a plan to increase renewable ...generation capacity, while an estimated 76% of Guatemalans are energy poor. In this paper, we evaluate the trade-offs between alleviating energy poverty and achieving renewable energy goals in Guatemala. We present a framework that combines an electricity cost model with a household expenditure survey to assess the effects that a national renewable energy development goal could have on energy poverty through added electricity expenditures. We find that the development of new renewable electricity generation has potential to significantly increase tariffs for residential electricity consumers across the country, whereby 80% of municipalities could experience more than one-third increase in monthly energy expenditures. More importantly, we find that the distribution of impacts will not be equal everywhere: households in the western, rural part of Guatemala that are already energy stressed will likely experience the greatest cost burdens because natural resource availability is low while overall poverty is already high. In addition, we compare the costs of renewable versus fossil fuel development and find that the least-cost policy in Guatemala includes a mix of both renewable and fossil technologies.
•Renewable energy projects can worsen energy poverty via higher electricity costs•We assess electricity costs using a novel model and survey framework•Renewable mandates will most affect already-energy poor regions in Guatemala•Renewable energy subsidies would minimize impacts on low-income households•Least-cost policy in Guatemala includes both renewable and fossil fuel technologies
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
The costs and technical expertise associated with forest carbon offset projects can be significant, while decades-long time commitments can discourage participation from the outset. Considering these ...challenges, several new approaches have emerged in the United States under the auspices of both long-standing and recently-established programs, attempting to leverage increased carbon mitigation. What several of these approaches have in common is reduced emphasis on long-term storage, what we refer to as a traditional perspective of permanence. Instead, each considers shorter periods of time—up to and including single year harvest deferrals—as eligible project commitments. Here, we provide a brief discussion of the historical permanence and accounting literature, with an emphasis on contradictory views and how these perspectives have evolved over time. Next, we quantitatively assess the long-term influence of different permanence requirements as envisioned in several new and existing forest carbon programs, estimating net mitigation across a variety of forest types and project configurations. We conclude with a presentation of our quantitative findings in the context of the existing literature, while also highlighting unmet research needs on these so-called
new offsets
, those emerging novel approaches for forest carbon mitigation that challenge the research and practice
status quo
.
Conversion of natural land cover can degrade water quality in water supply watersheds and increase treatment costs for Public Water Systems (PWSs), but there are few studies that have fully evaluated ...land cover and water quality relationships in mixed use watersheds across broad hydroclimatic settings. We related upstream land cover (forest, other natural land covers, development, and agriculture) to observed and modeled water quality across the southeastern US and specifically at 1746 PWS drinking water intake facilities. While there was considerable complexity and variability in the relationship between land cover and water quality, results suggest that Total Nitrogen (TN), Total Phosphorus (TP) and Suspended Sediment (SS) concentrations decrease significantly with increasing forest cover, and increase with increasing developed or agricultural cover. Catchments with dominant (>90 %) agricultural land cover had the greatest export rates for TN, TP, and SS based on SPARROW model estimates, followed by developed-dominant, then forest- and other-natural-dominant catchments. Variability in modeled TN, TP, and SS export rates by land cover type was driven by variability in natural background sources and catchment characteristics that affected water quality even in forest-dominated catchments. Both intake setting (i.e., run-of-river or reservoir) and upstream land cover were important determinants of water quality at PWS intakes. Of all PWS intakes, 15 % had high raw water quality, and 85 % of those were on reservoirs. Of the run-of-river intakes with high raw water quality, 75 % had at least 50 % forest land cover upstream. In addition, PWS intakes obtaining surface water supply from smaller upstream catchments may experience the largest losses of natural land cover based on projections of land cover in 2070. These results illustrate the complexity and variability in the relationship between land cover and water quality at broad scales, but also suggest that forest conservation can enhance the resilience of drinking water supplies.
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•Land cover and water quality were linked regionally and at public water intakes.•Nutrient and sediment concentrations decreased with increasing forest land cover.•Both intake setting and land cover were important determinants of water quality.•Small watersheds may experience the largest losses of natural land cover by 2070.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
This paper applies a spatial allocation optimization model to evaluate logging residue supply potential and costs for bioelectricity generation within the conterminous United States. Simulations are ...developed to estimate a range in supply potential and costs across a broad range of sensitivity scenarios, including (1) different biomass availability rates based on observed roundwood removals, (2) renewable energy targets set nationally or at a state-level, (3) with and without biomass sourcing restrictions within a state, (4) with and without access to public lands, and (5) policy restrictions on eligible facility types. Under the least restrictive policy scenario (a hypothetical national mandate), total supply is 8.8 million dry tons (MDT) at $20/DT and increases to 32.5 MDT at $80/DT. Results fall within the range of previous logging residue supply studies in the U.S., including the last two Billion Ton reports. Results from this paper offer important policy insight into the potential cost efficiency of a flexible policy design. Sensitivity scenarios show potential supply cost increases that could result from policies imposing regional restrictions, limiting access to public lands, and restricting eligible facilities. Restricting biomass supply sources within state boundaries reduces total supply up to 10% relative to an unrestricted national policy.
•Logging residues can provide an important renewable energy fuel source.•Supply potential varies with the biomass price and regional forest harvests.•Eligible facilities and their locations are key determinants of supply costs.•Certain policy considerations result in cost inefficiencies and reduced supply.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
Agriculture is one of the sectors that is expected to be most significantly impacted by climate change. There has been considerable interest in assessing these impacts and many recent studies ...investigating agricultural impacts for individual countries and regions using an array of models. However, the great majority of existing studies explore impacts on a country or region of interest without explicitly accounting for impacts on the rest of the world. This approach can bias the results of impact assessments for agriculture given the importance of global trade in this sector. Due to potential impacts on relative competitiveness, international trade, global supply, and prices, the net impacts of climate change on the agricultural sector in each region depend not only on productivity impacts within that region, but on how climate change impacts agricultural productivity throughout the world. In this study, we apply a global model of agriculture and forestry to evaluate climate change impacts on US agriculture with and without accounting for climate change impacts in the rest of the world. In addition, we examine scenarios where trade is expanded to explore the implications for regional allocation of production, trade volumes, and prices. To our knowledge, this is one of the only attempts to explicitly quantify the relative importance of accounting for global climate change when conducting regional assessments of climate change impacts. The results of our analyses reveal substantial differences in estimated impacts on the US agricultural sector when accounting for global impacts vs. US-only impacts, particularly for commodities where the United States has a smaller share of global production. In addition, we find that freer trade can play an important role in helping to buffer regional productivity shocks.
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