Climate Change and...
Effects of Climate Change
- Climate Variability
- Climate Models
Effects of Climate Change
E. Eriksson, A. R. Gillespie, L. Gustavsson, O. Langvall, M. Olsson, R. Sathre, J. Stendahl (2007). Integrated carbon analysis of forest management practices and wood substitution. Canadian Journal of Forest Research 37 (3): 671-681
ABSTRACT: The complex fluxes between standing and harvested carbon stocks, and the linkage between harvested biomass and fossil fuel substitution, call for a holistic, system-wide analysis in a life-cycle perspective to evaluate the impacts of forest management and forest product use on carbon balances. We have analysed the net carbon emission under alternative forest management strategies and product uses, considering the carbon fluxes and stocks associated with tree biomass, soils, and forest products. Simulations were made using three Norway spruce (Picea abies (L.) Karst.) forest management regimes (traditional, intensive management, and intensive fertilization), three slash management practices (no removal, removal, and removal with stumps), two forest product uses (construction material and biofuel), and two reference fossil fuels (coal and natural gas). The greatest reduction of net carbon emission occurred when the forest was fertilized, slash and stumps were harvested, wood was used as construction material, and the reference fossil fuel was coal. The lowest reduction occurred with a traditional forest management, forest residues retained on site, and harvested biomass was used as biofuel to replace natural gas. Product use had the greatest impact on net carbon emission, whereas forest management regime, reference fossil fuel, and forest residue usage as biofuel were less significant.
INTRODUCTION: Atmospheric concentrations of carbon dioxide (CO2 ) and other greenhouse gases have been increasing since the beginning of the industrial revolution in 1850. Over the next century, increasing gas concentrations could cause the temperature on the surface of the Earth to rise as much as 2–3°C over historic mean annual levels. Variation in annual climate could also increase.
The United States experienced one indication of climate change in 1988: The summer of that year was one of the hottest, driest ever recorded across the nation. Barges were stranded on the Mississippi River, and forest fires burned millions of acres in the western United States. In the eastern United States, temperatures were so high that many factory assembly lines had to be shut down. The former Soviet Union states and China also experienced severe drought, while Africa, India, and Bangladesh witnessed torrential rains and flooding.
These events triggered televised congressional debates, which concluded that atmospheric greenhouse gas inputs would very likely increase the intensity and severity of weather patterns during the next 100 years. The potential negative effects of global warming—melting of polar ice caps, a rise in the sea level, reduced agricultural and forest productivity, water shortages, and extinction of sensitive species—were also discussed.
These findings prompted the passage of the 1990 Global Change Research Act (GCRA) and the establishment of the US Global Change Research Program (USGCRP). The program sponsors ongoing research (over $1.6 billion in 2000) at several federal agencies, including the National Aeronautics and Space Administration, Department of Energy, US Department of Agriculture, Environmental Protection Agency, National Institutes of Health, Department of Commerce, and National Science Foundation, among others (USGCRP 1999). In addition to providing a mechanism for funding research on global change, the GCRA mandates that an assessment be conducted periodically to summarize research findings. Begun in 1997, the first National Assessment of the Potential Consequences of Climate Variability and Change was published in 2001 (USGCRP 2001). The assessment was a collaboration between federal and nonfederal researchers, resource managers, and users. The assessment is divided into five sectors: (1) water resources and availability, (2) agriculture and food production, (3) human health, (4) coastal areas, and (5) forests. These sectors represent important or potentially sensitive US resources that could be adversely affected by climate change. The assessment also includes over 20 regional studies, which examine the impacts of climate change for specific geographical areas of the United States. This special section of BioScience focuses on a summary of research findings from the forest sector and regional findings of the 2001 national assessment (USGCRP 2001).
The impacts of climate change on the forest sector are divided into four categories: (1) forest processes, (2) biodiversity change, (3) disturbance interactions, and (4) socioeconomic change. These categories represent key interactions between a changing climate, forest structure or function, and human interactions with forests.
P. W. Mote, E. A. Parson, A. F. Hamlet, W. S. Keeton, D. Lettenmaier, N. Mantua, E. L. Miles, D. W. Peterson, D. L. Peterson, R. Slaughter, A. K. Snover (2003). Preparing for climatic change: the water, salmon, and forests of the Pacific Northwest. Climatic Change 61 (1-2): 45-88
ABSTRACT: The impacts of year-to-year and decade-to-decade climatic variations on some of the Pacific Northwest's key natural resources can be quantified to estimate sensitivity to regional climatic changes expected as part of anthropogenic global climatic change. Warmer, drier years, often associated with El Niño events and/or the warm phase of the Pacific Decadal Oscillation, tend to be associated with below-average snowpack, streamflow, and flood risk, below-average salmon survival, below-average forest growth, and above-average risk of forest fire. During the 20th century, the region experienced a warming of 0.8 °C. Using output from eight climate models, we project a further warming of 0.5–2.5 °C (central estimate 1.5 °C) by the 2020s, 1.5–3.2 °C (2.3 °C) by the 2040s, and an increase in precipitation except in summer. The foremost impact of a warming climate will be the reduction of regional snowpack, which presently supplies water for ecosystems and human uses during the dry summers. Our understanding of past climate also illustrates the responses of human management systems to climatic stresses, and suggests that a warming of the rate projected would pose significant challenges to the management of natural resources. Resource managers and planners currently have few plans for adapting to or mitigating the ecological and economic effects of climatic change.
Irland, L.C., D. Adams, R. Alig, C.J. Betz, C. Chen, M. Hutchins, B.A. McCarl, K. Skog, B.L. Sohngen (2001). Assessing socioeconomic impacts of climate change on US forests, wood-product markets, and forest recreation. BioScience 51 (9): 753-764
INTRODUCTION: Scientists have suggested that future climate change will significantly affect the distribution, condition, species composition, and productivity of forests (Aber et al. 2001, Dale et al. 2001, Hansen et al. 2001, McNulty and Aber 2001). These biological changes will set in motion complex regional changes in supplies of wood to sawmills and paper mills, producing effects on market prices. In turn, landowners and consumers will adapt in ways that cause further feedback effects on forests. For some time, social scientists have been assessing the manifold implications for social and economic welfare. In particular, they have been examining ways in which price responses to changing supplies cause timber growers, sawmills and pulpmills, producers, and consumers to adapt. This paper reviews this research, focusing on the forest benefits of timber production and outdoor recreation. Analyzing these sectors involves quite different methods and issues because wood products are primarily producer goods that reach consumers through a complex marketing chain, whereas forest-recreation experiences are directly consumed by visitors. As part of the national assessment of climate change, a socioeconomic team (the authors of this article) assembled existing data and conducted limited new analyses. In this short summary, many important topics must be left aside.
In this paper we discuss the problems of projecting social and economic changes affecting forests and review recent efforts to assess the wood-market impacts of possible climate changes. To illustrate the range of conditions encountered in projecting socioeconomic change linked to forests, we consider two markedly different uses: forest products markets and forest recreation. In the case of forest products, we use an existing forest-sector model to arrive at new simulation results concerning the impacts of climate change. The impact of climate change on recreation has received less attention; here we consider a case study of downhill skiing. Other important forest values were not treated explicitly in this research. Our primary emphasis is on methods and issues in the socioeconomic assessment process. Our efforts may be viewed as an exercise in human ecology, studying complex interactions between human societies and their forests. We close with suggestions for future research.
ABSTRACT: Greenhouse gas mitigation possibilities in the agricultural and forest sector represent a complex system of interlinked strategies. To assess their true economic implementation potential, major mitigation strategies are simultaneously examined with a U.S. agricultural sector model over a large range of hypothetical carbon prices. Soil carbon sequestration through reduced tillage appears most attractive for relatively low carbon prices. Afforestation and biofuel generation, however, dominate at higher price levels. For politically feasible prices, the competitive economic contribution of all major strategies is greatly below their technical potential. However, positive environmental and social coeffects may increase the importance of agricultural mitigation policies.
Mote, P. W., D. J. Canning, D. L. Fluharty, R.C. Francis, J. F. Franklin, A. F. Hamlet, M. Hershman, M. Holmberg, K. N. Ideker, W. S. Keeton, D. P. Lettenmaier, L. R. Leung, N. J. Mantua, E. L. Miles, B. Noble, H. Parandvash, D. W. Peterson, A. K. Snover, S. R. Willard (1999). Impacts of climate variability and change, Pacific Northwest. National Atmospheric and Oceanic Administration, Office of Global Programs, and JISAO/SMA Climate Impacts Group: 110 pp.
OVERVIEW: Experience of the recent past illustrates the impacts that the climate variations have on the Pacific Northwest, and illustrates that there are both winners and loser when the climate is different from the “average.” The mild winter and spring of 1997—98 saw an early snow melt, which strained regional water supplies during the summer and fall months. An especially warm and dry summer, coupled with the early melt, led to exceptionally low flows and high temperatures in many Northwest streams. These conditions in turn caused severe difficulties for salmon. However, 1997—98 also had benefits for the region, which avoided the damage and disruption caused by heavy snow fall and winter flooding during the previous two winters.
Climate is not a constant, and yet many aspects of human infrastructure and activities are planned with the assumption that it is constant. But what happens when climate produces a surprise? What if, furthermore, there are long-term changes in climate? Humans have altered the composition of Earth’s atmosphere to such an extent that climate itself appears to be changing. The consequences of a changing climate may be beneficial for some places and activities, and detrimental for others.
This report describes the possible impacts of human-induced climate change and of natural climate variability like El Niño, focusing on the water resources, salmon, forests, and coasts of the Pacific Northwest (PNW). It has been prepared largely by the Climate Impacts Group (CIG) at the University of Washington. The CIG, under the direction of Professor Edward L. Miles, is an interdisciplinary group of researchers from the physical, biological, and social sciences working together to understand the impacts of climate variability and change on the Northwest.
Looking at the recent past, much of the climate history of the PNW can be described by a few recurring patterns. The strongest pattern highlights the tendency for winter climate to be either relatively cool and wet or relatively warm and dry. Cool-wet winters are generally associated with increased risks of flooding and landslides, abundant summer water supply, more abundant salmon, reduced risk of forest fires, and improved tree growth (except at high elevation). Warm-dry winters are often followed by summer water shortages, less abundant salmon, and increased risk of forest fires. The occurrence of the cool-wet or warm-dry winter pattern is influenced by two main climate variations in the Pacific Basin: ENSO (El Niño-Southern Oscillation) primarily on year-to-year timescales and PDO (the Pacific Decadal oscillation) primarily on decade-to-decade timescales. ENSO and PDO cause variation sin snowpack and streamflow, and hence the ability to meet water resource objectives; with respect tot he region’s water resources, ENSO and PDO can reinforce or cancel each other. In contrast, the response of forests and salmon is correlated more strongly with the PDO than with ENSO. The magnitude of seasonal anomalies of temperature and precipitation leading to the above effects is strikingly small, but these past anomalies enable us to calibrate the possible responses to long-term climate change.
Looking to the future, computer models of climate generally agree that the PNW will become, over the next half century, gradually warmer and wetter, with most of the precipitation increase in winter. These trends mostly agree with observed changes over the past century. Wetter winters would likely mean more flooding of certain rivers, and landslides on steep coastal bluffs. The region’s warm, dry summers may see slight increases in rainfall, according to the models, but the gains in rainfall will be more than offset by losses due to increases in evaporation. Loss of moderate-elevation snowpack in response to warmer winter temperatures would have enormous and mostly negative impacts on the region’s water resources, forests, and salmon. Among these impacts are a diminished ability to store water in reservoirs for summer use, more drought-stressed tress leading to reductions in forested area, and spawning and rearing difficulties for salmon.
Knowing what changes might occur is only part of the challenge, however. This knowledge must make its way from the realm of research to the realm of decisions, and be used in decisions. Large practical and, in some cases, legal constraints prevent climate information from being fully utilized. Meeting the challenges posed by climate variations and climate change will require considerable revision of the policies and practices concerning how the region’s natural resources are managed. An indication of the scope of such revisions comes from considering how government agencies have handled climate-related stresses in the past, like droughts and coastal erosion. In many cases, agencies cannot even make use of a good seasonal forecast in making short-term planning decision: the operating assumption is often that climate is constant and extremes do not occur. There are wide variations among the four sectors considered here in how management presently makes use of climate information.
DESCRIPTION: Increasing recognition that anthropogenic CO2 and other greenhouse gas emissions may effect climate change has prompted research studies on global carbon (C) budgets and international agreements for action. At the United Nations Conference on Environment and Development in 1992, world leaders and citizens gathered and initiated the Framework Convention for Climate Change (FCCC), an agreement to address global climate change concerns.
L. A. Joyce, J. R. Mills, L. S. Heath, A. D. McGuire, R. W. Haynes, R. A. Birdsey (1995). Forest sector impacts from changes in forest productivity under climate change. Journal of Biogeography 22 (4/5): 703-713
ABSTRACT: The consequences of elevated carbon dioxide and climate change on forest systems and the role that economics could play in timber harvest and vegetation change have not been addressed together. A framework was developed to link climate change scenarios, an ecosystem model, a forest sector model and a carbon accounting model. Four climate scenarios were used to estimate net primary productivity (NPP) for forests in the United States. Changes in NPP were estimated using TEM, the Terrestrial Ecosystem Model which uses spatially referenced information on climate, soils and vegetation to estimate important carbon and nitrogen fluxes and pool sizes within ecosystems at the continental scale. Changes in NPP under climate change were used to modify timber growth within the Aggregate Timberland Assessment Model (ATLAS), which is a part of the forest sector model (TAMM-ATLAS) used by the Forest Service to examine timber policy questions. The changes in timber were the translated into changes in the amount of carbon stored on private timberlands using a national carbon model (FORCARB). Regional changes in productivity filter through the forest sector and result in changes in land use and timber consumption. Long-term changes in carbon storage indicate that these private timberlands will be a source of carbon dioxide for all but the most optimistic climate change scenario.
ABSTRACT: This study provides historical estimates and projections of U.S. carbon sequestered in wood and paper products and compares them to amounts sequestered in U.S. forests. There are large pools of carbon in forests, in wood and paper products in use, and in dumps and landfills. The size of these carbon pools is increasing. Since 1910, an estimated 2.7 Pg (petagrams; × 109 metric tons) of carbon have accumulated and currently reside in wood and paper products in use and in dumps and landfills, including net imports. This is notable compared with the current inventory of carbon in forest trees (13.8 Pg) and forest soils (24.7 Pg). On a yearly basis, net sequestration of carbon in U.S. wood and paper products (additions including net imports, minus emissions from decay and burning each year) is projected to increase from 61 Tg/year in 1990 to 74 Tg/year by 2040, while net additions (sequestration) in forests is projected to decrease from 274 to 161 Tg/year. Net sequestration is increasing in products and landfills because of an increase in wood consumption and a decrease in decay in landfills compared with phased-out dumps. If the total projected amount of products required is regarded as fixed, the net carbon sequestration in products and landfills can be increased by 1) shifting product mix to a greater proportion of lignin-containing products, which decay less in landfills; 2) increasing product recycling; 3) increasing product use-life; and 4) increasing landfill CH4 burning in place of fossil fuels.
FIRST PARAGRAPH: The popular dictum is “Think globally, act locally.” We might want to modify it somewhat to “Protect globally, recycle locally.” Poll after poll indicates that citizens connect recycling with saving the environment — by saving energy and water resources, reducing timber harvests and keeping recoverable materials out of landfills. But there may be another, larger benefit, one that will affect not just the environment in the United States, but that of all countries.
Recent research conducted by the Forest Products Laboratory (Madison, Wisconsin) found that 10 to 20 percent of the U.S. carbon reduction goal could be met through a range of scenarios for paper and wood recycling. More aggressive paper and wood recycling — as well as composting, source reducing and recycling other recoverable materials — can provide even more dramatic decreases.
ABSTRACT: The path and magnitude of future anthropogenic emissions of carbon dioxide will likely influence changes in climate that may impact the global forest sector. These responses in the global forest sector may have implications for international efforts to stabilize the atmospheric concentration of carbon dioxide. This study takes a step toward including the role of global forest sector in integrated assessments of the global carbon cycle by linking global models of climate dynamics, ecosystem processes and forest economics to assess the potential responses of the global forest sector to different levels of greenhouse gas emissions. We utilize three climate scenarios and two economic scenarios to represent a range of greenhouse gas emissions and economic behavior. At the end of the analysis period (2040), the potential responses in regional forest growing stock simulated by the global ecosystem model range from decreases and increases for the low emissions climate scenario to increases in all regions for the high emissions climate scenario. The changes in vegetation are used to adjust timber supply in the softwood and hardwood sectors of the economic model. In general, the global changes in welfare are positive, but small across all scenarios. At the regional level, the changes in welfare can be large and either negative or positive. Markets and trade in forest products play important roles in whether a region realizes any gains associated with climate change. In general, regions with the lowest wood fiber production cost are able to expand harvests. Trade in forest products leads to lower prices elsewhere. The low-cost regions expand market shares and force higher-cost regions to decrease their harvests. Trade produces different economic gains and losses across the globe even though, globally, economic welfare increases. The results of this study indicate that assumptions within alternative climate scenarios and about trade in forest products are important factors that strongly influence the effects of climate change on the global forest sector.
ABSTRACT: Changing temperature and precipitation pattern and increasing concentrations of atmospheric CO2 are likely to drive significant modifications in natural and modified forests. Our review is focused on recent publications that discuss the changes in commercial forestry, excluding the ecosystem functions of forests and nontimber forest products. We concentrate on potential direct and indirect impacts of climate change on forest industry, the projections of future trends in commercial forestry, the possible role of biofuels, and changes in supply and demand.