IPCC SECOND ASSESSMENT REPORT
Working Group II Table Of Contents

Each chapter listed in this Table of Contents is linked to a brief summary of that chapter. The chapter summaries rely mainly on language from the Working Group II Summary for Policymakers. For an official summary of the report, the Working Group II Summary for Policymakers and Technical Summary: is available on the IPCC Secretariat website.

Introductory Materials: Primers

  1. Ecophysiological, Ecological, and Soil Processes in Terrestrial Ecosystems: A Primer on General Concepts and Relationships-- Miko Kirschbaum/Australia
  2. B. Energy Primer-- Nebojsa Nakicenovic/IIASA
I. Assessment of Impacts and Adaptation Options
  1. Climate Change Impacts On Forests-- Miko Kirschbaum/Australia, Andreas Fischlin/Switzerland
  2. Rangelands in a Changing Climate: Impacts, Adaptations, and Mitigation-- Barbara Allen-Diaz/USA
  3. Deserts in a Changing Climate: Impacts-- Ian Noble/Australia, Habiba Gitay/Australia
  4. Land Degradation and Desertification-- Peter Bullock/UK, Henri Le Houerou/France
  5. Impacts of Climate Change on Mountain Regions-- Martin Beniston/Switzerland, Douglas Fox/USA
  6. Non-Tidal Wetlands-- Bo Svensson/Sweden, Mats Oquist/Sweden
  7. The Cryosphere: Changes and Their Impacts-- B. Blair Fitzharris/New Zealand
  8. Oceans-- Venugopalan Ittekkot/Germany
  9. Coastal Zones and Small Islands-- Luitzen Bijlsma/The Netherlands
  10. Hydrology and Freshwater Ecology-- Nigel Arnell/UK, Bryson Bates/Australia, Herbert Lang/Switzerland, John Magnuson/USA, Patrick Mulholland/USA
  11. Industry, Energy, and Transportation: Impacts and Adaptation-- Jim Skea/UK, Roberto Acosta Moreno/Cuba
  12. Human Settlements in a Changing Climate: Impacts and Adaptation-- Michael Scott/USA
  13. Agriculture in a Changing Climate: Impacts and Adaptation-- John Reilly/USA
  14. Water Resources Management-- Zdzislaw Kaczmarek/Poland
  15. Wood Production under Changing Climate and Land Use-- Allen Solomon/USA
  16. Fisheries-- John Everett/USA
  17. Financial Services-- Andrew Dlugolecki/UK
  18. Human Population Health-- Anthony McMichael/Australia & UK
II. Assessment of Mitigation Options
  1. Energy Supply Mitigation Options-- Hisashi Ishitani/Japan, Thomas Johansson/Sweden
  2. Industry-- Takao Kashiwagi/Japan
  3. Mitigation Options in the Transportation Sector-- Laurie Michaelis/OECD
  4. Mitigation Options for Human Settlements-- Mark Levine/USA
  5. Agricultural Options for Mitigation of Greenhouse Gas Emissions-- Vernon Cole/USA
  6. Management of Forests for Mitigation of Greenhouse Gas Emissions-- Sandra Brown/USA
  7. Mitigation: Cross-Sectoral and Other Issues-- Rik Leemans/The Netherlands
III. Technical Appendices
  1. Technical Guidelines for Assessing Climate Change Impacts and Adaptations-- Shuzo Nishioka/Japan, Martin Parry/UK
  2. Methods for Assessment of Mitigation Options-- Dennis Tirpak/USA
  3. Inventory of Technologies, Methods, and Practices-- David Streets/USA

 

Ecophysiological, Ecological, and Soil Processes in Terrestrial Ecosystems: A Primer on General Concepts and Relationships

This primer provides a brief overview of the major ecological factors that must be considered in assessing the impact of climate change on terrestrial ecosystems. The primer begins with a summary of the effects of important climatic driving forces that are likely to change (temperature, precipitation and soil water availability, and CO2 concentrations), then discusses effects of climate change on soil carbon and nitrogen dynamics, looks at the potential modifying effects of soil fertility, and briefly addresses other soil biological factors. Because these broad ecosystem responses are modified by interactions between the different organisms in each ecosystem, the primer also provides a background discussion on some of the processes and interactions that most affect the response of ecological communities to climate change.

Energy Primer

This primer introduces concepts and terms used in the energy-related chapters of the SAR that deal with adaptation to and mitigation of climate change, along with some of the more commonly used energy units. The primer begins by describing the global energy system and documents 1990 energy-consumption patterns and CO2 emissions. It then discusses energy efficiency data from 1990; provides estimates of maximum achievable efficiencies; and describes the historical development of energy consumption and associated CO2 emissions for the world and for major regions. The primer concludes with a comparison of historical and current energy consumption, with estimates of fossil and nuclear energy reserves and resources, and with potentials of renewable energy sources.

Chapter 1: Climate Change Impacts On Forests

Forests contain a wide range of species with complex life cycles. Forests, particularly in the tropics, harbor as much as two-thirds of the world's biodiversity. They directly affect climate up to the continental scale by influencing ground temperatures, evapotranspiration, surface roughness, albedo, cloud formation, and precipitation. These ecosystems contain 80% of all aboveground carbon in vegetation and about 40% of all soil carbon. Forests and forest soils play a major role in the carbon cycle as sources (e.g., forest degradation and deforestation) and sinks (reforestation, afforestation, and possibly enhanced growth resulting from carbon dioxide fertilization).

Models project that a sustained increase of 1 degree C in global mean temperature is sufficient to cause changes in regional climates that will affect the growth and regeneration capacity of forests in many regions. In several instances, this will alter the function and composition of forests significantly. As a consequence of possible changes in temperature and water availability under doubled equivalent-carbon dioxide equilibrium conditions, a substantial fraction (a global average of one-third, varying by region from one-seventh to two-thirds) of the existing forested area of the world will undergo major changes in broad vegetation types-with the greatest changes occurring in high latitudes and the least in the tropics. Climate change is expected to occur at a rapid rate relative to the speed at which forest species can grow, reproduce, and reestablish themselves at new locations. Although net primary productivity could increase, the standing biomass of forests may not because of more frequent outbreaks and extended ranges of pests and pathogens, and increasing frequency and intensity of fires. Large amounts of carbon could be released into the atmosphere during transitions from one forest type to another because the rate at which carbon can be lost during times of high forest mortality is greater than the rate at which it can be gained through growth to maturity.

Climate change is likely to have its most significant impact on boreal forests through loss of the southern boreal forests, slow invasion of northern treelines into tundra areas, increased fire frequency, and pest outbreaks. The potential area for temperate forests is projected to change the least, but some existing forests, especially in dry regions, will undergo significant changes in species composition. Tropical forests are likely to be more affected by changes in land use than by climate change as long as deforestation continues at its current rate; the greatest effect of climate change on tropical forests is likely to result from changes in soil water availability.

Chapter 2: Rangelands in a Changing Climate: Impacts, Adaptations, and Mitigation

Rangelands (i.e., unimproved grasslands, shrublands, savannas, deserts, and tundra) occupy 51% of the Earth's land surface. They contain about 36% of its total carbon in living and dead biomass, include a large number of economically important species and ecotypes, and sustain millions of people. Rangelands support 50% of the world's livestock and provide forage for domesticated animals and wildlife.

Boundaries between rangelands and other ecosystems appear likely to change as a result of direct climate effects on species composition, as well as indirect factors such as changes in wildfire frequency and land use. Temperate rangelands will experience these effects the most. Migration rates of rangeland vegetation appear to be faster than for forests. The amounts and seasonal distribution of precipitation are the primary controls on rangeland carbon cycling and productivity. Water availability and balance play vital roles in controlling the productivity and geographic distribution of rangeland ecosystems; thus, small changes in precipitation and in extreme temperatures may have disproportionate effects. Devising adaptation strategies for rangeland systems may prove difficult in marginal food-producing areas where production is very sensitive to climate change, changing of technology is risky, and the rate of adoption of new techniques and practices is slow. Decreases in rangeland productivity would likely result in a decline in the overall contribution of the livestock industries to national economies, especially in many developing areas with pastoral economies. Adaptation options in more highly managed pastures include management of forage, animal breeding, and irrigation. Mitigation options to increase carbon sequestration and reduce methane emissions focus on improving vegetation and soil conditions and improving animal management practices.

Chapter 3: Deserts in a Changing Climate: Impacts

If the Earth's climate does change as projected in current scenarios, most deserts are likely to experience temperature increases due to climate change; the impacts on water balance, hydrology, and vegetation in desert ecosystems remain less certain and would probably vary significantly among regions. Changes in temperature or rainfall patterns are likely to affect the composition of flora and fauna in desert areas. Higher temperatures could threaten the survival of organisms that now exist near their heat-tolerance limits. Increases in the frequency or intensity of rainfall events could allow the invasion of desert ecosystems by outside species; decreased rainfall intensity could disrupt the lifecycles of desert organisms. Although there are few opportunities to mitigate greenhouse gas emissions in deserts, human management will be an important factor in determining the overall impacts of climate change on these regions.

Chapter 4: Land Degradation and Desertification

Land degradation-which reduces the physical, chemical, or biological quality of land and lowers its productive capacity-already poses a major problem in many countries. Current general circulation models (GCMs) project that in some regions, climate change might increase aridity. This could increase the potential for land degradation, including loss of organic matter and nutrients, weakening of soil structure, decline in soil stability, and an increase in soil erosion and salinization. Areas that would experience increased rainfall and soil moisture will benefit from the opportunities for more flexible use.

Desertification, as defined by the United Nations Convention to Combat Desertification, is land degradation in arid, semi-arid, and dry sub-humid areas, resulting from various factors, particularly human activities and climatic variations. Overstocking, overcultivation, and wood collection can strip the land of its cover, leaving it more vulnerable to climatic events. Droughts may trigger or accelerate desertification by reducing the growth of important plant species. The amount of precipitation needed to sustain growth varies with the temperature, soil moisture capacity, and species. Adaptation to drought and desertification may rely on the development of diversified production systems, such as agroforestry techniques and ranching of animals better adapted to local conditions. However, adaptation also needs political, social, extension service, and educational inputs.

Chapter 5: Impacts of Climate Change on Mountain Regions

Mountains cover about 20% of continental surfaces and are the source of most of the world's major river systems. Mountains are under considerable stress from humans, and climate change would exacerbate existing conflicts between environmental and socioeconomic concerns. Paleo-environmental records indicate that past warming of climate has caused the distribution of vegetation to shift to higher elevations, resulting in the loss of some species and ecosystems. Simulated scenarios suggest that continued warming could have similar consequences for ecosystems in mountains in all latitude belts, and thus species and ecosystems with limited climatic ranges could disappear.

In most mountain regions, a warmer climate will reduce the extent and volume of glaciers and the amount of permafrost and seasonal snow cover. Along with possible precipitation changes, this would affect soil stability and a range of socioeconomic activities (e.g., agriculture, tourism, hydropower, and logging). Climate change may disrupt mountain resources for indigenous populations (e.g., fuel and subsistence and cash crops) in many developing countries. Recreational activities, which are increasingly important economically to many regions, also face likely disruptions. Perturbations to water regimes in mountains would have major consequences for people living downstream, outside of the mountains, who are heavily dependent on their hydrological resources.

Because of their climatic and habitat diversity, mountains provide excellent locations for maintaining biological diversity. In particular, large north-south mountain chains can facilitate migration if appropriately managed, and anticipating for climate change.

Chapter 6:Non-Tidal Wetlands

Wetlands exist on all continents except Antarctica, in both inland and coastal areas, and cover approximately 4-6% of the Earth's surface. Non-tidal (primarily inland) wetlands provide refuge and breeding grounds for many species, are an important repository of biodiversity, control floods and droughts, improve water quality, and play an important role in the carbon cycle (as sinks and/or sources of carbon dioxide and methane). Human activities such as agricultural development, construction of dams and embankments, and peat mining already threaten these ecosystems and have contributed to the disappearance of more than half of the world's wetlands during the last century.

Climate change will most greatly influence the distribution and functions of wetlands by altering their hydrologic regimes (e.g., increasing or decreasing water availability; changing the depth, duration, frequency, and season of flooding). These changes will alter the value of wetlands to societies for such functions as aquifer recharge, sediment retention, waste processing, and carbon storage. For example, some Arctic areas have already shifted from weak carbon sinks to weak carbon sources due to drying. However, due to the heterogeneity of non-tidal wetlands, and because their hydrologic conditions vary greatly within and among different wetland types and sites, the impact of climate change on these ecosystems will be site-specific, and cannot be generalized in terms of locations or wetland categories. While there are possibilities for adaptation, restoration, and creation of local-scale wetland functions (e.g., habitat value, pollution trapping, and to some degree flood control), for the regional and global functions (e.g., carbon storage and trace gas fluxes), there are no human responses that can be applied at the necessary scale.

Chapter 7: The Cryosphere: Changes and Their Impacts

Many components of the cryosphere (i.e., global snow, ice, and permafrost) are particularly sensitive to changes in atmospheric temperature. The last century has witnessed a massive loss and retreat of mountain glaciers, a reduction in the areal distribution of permafrost, and evidence of later freeze-up and earlier break-up of river and lake ice in many northern countries. These observations are consistent with a 0.5 degree C increase in the annual global mean temperature during the last century.

Projected changes in climate will substantially reduce the extent and volume of the cryosphere over the next century, causing pronounced reductions in mountain glaciers, permafrost, and seasonal snow cover. By the year 2100, between one-third and one-half of existing mountain glacier mass could disappear. Changes in the cryosphere are projected to have multiple effects on other systems. The reduced extent of glaciers and depth of snow cover would affect the seasonal distribution of river flow and water supply for hydroelectric generation and agriculture; increased glacial runoff would enhance water resources in some areas, while other areas would experience water shortages as glaciers disappear. Anticipated hydrological changes and reductions in the areal extent and depth of permafrost could lead to large-scale damage to infrastructure, an additional flux of carbon dioxide into the atmosphere, and changes in processes that contribute to the flux of methane into the atmosphere. Thawing permafrost in the tundra could also disrupt petroleum production and distribution systems. There would be striking changes in the landscapes of many high mountains; reduced snow cover and glaciers would restrict alpine skiing and winter tourism.

On the positive side, reduced sea-ice extent and thickness would increase the seasonal duration of navigation on rivers and in coastal areas that are presently affected by seasonal ice cover and could increase navigability in the Arctic Ocean. Little change in the overall extent of the Greenland and Antarctic ice sheets is expected over the next 50-100 years.

Chapter 8: Oceans

Oceans are an important component of the climate system, due to their role in controlling the distribution and transfer of heat and carbon dioxide (internally and with the atmosphere) and in the transfer of water back to the continents as precipitation. They provide vital mineral resources, an environment for living resources, ranging from phytoplankton to whales, and socioeconomic activities such as transportation, fishing, and recreation.

Oceans are sensitive to changes in temperature, freshwater inputs from continents and atmospheric circulation, and the interaction of these factors with other environmental factors such as UV-B radiation and pollution (which is especially important in inland seas, bays, and other coastal areas). Climate change may alter sea level, increasing it on average, and also could lead to altered ocean circulation, vertical mixing, wave climate, and reductions in sea-ice cover. As a result, nutrient availability, biological productivity, the structure and functions of marine ecosystems, the ocean's heat- and carbon-storage capacity, and important feedbacks to the climate system would change as well. Paleoclimatic data and model experiments suggest that abrupt climatic changes can occur if freshwater influx from the movement and melting of sea ice or ice sheets significantly weakens global thermohaline circulation (the sinking of dense surface waters in polar seas that moves bottom water toward the equator).

The most pervasive effects on human uses of the oceans would be due to impacts on biotic resources. Some anticipated adverse effects to humans are increased coral bleaching; the need for expanded dredging operations to maintain Northern Hemisphere ports; possible reductions in commercial fish yields; and possible increases in tropical storms and hurricanes. A potential benefit to human populations is the introduction of routine shipping into the Northwest Passage and Northern Sea Route of Russia. The limited possibilities for adapting to the impacts of climate change on oceans include reducing land-based pollution and improving design standards for off-shore oil rigs to mitigate the effects of tropical storms.

Chapter 9:Coastal Zones and Small Islands

Many commercially important marine species depend on coastal ecosystems for some part of their life cycle, and some coastal ecosystems (e.g., coral reefs, mangrove communities, and beaches) provide an important buffer against storms and surges. Sea-level rise, altered rainfall patterns, and changes in ocean temperature likely will result in additional adverse impacts on coastal ecosystems, particularly where human activities already affect environmental conditions.

Coastal systems are ecologically and economically important and are expected to vary widely in their response to changes in climate and sea level. Climate change and a rise in sea level or changes in storms or storm surges could result in the displacement of wetlands and lowlands, erosion of shores and associated habitat, increased salinity of estuaries and freshwater aquifers, altered tidal ranges in rivers and bays, changes in sediment and nutrient transport, a change in the pattern of chemical and microbiological contamination in coastal areas, and increased coastal flooding. In many areas, intensive human alteration and use of coastal environments already have reduced the capacity of natural systems to respond dynamically. Other regions, however, may prove far less sensitive and may keep pace with climate and sea-level change.

Some coastal ecosystems face heightened risks from changes in climate and sea level. A number of regional studies show the disappearance of saltwater marshes, mangrove ecosystems, and coastal wetlands at a rate of 0.5-1.5% per year over the last few decades, mainly as a result of human development. The interaction of climate change, sea-level rise, and human development would further threaten these particularly sensitive ecosystems. For example, the sea level may rise faster than sediment accretion rates in many coastal areas; thus, existing wetlands will disappear faster than new ones appear. Ecosystems on coral atolls and in river deltas show special sensitivity to climate and sea-level change. Changes in these ecosystems almost certainly will have major negative effects on tourism, freshwater supplies, fisheries, and biodiversity. Such impacts would further modify the functioning of coastal oceans and inland waters already stressed by human activities.

Coral reefs are the most biologically diverse marine ecosystems; they also are very sensitive to temperature changes. Short-term increases in water temperatures on the order of only 1 to 2 degrees C can cause "bleaching," leading to reef destruction. Sustained increases of 3 to 4 degrees C above long-term average seasonal maxima over a 6-month period can cause significant coral mortality. Biologists suggest that fully restoring these coral communities could require several centuries. A rising sea level also could harm coral reefs. Although available studies indicate that even slow-growing corals can keep pace with the "central estimate" of sea-level rise (approximately 0.5 cm per year), these studies do not take account of other pressures on coral populations, such as pollution or enhanced sedimentation.

Climate change clearly will increase the vulnerability of some coastal populations to flooding and erosional land loss. Estimates put about 46 million people per year currently at risk of flooding due to storm surges. This estimate results from multiplying the total number of people currently living in areas potentially affected by ocean flooding by the probability of flooding at these locations in any year, given the present protection levels and population density. In the absence of adaptation measures, a 50-cm sea-level rise would increase this number to about 92 million; a 1-meter sea-level rise would raise it to 118 million. If one incorporates anticipated population growth, the estimates increase substantially. Some small island nations and other countries will confront greater vulnerability because their existing sea and coastal defense systems are less well-established. Countries with higher population densities would be more vulnerable. For these countries, sea-level rise could force internal or international migration of populations.

A number of studies have evaluated sensitivity to a 1-meter sea-level rise. This increase is at the top of the range of IPCC Working Group I estimates for 2100; it should be noted, however, that sea level is actually projected to continue to rise in future centuries beyond 2100. Studies using this 1-meter projection show a particular risk for small islands and deltas. Estimated land losses range from 0.05% in Uruguay, 1.0% for Egypt, 6% for the Netherlands, and 17.5% for Bangladesh to about 80% for the Majuro Atoll in the Marshall Islands, given the present state of protection systems. Large numbers of people are also affected-for example, about 70 million each in China and Bangladesh. Many nations face lost capital value in excess of 10% of their Gross Domestic Product (GDP). Although annual protection costs for many nations are relatively modest (about 0.1% of GDP), the average annual costs to many small island states total several percent of GDP. For some island nations, the high cost of providing storm-surge protection would make it essentially infeasible, especially given the limited availability of capital for investment.

Chapter 10: Hydrology and Freshwater Ecology

The hydrological system is potentially very sensitive to changes in climate. Changes in the total amount of precipitation and in its frequency and intensity directly affect the magnitude and timing of runoff and the intensity of floods and droughts; however, at present, specific regional effects are uncertain. Relatively small changes in temperature and precipitation, together with the non-linear effects on evapotranspiration and soil moisture, can result in relatively large changes in runoff, especially in arid and semi-arid regions. High-latitude regions may experience increased runoff due to increased precipitation, whereas runoff may decrease at lower latitudes due to the combined effects of increased evapotranspiration and decreased precipitation. More intense rainfall would tend to increase runoff and the risk of flooding, although this would depend not only on the change in rainfall but also on catchment physical and biological characteristics. A warmer climate could decrease the proportion of precipitation falling as snow, leading to reductions in spring runoff and increases in winter runoff.

Freshwater aquatic ecosystems encompass lakes, streams, and non-tidal wetlands. These systems are sensitive to changes in temperature, precipitation, and water level and in turn exert important feedbacks on climate by influencing carbon fluxes. They provide a range of socioeconomic values and benefits-including food, energy, transportation, timber, flood mitigation, erosion control, water supply, and recreation.

Inland aquatic ecosystems will be influenced by climate change through altered water temperatures, flow regimes, and water levels. These will directly affect the survival, reproduction, and growth of organisms; the productivity of ecosystems; the persistence and diversity of species; and the regional distribution of biota. Climatic warming would tend to shift geographic ranges of many species poleward. In lakes and streams, warming would have the greatest biological effects at high latitudes, where biological productivity would increase, and at the low-latitude boundaries of cold- and coolwater species ranges, where extinctions would be greatest. Warming of larger and deeper temperate zone lakes would increase their productivity, although in some shallow lakes and in streams warming could increase the likelihood of anoxic conditions. Deep tropical lakes may become less productive as thermal stratification intensifies and nutrients become trapped below the mixed layer.

Changes in hydrologic variability are expected to have greater ecological effects than changes in mean values. Increases in flow variability, particularly the frequency and duration of large floods and droughts, would tend to reduce water quality and biological productivity and habitat in streams. Water-level declines will be most severe in lakes and streams in dry evaporative drainages and in basins with small catchments. For many lakes and streams, the most severe effects of climate change may be the exacerbation of current stresses resulting from human activities, including increasing demands for consumptive uses, increasing waste effluent loadings, and runoff of agricultural and urban pollutants.

Chapter 11: Industry, Energy, and Transportation: Impacts and Adaptation

In general, the sensitivity of the energy, industry, and transportation sectors is relatively low compared to that of agricultural or natural ecosystems, and the capacity for adaptation through management and normal replacement of capital is high. However, infrastructure and activities in these sectors would be susceptible to sudden changes, surprises, and increased frequency or intensity of extreme events. Diversifying economic activity could facilitate successful adaptation in developing countries that currently rely on a limited range of economic activities.

Climate change would have direct impacts on economic activity in the industry, energy, and transportation sectors; impacts on markets for goods and services; and impacts on the natural resources on which economic activity depends. The subsectors and activities most sensitive to climate change include agroindustry, energy demand, production of renewable energy such as hydroelectricity and biomass, construction, some transportation activities, existing flood mitigation structures, and transportation infrastructure located in many areas, including vulnerable coastal zones and permafrost regions. In the energy sector, the consequences for hydroelectric power generation would depend upon changes in the balance between the amount and timing of precipitation and evaporation. Increased scarcity of fuelwood in dry and densely populated regions could exacerbate problems caused by deforestation. Winter demand for primary energy would decrease due to a reduction in space-heating needs; summer demand for electricity is likely to increase with greater cooling requirements in some regions. Total energy demand would fall in regions in the higher latitudes but could rise in warmer regions. For some countries with temperate climates, different studies come to different conclusions.

In contrast to research on mitigation options, relatively few studies exist on climate change impacts on and adaptation options for the industry, energy, and transportation sectors. This situation reflects a perception of low vulnerability to climate change for these sectors. Even fewer studies refer to impacts on developing countries.

Chapter 12: Human Settlements in a Changing Climate: Impacts and Adaptation

Projected climate change will affect human settlements in the context of changes such as population growth, migration, and industrialization. Settlements where these forces already stress the infrastructure are most vulnerable. Besides coastal communities and those dependent on subsistence, rain-fed agriculture or commercial fishing, vulnerable settlements include large primary coastal cities and squatter settlements located in flood plains and steep hillsides. Many of the expected impacts in the developing world could occur because climate change may reduce natural resource productivity in rural areas and may thus generally accelerate rural-to-urban migration. Direct impacts on infrastructure would most likely occur as a result of changes in the frequency and intensity of extreme events. These include coastal storm surges, floods and landslides induced by local downpours, windstorms, rapid snowmelt, tropical cyclones and hurricanes, and forest and bush fires made possible in part by more intense or lengthier droughts. One of the potentially unique and destructive effects on human settlements is forced internal or international migration of populations.

Many adaptive mechanisms are available to address each of the potential direct and indirect impacts of climate change on human settlements. The cost and effectiveness of each depend on local circumstances. Effective coastal-zone management and land-use regulation can help direct population shifts away from vulnerable locations such as flood plains, steep hillsides, and low-lying coastlines. Programs of disaster assistance can offset some of the more serious negative consequences of climate change and reduce the number of ecological refugees. Many of the most vulnerable human settlements, however, are located in damage-prone areas of the developing world that do not have the resources to cope with impacts.

Chapter 13: Agriculture in a Changing Climate: Impacts and Adaptation

Crop yields and changes in productivity due to climate change will vary considerably across regions and among localities, thus changing the patterns of production. Productivity is projected to increase in some areas and decrease in others, especially the tropics and subtropics. However, existing studies show that, on the whole, global agricultural production could be maintained relative to baseline production in the face of climate change modeled by general circulation models (GCMs) at doubled-equivalent carbon dioxide equilibrium conditions, but that regional effects would vary widely. This conclusion takes into account the beneficial effects of carbon dioxide fertilization but does not allow for changes in agricultural pests and the possible effects of changing climatic variability.

Focusing on global agricultural production does not address the potentially serious consequences of large differences at local and regional scales, even at midlatitudes. There may be increased risk of hunger and famine in some locations; many of the world's poorest people-particularly those living in subtropical and tropical areas and dependent on isolated agricultural systems in semi-arid and arid regions-are most at risk of increased hunger. Many of these at-risk populations are found in sub-Saharan Africa; South, East, and Southeast Asia; and tropical areas of Latin America, as well as some Pacific island nations.

Adaptation-such as changes in crops and crop varieties, improved water-management and irrigation systems, and changes in planting schedules and tillage practices-will be important in limiting negative effects and taking advantage of beneficial changes in climate. The extent of adaptation depends on the affordability of such measures, particularly in developing countries; access to know-how and technology; the rate of climate change; and biophysical constraints such as water availability, soil characteristics, and crop genetics. The incremental costs of adaptation strategies could create a serious burden for some developing countries; some adaptation strategies may result in cost savings for some countries. There are significant uncertainties about the capacity of different regimes to adapt successfully to projected climate change.

Chapter 14: Water Resources Management

Climate change will lead to an intensification of the global hydrological cycle and can have major impacts on regional water resources. A change in the volume and distribution of water will affect both ground and surface water supply for domestic and industrial uses, irrigation, hydropower generation, navigation, instream ecosystems, and water-based recreation.

The quantity and quality of water supplies already are serious problems today in many regions, including some low-lying coastal areas, deltas, and small islands, making countries in these regions particularly vulnerable to any additional reduction in indigenous water supplies. Water availability currently falls below 1,000 m3 per person per year-a common benchmark for water scarcity-in a number of countries (e.g., Kuwait, Jordan, Israel, Rwanda, Somalia, Algeria, Kenya) or is expected to fall below this benchmark in the next two to three decades (e.g., Libya, Egypt, South Africa, Iran, Ethiopia). In addition, a number of countries in conflict-prone areas are highly dependent on water originating outside their borders (e.g., Cambodia, Syria, Sudan, Egypt, Iraq).

The impacts of climate change will depend on the baseline condition of the water supply system and the ability of water resource managers to respond not only to climate change but also to population growth and changes in demands, technology, and economic, social, and legislative conditions. In some cases-particularly in wealthier countries with integrated water-management systems-improved management may protect water users from climate change at minimal cost; in many others, however, there could be substantial economic, social, and environmental costs, particularly in regions that already are water-limited and where there is a considerable competition among users. Experts disagree over whether water supply systems will evolve substantially enough in the future to compensate for the anticipated negative impacts of climate change on water resources and for potential increases in demand.

Options for dealing with the possible impacts of a changed climate and increased uncertainty about future supply and demand for freshwater include more efficient management of existing supplies and infrastructure; institutional arrangements to limit future demands/promote conservation; improved monitoring and forecasting systems for floods/droughts; rehabilitation of watersheds, especially in the tropics; and construction of new reservoir capacity to capture and store excess flows produced by altered patterns of snowmelt and storms.

Chapter 15: Wood Production under Changing Climate and Land Use

Global wood supplies during the next century may become increasingly inadequate to meet projected consumption due to both climatic and non-climatic factors. Boreal forests are likely to undergo irregular and large-scale losses of living trees because of the impacts of projected climate change. Such losses could initially generate additional wood supply from salvage harvests, but could severely reduce standing stocks and wood-product availability over the long term. The exact timing and extent of this pattern is uncertain. Climate and land-use impacts on the production of temperate forest products are expected to be relatively small. In tropical regions, the availability of forest products is projected to decline by about half for non-climatic reasons related to human activities.

Options for ameliorating and adapting to the potential global timber shortages include reducing social pressures driving land conversion and developing tree plantations in the tropics; using modern forestry practices and substituting non-timber products in temperate regions; and rapid reforestation with warmth-adapted seeds in boreal regions.

Chapter 16: Fisheries

Climate-change effects interact with those of pervasive overfishing, diminishing nursery areas, and extensive inshore and coastal pollution. Globally, marine fisheries production is expected to remain about the same; high-latitude freshwater and aquaculture production are likely to increase, assuming that natural climate variability and the structure and strength of ocean currents remain about the same. The principal impacts will be felt at the national and local levels as species mix and centers of production shift. The positive effects of climate change--such as from longer growing seasons, lower natural winter mortality, and faster growth rates in higher latitudes--may be offset by negative factors such as changes in established reproductive patterns, migration routes, and ecosystem relationships. National fisheries will suffer if institutional mechanisms are not in place that enable fishing interests to move within and across national boundaries. Subsistence and other small-scale fishers will suffer disproportionately from changes. Some adaptation options include implementing national and international fishery-management institutions; research on management systems and aquatic ecosystems; expansion of aquaculture; and augmentation of stocks.

Chapter 17: Financial Services

Within the Financial Services sector, property insurance is most vulnerable to direct climatic influence. A higher risk of extreme events due to climate change could lead to higher insurance premiums, or the restriction of coverage for property in some vulnerable areas. Withdrawal of insurance would increase direct financial losses to property owners and business, with serious long-term implications for communities and governments. If unexpectedly severe events lead to insolvency of insurance companies, this could weaken other economic sectors, such as banking and public finance. However, detailed changes in the risk of extreme events are uncertain, making it difficult for insurance companies to adjust products and capital reserves appropriately.

The insurance industry currently is under stress from a series of "Billion Dollar" storms since 1987, resulting in dramatic increases in claims, reduced availability of insurance, and higher premiums. These higher losses reflect significant increases in infrastructure and economic worth, as well as a possible shift in the intensity and frequency of extreme weather events. (Parallel trends in drought and flood losses have often not been insured, placing the burden directly on other sectors.)

The implications of climate change for financial services other than property insurance are less clear. Changes in human health may affect the life insurance and pension industries. Banking may be vulnerable to repercussions from property damage. The economies of selected regions, such as coastal areas, may be disadvantaged. Returns on investment may be affected by changes in the economics of energy-consuming industries.

The insurance sector can help authorities improve the response to property damage from extreme events through providing information on the cost of weather hazards, advice on vulnerable construction design, and disaster-recovery services. However, the insurance industry is not likely to be able to provide all the necessary funds for the post-disaster reconstruction.

Chapter 18: Human Population Health

Climate change is likely to have wide-ranging and mostly adverse impacts on human health, with significant loss of life. These impacts would arise by both direct and indirect pathways, and it is likely that the indirect impacts would, in the longer term, predominate. Direct health effects include increases in (predominantly cardiorespiratory) mortality and illness due to an anticipated increase in the intensity and duration of heat waves-while temperature increases in colder regions should result in fewer cold-related deaths. An increase in extreme weather would cause a higher incidence of death, injury, psychological disorders, and exposure to contaminated water supplies.

Indirect effects of climate change include increases in the potential transmission of vector-borne infectious diseases (e.g., malaria, dengue, yellow fever, and some viral encephalitis) resulting from extensions of the geographical range and season for vector organisms. This could lead to potential increases in malaria incidence, primarily in tropical, subtropical, and less well-protected temperate-zone populations. Some increases in non-vector-borne infectious diseases-such as salmonellosis, cholera, and giardiasis-also could occur, particularly in tropical and subtropical regions, as a result of elevated temperatures and increased flooding. Additional indirect effects include increases in respiratory and allergic disorders due to climate-enhanced increases in some air pollutants, pollens and mold spores. Exposure to air pollution and stressful weather events combine to increase the likelihood of morbidity and mortality. Some regions could experience a decline in nutritional status as a result of adverse impacts on food and fisheries productivity. A range of adverse public health effects would result from physical and demographic disruptions due to sea-level rise. Other potentially adverse health effects could be associated with water shortages, conflicts over environmental resources, and the destruction of the stratospheric ozone layer.

These and other impacts of climate change would affect different populations differently. Quantifying the projected impacts is difficult because the extent of climate-induced health disorders depends on numerous coexistent and interacting factors that characterize the vulnerability of the particular population, including environmental and socioeconomic circumstances, nutritional and immune status, population density, and access to quality health care services. Most vulnerable are populations characterized by overcrowding, food insecurity, local environmental degradation, and perturbed ecosystems, generally in developing countries.

Various technological, organizational, and behavioral adaptations would lessen these adverse effects. Adaptive options include improved and extended medical care services; environmental management; disaster preparedness; public education; and the pre-assessment of risks from proposed technological innovations. There is also need for international monitoring of health-risk indicators in relation to climate change. However, the tropical and subtropical countries at highest risk from many of these impacts may still lack adequate resources for adaptation.

Chapter 19: Energy Supply Mitigation Options

This chapter focuses on energy supply options that can sharply reduce greenhouse gas (GHG) emissions while providing needed energy services. By the year 2100, the world's commercial energy system will be replaced at least twice, which offers opportunities to change the present energy system in step with the normal timing of the corresponding investments, using emerging technologies in environmentally sound ways.

In the energy supply sector, the authors have a high degree of confidence that GHG emissions reductions can be achieved through more efficient conversion of fossil fuels; switching to low-carbon fossil fuels and suppressing emissions; decarbonization of fuels and flue gases, and carbon dioxide (CO2) storage; increasing the use of nuclear energy; and increasing the use of renewable sources of energy.

Since the preparation of the IPCC 1990 Assessment Report, there have been some significant advances in the understanding of modern technology and technological innovations relating to energy systems that can reduce GHG emissions. Examples of such technologies are found, inter alia, in gas turbine technology; coal and biomass gasification technology; production of transportation fuels from biomass; wind energy utilization; electricity generation with photovoltaic and solar thermal electric technologies; approaches to handling intermittent generation of electricity; fuel cells for transportation and power generation; nuclear energy; CO2 sequestering; and hydrogen as a major new energy carrier, produced first from natural gas and later from biomass, coal, and electrolysis.

In addition to climate change concerns, the energy supply options discussed here (with the exception of carbon sequestering) could address local and regional environmental problems, generate rural income and employment, and promote land restoration and preservation.

A wide range of modular renewable and other emission-reducing technologies are good candidates for cost-cutting through innovation and experience. For such technologies, the cost of the needed research, development, and demonstration (RD&D) and commercialization support is relatively modest. The availability, cost, and penetration of technology options will strongly depend on government action. While some technology options would penetrate the current marketplace, to realize other options, governments would have to take integrated action-by improving market efficiency, by finding new ways to internalize external costs, by accelerating RD&D on low- and zero-CO2 emitting technologies, and by providing temporary incentives for early market development for these technologies.

To assess the potential impact of combinations of individual measures at the energy system level, in contrast to the level of individual technologies, "thought experiments" exploring possible energy systems are described. These low CO2-emitting energy supply systems (LESS) were constructed to meet energy demand in (i) a low energy demand variant, developed for the IPCC's First Assessment Report (1990), where global primary commercial energy use approximately doubles, with no net change for industrialized countries but a 4.4-fold increase for developing countries from 1990 to 2100; and (ii) a higher energy demand variant, based on the IPCC IS92a scenario where energy demand quadruples from 1990 to 2100.

The analysis of these variants leads to the conclusions that deep reductions of CO2 emissions from energy supply systems are technically possible within 50 to 100 years. Many combinations of the options identified in this assessment could reduce global CO2 emissions from fossil fuels from about 6 Gt C in 1990 to about 4 Gt C per year by 2050, and to about 2 Gt C per year by 2100. Cumulative CO2 emissions from 1990 to 2100 would range from about 450 to about 470 Gt C in the alternative LESS constructions. Improvements in energy efficiency are important for achieving deep reductions in CO2 emissions, for increasing the flexibility of supply-side combinations, and for reducing overall energy system costs. Trade in energy grows in the LESS constructions compared to today's levels, expanding sustainable development options for Africa, Latin America, and the Middle East during the next century.

Costs for energy services in these "thought experiments" relative to costs for conventional energy depend on relative future energy prices, which are uncertain within a wide range, and on the performance and cost characteristics assumed for alternative technologies. However, within the wide range of future energy prices, one or more of the variants would plausibly be capable of providing the demanded energy services at estimated costs that are approximately the same as estimated future costs for current conventional energy. It is not possible to identify a least-cost future energy system for the longer term, as the relative costs of options depend on resource constraints and technological opportunities that are imperfectly known, and on actions by governments and the private sector. The literature provides strong support for the feasibility of achieving the performance and cost characteristics assumed for energy technologies in the LESS constructions within the next two decades. However, these performance and cost characteristics cannot be achieved without a strong and sustained investment in R,D&D. Market penetration and continued acceptability of different energy technologies ultimately depends on their relative cost, performance (including environmental performance), institutional arrangements, and regulations and policies. Because of the large number of options, there is flexibility as to how the energy supply system could evolve, and paths of energy system development could be influenced by considerations other than climate change, including political, environmental, and socioeconomic circumstances.

Chapter 20: Industry

Countries differ widely in their current industrial energy-use and energy-related greenhouse gas emissions trends. Industrial energy emissions from the developed industrial countries have remained relatively constant over the past two decades through restructuring and technological innovations, while emissions from developing countries continue to grow as their industrial base expands. A few basic processes, including the production of iron and steel, chemicals, paper, building materials, and food, account for more than half of all energy use in the industrial sector. Existing technologies, processes, and new product design concepts could substantially reduce energy-related greenhouse gas emissions from this sector. These technologies and measures include improving efficiency (e.g., energy and materials savings, cogeneration, energy cascading and steam recovery, and use of more-efficient motors and other electrical devices); recycling materials (e.g., aluminum, steel, and paper) and switching to those with lower greenhouse gas emissions; eliminating solvents; and restricting whenever feasible other industrial process emissions such as carbon dioxide, halocarbons, methane, and nitrous oxide associated with the production of iron, steel, aluminum, nylon, ammonia, and other materials.

Numerous studies have indicated that 10-30% energy efficiency gains above present levels are feasible at little or no net cost in many parts of the world through technical conservation measures and improved management practices over the next 2 to 3 decades. Using technologies that presently yield the highest output of energy services for a given input of energy, efficiency gains of 50-60% would be technically feasible in many countries over the same time period. The potential for greenhouse gas emissions reductions exceeds the potential for energy use efficiency because of the possibility of switching fuels and energy sources.

Improving energy efficiency, reducing the material content of products, and using fuels with a lower carbon content are essential activities for industrialized countries. Shifting to more advanced technologies will also place developing countries and those with economies in transition on a lower greenhouse gas development trajectory. Implementing more energy-efficient industrial technologies will depend on many factors. Chief among them are future cost reductions, financing, and technology transfer, as well as measures to overcome a variety of non-technical barriers.

Chapter 21: Mitigation Options in the Transportation Sector

Transportation ranks among the fastest-growing sources of greenhouse gas emissions. Although industrialized countries account for about 75% of current energy use and greenhouse gas emissions from this sector, the greatest growth is expected in developing countries and transition economies. By 2025, these countries could generate the majority of transport-related emissions.

Energy use in 1990 was estimated to be 61-65 EJ, and is projected to grow to 90-140 EJ in 2025 without new measures. Projected energy use in 2025 could be reduced by about a third to 60-100 EJ through vehicles using very efficient drive-trains, light-weight construction and low-air-resistance design, without compromising comfort and performance. Further energy-use reductions are possible through the use of smaller vehicles; altered land-use patterns, transport systems, mobility patterns and lifestyles; and shifting to less energy-intensive transport modes. Greenhouse gas emissions per unit of energy used could be reduced through the use of alternative fuels and electricity from renewable sources. These measures, taken together, provide the opportunity for reducing global transport energy-related greenhouse gas emissions by as much as 40% of projected emissions by 2025. Actions to reduce energy-related greenhouse gas emissions from transport can simultaneously address other problems such as local air pollution.

Realizing these opportunities seems unlikely, however, without new policies and measures in many countries. Developing cheap, lightweight, recyclable materials and advanced propulsion and vehicle-control systems will require continued research. Policies that affect traffic volume also play an important role. These include road tolls, restriction of car access and parking in town centers, and the provision of infrastructure for nonmotorized transport in town centers. Several cities in Latin America, Southeast Asia, and Europe have succeeded in stemming growth in car use by employing combined strategies. Success in reducing carbon emissions will require integrated approaches and probably will depend on simultaneously addressing other problems such as congestion and air pollution.

Chapter 22: Mitigation Options for Human Settlements

Energy use in 1990 was estimated to be about 103 EJ. A typical projection would see this approximately double to 205 EJ by 2025. Projected growth in energy use could be cut about in half, to about 150 EJ by 2025 without diminishing services through the use of energy-efficient technology. The potential for reducing energy-related greenhouse gas emissions is greater than this, if less carbon-intensive fuels are used to meet these demands. Technical changes to increase end-use energy efficiency include reduced heat transfer through building structures and more-efficient space-conditioning and water supply systems, lighting, and appliances. Ambient temperatures in urban areas can be reduced through increased vegetation and greater reflectivity of building surfaces, reducing the energy required for space conditioning. As noted, greenhouse gas emission reductions beyond those obtained through reduced energy use could be achieved through changes in energy sources. Finally, technologies that can capture, reduce, or prevent methane emissions (e.g., from landfills and wastewater systems) are increasingly available. According to energy scenarios, by 2025 energy efficiency measures alone could contribute about half of the reductions needed to maintain 1990 levels of carbon dioxide emissions if strong policy measures are adopted; technologies for controlling emissions from landfills and wastewater could achieve comparable methane emissions reductions.

Improvements in energy efficiency will be possible for many years in industrialized nations, and the developing world has even greater opportunities to improve energy efficiency if the appropriate resources are made available. Effective implementation requires well-designed combinations of financial incentives and other government policies, including energy pricing strategies, regulatory programs, utility demand-side management programs, and R&D. Strategies to reduce emissions likely will prove more effective if they use well-integrated mixes of policies, tailored for local situations and developed through consultation with and participation by those most affected.

Chapter 23: Agricultural Options for Mitigation of Greenhouse Gas Emissions

Agriculture accounts for one-fifth of the annual increase in anthropogenic greenhouse warming, mostly through emissions of methane and nitrous oxide. Measures to reduce emissions and sequester atmospheric carbon in the agricultural sector include altering management of agricultural soils and restoring degraded agricultural lands. Biofuel production and the recovery and conversion of crop residues could substitute for substantial amounts of fossil fuel, although these benefits could be partially offset by increases in nitrous oxide emissions.

Methane emissions from agriculture can be decreased significantly by improved nutrition of ruminant animals and better management of rice paddies (e.g., irrigation, nutrients, new cultivars). Altering the treatment and management of animal wastes and reducing agricultural biomass burning also will decrease methane releases. Nitrous oxide emissions from fertilizers, animal wastes, and legume cropping could be reduced by improving agricultural management. Finally, fossil fuel use for agriculture in industrialized countries could be reduced through the use of such practices as minimum tillage and irrigation scheduling. Proposed options for conserving and sequestering carbon and reducing other greenhouse gas emissions in the agriculture sector are consistent with sustainable development, protection of other natural resources (e.g., biodiversity, soil, water), and increasing agricultural productivity.

Chapter 24: Management of Forests for Mitigation of Greenhouse Gas Emissions

The management of forests can play an important role in reducing current emissions of carbon dioxide and enhancing carbon sinks. The sustainable growth and harvest of wood for substitution of fossil-fuels and other energy-expensive products would avoid the release of fossil carbon. In the long run, this would offer a more efficient strategy than one based on carbon storage in vegetation and soils, which would saturate with time. The development of this mitigation option will depend critically upon the competitiveness of woody biomass. However, managing forests to conserve and increase carbon storage offers an effective mitigation option during the transition period of many decades necessary to stabilize atmospheric concentrations of carbon.

In the forestry sector, assuming the present climate and no change in the estimated area of available lands, the cumulative amount of carbon that could feasibly be conserved and sequestered through establishment of plantations and agro-forestry, sustaining existing forest cover, forest regeneration, and slowing deforestation over the period 1995-2050 ranges between 60 and 90 GtC. The literature indicates that the tropics have the potential to conserve and sequester the largest quantity of carbon (80% of the global total in the forestry sector), while the temperate and boreal zones could sequester about 20% of the global total. Altering climate and land-use assumptions would reduce these estimates significantly.

The full costs of conserving or sequestering carbon in forests are difficult to generalize given the amenity value of forests, their importance in traditional economies, and their significance in maintaining regional environments and biodiversity; these costs, however, can be competitive with other mitigation options. Factors affecting costs include opportunity costs of land; initial costs of planting and establishment; costs of nurseries; the cost of annual maintenance and monitoring; and transaction costs. These costs generally increase from low- to high-latitude nations and most likely from methods of slowing deforestation to establishing plantations. Direct and indirect benefits will vary with national circumstances and could offset the costs.

Chapter 25: Mitigation: Cross-Sectoral and Other Issues

Mitigation of greenhouse gas emissions depends on reducing barriers to the diffusion of technology, supporting capacity building in developing countries, and other approaches to assist in the implementation of behavioral changes and technological opportunities in all regions of the globe. The optimum mix of policies will vary from country to country, depending upon political structure and societal receptiveness. This chapter examines issues and opportunities that cut across the options presented for individual sectors. Cross-sectoral assessment of different combinations of mitigation options focuses on the interactions of the full range of technologies and practices which are potentially capable of reducing emissions of greenhouse gases or sequestering carbon. Several cross-cutting issues addressed are:

Chapter 26: Technical Guidelines for Assessing Climate Change Impacts and Adaptations

Working Group II of IPCC has prepared Guidelines to assess the impacts of potential climate change and to evaluate appropriate adaptations. They reflect current knowledge and will be updated as improved methodologies are developed. The Guidelines outline a study framework that will allow comparable assessments to be made of impacts and adaptations in different regions/geographical areas, economic sectors, and countries. The Guidelines are intended to help contracting parties meet, in part, their commitments under Article 4 of the UN Framework Convention on Climate Change. Impact and adaptation assessments involve seven steps: Definition of the problem, selection of the methods, testing of the methods, selection of scenarios, assessment of biophysical and socio-economic impacts, assessment of autonomous adjustments, and evaluation of adaptation strategies.

Chapter 27: Methods for Assessment of Mitigation Options

The IPCC has prepared Guidelines to assess mitigation options. The guidelines provide a range of analytical methods and approaches for assessing mitigation options and developing national mitigation plans and strategies, recognizing that there are many viable approaches for mitigating greenhouse gas emissions and that countries need to identify those approaches best suited to their needs and conditions. The chapter provides policy analysts and decisionmakers -- especially those in developing countries and countries with economies in transition -- objective information on mitigation methods.

The types of methods covered in the guidelines include macroeconomic models; decision analysis tools; forecasting methods; costing models; market research methods; and monitoring and evaluation methods. In addition to descriptions of methods, the guidelines describe several broader aspects of the mitigation options assessment process, including the strategic, analytical and informational challenges; organizational issues; and important cross-cutting issues such as top-down versus bottom-up modeling, accounting for uncertainty, and incorporating externalities.

While the guidelines place a special emphasis on the needs of developing countries and countries with economies in transition, the methods and models addressed are intended to match a range of analytical capabilities and resource constraints. Research in the preparation of these guidelines has demonstrated that methods to assess mitigation options are available to all countries to use in developing strategies and evaluating programs that support national economic, social, and institutional development goals; and that can slow the growth rate of greenhouse gas emissions. Although they involve analytical challenges, these methods have been widely applied in both industrialized and developing countries. The Global Environment Facility, other international organizations, and bilateral programs also provide resources to assist developing countries and those with economies in transition in obtaining information on, testing, and using these methods. The IPCC recommends that all countries evaluate and use, as appropriate, these draft methods in preparing country studies and their national communications. In the future, development and application of mitigation assessment methods will result in further improvements in the methods and the capabilities of countries to assess mitigation options. The IPCC, in coordination with other multilateral institutions, could accelerate the dissemination of selected information on assessment methods through seminars, workshops and educational materials.

Chapter 28: Inventory of Technologies, Methods, and Practices

This chapter describes a database of information on technologies, methods, and practices that can help limit emissions of greenhouse gases. The inventory, which is published as an appendix volume to the Second Assessment Report, is intended to provide energy and environmental planners with access to technical and economic information on current options available to reduce emissions and mitigate climate change. The inventory contains information on performance characteristics and applications, capital and operating costs, environmental characteristics (including emissions of greenhouse gases), and infrastructure requirements. It contains information about 105 technologies, each compiled in a two-page, standardized format, including energy supply technologies (44), energy end-use technologies (47), agricultural and forestry practices (12), and other techniques (2).

For questions or comments on these Web Pages, please contact: ipcc_sec@gateway.wmo.ch

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