5
Selected Topics

INTRODUCTION

The panel was asked to select a limited number of disciplines or research areas that complement specific components of the U.S. national global change research agenda and the International Geosphere-Biosphere Programs (IGBP) core projects and to report on these topics in greater detail. Specifically, the panel was asked to report on Chinese capabilities, policy commitments, and potential for collaboration with the U.S. scientific community and for contributions to international research efforts.

The panel chose two focal areas: atmospheric chemistry and physical and ecological interactions of the atmosphere and land surface. The topics in the atmospheric chemistry focal area are very narrowly defined, while the topics in the second focal area are necessarily more broadly defined. Within these areas, specific topics were chosen by the panel based on members' expertise and on panel opinion about the relevance to U.S. and international research.

It should be noted that no attempt was made to be comprehensive in examining all of the possible topics available for discussion in a given focal area. For example, even though biogeochemistry includes more than trace gas research, the panel chose to limit its detailed investigation to biotic controls on selected trace gases, climate-vegetation dynamics, and soil organic matter and soil nutrient turnover.



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China and Global Change: Opportunities for Collaboration 5 Selected Topics INTRODUCTION The panel was asked to select a limited number of disciplines or research areas that complement specific components of the U.S. national global change research agenda and the International Geosphere-Biosphere Programs (IGBP) core projects and to report on these topics in greater detail. Specifically, the panel was asked to report on Chinese capabilities, policy commitments, and potential for collaboration with the U.S. scientific community and for contributions to international research efforts. The panel chose two focal areas: atmospheric chemistry and physical and ecological interactions of the atmosphere and land surface. The topics in the atmospheric chemistry focal area are very narrowly defined, while the topics in the second focal area are necessarily more broadly defined. Within these areas, specific topics were chosen by the panel based on members' expertise and on panel opinion about the relevance to U.S. and international research. It should be noted that no attempt was made to be comprehensive in examining all of the possible topics available for discussion in a given focal area. For example, even though biogeochemistry includes more than trace gas research, the panel chose to limit its detailed investigation to biotic controls on selected trace gases, climate-vegetation dynamics, and soil organic matter and soil nutrient turnover.

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China and Global Change: Opportunities for Collaboration ATMOSPHERIC CHEMISTRY Coal accounts for approximately 75 percent of China's annual energy consumption. Emissions of particulate matter and sulfur dioxide (SO2) from burning coal are major contributors to regional air pollution. These emissions not only lead to urban and regional pollution problems such as oxidants and acid precipitation, but potentially also have global impacts. Anthropogenic emissions of ozone (O3) precursors, such as nitrogen oxides (NOx) and hydrocarbons, can lead to a significant increase in tropospheric O3 (IPCC 1990). For example, O3 is known to contribute significantly to the infrared radiation in the upper troposphere and, therefore, plays an important role in climate change (IPCC 1990). Remarkably high levels of tropospheric O3 over northeastern China and Japan in spring and summer have been deduced from satellite observations (Fishman et al. 1990). While both natural (stratospheric intrusion and lightning) and anthropogenic processes may contribute to the high levels of O3, the processes need to be quantitatively evaluated (Liu et al. 1987). Chinese atmospheric chemistry research has been conducted primarily in areas of urban pollution, for example, suspended particles, O3 and O3 precursors, and toxic species. Recently, there have been some important efforts to address large-scale background atmospheric chemistry issues that have regional or global implications. The major foci of these efforts include tropospheric oxidants, greenhouse gases, aerosols, stratospheric O3, and acid precipitation. However, these efforts are severely limited due to a lack of funding, advanced instruments, and certain expertise in a few global change-related disciplines. It appears that atmospheric chemistry is not a field of high priority. This is also reflected in the field of atmospheric chemistry modeling, which is in its infancy compared to modeling efforts in climate or meteorology. Given the availability of highly trained theoreticians and relatively small capital investment required, one would expect to find more activities in atmospheric chemistry modeling. The extent and nature of current atmospheric chemistry research is indicated by a survey of papers published in five leading Chinese journals1 over a 3-year period: China Environmental Science (Zhongguo Huanjing Kexue, Chinese language, bimonthly); Acta Scientiae Circumstantiae (Journal of Environmental Science [Huanjing Kexue Xuebao], Chinese language, quarterly); Environmental Science, (Huanjing Kexue, Chinese language, bimonthly); Environmental Chemistry, (Huanjing Huaxue, Chinese language, bimonthly); and Scientia Atmospherica Sinica, (Daqi Kexue, Chinese language, quarterly). Between 1988 and 1990, 1,059 articles were published in these journals, and the majority dealt with water or soil

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China and Global Change: Opportunities for Collaboration pollution. A smaller number of papers dealt with atmospheric chemistry and air pollution. Out of these papers, the majority dealt with urban pollution, and only rarely with larger than regional-scale characterization. Eighty-seven of these reported results from studies of precipitation and aerosol chemistry, especially acid rain, and 25 of these papers focused primarily on aerosols. A similar indication of the scope of atmospheric chemistry research in China is given by the proceedings of the International Conference on Global and Regional Environmental Atmospheric Chemistry held in Beijing, May 3–10, 1990. At that conference, 89 of the 173 platform or poster papers reported mainly regional and urban-scale Chinese research, and of these, 38 papers addressed acid rain. Twelve papers dealt with urban and regional oxidants and trace gases. Eight papers on aerosol studies reported measurements of chemical composition. Only eight papers discussed topics in the remote atmosphere, four of them on the stratospheric species and the other four on shipboard measurements of tropospheric trace gases and aerosols. This record of publications indicates a preponderance of air quality and environmental impact studies that have an immediate importance to the lives of people in China. Atmospheric chemistry studies related to global climate change are far fewer. Yet, the experience gained in the environmental impact studies have laid a basis on which larger scale investigations can be conducted when future opportunities arise. Atmospheric chemistry research is carried out primarily in a few, relatively large institutes. These include the Chinese Research Academy of Environmental Sciences (CRAES) of the National Environmental Protection Agency (NEPA), the Research Center for Eco-Environmental Sciences (RCEES) of the Chinese Academy of Sciences (CAS), the Chinese Academy of Meteorological Sciences (CAMS) of the State Meteorological Administration (SMA), CAS Institute of Atmospheric Physics, CAS University of Science and Technology of China, Peking University, and Nanjing University. Many of these institutes are involved in cooperative international research projects. However, collaboration or coordination of research activities among these institutes appears to be limited. Trace Gases and Oxidants Research on trace gases other than urban air pollutants started in recent years when it was realized that all of the trace gases other than carbon dioxide (CO2) contribute equally to climate change as does CO2. Much of the attention has been on methane (CH4), nitrous

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China and Global Change: Opportunities for Collaboration oxide (N2O), and CO2 emissions from various biogenic sources such as rice Paddies and forests. This will be discussed below in the section that discusses atmosphere-land surface interactions. The Chinese Waliguanshan Atmospheric Baseline Observatory for long-term monitoring of trace gases and aerosols—similar to the Global Monitoring of Climate Change stations of the U.S. National Atmospheric and Oceanographic Administration (NOAA)—is being established on the Qinghai-Tibet Plateau by CAMS with support from NOAA and the World Meteorological Organization. The plateau has an elevation of about 6 km and is remote from direct anthropogenic influence. This observatory will be open to foreign scientists when it is complete. A joint program with NOAA to measure CO2 has just started. There is a plan to measure other trace gases and aerosols that play an important role in the greenhouse effect. But, shortages of funds and sophisticated instruments may delay the implementation of these measurements. Like many cities in the world, high levels of O3 are a major air pollution problem in most urban areas. While O3 concentrations are routinely monitored over urban areas by local NEPA bureaux, few observations are being made in remote regions. An exception was the shipboard measurements of atmospheric O3 over the western Pacific Ocean (Fu et al. 1990). Recently, as part of International Global Atmospheric Chemistry (IGAC) projects in eastern Asia and the northern Pacific, experiments to measure concentrations of oxidants, O3 precursors, SO2, carbon disulfide, carbonyl sulfide, aerosols, and precipitation chemistry have been carried out separately at a number of background atmosphere stations by CAMS (in collaboration with the Georgia Institute of Technology and NOAA), Peking University, and RCEES. This work is part of the East Asia-North Pacific Regional Experiments (APARE), which include ground station measurements from China, Hong Kong, Japan, Korea, Taiwan, and the United States. In addition, collaborating aircraft experiments over the western Pacific Ocean have been flown by the Japanese Environmental Protection Agency and the U.S. National Aeronautic and Space Administration (NASA). The experiments are called PEM-West (Chapter 4). The experiments include measurements of O3, NOx, nitric acid, N2O, carbon monoxide, CH4, non-methane hydrocarbons, SO2, carbon disulfide, carbonyl disulfate, sulfate, CO2, and some halogen gases. The major objectives of the experiments are (a) to evaluate the natural budgets of and anthropogenic impact on oxidants including O3 and O3 precursors, (b) to study the photochemical processes controlling

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China and Global Change: Opportunities for Collaboration the sulfur cycle, and (c) to study the distributions and budgets of CO2, CH4, and N2O over eastern Asia and the western Pacific. The first phase of PEM-West was completed in the fall of 1991. Scientific results were presented recently at the Western Pacific Conference held in Hong Kong and will be reported in various journals and other conferences over the next few years. A second phase is being planned for the spring of 1994. The background atmosphere stations in China have made some valuable measurements. However, the capabilities of these stations are severely limited by lack of funding and advanced instruments. Without additional support, the future of these stations is uncertain. Aerosols Current research in aerosol chemistry in China is more limited than in other areas of atmospheric chemistry. As discussed above, aerosol studies focus primarily on urban- and regional-scale problems. Only a few studies directly address global aerosol distributions and trends or link aerosols to climate change. From the information available to the panel, it appears that the importance of aerosols to climate change is not generally appreciated by researchers in China. Wind-blown dust is believed to contribute significantly to particulate loading, especially in northern China (Yang et al. 1990). Dust storms carry not only soil mineral particles, but also air pollutants released from populated areas over which a dust cloud passes. These pollutants include sulfate, nitrate, soot carbon, trace metals, and organic compounds. During transport, several natural and pollution constituents may undergo chemical interaction and transformation and result in a complex aerosol mixture with atmospheric physics, chemistry, radiation, and other properties different from those of any single original soil mineral or pollution particulate constituent. Measurements of aerosols over China, Japan, and the northern Pacific have shown convincingly that dust storms originating from central Asia are the major sources of dust, sulfate, nitrate, and other particulate matter transported to the northern Pacific (Darzi and Winchester 1982, Iwasaka et al. 1988, Muayama 1988). Given the important role played by aerosol particles in atmospheric radiation, the effect of Asian dust storms on regional—as well as global—climate needs to be carefully studied.2 CAMS has a program to study the meteorological characteristics of dust storms, including the formation and transport of the storm's dust. A comprehensive program that addresses the chemical as well as physical

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China and Global Change: Opportunities for Collaboration properties of dust storms would be welcome. As discussed in Chapter 4, a cooperative international program called the China and America Air-Sea Experiments (CHAASE), studying the compositions of aerosols and rain over eastern Asia, has been carried out since 1990 (Arimoto et al. 1990, Gao et al. 1992a,b). As part of the Tropical Ocean and Global Atmosphere (TOGA) program, compositions of rain and aerosol samples collected over the Pacific were analyzed under a collaborative experiment between the Chinese National Research Center for Marine Environment Forecasts at the State Oceanographic Administration and NOAA. Stratospheric Ozone At least four institutions, the CAS Institute of Atmospheric Physics, SMA, the CAS University of Science and Technology of China, and Peking University, are engaged in the development of one- and two-dimensional models for stratospheric chemistry studies. The CAS Institute of Atmospheric Physics and SMA have sent scientists to work with modelers in the United States.3 Total O3 is measured regularly by CAS Institute of Atmospheric Physics scientists at a station in Beijing and another in Yunnan Province. Ground-based remote sensing techniques for measuring stratospheric trace gases such as O3 and nitrite (NO2) are under development at Peking University, CAS Anhui Institute of Optics and Fine Mechanics, and CAMS. Of particular interest are the measurements of O3 and NO2 column abundances at the Chinese Great Wall Station in Antarctica (Mao 1990). NEPA has been collecting data on halon and chlorofluorocarbon (CFC) consumption over the past several years, which have been reported through the United Nations Development Program (UNDP 1992). Because most of the stratospheric observations and laboratory measurements are carried out in the United States and Europe, Chinese modelers do not often have timely access to these data sets. Computer facilities are also somewhat inadequate to run fully coupled two-dimensional transport and chemical models efficiently. As a result, the status of stratospheric models in China is not as advanced as those in developed countries. In particular, lack of access to observational data is a serious limitation for the development of Chinese stratospheric models. Atmospheric Deposition National-scale programs on the measurement of precipitation chemistry are being performed by NEPA and SMA and on the regional

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China and Global Change: Opportunities for Collaboration scale by RCEES and several provincial units. A review of these programs is difficult for two reasons. First, details of the design and structure of the programs were not available to the panel and second, the results of the programs have not been widely distributed. Furthermore, based on the panel's experience, when institutional reports are available, they often cannot be cited. Several institutes in China have the skilled personnel to make state-of-the-art determinations of precipitation composition and indeed, have done so on a regional basis. The data sets from these studies, especially the more recent ones, are of high quality and the publications resulting from those data are of interest to the global community. However, the use of precipitation chemistry data to address global change issues requires integrated data obtained by similar methods over national scales over an extended period of time. Unfortunately, the precipitation composition data currently available are generally not adequate to address the question of China's impact on global change. Several reasons can be offered for this lack of data: Although several institutes measure precipitation composition on a regional basis, the collection and analytical methods are significantly different at times and so the integration of the data into a national database would be problematic. The quality of data from the regional programs varies with the program. Generally, the more recent data are better, but again, the absence of a standard methodology makes it difficult to come up with common quality assurance techniques. NEPA apparently has a database from a national monitoring network. Up to this point, it has not been possible to obtain the details of the design of the network, and it has been impossible to obtain the data. These data are not available for ''outside'' scrutiny. In all fairness, it must be pointed out that the regional programs of the various institutes were not designed to address global or even national-scale phenomena. Therefore, their lack of integration, while making it difficult to address global questions, does not counter the objectives of the regional programs. The potential for collaboration in this area is uncertain. The problems of data quality and standardization of methods are solvable, and indeed, are beginning to be addressed. The most intractable problem is one of data availability. If Chinese agencies do not provide open access to their data by scientists both within and outside China, then questions that require the use of precipitation data cannot be adequately answered.

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China and Global Change: Opportunities for Collaboration PHYSICAL AND ECOLOGICAL INTERACTIONS OF THE ATMOSPHERE AND LAND SURFACE4 Hydrology Because of its vital importance to agriculture and economic development, water is considered by the Chinese to be their most precious natural resource. Irrigation is at least double that of the United States and it is perhaps the most important priority in water resource policy, with hydropower ranking second and flooding ranking third. According to recent estimates, the total amount of water is about 2,800 km3 (Xie and Chen 1990). The volume of water resources in China is 5 percent of the water resources of other countries in the world, and when volume is calculated on a per capita basis, China's is only 25 percent of the world average (NCCCG 1990). The field of hydrology is a vast enterprise in China, but, as with all such activities, it is highly self-contained institutionally. However, as will be described in greater detail below, certain hydrology research programs are large enough to involve multiple institutions. The Ministry of Water Resources (MOWR) is responsible for hydrological studies within China, and under it are seven commissions that manage the most important river systems. The Huanghe River Commission, for example, employs about 30,000 employees and responsibilities include all infrastructure—from cooking to communications. The ministry runs two training universities, the Nanjing Institute of Hydrology and Water Resources and the Wuhan Hydraulic and Electrical Engineering University, where training includes flood forecasting, water supply, and river forecasting; the work tends to be extremely practical and aimed at day-to-day operations. In addition to MOWR, other institutions have mandates relating to water resource management. The CAS Institute of Geography is responsible for conducting surveys and research related to hydrology, mostly by using remote sensing and geographic information systems (GIS) for research tools. Other state agencies dealing with agriculture and energy are all involved in water resources one way or another. In addition, accurate forecasting of seasonal precipitation has always been SMA's function. The severe flood in the lower Yangtze River valley in 1991 further pushed precipitation forecasting up the list of priorities. Other organizations carrying out hydrology research are mainly CAMS and the CAS Institute of Atmospheric Physics. Tang and Zhang (1989) describe research that focuses on two problems of water resource management. The first problem involves increased water pollution due to increasing population, urbanization,

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China and Global Change: Opportunities for Collaboration and demand for industrial-agricultural output. To counter this problem, hydrology research has been focused on the following aspects: (1) distribution of annual runoff and interannual variability; (2) solid discharge and its effect on the coastal regions; (3) hydrology in arid lands, urban areas, and the Huang-Huai-Hai Plain regions; and (4) lakes, glaciers, swamps, and estuaries (Tang and Zhou 1988). The second problem concerns the uneven distribution of water resources, since most of the water supply is concentrated in the southern part of China while the northern areas have experienced increasing levels of drought in recent years. The problem is particularly severe in the major cities such as Beijing and Shanghai where groundwater supplies are almost exhausted. One strategy under investigation is to construct waterways to link the Yangtze River in the south to the Huanghe River in the north. In 1992, the MOWR will begin a large, multi-institutional, multi-component project on the effects of climate change on hydrology. The project will continue research on the effects of climate change on basin hydrology and water resources of several major rivers located in different climate zones of the country. Subsequently, researchers will develop response strategies based on the results. For this project, the ministry wants to continue to improve research methods, for example, paying further attention to changes in the distribution of rainfall and air temperature within a given year. Four different methods are being applied to various regions: Statistical generation of nonstationary time series for different types of climate (pilot study area is the Haihe River) Large-scale hydrologic modeling on a grid and a geographical distribution model of hydrologic parameters (pilot study area is the Huaihe River basin) Conceptual modeling of the Yangtze and Pearl Rivers Statistical modeling of sediment deposition in the Huanghe River Five tasks have been identified: Investigate the one-way connection between a regional climate model and a large-scale hydrologic model. Analyze time and space variations of precipitation and evaporation. Measure and analyze variations in precipitation amounts over a long series of hydrological and meteorological records. Research variations in the amount of water entering the sea and on the water quality of the seven major river systems.

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China and Global Change: Opportunities for Collaboration Research the effects of climate variations on agricultural irrigation, residential and industrial water use, electric energy production, navigation, and urban drainage, including studying adaptation strategies and conducting cost-benefit analysis. This project will be undertaken cooperatively by the MOWR Hydrological Forecasting and Water Control Center (principal investigator: Liu Chunzheng), Nanjing Institute of Hydrology and Water Resources (Zhang Shifa), Hehai University (Liu Xinren), Wuhan Hydraulic and Electric Engineering University (Ye Shouze), the Water Science Institute of the Yellow River Basin Commission, the Hydrological Bureau of the Yangtze River Basin Commission, CAMS, and the CAS Institute of Atmospheric Physics. Other institutions may also be recruited into the project. Relevant hydrological research at CAS includes climate change and sea-level changes, the impact of climate change on water resources, and water use efficiency studies. The project, "Preliminary Research on the Relation of China's Climate and Sea-Level Changes and its Trends and Effects," has been ongoing since 1988. It has a subproject, "Effects of Climate Change on Water Resources in North and Northwest China as well as Forecasting of Trends," that has two components—the Northwest China Project and the North China Project. The northwest China research area includes the arid regions to the north of the Kunlun Mountains and to the west of the Helanshan Mountains, including all of Xinjiang Uighur Autonomous Region, the northern part of Qinghai Province, the Hexi Corridor in Gansu Province and the western part of Inner Mongolia Autonomous Region. Participating research units are the CAS Lanzhou Institute of Glaciology and Geocryology and the CAS Nanjing Institute of the Geography and Limnology. The Lanzhou institute is the lead unit and Shi Yafeng is the principal investigator. The Northwest China Project has four objectives: Study the ice layers of the Guode ice-cap in the Qilianshan Mountains, research the ice core of the last ice age, and establish climate fluctuations over the past 10,000 years for the alpine areas in the western part of China. Study glacial changes of the last 500 years. Study changes in lake water in the arid areas in the northwest. Study changes of runoff of 51 mountain rivers, mountain air temperature in the summer, and annual precipitation. The North China Project research area includes the drainage basin of the Haihe and Liaohe Rivers. Participating research units are the MOWR Hydrological Forecasting and Water Control Center, the

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China and Global Change: Opportunities for Collaboration Nanjing Institute of Hydrology and Water Resources, the Hebei Province General Hydrology Station, and Hehai University in Nanjing. The Hydrological Forecasting and Water Control Center is the lead unit and Liu Chunzheng is the principal investigator. The North China Project has five objectives: Classify, count, and statistically analyze the drought and waterlogging index data for the past 500 years and the rainfall record and air temperature of the past 100 years to ascertain spatial and temporal patterns of rainfall and air temperature in North China. Calculate atmospheric vapor conveyance. Statistically analyze the water balance variation of the land-atmosphere system by using nearly 40 years of rainfall, air temperature, and runoff records. Research the variations in the hydrological cycle such as precipitation and evaporation, surface water, soil water, groundwater level, storage capacity of some typical reservoirs and runoff (prompted by the fact that the 1980s were the driest 10-year period of the past 250 years). Calculate total annual water resources from representative drainage basins in both mountain and plains areas and study its relationship with the transformation between water and heat in the land-atmosphere system. Use watershed hydraulic models and climate scenarios to study the effects upon multiyear average hydrologic circumstances, such as future climate change, or annual variations of stream runoff, groundwater level, soil water, and evaporation. This research is almost completed, and a monograph is scheduled for publication in 1993. Water-use efficiency studies, such as those conducted at the CAS Institute of Geography and the CAS Shanghai Institute of Plant Physiology, are considered a new trend in Chinese hydrological research. CAS researchers describe a soil-plant-atmosphere continuum to refer to "sequential system studies" of the hydrological flow through that continuum (CAS 1991). The Regional Hydrological Response to Global Warming Study Group has been approved by the executive committee of the International Geographical Union. The study group is housed at the CAS Institute of Geography (CAS 1991). Summary of Hydrology Because the impact of drought or flood is often devastating, and because of the intense pressures on agricultural production, under

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China and Global Change: Opportunities for Collaboration collaborative arrangements among institutions within China and encouragement of young scientists to undertake such collaborations. It will be crucial that leading senior scientists provide appropriate role models for these activities to increase in vigor. The Sino-Japanese Atmosphere-Land Surface Processes Experiment, the Huang-Huai-Hai Plain water use efficiency project, and other large-scale collaborations provide a model for Chinese research in global change in the next decade. Climate Change Effects on Land Cover Change Dynamics Land cover is defined here as the vegetation and surface soil horizons or other land surfaces such as snow or ice that comprise a defined geographic area. Changes in land cover may be caused directly by human influences manifested on the global scale through climate change and enhanced CO2 effects. These global causes can alter land cover indirectly as well, through pedological and geomorphological change. But, land cover change will be more probable and rapid in many parts of the world through direct intervention of human influences in land use change than through these other global factors of climate and direct CO2 effects. Whereas climate change is hypothesized to occur over the next 50 years, land use change over that period is a present and continuing reality deserving attention at least equal to climate change and direct CO2 effects. Land cover change underlies some of the other focal areas addressed by this study and it is basic to some of the IGBP core projects described in this report. Land cover is a structural expression of terrestrial ecosystems underlying their contributions to energy and water budgets, biogenic trace gas fluxes, and the export of materials from land to the coastal zone through fluvial and eolian transport. For these and other reasons, land cover change is a focal area for the IGBP core project Global Change and Terrestrial Ecosystems (GCTE) (IGBP 1990). Research on land cover change can be approached by spatial scale, by different time frames, and by different modeling methods. Several spatial scales are exhibited in the GCTE organizational plan, where land cover change will be addressed at the patch scale, the landscape scale, and the regional or continental scale (GCTE News 1991). Different time frame approaches include past (historical analysis of change), present (monitoring of contemporary change), and future (prediction of future change). Research activities in China pertaining

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China and Global Change: Opportunities for Collaboration to land cover change are evaluated below mainly in terms of these time frames. Historical analysis of land cover change is useful as a measure of the variance of the past, its causal factors, and its associated results. Used with caution, this information can help predict future changes. Historical analysis can be done with proxy data such as buried or altered soil profiles, preserved pollen, or tree rings; or, it may be done with direct data such as textual, photographic, or digital records that are now available from remote sensing data archives. Historical analysis is, of course, directly related to activities of the Past Global Changes Core Project (PAGES). Monitoring contemporary land cover change provides a broad index of large-scale alterations that can be propagated to other areas such as those downstream of eolian or fluvial transport. Or, contemporary changes can be important to global processes such as land-atmosphere surface interactions pertinent to trace gas fluxes or global climate models. Monitoring can be carried out at all scales, from individual perceptions of changes in local ecosystems or crop performances, to continental scale reflectances measured by remote sensing devices. Prediction of future change of land cover is much more difficult than monitoring contemporary change but can be approximated with a wide variety of modeling approaches such as those cited above. Prediction of change is necessary in order to evaluate the effects of policies and practices regarding greenhouse gas emissions and land use. The predictive modeling of land cover change has no widely accepted approach. Different approaches are appropriate for different scales of concern. In general, modeling approaches can be divided into (a) correlational modeling (Box 1981), (b) patch scale/mechanistic modeling (Shugart 1984), and (c) regional scale/mechanistic modeling (Neilson et al. 1989). Land Cover Change Research As the world's third largest country in land area, and with a long history of civilization, China has experienced climate and land use-engendered land cover change. In fact, this issue is prominent in natural resources research and in the planning of China's national global change program. Because China has a centralized form of government, the country can exert considerable influence on how the land is used (BLM 1989) and develop national land resource accounting systems and strategies for land use (Li et al. 1990). This political

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China and Global Change: Opportunities for Collaboration factor helps explain China's large amounts of data on land condition and use (Natural Resource Study Committee 1990). Literature. Research on land cover and land use change—particularly on historical change—is profuse. Examples of paleobotanical treatises are Hsu (1983) and Walker (1986); change over historical time are Olsen (1987) and Richardson (1990); contemporary vegetational patterns are Tinachen (1988) and Uemura et al. (1990); the relation between climate and vegetation are Xu (1982), Xiwen and Walker (1986) and Huke and Huke (1982); changes in the soil component are Jin (1990) and Wohlke et al. (1988); the use of remote sensing are Liu (1989) and Fang et al. (1990), and on the historical transformation of the Huang-Huai-Hai Plain are Zuo and Zhang (1990). More recently, literature has begun to emerge that treats land cover change as part of global change science, although it is no more than regional in scope. Zhu et al. (1988a) carefully define desertification as ''a process of environmental degradation that is indicated by eolian activities and drifting sands caused by discordances between excessive human activities, resources, and environment on the basis of certain sand material sources under the dynamics of serious drought and frequent winds.'' They describe the distribution and trends in desertification for the world in general and China in particular, and analyze underlying causal factors and consequences. Most of the land defined as prone to or having undergone desertification lies in the northern tier of the country. Zhu et al. (1988b) also review these processes in more detail for a limited area of the country. More succinct analyses of desertification trends are translated from another article by Zhu and Wang (1990). Readers of broader Chinese literature should be cautioned that not all researchers use the term "desertification" as carefully and strictly as do Zhu et al. Some use the term for any form of deterioration of ecosystems or soils including the erosion of formerly forested land under moist conditions. Chinese desertification research has a significant international link through the hosting of an international desertification training center at the CAS Lanzhou Institute of Desert Research under UNEP's auspices. Notably, in 1990, an international seminar on desertification processes was held at the Lanzhou institute (UNCSTD 1990). Another example of global change research is in literature dealing with China's grasslands. The Gansu Grassland Ecological Research Institute (Chen 1990), in describing its national key project to monitor grasslands, states that Chinese grasslands are degrading rapidly through increase in weediness, soil degradation, and decreased productivity. This message about grassland degradation is echoed by

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China and Global Change: Opportunities for Collaboration Reardon-Anderson and Ellis (1990). Grasslands and Grassland Sciences in Northern China (CSCPRC 1992) is an extensive and very sophisticated analysis of the state of change of Chinese grasslands and the underlying reasons. This study provides detailed descriptions of the degrees of conversion of grasslands to farmlands, rangeland degradation, and desertification. Collectively, the northern tier of China, especially the area surrounding marginal farmlands and grasslands appears to be relatively well studied. Some brief discussion on "aridization tendencies" in northwest China and dryness, wetness, and chillness in east China are discussed in terms of changes in crops and forest cover in Zhu and Wang (1990). This is an example of land cover change caused, in large part, by climate change rather than from land use. In contrast with much of the literature available that focuses on historical change, a notable attempt has been made by the Second Working Team of the National Climate Change Coordination Group (NCCCG 1990) to predict the effects of climate change, at least qualitatively, on agriculture, forests, water resources, and energy.5 Under agriculture, the report gives four examples respectively of positive and negative effects and concludes that "in short, the overall effect of climate change on agriculture will reduce China's agricultural production capacity by at least 5 percent." This seems to be a modest estimate of change compared with the descriptions of negative effects preceding the summary. After analyzing effects of climate and CO2 change on six commercial species, the report offers no such summary for forests, but prognoses for those individual species seem mostly negative. As described in Chapter 4, land cover change projections caused by climate and land use changes are attempted to a small degree, but little research was identified showing work on the direct effects of CO2. IGBP Research. The Chinese National Committee for the IGBP (CNCIGBP) describes a core project, "Measurement and Prediction of Changes and Trends in the Life-Supporting Environment in the next 20 to 50 Years in China," that will include land cover change, although it was not very specific in this regard (CNCIGBP 1990a). Another core project was based on setting up north-south and east-west transects of CERN stations to monitor land cover and other changes in fragile ecotones. A pilot study has been undertaken to survey existing data and Chinese literature on changes in atmosphere, vegetation cover, soils, and water. The CNCIGBP, in 1991, announced its intention to develop five workshops to help define global change research (CNCIGBP 1991),

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China and Global Change: Opportunities for Collaboration three of which would be relevant to land cover change: (1) climate change effects on terrestrial ecosystems, (2) sensitive areas of environmental change and detection of early signals of significant global change, and (3) characteristics and trends of changes of the life-supporting environment in China. Of the major global change research projects listed by the CNCIGBP for the Eighth 5-Year Plan, six can be easily defined as land cover change research: (1) the development and utilization of the Loess Plateau and global environmental change; (2) development and application of remote sensing techniques; (3) comprehensive land restoration experiment in the Sanjiang Plain in northeast China; (4) regional comprehensive development and land restoration strategies in southwest China; (5) comprehensive scientific study of the Karakorum-Kunlun Mountain region; and (6) study of comprehensive regional development and land restoration in Xinjiang Uighur Autonomous Region. Collectively, research on land cover change does not seem to be a distinguishable focus for the Chinese program on global change. The Chinese Ecological Research Network (CERN), which is described in detail in Chapter 4, will be actively involved in research and monitoring of land use and land cover changes. Appendix D contains an example of the type of research planned for this network. The National Natural Science Foundation of China (NSFC) describes projects it funds that contribute to IGBP goals (Zhang 1991). Some projects listed under PAGES might contribute to land cover change research from an historical viewpoint. Some projects listed under the "Human Dimensions of Global Change Program" look very interesting for further modeling of the land use change component of land cover change. See Appendix B. A jointly sponsored (U.S. Environmental Protection Agency, NEPA, CAS) symposium on climate—biosphere interactions was held in Beijing in May 1991, during which participants were asked to recommend future collaborative work. Concerning models, participants recommended four areas for cooperation: (1) data compilations on land cover and use in Asia including inputs to large-scale models; (2) specific emphasis on rates of reforestation/afforestation; (3) cooperative AVHRR land cover study as part of the Data and Information Systems for the IGBP and inclusion of other satellite data; and (4) regional, mesoscale, forest, agricultural, and soil ecosystem models with processes. Research activities that could broadly be interpreted as addressing land cover change can be found in many of the institutional reports in Appendix A; the following give a sampling of the diversity of activities.

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China and Global Change: Opportunities for Collaboration The Commission for Integrated Survey of Natural Resources (CISNAR) has a role to play in land use and land cover change research. The many expeditionary and cartographic activities it carries out would be an excellent source for the development of a contemporary land cover database for the nation. Institute officials say it will be the database center for land resources in the national global change program. CISNAR already houses World Data Center-D for Renewable Resources and Environment and the Integrated Research Center for Natural Resources and Agricultural Development (a joint database project with the Ministry of Agriculture) and has regional and national databases for resources, ecology, and the environment. Additionally, CISNAR is the designated host of the CERN Synthesis Center, where synthesis and analysis of CERN-generated data will be conducted. Clearly, CISNAR has an important role to play and it is hoped that it will receive the extensive training, expertise, and appropriate equipment that will be required to realize this role successfully. Through CISNAR, CAS has produced a very impressive compendium of natural resources that indicates a kind of database management (Natural Resources Study Committee 1990). A little historical analysis is visible here in the way of dendrochronology, but no evidence of predictive modeling activities. Feng Zongwei and Zhuang Yahui at RCEES are carrying out a large-scale, collaborative forest ecology project with the objective of providing specific data on China's forest ecology for input to global change studies. Methodology includes soils and plant classification and mapping, experimental studies of material and energy flows, measurements of atmospheric gas concentrations (CO2, NOx, SO2, and O3), and comparison of differences between urban Beijing atmosphere and nearby mountain atmosphere. Comparisons will be made in different seasons, trends will be monitored for 5 years, and some modeling will be included. The mountain area studies will be conducted at the CAS Beijing Forest Ecosystem Station, which is located about 2 hours west of Beijing. The cost of the project is 1.8 million yuan, and funding is from the State Science and Technology Commission and NSFC. In Nanjing, a few institutes are or could be contributing to land cover change research. At the CAS Nanjing Institute of Geography and Limnology, considerable historical analysis could be relevant. At the Department of Geo and Ocean Sciences at Nanjing University, high-quality historical analysis and qualitative land cover change projections are being developed. The projections are done mainly through land use change, and are coupled with hydrological and sedimento

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China and Global Change: Opportunities for Collaboration logical consequences. (One of the most holistic and imaginative proposals on these linkages has been proposed by Ren Mei-e to NSFC, and a preliminary manuscript [Ren and Zhu 1991] already shows some very interesting results.) Under NEPA, the Nanjing Institute of Environmental Science is conducting work on preserving biological diversity, deforestation and reforestation, and desertification, although little evidence exists of any kind of spatially extensive program or aspiration to such an approach. The CAS Institute of Botany presented the most sophisticated example of predictive capability that members of this panel encountered. Potential natural vegetation defined by the Holdridge system of physiognomic-climate relationships and agricultural cropland are linked with climate variables through discriminate analysis (Chang and Yang 1991). Climate variables are interpreted in terms of large-scale drivers for the subcontinental weather system such as the Qinghai-Tibet Plateau and East Asian monsoon and therefore are linked to potential scenarios of large-scale meteorological expressions of climate change. This entire system is built on national-scale GIS with variable grid cell sizes for different attributes. The result is a ready system for portrayal and manipulation of vegetation data for the country. The nationwide soils map is also in this system. This is a prime example of the application of a simple correlation modeling approach to large-scale prediction of vegetation change that has no readily apparent comparison elsewhere in the world. Other, more sophisticated, mechanistic models exist but are not applied to a large-scale database system. With more sophisticated models, first order assessments of direct CO2 effects could be made when more physiological understanding exists. This GIS system is assessed with satellite imagery country-wide and is in a format that can be used for equilibrium prediction for altered climates. Predicted changes in annual precipitation or temperature are used to recalculate productivity and regenerate maps. In this system, China has a tool for assessing the impacts of climate change and land use change on large-scale land cover and for evaluating the climate, hydrological, and ecological consequences through linked models. These are not dynamic models in the sense that they cannot simulate rates of change. They are, however, comparable in sophistication to similar models employed in the West. The CAS Institute of Geography's historical and contemporary land cover studies are highly germane to the study of land cover change. The National Key Laboratory for Resources and Environment Information Systems conducts some of the most comprehensive

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China and Global Change: Opportunities for Collaboration and sophisticated GIS work in China, although it is notable that it is done in complete isolation from other solid work such as that described above at the Institute of Botany. At a recent international meeting on GIS sponsored by the laboratory, 17 of the 55 Chinese papers submitted were generated by the CAS Institute of Geography. Seven papers each were presented from Wuhan and Peking Universities, four (mainly statements of need) from CISNAR, three from Nanjing University, two from the CAS University of Science and Technology of China, and one each from 13 other organizations (Chen Shupeng et al. 1990). Although a marked contrast in the technical sophistication of these papers was evident, this brief survey was remarkable and encouraging, nevertheless, as to the potential for developing GIS and remote sensing capacities in China. Summary of Land Cover Change Dynamics In order to describe land cover change in the past and present, or to make predictions, appropriate land cover classifications have to be devised and broadly accepted at appropriate scales, and there has to be sound geographic control of land cover in the form of maps or digital database systems. Although a methodological review of map resources was not conducted, it would seem that China is rich in fine soil and vegetation maps at local to national scales. A quick review of information available through CAS shows many valuable components that could contribute to a more systemized land cover accounting system. For example, the National Key Laboratory of Resources and Environment Information Systems at the CAS Institute of Geography has substantive mapping and GIS capabilities. China receives Landsat data and has the resources of the CAS Institute for Remote Sensing Applications. And, digitizing maps is a project within CERN. Ultimately, an appropriate GIS system and coordinated remote sensing system for the country will be needed to bring order to the spatial data and to monitor continuing land cover change expediently. The other ingredient needed for projecting land cover change is a system of relating vegetation components (species or functional groups) to climate for natural vegetation, cropping systems to climate, CO2 increase, and social and economic factors through the use of models, such as the modeling objectives at the CAS Institute of Botany described previously. Also, current plans for the CERN Synthesis Center at CISNAR call for collecting such data and for having the resources to build those types of models. Contemporary and planned research on land cover change in China is fragmented and largely historical in approach. Research currently

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China and Global Change: Opportunities for Collaboration is a national program on phenomena driven, in part, by global mechanisms. Within China, there seems to be more progress in the north, particularly on lands surrounding and including grasslands, than in the far northeast or south. Much of the work under way is in the category of historical analysis. China does not appear to have a comprehensive or interinstitutionally systematic monitoring system. CAS has launched a major program to create a network of ecological stations that will have monitoring functions (Chapter 4). SMA has over a thousand monitoring stations. NEPA has hundreds of various types of monitoring stations and is implementing a national monitoring system. Various ministries, such as the Ministry of Agriculture, monitor resources under their jurisdiction. It would be useful to nurture modeling efforts that use more mechanistic approaches to modeling the relationships between vegetation and soils (as the elements of land cover) and climate and land use. The panel did not find that such activity is planned, even though this is key for global change research. The obvious importance to policy makers will lie in having predictive descriptions of land cover change. In China, extensive land cover changes have already occurred and are ongoing today. Much of this is driven by land use change rather than by changing climate per se. Many components are available to develop a focused land cover change program in China: maps, remote sensing, historical records, and some modeling capacity. This is an area in which some catalytic action through international collaboration could make a big difference. Additionally, as in other countries, an entirely different genre of social science models is needed for predicting how land use would be likely to change in response to climate, population, economic, and technological change scenarios. Furthermore, land cover change research must have strong ties to research on the human dimensions of global change, which, in the case of China, is an area of great relevance and potential. NOTES 1.   In China, it is common for individual institutes to publish journals of the institute's research work, often without external peer review. It is notable, though, that some journals are now accepting substantial numbers of papers from outside institutes. 2.   In June 1992, a workshop on Asian dust was organized by Richard Arimoto, University of Rhode Island, that brought together more than 30 scientists from China, Japan, and the United States to report on recent research and to discuss future cooperative studies.

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China and Global Change: Opportunities for Collaboration 3.   Under a bilateral project between NASA and CAMS, two workshops on atmospheric chemistry were held in 1990 and 1992, and stratospheric O3 was one of the selected topics. Each workshop involved between six and 15 scientists from each country who presented key findings from their research. 4.   This area has been nourished by international exchanges and by the strong scientific leadership of Ye Duzheng, who has collaborated extensively with foreign and Chinese research communities, bringing them together. Early on, Ye emphasized the important and unique role of the Qinghai-Tibet Plateau as a strong dynamic and thermodynamic perturbation on the global general circulation. He organized measurement programs and data collection to examine this effect and he has carried out a numerical sensitivity study of the effects of soil moisture on climate and hydrological variability. 5.   This report was drafted for the Intergovernmental Panel on Climate Change's deliberations.

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