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Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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.

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

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.

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

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,

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

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.

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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  • 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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

standing the hydrologic cycle and the proper management of water resources are vital to China's national interests. China's approach to studying the hydrological cycle probably will remain very focused on Chinese resource management issues and on social and economic impacts. The relationship between climate change and hydrology appears to be a priority, as evidenced by the work of the National Climate Change Coordination Group and by current and planned research by major institutions such as MOWR and CAS.

The characteristics of Chinese hydrological and respective research are a very attractive area for collaboration. Under the U.S. global change research program, the Department of the Interior is conducting or planning research activities that complement the objectives of Chinese investigations. Furthermore, the U.S. Bureau of Reclamation has devised a Global Change Response Program to investigate the potential impacts of global climate change on water resources in 17 western states. Many universities, particularly in the western United States, are conducting or planning investigations of the impacts of global climate change on regional hydrology that would be conducive to collaboration with Chinese investigators.

Biotic Controls on Trace Gases

The discipline that studies the fluxes of chemicals in the environment mediated by the biota is known as biogeochemistry. Storage of elements, especially carbon, is especially important in understanding global element cycles as changes in carbon storage can have large effects on atmospheric CO2 concentrations. Biogeochemistry and physical climate can interact to produce feedbacks, if, for example, a change in climate causes an increase or decrease in a greenhouse gas such as CO2 or CH4, which causes a further change in climate.

The Chinese effort in biogeochemistry has numerous components relevant to land-atmosphere interactions. Here, the panel reports on several that were observed in some depth. First, a program measuring CH4 emissions from rice cultivation is in progress, conducted as bilateral collaborations between CAS and the Fraunhofer Institute in Germany and between CAS and the U.S. Department of Energy (DOE). Second, the Chinese have initiated efforts to examine N2O production and CH4 consumption from upland soils at RCEES. Third, an ambitious program analyzing vegetation dynamics supports national and regional estimates of carbon storage and primary productivity is under way at the CAS Institute of Botany. There are also some Chinese studies of soil nutrients and organic matter. These activities are described in more detail below.

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×
CH4Studies

Rice production is of considerable importance in the global CH4 budget, contributing ~35–60 Tg/year out of total global emissions of 300–400 Tg. Some estimates from Chinese data suggest an even higher flux of 70–110 Tg/year (Wang et al. 1992). Rice is a major crop in China and Chinese rice production contributes a significant fraction of total global rice production, and so, presumably, CH4 from rice.

Some noteworthy research on CH4 from rice in China has been carried out through collaborations under the CAS-DOE Joint Research on the Greenhouse Effect (Riches et al. 1992) and with the Fraunhofer Institute in Germany (Schultz et al. 1990, Wang et al. 1992). Continuous sampling chambers allowing the collection of high temporal resolution data was undertaken in the latter collaboration. This work has made clear the significance of relatively transient high fluxes in determining overall flux. Fluxes in all Chinese studies show considerable seasonal variability and in many cases diurnal variability. In addition, the intensive nature of rice cultivation in China promotes high rice productivity and hence high CH4 emissions. Different fertilizer sources did not seem to have large effects on CH4 emissions integrated over the year.

Studies at the CAS Taihu Lake Comprehensive (agroecology) Experiment Station address not only CH4 fluxes but also microbial and carbon cycling controls over methanogenesis. Studies are in progress to address the role of plant growth, root turnover, exudation, and microclimate and the relation to CO2 emissions. Experiments are being carried out in a number of fertilizer treatments in order to understand the consequences of different agricultural management systems on CH4 production.

N2O Emissions

About 90 percent of global N2O emissions are thought to be from soils. The potential contribution of these emissions to global warming is large because it is an effective absorber of infrared radiation and very long lived in the atmosphere with a potential for thermal absorption of 150 relative to one for CO2—based on turnover rate, etc. (Bouwman 1990). It is currently thought to contribute about 5 percent to radiative forcing. While the biology of N2O is relatively well known, ". . . the budget for the N2O-exchange between terrestrial ecosystems and the atmosphere is largely unknown" (Bouwman 1990). The geographic distribution and magnitude of sources are poorly known. This lack of information makes additional research a

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

priority, especially in areas of intensive agriculture and in areas where fertilizer use is increasing.

Research on N2O emissions in China is in its infancy. Currently a record of atmospheric concentrations has begun, and some flux measurements have been made. The Chinese background station (Wudaoliang) is in western China at 4,300 m elevation. Su et al. (1990), in a review paper on Chinese N2O research, report a mean atmospheric concentration of 308 ppb +/- and a range from 303 to 315 ppb, data which are in the range reported from U.S. studies. N2O emissions are often linked to CH4 uptake and studies on this phenomenon are beginning in China. Some work on N2O in rice paddy systems is also going on at the CAS Nanjing Institute of Soil Science.

Climate-Vegetation Dynamics, Net Primary Productivity, and CO2-Vegetation Interactions

The CAS Institute of Botany group led by Zhang Xinshi has an ambitious and integrated effort linking Chinese climate, vegetation, and productivity. Their effort is based on a climate-vegetation classification modified from that of Holdridge. This scheme links potential natural and agricultural vegetation to climate parameters. The effort is supported by extensive geographic data, including satellite data (advanced very high resolution radiometer [AVHRR]) for the production of a normalized difference vegetation index (NDVI). This classification, which predicts structural characteristics of vegetation, is used as a foundation for a climate-based predictor of productivity—the radiative dryness index. By using this approach, researchers have calculated net primary productivity (NPP) levels ranging from 19.5 T ha-1 y-1 on a tropical South China Sea island to <0.1 to 0.4 in extreme and temperate deserts. Because this analytical effort is fully integrated into GIS software and based on climate models, they can easily estimate national NPP levels, or calculate them under altered climates. Also, the institute has an extensive database of the chemical composition of tissues of many of the plant species of China so that budgets of nitrogen, phosphorus, and many other elements may be derived from models of NPP or biomass. This effort is the one area where modeling is central and quite strong in the field of biogeochemistry. The CAS Institute of Botany's efforts in ecosystem modeling and analysis are world-class in integration and sophistication.

Fu Congbin at the CAS Institute of Atmospheric Physics has been using NDVI for China from October 1988 through October 1989 as the basis for a pilot project on climate-vegetation interactions. The

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

NDVI clearly shows a vegetation boundary along the semi-arid zone of northwest China, which also delineates the northern edge of the summer monsoon. Further studies are needed to investigate the role of summer monsoons and expose interannual variability of vegetation dynamics.

CO2-vegetation interactions, which has been a major research focus within the U.S. program, has received comparatively less emphasis in the Chinese research program. At least two reasons can be identified for this difference. First, facilities are limited for experimental studies of growth at elevated CO2. Second, the panel did not find any perception that changes in carbon storage in terrestrial ecosystems will play a major role in mitigating or modifying CO2- dependent feedback on the physical climate system. Rather, the primary Chinese interest identified to the panel is in the possible implications of CO2 fertilization on agricultural yields.

One notable exception has been work at the CAS Shanghai Institute of Plant Physiology, where studies on the effects of CO2 enrichment on crop growth have been conducted since 1960 (CAS 1991). Initial experiments by using elevated CO2 for approximately two weeks after flowering increased rice yields by up to 30 percent and reduced the dropping of cotton balls prematurely by up to 47 percent.

In the early 1970s, experiments were conducted on cucumber, tomato, and rice seedlings that were placed under PVC tents in late spring. Cucumber yields improved by 87 percent and cucumbers reached marketable sizes 10 days earlier than those grown under control conditions. Rice seedlings grew faster and matured 3 to 4 days earlier than those in the control group.

In 1988, a CO2 enrichment experiment on a natural coastal ecosystem was carried out in collaboration with D.O. Hall of London University with funding from the United Nations Environment Program (UNEP). Reed was the dominant species in the ecosystem. Two open-top PVC chambers of 2 m diameter were installed and CO2 was doubled during daytime from the time new shoots appeared in the spring and continued for 44 days. Afterward, dry weight above ground biomass was increased by 44 percent and below ground by 8 percent.

Currently, a CO2-doubling experiment is being carried out by Xu Daquan in Jiangsu Province, where a well containing a continuous natural flow of highly purified CO2 is located. The experiment consists of four open-top chambers (two for elevated CO2 and two for control purposes) containing more than ten species of weeds. This experiment will study the long-term effects of doubled CO2 concentrations on plant productivity and succession.

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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Soil Nutrient Studies

Soil organic matter and soil nutrient turnover has been a major research area in Western biogeochemistry (Paul and Clark 1991). Soil nutrients constrain NPP and interact strongly with climate change in controlling vegetation response. Soil organic matter is one of the largest reservoirs of carbon in the earth system and is quite dynamic in response to either land use or climate. The Chinese effort in these areas was not as evident in their global change program as were other efforts (as is the case in the United States as well) but some work is ongoing.

The CAS Nanjing Institute of Soil Science conducts considerable research on soil organic matter and has published a compendium of soil properties, including nutrients and organic matter for the major soil regions of China, as well as a national soil survey. This institute has also conducted studies of organic matter turnover in paddy soils that are integrated with CH4 studies.

The CAS Northwest Institute of Soil and Water Conservation has performed extensive studies of soil and nutrient loss due to soil erosion and is involved in integrated studies of soil erosion, crop productivity, and nutrient cycling.

The CAS Inner Mongolia Grassland Ecosystem Experiment Station has published extensive results on soil carbon and nutrient pools, inorganic nutrient levels and turnover, and stable isotope biogeochemistry of grassland plants (the latter in collaboration with Larry Tieszen of Augustana College, South Dakota). Some studies on microbial ecology have also been undertaken. The work reported from Inner Mongolia and similar work conducted at the CAS Xinjiang Institute of Biology, Pedology, and Desert Research is primarily descriptive in nature but provides valuable information. The value of Chinese data on soil element storage and turnover is twofold: it augments the global database on these properties and, because soil nutrients and nutrient turnover are controls over many aspects of atmosphere-biosphere exchange, it provides context for other process studies in China, such as on trace gases or biophysics.

Summary of Biotic Controls on Trace Gases

Biogeochemistry is a relatively young discipline. Moreover, soil nutrient turnover and trace gas biogeochemistry, while central in the global change research agenda, have been slow to develop fully, lying as they do on the disciplinary boundaries of atmospheric chemistry, soil science, microbiology, and ecology. In the United States,

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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progress has been curbed by lack of communication between disciplines viewed as basic (for example, geochemistry or ecology) or applied (for example, soil science); these barriers exist but in a different form in China. While soil science and botany, for example, are studied under the auspices of separate institutes, they are all within CAS. Soil science and soil microbiology are central fields in global change, but as in the United States, the soil sciences are just starting to develop research agendas separate from agronomy and related to the earth and ecological sciences.

The barriers to interdisciplinary study of biogeochemistry in China are clear, given the disciplinary nature of the basic research and funding organizations. In addition, state-of-the-art research in biogeochemistry requires access to instrumentation, reliable analytical standards, and field site travel. All of these requirements can be constraining in China. However, many activities are quite vigorous and international collaboration is strong. The potential for enhanced collaboration seems high, and Chinese scientists are eager.

Two areas are especially weak in Chinese biogeochemistry. First, great progress has been made in the West by the development of techniques for the measurement of microbial processes in soil, including the conversion of organic nitrogen to mineral nitrogen, the release of organic carbon as CO2 and similar phenomena for phosphorus. These techniques often rely on stable or radioactive isotopic tracers and have been fundamental in understanding processes like the rate of N2O production, the stabilization of carbon in soils and the leaching of nitrate to groundwater. These techniques require sophisticated but increasingly accessible technology for gas concentration and isotopic measurements and some sophistication in the quantitative analysis of data. The former is limiting and found at only a few institutes while the latter is abundant in China.

Secondly, in many cases, process measurements are indirect and key process rates must be estimated by system-level mass balances via modeling. While the relevant groups in Chinese institutions are aware of the significance of this type of modeling in understanding biogeochemical cycles, very little work is ongoing. Collaborative relationships could be very profitable given the mathematical sophistication of many Chinese scientists. Note also that while progress in atmospheric modeling is very limited in China by a lack of access to modern supercomputers, most ecological and biogeochemical models run satisfactorily on personal computers.

Finally, the type of teamwork and interdisciplinary collaboration that has been required for progress in biogeochemistry in the West is just developing in China. Progress will require increasingly flexible

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
×

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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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),

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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.

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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.

Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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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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Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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Suggested Citation:"Selected Topics." National Research Council. 1992. China and Global Change: Opportunities for Collaboration. Washington, DC: The National Academies Press. doi: 10.17226/2075.
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China and Global Change: Opportunities for Collaboration Get This Book
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Given China's current and potential impacts on the global environment and the contributions Chinese science can make to global change research, China's full participation in international research programs dealing with global change is very important.

This book provides insights into how research priorities are determined and detailed information about institutional infrastructure, human resources, and other factors that will constrain or facilitate Chinese responses to and research on global change issues.

An overview of research relevant to the International Geosphere-Biosphere Program and the World Climate Research Program is presented. Additionally, research in certain areas of atmospheric chemistry and physical and ecological interactions of the atmosphere and land surface are explored in further detail.

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