This workshop explored the interplay of large urban areas and surrounding agricultural lands. Consideration was given to air pollution and water pollution flowing between agricultural and urban sources. Attention was also given to air pollutants and their photochemical evolution in the atmosphere and downwind deposition onto crop lands. Considering regions in Europe, North America, China, and Japan, participants discussed the impacts of economic development–ranging from carbon emissions to population growth and strained infrastructures. Emphasis was placed on the role technological development might have in relieving associated pressures to the environment. Case studies from China were presented.
Keywords: human interactions; economics; land use change, urban ecology, agriculture
About the Workshop
Overview & Relevance:
The unprecedented increase in humankind’s standard of living since the Industrial Revolution can be attributed in large part to two factors: the development of high-input/high-yield agriculture capable of feeding an increasingly urban population, and an urban-industrial infrastructure, heavily dependent upon fossil fuels for the production and transport of manufactured goods. This interdependence between agriculture and fossil-fuel burning is most pronounced in three regions of the northern mid-latitudes: (I) Eastern North America (25-50°N, 105-60°W) ; (ii) Europe (36-70°N, 10°W-90°E); and (iii) eastern China and Japan (25-45°N, 100-146°E). Within each of these regions, urban-industrial and agricultural activities tend to cluster together into a single large network or plexus of human-impacted land-use categories.
Chameides et al. (1994) have proposed the term Metro-Agro-Plex (or MAP) as a shorthand to describe this intermingling of agricultural and urban-industrial activities within a developed or developing geographical area. They have used the term Continental-Scale Metro-Agro-Plexes (or CS-MAPs) to specifically refer to the three large MAPs of the northern mid-latitudes. Collectively, the CS-MAPs represent a major force in the global economy and also in environmental change. Although they comprise only 23% of the Earth’s land surface, the three CS-MAPs account for about 75% of the world’s consumption of commercial energy and fertilizers and about 60% of the food crop production and food exports. They are also major source regions for atmospheric pollutants such as carbon dioxide, the nitrogen oxides (NOx) and the sulfur oxides (SOx), which affect global and regional climate and air quality. It is this interplay between urbanization and high-input/high-output agriculture, the environmental changes that they cause, and the effects these environmental changes have, in turn, upon socially and economically important institutions within a MAP that formed the basis for the discussions of this Aspen Global Change Institute session.
Content:
The China Perspective
In order to provide a focus for our discussions, this AGCI session undertook a regional-scale case study of China as an evolving CS-MAP. The choice of China was based on its status as the most populous and most rapidly developing nation in the world, with a population estimated at 1.1 billion people and a Gross Domestic Product that is growing at an annual rate of about 13%. By the year 2000, China’s population is projected to reach 1.25 billion and by the beginning of the 21st century its economy will likely surpass that of the United States in terms of purchasing power. China also plays an important role in the world food economy, accounting for roughly 20% of global production and consumption of the major staple crops wheat, rice, and maize (FAO, 1991).
The unprecedented combination of economic and population growth in China will bring about profound changes in the nation’s landscape and demographics. Large tracts of land now in cultivation will be urbanized or converted to other uses (Streets et al., 1995). Enormous shifts in population will occur as well. About 80% of China’s people now live in rural/agricultural areas. However, government plans for China’s economic development call for a population of only 200 million in the agricultural sector (Zhou, 1995). To meet this goal, approximately 500 million people will be moved out of these rural areas. Rather than have them move to mega-cities, with their attendant infrastructural and cultural problems, however, the government plans to have them relocate to some 5000 different township and village enterprise zones or TVE’s (Tao, 1995). Each TVE will be a small city, with a population of about 100,000 and will be interspersed in and among the agricultural areas of the nation. The resulting land use pattern will make China a patchwork of Metro-Agro-Plexes of unprecedented proportion and complexity. All of this contributed to the choice of China as a focus for the AGCI session on Metro-Agro-Plexes.
Key Issues
Several important issues emerged from the AGCI discussions of China as an evolving Metro-Agro-Plex . These are outlined below:
1 Environmental Change and Agriculture
In terms of CO2 emissions alone and their impact upon the climate, the global implications of China’s impending economic and industrial explosion are serious. The likelihood that this economic explosion will be fueled by China’s abundant coal reserves raise the level of concern. From China’s point-of-view, however, the issues of sustainable development and food self-sufficiency are probably more pressing than those of global change.
China maintains its current level of food self-sufficiency at a significant price. China’s arable land amounts to only about 0.08 hectares per capita, a factor of 10 less than that of the United States and a factor of three less than the global average (Tao, 1992). To compensate, China uses enormous amounts of fertilizer and irrigation. The resulting fluxes of fixed nitrogen into China’s fresh waters, and N-containing gases, especially N2O and NOX, into the atmosphere are significant and present growing environmental burdens on regional and global scales (Tao, 1992; Galloway et al. 1995). The projected population increase of 100 million people by the year 2000 will be an additional burden on an agricultural system that is already stretched to meet current demand. At the same time, Chinese agriculture will have to cope with the loss of significant lands for cultivation as China’s economic development forces the conversion of farmland to other uses (Streets et al., 1995).
In addition, observations in China indicate that the past few decades’ global warming trend has coincided with a significant falloff in precipitation over some of China’s most productive rice and wheat fields in the eastern half of the nation. Moreover, regional and local pollution may already be taking their toll on China’s harvests, causing the loss of about 5% of the nation’s annual production of grains, and estimates of sulfur deposition indicate that these regions are receiving deposition in excess of their critical load values (Arndt and Carmichael, 1995).
The projected rapid economic development of China over the next 20-30 years will likely further exacerbate the problem. Thus the picture of China one or two decades hence filled with burgeoning TVEs, interspersed among the nation’s farmlands and fueled by energy derived from burning cheap, high-sulfur coal is a China with enormous air pollution problems that seem bound to impact agriculture negatively. How large will this impact be and what can be done to avert it? On the other hand, what will the role of agriculture be in driving environmental change? These are complex and difficult questions, but nevertheless questions of critical importance that require the attention of the scientific communities.
2 Understanding Climate Change in China
Because of the critical role meteorology plays in agriculture, any assessment of the viability of China’s agriculture must also address the issue of regional climate change. This in turn requires an ability to simulate with reasonable accuracy China’s present climatic conditions, in terms of the magnitude, temporal variability, and spatial distribution of key variables such as temperature and precipitation. Although numerous assessments of regional climate change and its impact upon agriculture have been addressed using global climate models, simulations indicate that, at least for China, these global models do a poor job of replicating basic climatic features in China.
3 The Yangtze Delta
With a population approaching 200 million, the region hosts approximately 530 people per km2, making it the most densely populated area in all of eastern Asia (Leman, 1995). Moreover, its major province, Jiangsu Province, has the distinction of having led China in both grain production and industrial output (Streets et al., 1995). Thus we can think of the Yangtze Delta region as one of the most productive Metro-Agro-Plexes in Asia, if not the world.
The government plans to create a modern highway system in the region that will link its cities, townships, and rural areas together (and no doubt create the same regional photochemical smog episodes that plague the U.S. ). The projected rapid growth of the Yangtze Delta presents a unique target of opportunity to the scientific community to document, analyze, and better understand the dynamic interactions between economic development, rapid population growth, high-input/high-yield agriculture, and regional and global environmental change.
Recommendation: Implement Interdisciplinary, Regionally-Focused Study
The participants of the AGCI session agreed that much benefit could be gained from the implementation of an interdisciplinary research project aimed at documenting and analyzing the changes occurring in China in general, and the Yangtze Delta in particular, and assessing the likely impact of these changes on critical ecosystems in the region. It was also recommended that this research be closely aligned with the political and industrial organizations active in the region, in order to maximize the translation of the project findings into new technologies and economic and social policies that foster a sustainable economy and environment.
Event Co-Chair
The attendee list and participant profiles are regularly updated. For information on participant affiliation at the time of workshop, please refer to the historical roster. If you are aware of updates needed to participant or workshop records, please notify AGCI’s workshops team.
