The present study aimed to quantitatively clarify the impact of human activity (with regard diet habits, waste disposal and farming method) on the nitrogen flow of agro-ecosystem and the water environmental problem by both statistical material and field investigation. According to our estimates, the total amount of nitrogen transported to the surface waters increased from 1.98 Tg-N in 1980 to 3.03 Tg-N in 1990 and to 4.50 Tg-N in 2000, showing a 2.3-fold increase between 1980 and 2000. The areas that exported large amounts of riverine nitrogen expanded widely from the Changjiang lower plain to the Changjiang middle plain and surrounding areas between 1980 and 2000. The high rate of nitrogen fertilizer application and the low fertilizer use efficiency were implicated as major causal factors of increased riverine N transport. Regarding per-capita annual potential nitrogen loading from human excrement, approximately 1.02 kg-N is returned to farmland and 5.49 kg-N is discharged into rivers in urban area. In rural regions, on the other hand, approximately 4.33 kg-N is returned to farmlands and 1.60 kg-N is directly discharged into rivers. Furthermore, the economic growth and urbanization lead to an increased proportion of meat in the diet, greater use of flush toilets, less recycling of human and animal wasters onto agricultural land, which makes rural communities more dependent on chemical fertilizer and imported animal feeds. China is facing serious water pollution problems; therefore, increasing organic matter recycling rate and decreasing chemical fertilizer application rate requires consideration.

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By using ion exchange resin columns, nitrogen (ammonium and nitrate) deposition rates were measured in 6 forest areas in China (Hailar, Changchun, Chanbaishan, Beijing, and Guangdong (Heishiding and Dinghushan)) and at 6 forests in Nagano in Japan. The annual nitrogen deposition rates ranged from 2.5 to 20.7 kg N ha^-1 year^-1 by precipitation (without canopy), and from 1.4 to 39.2 kg N ha^-1 year^-1 by throughfall in forest areas in China. The rates were higher in southern parts of China, and significantly correlated with population density. The rates by throughfall exceeded those by precipitation in the forests having large nitrogen deposition. Dry deposition on tree leaves and twigs might contribute significantly to the nitrogen deposition in air polluted area. Ammonium nitrogen predominated the nitrogen deposition in forests having large nitrogen deposition. Nitrogen leaching losses measured by buried resin bags positively related with and mostly exceeded nitrogen deposition by throughfall in forest areas in China. Large nitrogen leaching loss (40 - 50 kg N ha^-1 9months^-1) observed by the buried bags was in accordance with the values estimated by a water budget approach in a small watershed in Dinghushan. High nitrate concentrations were observed throughout the rainy season there. Increase in nitrogen deposition accompanying with human activities might increase nitrogen leaching loss from forest areas in China.

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Characteristics and research questions in nitrogen cycling in natural forest ecosystems of northern Hokkaido were discussed based on the case studies in Hokkaido University's experimental forests. Most atmospheric nitrogen deposition was net retained in forest ecosystem and the nitrate leaching from soil was mostly occurred during the snowmelt period. The rapid microbial immobilization of nitrogen in surface soil was important processes for the nitrogen retention. However, the removal of soil surface and vegetation for the forest practices caused the increase of nitrate leaching potential due to the decreases of the nutrient uptake and the microbial nitrogen immobilization. On the other hands, the increase of fine root biomass and the nitrogen uptake by dense understory vegetation, Sasa dwarf bamboo prevented the nitrate leaching to stream against the clear-cutting of trees in the basin. The riparian processes (denitrification and biological nitrogen uptake) were important for the stream chemistry in the basin with gentle topography in northern Hokkaido. These results address that development of the process model including the biological and hydro-topographical controls under the cold and snowy climate would be important for the further understandings of the ecosystem responses against the various environmental changes.

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Amid the demand for the promotion of countermeasures against global warming as a result of its more severity, further strengthening of energy measures taken by local governments is expected. This study focuses on such energy measures and examines “policy matrix” which grasps their problems and challenges. This idea is to establish three aspects of the roles played by local governments, that is, consumer, business entity and policy subject as well as three fields of measures, demand side, supply side and both sides of demand/supply, which are the targets of regional countermeasures, in order to understand the energy measures systematically.
Next, “a checklist of energy measures” based on the policy matrix is devised for the purpose of analyzing the system of local governments' administration of energy and those systematized items are stated clearly. Then, a case study is conducted targeting two local governments near big cities (Hino City and Hirakata City) to test the applicability of the checklist approach and extract the agendas of their measures. The result of the study clarifies the usefulness of the checklist approach and distills the future agendas to be considered for the local governments' administration of energy.

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In this paper, we quantitatively analyzed the implementing patterns of global warming prevention policies in municipalities. Based upon the analysis, we classified the municipalities according to observed patterns, analyzed recent characteristics of the implementation of global warming prevention policies in municipalities, and further clarified this problem. Based on the results of 1,111 responses to a questionnaire, conducted in municipalities at the beginning of the implementation process, the average implementation rate of the measures was only 8.6%, which indicates that global warming prevention policies have not been implemented to the extent intended. Although energy saving policies have been implemented in public facilities and the dissemination of information to citizens and businesses has proceeded relatively well, the upgrading of urban infrastructure to facilitate the creation of low carbon cities has not proceeded as intended. The implementation rate of the measures tended to be highest in municipalities with large populations, but lower in those with smaller populations. The implementation rate was higher in municipalities that had instituted plans addressing global warming than those that had not. Focusing on the similarities among the implementation patterns of the measures, we performed a quantitative analysis III. As a result, we extracted the following three axes: “nature - artificiality”, “social system - facilities” and “new technology - conventional technology.” Using the sample scores of the 1st and the 2nd axes from the quantitative analysis III, we broke down 855 municipalities targeted for the analysis into five categories. As a result, 272 municipalities were classified into “nature - social system”. 67 into “artificiality - social system”. 274 into “artificiality - facilities”. 104 into “nature - facilities” and 138 into “neutral”. Based on analyses of the classification of municipalities by population, many municipalities with small populations belong to the “nature - social system” category and those with large populations belong to the “artificiality - facilities” category.

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Japan's CO₂ reduction plan, which set a reduction goal of around ten years, included only simple, short-term actions, such as switching to high-efficiency devices including electric appliances, cars and production equipment; the spreading of photovoltaic power generation and the promotion of energy-saving actions by consumers and businesses. From a long-term perspective, it is also necessary to make changes to urban structures, traffic systems, energy supply systems etc. To help achieve a low-carbon society, I researched a long-term roadmap for reducing CO₂ by changing those systems in the city of Nagoya, and formulated two types of scenarios for reducing CO₂ emissions by 80% in the greater Nagoya area by 2050.

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The object of this research is to focus on local climate policies and analyze the action plans of environment model cities based on the fixed standard. This paper aims to look at the possibility of substantially reducing greenhouse gases in the medium- to long-term.
After constructing five hypotheses on the factors that have an influence on viability, and showing five analysis standards by referencing existing research, I arranged the information pertaining to 13 cities' action plans in a catalogue and scored them in accordance with the standard concerned. As a result, the following four points were clarified.
First, “newcomer” local governments obtained higher scores than “older” local governments.
Second, in small towns and villages, the climate policy is limited in scope and greenhouse gas emissions data gathering is sparse.
Third, small towns and villages are unable to properly establish the organizations that would be responsible for the implementation of their plans; further small towns and villages find it difficult to establish a climate policy department.
Last, assessing the weight balance over the five hypotheses is the main task for the future.

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In June 2008, the Tokyo metropolitan government (TMG) has established a cap-and-trade measure via its ordinance amendment. It was the first governmental attempt in Japan that engendered pro and con arguments. Yet, both sides shared the same view that the TMG's cap-and-trade can be mimicked by other local and national governments and eventually become institutionalized as a nation-wade regulatory scheme. Thus, from the perspectives of political science, this article explores the possibilities of such policy diffusion by finding factors that affected the TMG scheme's implementabilities. As a result, the article highlights the importance of the following points. 1) The composition of emission sources in Tokyo provided opportunities for political deal-makings. 2) CO₂ reduction measures were placed as a pivotal part of the campaign in hosting the 2016 Olympics. 3) Abundant expenditures and budgets were thus made possible. Because these are unique geopolitical factors that equally define Tokyo's own policy context, mimicking the TMG's cap-and-trade in areas other than Tokyo rather deprives opportunities to reach needed consensus and undermines the policy rationale for proper CO₂ reduction measures. Therefore, the article concludes that the possibilities of diffusion of the TMG's cap-and-trade occurring among the other governments are very low.

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Bioenergy production has been expected as one of climate change mitigation options, but recently it has been criticized for environmental impact of land use change. This paper discussed about environmental impact reduction options against expansion of palm oil production in Indonesia. Palm oil is also expected as biofuel feedstock. This paper summarized information about condition of tropical rainforest and expansion of oil palm plantation in Indonesia. This paper also presented environmental impact by expansion of palm oil production as 1) biodiversity loss due to tropical rainforest logging, 2) greenhouse gas emission, 3) energy resources consumption, and discussed about its environmental impact reduction options. In this result, this paper indicated that natural rain forest logging is directly and indirectly related to loss biological diversity and individual. Land sparing options such as improving crop yield were considered as mitigation options for this ecosystem impact in this region. In addition, this paper showed the result of comparison energy resources consumption of palm oil and other vegetable oils. Energy recourses consumption problems by biofuel production from palm oil in Indonesia were also pointed out in this study. Development of agricultural and biomass utilization technology and action from demand side are expected to minimized energy resources consumption and land use for sustainable consumption.

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