The evolution of thinking about energy is discussed. When the authors began collaborating 20 years ago, energy was typically considered from a growth-oriented, supply-side perspective, with a focus on consumption trends and how to expand supplies to meet rising demand. They were deeply troubled by the environmental, security and equity implications of that approach. For instance, about two billion people lack access to affordable modern energy, seriously limiting their opportunities for a better life. And energy is a significant contributor to environmental problems, including indoor air pollution, urban air pollution, acidification, and global warming. The authors saw the need to evolve a different perspective in which energy is provided in ways that help solve such serious problems. They argued that energy must become an instrument for advancing sustainable development—economically viable, need-oriented, self-reliant and environmentally sound development—and that the focus should be on the end uses of energy and the services that energy provides. Energy technological options that can help meet sustainable development goals are discussed. The necessity of developing and employing innovative technological solutions is stressed. The possibilities of technological leap-frogging that could enable developing countries to avoid repeating the mistakes of the industrialized countries is illustrated with a discussion of ethanol in Brazil. The role foreign direct investment might play in bringing advanced technologies to developing countries is highlighted. Near- and long-term strategies for rural energy are discussed. Finally, policy issues are considered for evolving the energy system so that it will be consistent with and supportive of sustainable development.

The development of the spatial N export and retention model N_EXRET for large river basins is presented, utilizing remote-sensing-based land use and forest classification. Export coefficients describing the contribution from agriculture, forestry and peat harvesting were estimated based on empirical studies. Representativeness of forest treatment coefficients have been evaluated by use of data from a small, well-documented test catchment. Simulation results from the application of the model to the Oulujoki river basin (22 840 km²) are discussed. Model estimated N fluxes were compared with measured N fluxes in separate points of the river basin. Based on source apportionment, agriculture contributes 17% of the total export, varying between 8% in the uppermost subbasin and 38% in the lowermost subbasin close to the sea. Forestry contributes almost as much, 16%, with less pronounced variation (11–24%) between the different sub-basins. In the separate subbasins, 7–37% of the incoming gross N export was retained. Based on mass balances and sensitivity analyses, retention was estimated to be in the range of 5–10 kg ha⁻¹yr⁻¹ in lakes and 0–1 kg ha⁻¹yr⁻¹ in peatlands. The model results were validated by testing to data from the 3 closely situated river basins. However, further testing is needed in river basins where land use and deposition patterns differ clearly from these northern basins.

Joint Implementation under the Climate Change Convention and Clean Development Mechanism of the Kyoto Protocol require a scientific understanding of current carbon stocks, fluxes, and sequestration potential, especially in tropical ecosystems where there are large carbon reservoirs, significant carbon emissions, and large land areas available for reforestation. Central Africa contains 10% of the world's remaining tropical moist forests and has received little attention in carbon studies. In 1980, above-ground carbon stocks in the central African ecosystem were 28.92 Pg and were reduced to 24.79 Pg by 1990. Improved forest management aimed at increasing biomass density could sequester 18.32 Pg of carbon, and over 500 000 km² formerly forested land will be available by 2050 for reforestation with a capacity to offset 10 Pg carbon. Understanding the spatial distribution of biomass carbon and sequestration potential will be essential for carbon trading initiatives through Joint Implementation and Clean Development Mechanism.

Pyrodinium bahamense (var. compressum) has been the only dinoflagellate species that has caused major public health and economic problems in the Southeast Asian region for more than 2 decades now. It produces saxitoxin, a suite of toxins that cause Paralytic Shellfish Poisoning (PSP). A serious toxicological problem affecting many countries of the world, mild cases of this poisoning can occur within 30 minutes while in extreme cases, death through respiratory paralysis may occur within 2–24 hrs of ingestion of intoxicated shellfish. Blooms of the organism have been reported in Malaysia, Brunei Darussalam, the Philippines and Indonesia. The ASEAN-Canada Red Tide Network has recorded 31 blooms of the organism in 26 areas since 1976 when it first occurred in Sabah, Malaysia. As of 1999, the most hard hit country has been the Philippines which has the greatest number of areas affected (18) and highest number of Paralytic Shellfish Poisoning (PSP) cases (about 1995). Malaysia has reported a total of 609 PSP cases and 44 deaths while Brunei has recorded 14 PSP cases and no fatalities. Indonesia, on the other hand has a record of 427 PSP cases and 17 deaths. Studies on ecological/environmental impacts of these blooms have not been done in the region. Estimates of economic impacts have shown that the loss could be up to USD 300 000 day⁻¹. Most of the data and information useful for understanding Pyrodinium bloom dynamics have come from harmful/toxic algal monitoring and research that have developed to different degrees in the various countries in the region affected by the organism's bloom. Regional collaborative research and monitoring efforts can help harmonize local data sets and ensure their quality and availability for comparative analysis and modeling. Temporal patterns of the blooms at local and regional scales and possible signals and trends in the occurrence/recurrence and spread of Pyrodinium blooms could be investigated. Existing descriptive and simple predictive models of Pyrodinium blooms can be improved and refined to help in the management of the wild harvest and aquaculture of shellfish in a region where the people are dependent on these resources for their daily food sustainance and livelihood.

Rural people in the Peruvian Amazon practice agriculture and extract a wide range of products from natural forests, rivers and lakes. Their diversified livelihood system includes fish, game, and plant products. In 2 flood-plain villages, data for one year have been collected to compare the economy of local agriculture with the economy of extracted forest products for subsistence as well as for commerce. The study includes both fauna (game and fish) and flora (timber as well as nontimber). The results show that extracted forest products for subsistence, especially fish, are a main factor in the local economy. The daily net income from extraction activities exceeds both income from cultivation and the normal daily wages for unskilled workers, emphasizing the need for thorough socioeconomic investigations before any alternative land-use option is implemented. The average value per ha of natural forest used for extraction is in the order of USD 13 yr⁻¹, and the average extraction area is 113 ha household⁻¹. When yield from agriculture is included in the calculations, the total per ha value of current extraction and agricultural activities increases to USD 21 yr⁻¹.

Diffuse pollution from agricultural land is one of the main causes for lake eutrophication. Multipond systems, an ancient invention in China, are composed of many tiny ponds and ditches, scattered in agricultural fields. After a long period of research in an experimental watershed in Liuchahe, it was found that multipond systems constitute diffuse pollution control. They have a large capacity for water storage and serve to control the export of water, suspended matter, and phosphorus. Multipond systems significantly reduce runoff velocity. Sediments and phosphorus retained in the Liuchahe watershed were 14.38 · 10⁶ and 7016 kg yr⁻¹, respectively (area 691.6 ha). Irrigation provides an effective way to recycle and remove phosphorus. The use of multipond systems is a sustainable way to recycle valuable nutrients and reduce their discharge and thus pollution of downstream lakes.

The middle reaches of the Yarlung Zangbo, the Lhasa, and the Nianchu rivers form the center of politics, economy, and culture in the Tibetan Autonomous Region. Due to the fragility of the natural environment and overexploitation of land by the local people, desertification is becoming a serious problem in the valleys. Shifting sands cover an area of 578 km² and have caused problems such as damage to farmland and grassland, traffic blockage and burying of water projects. This paper discusses strategies and techniques for combating shifting sands, including reformation of the agricultural structure, exploitation of new sources of energy, and combinations of mechanical and biotic measures. Using mechanical measures, straw barriers, and gravel layer covers, artificial vegetation can be established on the mobile sand dune by sowing and planting introduced species.