International CO2 emissions targets and timetables: An analysis of the AOSIS proposal

In this paper, we use a two-region version of the CETA model to analyze international CO₂ emission control policies. The policies we consider are all substantially equivalent to a policy recently proposed by the Alliance of Small Island States (AOSIS). The AOSIS proposal requires the OECD alone to reduce emissions, while the alternatives we consider achieve equivalent reductions via emission rights traded (1) between regions, (2) between time periods, or (3) both. We find that tradeable rights systems provide significant overall cost savings relative to the AOSIS proposal. Cost reductions may be roughly 60% for rights tradeable between regions, 50% for rights tradeable between time periods, and 95% for rights tradeable between regions and time periods. The benefits of these cost reductions accrue to both the OECD and the Rest of the World. Our results underscore the importance of using an efficient policy to achieve any given atmospheric concentration objective.     

PREDICTING THE SUMMER TEMPERATURE OF SMALL STREAMS IN SOUTHWESTERN WISCONSIN1

ABSTRACT: One of the biggest challenges in managing cold water streams in the Midwest is understanding how stream temperature is controlled by the complex interactions among meteorologic processes, channel geometry, and ground water inflow. Inflow of cold ground water, shade provided by riparian vegetation, and channel width are the most important factors controlling summer stream temperatures. A simple screening model was used to quantitatively evaluate the importance of these factors and guide management decisions. The model uses an analytical solution to the heat transport equation to predict steady‐state temperature throughout a stream reach. The model matches field data from four streams in southwestern Wisconsin quite well (typically within 1°C) and helps explain the observed warming and cooling trends along each stream reach. The distribution of ground water inflow throughout a stream reach has an important influence on stream temperature, and springs are especially effective at providing thermal refuge for fish. Although simple, this model provides insight into the importance of ground water and the impact different management strategies, such as planting trees to increase shade, may have on summer stream temperature.     

SPATIAL AND TEMPORAL DYNAMICS OF WOOD IN HEADWATER STREAMS OF THE PACIFIC NORTHWEST1

This paper synthesizes information on the spatial and temporal dynamics of wood in small streams in the Pacific Northwest region of North America. The literature on this topic is somewhat confused due to a lack of an accepted definition of what constitutes “small” streams and what is the relative size of woody debris contained within the channel. This paper presents a matrix that defines woody debris relative to channel size and then discusses the components of a wood budget. Headwater streams are in close proximity to wood sources and, in steeplands, are often tightly constrained by steep hillslopes. Special consideration is given to ecosystem characteristics and to management practices that affect the wood dynamics in this context. Knowledge gaps and uncertainties that can be used to guide future research are identified. Very little is currently known about the role of mass wasting in wood recruitment and storage relative to other processes, such as bank erosion and mortality, in larger streams. Further, very little work has addressed the relative importance of different wood depletion processes, especially those associated with wood transport. The effect of other ecosystem variables on wood dynamics locally across a watershed (from valley bottom to mountaintop) and regionally across the landscape (from maritime to continental climates) is not addressed. Finally, the scientific community has only begun to deal with the effects of management practices on wood quantity, structure, and movement in small streams.     

ASSESSING SATELLITE‐BASED AND AIRCRAFT‐BASED THERMAL INFRARED REMOTE SENSING FOR MONITORING PACIFIC NORTHWEST RIVER TEMPERATURE1

One central issue affecting the health of native fish species in the Pacific Northwest is water temperature. In situ observation methods monitor point temperatures, while thermal infrared (TIR) remote sensing captures spatial variations. Satellite‐based TIR sensors have the ability to view large regions in an instant. Four Pacific Northwest river reaches were selected to test the ability of both satellite‐based and moderate resolution aircraft‐based TIR remote sensing products to measure river temperatures. Images with resolutions of 5, 15, and 90 meters were compared with instream temperature observations to assess how along stream radiant temperatures are affected by resolution, reach width, and sensor platform. Where the stream reach can be resolved by the sensor, all sensors obtain water temperatures within ±2°C of instream observations. Along stream temperature variations of up to ±5°C were also observed. Trends were similar between two sets of TIR images taken several hours apart, indicating that the sensors are observing actual temperature patterns from the river surface. If sensor resolution is sufficient to obtain fully resolved water pixels in the river reach, accurate temperatures and spatial patterns can be observed. The current generation of satellite‐based TIR sensors is, however, only able to resolve about 6 percent of all Washington reaches listed as thermally impaired.     

Pollution and Self-Cleansing of an Urban River in a Developing Country: A Case Study in Dar es Salaam, Tanzania

Pollution and self-purification trends of an urban river namely, Msimbazi River, in Dar es Salaam City, Tanzania, were investigated. Site investigations and water quality analyses were done. The river is polluted in terms of high organic and nutrient concentrations, low dissolved oxygen, and high counts of indicator organisms. Biochemical oxygen demand (BOD₅) concentrations were 27– 340 mg/L. Dissolved oxygen was found to be as low as 0.9 mg O₂/L. Bacteriological pollution increased with distance downstream of the river, a trend attributable to an increase in the catchment of pollution sources, which are on-site sanitation systems. Although the river has an appreciable self-purification capacity, the capacity is strained by persistent pollution overloads. The pollution plight of the river is attributable to its being flanked by expanding human habitats and vibrant industrial, institutional, and socio-economic activities. Provision for pretreatment of discharges into the river is put forward as a remedial measure for the observed pollution. Matching nontechnical and techno-social remedial measures are also recommended. These include sensitization of polluters on merits of environmental protection practices such as cleaner production and strict enforcement of environmental protection laws.     

The Evolution of Urban Form in Portland and Toronto: implications for sustainability planning

This paper analyses the evolution of urban form in two North American metropolitan regions (Portland and Toronto) and asks how more sustainable regional form might come about in the future in these and other urban areas. In the past, dominant patterns of urban form have emerged in such regions at different historical periods. These morphological phases include mid 19th-century grids, streetcar suburb grids, garden suburbs, automobile suburbs and New Urbanist neighbourhoods (which have only recently made an appearance and may or may not become widespread). Judging by the performance of past types of urban morphology, five design values appear particularly important for more sustainable urban form in the future: compactness, contiguity, connectivity, diversity and ecological integration. Although these principles were not well supported by 20th-century development, contemporary movements such as the New Urbanism and Smart Growth re-emphasise them. The example of these two regions indicates that, in the absence of new technological, economic or geographical forces, public sector institutions and urban social movements represent the most likely means to bring about new, more sustainable types of urban form.     

The current status and environmental impacts of glyphosate-resistant crops: a review

Glyphosate [N-(phosphonomethyl) glycine]-resistant crops (GRCs), canola (Brassica napus L.), cotton (Gossypium hirsutum L.), maize (Zea mays L.), and soybean [Glycine max (L.) Merr.] have been commercialized and grown extensively in the Western Hemisphere and, to a lesser extent, elsewhere. Glyphosate-resistant cotton and soybean have become dominant in those countries where their planting is permitted. Effects of glyphosate on contamination of soil, water, and air are minimal, compared to some of the herbicides that they replace. No risks have been found with food or feed safety or nutritional value in products from currently available GRCs. Glyphosate-resistant crops have promoted the adoption of reduced- or no-tillage agriculture in the USA and Argentina, providing a substantial environmental benefit. Weed species in GRC fields have shifted to those that can more successfully withstand glyphosate and to those that avoid the time of its application. Three weed species have evolved resistance to glyphosate in GRCs. Glyphosate-resistant crops have greater potential to become problems as volunteer crops than do conventional crops. Glyphosate resistance transgenes have been found in fields of canola that are supposed to be non-transgenic. Under some circumstances, the largest risk of GRCs may be transgene flow (introgression) from GRCs to related species that might become problems in natural ecosystems. Glyphosate resistance transgenes themselves are highly unlikely to be a risk in wild plant populations, but when linked to transgenes that may impart fitness benefits outside of agriculture (e.g., insect resistance), natural ecosystems could be affected. The development and use of failsafe introgression barriers in crops with such linked genes is needed.     

Managing Tree-of-Heaven (Ailanthus altissima) in Parks and Protected Areas: A Case Study of Rondeau Provincial Park (Ontario, Canada)

The Carolinian Life Zone in southwestern Ontario, Canada is valued because it represents an almost disjunct ecosystem (i.e., one that is typical of the mid-Atlantic United States, rather than the rest of Canada or the nearby states in the United States). The landscape of the Carolinian Life Zone has undergone dramatic transformation, especially in recent decades as agriculture, urbanization, and recreation have intensified. One of the most apparent changes is the invasion of exotic plant species that exacerbates the need for mass restoration efforts. Within the Carolinian Life Zone, Rondeau Provincial Park has experienced an influx of nonindigenous, invasive species in recent years. Tree-of-heaven (Ailanthus altissima) is one example. The infestation is still relatively localized to (mainly) the park, slowly spreading, and manageable as long as something is done immediately. We examined the effects of hand-pulling and mulching, cut stump and glyphosate application, cut stump alone, and the EZJect Capsule Injection System (using glyphosate) on the management of A. altissima within the park. Cut stump and glyphosate treatment was most effective and efficient in its control of young A. altissima shoots because it limits disturbance and has acceptable capital and operating costs. Hand-pulling and mulching was the second choice, mainly because of the risk of additional disturbance that increased shoot densities 1 year after treatment. Cut stump alone was not effective, worsened the infestation, and is not recommended for this species. The EZJect system was effective at managing mature, seed-producing shoots, although the somewhat higher capital costs mean that the system probably should be purchased for management of several invasive tree species to make it more cost-effective.     

The U.S. National biomonitoring specimen bank and the marine environmental specimen bank

The National Biomonitoring Specimen Bank (NBSB), established in 1979 at the NIST Neutron Research Facility, Gaithersburg, Maryland, was specifically designed to store environmental specimens over long periods of time (50-100 years). This bank contains specimens (e.g., human livers, marine sediments, fish tissues, mussels, oysters, human diet samples, and marine mammal tissues) collected as part of several monitoring and research programs supported by U.S. Federal agencies. In 2002, NIST completed the construction of a second environmental specimen bank facility specifically designed for supporting monitoring and research on marine environmental health issues. This facility, the Marine Environmental Specimen Bank (Marine ESB) is located at the Hollings Marine Laboratory in Charleston, South Carolina, in partnership with a U.S. Federal resource agency, two universities, and a State of South Carolina resource agency. The Marine ESB provides a resource of research specimens that are used to address questions regarding temporal and geographic trends in environmental contamination, genetic separation of populations of animals, and the health status of various types of marine animals. Specimens banked include marine mammal tissues, bird tissues, mussels, and oysters. Plans are underway to establish protocols and initiate banking procedures for other types of marine organisms and environmental materials as part of an expanded effort to support research on the health of marine biota.     

The development of cryoprobe nuclear magnetic resonance spectroscopy for the rapid detection of organic contaminants in potable water

The detection of trace levels of a range of organic contaminants (including pesticides, toxins and an explosive) in potable water, using cryoprobe NMR spectroscopy with limited sample preparation and rapid acquisition times, is described. Emphasis is placed on the applicability of NMR spectroscopy for use in emergency scenarios as the unbiased nature of the technique facilitates the detection and characterization of unknown compounds at levels as low as 50 microg L(-1).