Mapping and monitoring carbon stocks in forested regions of the world, particularly the tropics, has attracted a great deal of attention in recent years as deforestation and forest degradation account for up to 30% of anthropogenic carbon emissions, and are now included in climate change negotiations. We review the potential for satellites to measure carbon stocks, specifically aboveground biomass (AGB), and provide an overview of a range of approaches that have been developed and used to map AGB across a diverse set of conditions and geographic areas. We provide a summary of types of remote sensing measurements relevant to mapping AGB, and assess the relative merits and limitations of each. We then provide an overview of traditional techniques of mapping AGB based on ascribing field measurements to vegetation or land cover type classes, and describe the merits and limitations of those relative to recent data mining algorithms used in the context of an approach based on direct utilization of remote sensing measurements, whether optical or lidar reflectance, or radar backscatter. We conclude that while satellite remote sensing has often been discounted as inadequate for the task, attempts to map AGB without satellite imagery are insufficient. Moreover, the direct remote sensing approach provided more coherent maps of AGB relative to traditional approaches. We demonstrate this with a case study focused on continental Africa and discuss the work in the context of reducing uncertainty for carbon monitoring and markets.
The complexities inherent in land use, land-use change and forestry (LULUCF) activities have led to contentious and prolonged debates about the merits of their inclusion in the 2008-2012 first commitment period of the Kyoto Protocol. Yet the inclusion of these activities played a key role in agreement on the general framework of the Kyoto Protocol, and LULUCF will likely continue to play a substantial part in negotiations on national commitments post-2012. The Marrakech Accords dictate which LULUCF activities are to be included under the Kyoto Protocol and provide rules on how they are to be accounted in the first commitment period. However, these rules have limitations and drawbacks that may be avoided in the structure of future commitments beyond 2012. Through adherence to the objectives of the United Nations Framework Convention on Climate. Change (UNFCCC), and the incorporation of several critical features, a future framework can more effectively address the mitigation challenges and opportunities of this sector. (c) 2007 Elsevier Ltd. All rights reserved. [References: 22
As the United Nations Framework Convention on Climate Change nears the end of a two-year period of evaluation of the issue of reducing emissions from deforestation in developing countries, participating countries have agreed on the need to address this globally important source of greenhouse gas emissions. Negotiations on policy frameworks to monitor and reduce deforestation rely on an understanding of the scientific and technical capacity to support these efforts. Current UNFCCC programs to improve observation of land and forest cover change can provide valuable input to a future policy mechanism focusing on deforestation emissions from developing countries. Countries participating in the current debate have officially referenced the value of remote sensing tools and methods for deforestation monitoring, and have identified specific needs and goals related to their implementation. Based on these identified needs, this paper outlines recommendations for a monitoring framework that can be globally applied with sufficient levels of accuracy and certainty. This framework can serve as a starting point for monitoring programs, and can be modified in response to expected progress in establishing an international policy framework for reducing emissions from deforestation.
BackgroundThe detection of a sexually transmitted infection (STI) agent in a urine specimen from a young child is regarded as an indicator of sexual contact. False positives may conceivably arise from the transfer of environmental contaminants in clinic toilet or bathroom facilities into urine specimens.MethodsThe potential for contamination of urine specimens with environmental STI nucleic acid was tested empirically in the male and female toilets or bathrooms at 10 Northern Territory (Australia) clinics, on 7 separate occasions at each. At each of the 140 experiments, environmental contamination with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis nucleic acid contamination was determined by swabbing 10 locations, and urine collection was simulated 5 times, using a (1) synthetic urine surrogate and (2) a standardized finger contamination procedure.ResultsThe most contaminated toilets and bathrooms were in remote Indigenous communities. No contamination was found in the Northern Territory Government Sexual Assault Referral Centre clinics, and intermediate levels of contamination were found in sexual health clinics and in clinics in regional urban centres. The frequency of surrogate urine sample contamination was low but non-zero. For example, 4 of 558 of the urine surrogate specimens from remote clinics were STI positive.ConclusionsThis is by far the largest study addressing the potential environmental contamination of urine samples with STI agents. Positive STI tests arising from environmental contamination of urine specimens cannot be ruled out. The results emphasize that urine specimens from young children taken for STI testing should be obtained by trained staff in clean environments, and duplicate specimens should be obtained if possible.
ObjectivesThe objective was to determine the frequency of trachoma genotypes of Chlamydia trachomatis-positive urogenital tract (UGT) specimens from remote areas of the Australian Northern Territory (NT).SettingThe setting was analysis of remnants of C. trachomatis positive primarily UGT specimens obtained in the course of clinical practice. The specimens were obtained from two pathology service providers.ParticipantsFrom 3356 C. trachomatis specimens collected during May 2012–April 2013, 439 were selected for genotyping, with a focus on specimens from postpubescent patients, in remote Aboriginal communities where ocular trachoma is potentially present.Primary and secondary outcome measuresThe primary outcome measure was the proportion of successfully genotyped UGT specimens that were trachoma genotypes. The secondary outcome measures were the distribution of genotypes, and the frequencies of different classes of specimens able to be genotyped.ResultsZero of 217 successfully genotyped UGT specimens yielded trachoma genotypes (95% CI for frequency=0–0.017). For UGT specimens, the genotypes were E (41%), F (22%), D (21%) and K (7%), with J, H and G and mixed genotypes each at 1–4%. Four of the five genotyped eye swabs yielded trachoma genotype Ba, and the other genotype J. Two hundred twenty-two specimens (50.6%) were successfully genotyped. Urine specimens were less likely to be typable than vaginal swabs (p<0.0001).ConclusionsUnlike in some other studies, in the remote NT, trachoma genotypes of C. trachomatis were not found circulating in UGT specimens from 2012 to 2013. Therefore, C. trachomatis genotypes in UGT specimens from young children can be informative as to whether the organism has been acquired through sexual contact. We suggest inclusion of C. trachomatis genotyping in guidelines examining the source of sexually transmitted infections in young children in areas where trachoma genotypes may continue to circulate, and continued surveillance of UGT C. trachomatis genotypes.
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