Numerical model to assess the impact of the strategies to mitigate desertification

Desertification is considered a global environmental problem with political and socioeconomic implications. Desertification, exacerbated by climate change, is the largest environmental problem in Chile affecting almost two third of the national territory. This study takes place in a latitudinal gradient of the north-central Chilean drylands, where desertification is a threat to agriculture, livestock and forestry (ALF). In the context of the United Nations Convention to Combat Desertification (UNCCD) and the implementation of the Chilean National Action Programme (NAP), the country is conducting policies and investing in mitigation strategies to combat land degradation and desertification. The main objective of this paper is the development of an integrative methodological approach using real data of the territorial and socioeconomic indicators. With the proposed methodology we assess the impact of the mitigation and land degradation strategies supported by the ALF promotion agencies in the fight against desertification, projecting different scenarios of change. The data were collected in 2008 in Santiago, Chile. The results of the Principal Component Analysis (PCA) suggest that technical irrigation and the improvement of grasslands and pastures play an important role in the fight against desertification. The results of the model projections are consistent, suggesting that the efforts of the ALF promotion agencies have a positive impact in fighting desertification. Inaction of ALF mitigation strategies would increase desertification. This methodological approach, performed with real data, is a contribution for the development of integrative assessments, for replication and for forthcoming discussions.     

Reaching environmental decisions: Making subjective and objective judgments

Objective judgments, external to the judge, are compared with subjective, internal judgments. This analysis is made in the context of reaching regulatory decisions affecting the human environment. Examples given include evaluating the potential risk of industrial chemicals and comparing the potential effects of short- and long-term changes in land use. The analysis deals not with the decisions themselves, but rather with the kinds of questions that must be posed in orderto reach such decisions. Decision makers may spuriously distinguish objective from subjective types of judgment, though these are rarely wholly separate. Judges can hardly dispute about objective statements, if truly identical definitions are used. But subjective statements can reasonably be voted upon. Scientists, engineers, and economists represent logical or objective decision makers, tending to work in groups. Subjective thinkers include artists and performers, and others who often work alone. Moral and aesthetic aspects of questions, usually seen as intangible, are treated as if subjective. Financial decisions, usually viewed as tangible, are handled as objective problems. This mechanism for making decisions is well-established in environmental assessment. Though objective questions can be treated well in the monetary terms of cost-benefit analysis, subjective ones cannot. Mathematical and other variants are discussed in relation to the comparison of alternative types of tests.     

NORMALIZED AGRICULTURAL PRICES AND WATER RESOURCES PLANNING1

ABSTRACT: Short-term fluctuations in agricultural markets necesitate adjustments in market prices for use in water resources planning. Two procudures for this price normalizing are described and evaluated. The linear treand and weighted average normalizing procedures perform reasonably well, except in cases of dramatic price oscillations.     

Migrant land rights reception and 'clearing to claim' in sub-Saharan Africa: A deforestation example from southern Zambia

The relationship between migration and deforestation in the developing world continues to receive significant attention. However beyond direct population increase, the precise mechanisms that operate within the intersection of migrant/host land rights remain largely unexamined. Where migrants are provided with land and rights by the State and/or local communities, how such rights are perceived by the migrants is of primary importance in their interaction with land resources, and in aggregate it impacts the development opportunities and environmental repercussions of migration. The authors analyze the operative aspects of land rights reception (as opposed to provision) by migrant populations, and the relationship between this reception and deforestation. The article examines a case in Zambia to analyze how tenurial constructs, emerging from the way rights are perceived by migrants, lead to the continued clearing of areas much larger than needed for cultivation, even when the arrangement appears counter‐productive in terms of land rights provision and labour allocation. While valuable policy efforts have focused on providing resource rights to migrants, how such rights are received and the relationship of this reception to resource management needs greater policy attention.     

The annual course of TCA formation in the lower troposphere: a modeling study

We present a modeling study investigating the influence of climate conditions and solar radiation intensity on gas-phase trichloroacetic acid (TCA) formation. As part of the ECCA-project (Ecotoxicological Risk in the Caspian Catchment Area), this modeling study uses climate data specific for the two individual climate regimes, namely "Kalmykia" and "Kola Peninsula". A third regime has also been included in this study, namely "Central Europe", which serves as a reference to somehow more moderate climate conditions. The simulations have been performed with a box modeling package (SBOX, photoRACM), which uses Regional Atmospheric Chemistry Mechanism (RACM) as its chemistry scheme. For this model a mechanism supplement has been developed including the reaction pathways of methyl chloroform photooxidation. The investigations are completed by a detailed sensitivity study addressing the impact of temperature and relative humidity. Atmospheric OH and HO2 concentrations and the NOx/HO2 ratio were identified as the governing quantities controlling the TCA formation trough methyl chloroform oxidation in the gas phase. Model calculations show a TCA production rate ranging between almost zero and 6.5 x 10(3) molecules cm(-3) day(-1) depending on location and season. In the Kalmykia regime the model predicts mean TCA production rates of 1.3 x 10(-4) and 5.4 x 10(-5) microg m(-3) year(-1) for the urban and rural environment, respectively. From the comparison of model calculations with measured TCA burdens in the soil ranging between 130 g m(-3) and 1750 g m(-3) we conclude that TCA formation through methyl chloroform photooxidation in the gas-phase is probably not the principal atmospheric TCA source in this region.     

Polychlorinated dibenzofurans/dibenzo-p-dioxins (PCDF/PCDDs) and other dioxin-like substances in marine organisms from the Grenland fjords,S. Norway, 1975-2001: present contamination levels,trends and species specific accumulation of PCDF/PCDD congeners

Discharge of WHO toxicity equivalents (TEQs) of PCDF/PCDDs to Frierfjorden, Norway has been reduced from an estimated sum of 50-100 kg in the period 1951-1975 to about 6-7 kg in 1976-1990, and further to about 20 g for 1991-2000. In accordance with this, the yearly monitoring since 1987 has shown considerably decreasing contamination in organisms, first highly significant in all indicator species from 1990 to 1991, then levelling off. Present concentrations thus are still high. Compared with estimated "high background" (reference) concentrations of 10 ng TEQ(PCDF/PCDD)/kg w.w. in liver of cod and in hepatopancreas ("brown meat") of crabs, Frierfjord samples in 2001 were about 60 and 70 times higher, respectively. With considerable uncertainty due to large fluctuations, the rate of yearly decrease for TEQ(PCDF/PCDD) in cod liver 1991-2001 has been calculated to 10-12%. A hypothetic target value of 50 ng TEQ/kg w.w. will not be reached until 2015-2020, possibly even later. Including contributions from dioxin-like PCBs and PCNs, the weekly maximum tolerable amount of cod liver and crab hepatopancreas from Frierfjorden in 2001 were about 2-3 g. Multivariate analysis of PCDF/PCDD congener profiles in four fish species, mussels and crabs resulted in five distinct groups, separating four of the species and grouping the remaining two together, hence demonstrating examples of species specific accumulation characteristics.     

Rating accident models and investigation methodologies

This is a report of research to identify, rate, and rank accident models and accident investigation methodologies. Models and methodologies used in 17 selected government agencies were examined. The examination disclosed 14 accident models and 17 different accident investigation methodologies in those agencies. To determine their relative merit, evaluation criteria and a rating scheme were developed from user data, statutes, applications, and work products, and each model and methodology was rated. The ratings indicated significant differences in their relative merit. The highest rated model and methodology were tested to determine if the estimated ratings were supported by observable differences in actual performance and to compare investigative results against previously reported cases. Differences found prompted further examination of the benefits and problems that would result from implementation of the preferred model and methodology. Additional exploration of comparative performance measurement techniques disclosed further differences affecting the selection decisions. The models, methodologies, criteria, ratings, rankings, test results, and initial measurement findings are summarized in this report. Issues ranging from oversimplification to ethical questions were discovered during this work. The findings strongly suggest that significant accident investigation program changes should be considered in agencies and organizations using lower-ranked accident models or investigation methodologies and that a compelling need exists for more exhaustive research into accident model and accident investigation methodology selection decisions.     

瑞典山区的驯鹿:放牧影响的评价

过去十年中,几例放牧引起植被退化的事件曝光已经使瑞典官方认为一些山区有过度放牧现象以及驯鹿养殖在生态学上可能并非是可持续的.我们从时间和管理角度对这些例子进行研究,进而评价放牧对瑞典山区夏季草场的影响程度.有关驯鹿种群长期动态的数据表明,上个世纪驯鹿的数量在225000头左右波动,没有变化的趋势.根据达拉纳(Dalarna)的郎格夫贾莱特(Langfjallet)和海里耶达(Harjedalen)的米塔克勒盆(Mitaklappen)的数据,对放牧影响进行了详细的讨论.我们将这些数据与近几十年养殖在生态学上似乎不可持续的挪威芬马克地区以及芬兰北部的情况进行了比较,我们的结论是大规模的驯鹿过度放牧在瑞典山区不明显.但在封闭和围栏养殖时,可见过度放牧和践踏的影响.