Assessing regional impacts and adaptation strategies for climate change: the Washington Climate Change Impacts Assessment

Climate change in the twenty-first century will strongly affect the processes that define natural and human systems. The Washington Climate Change Impacts Assessment (WACCIA) was intended to identify the nature and effects of climate change on natural and human resources in Washington State over the next century. The assessment focused on eight sectors that were identified as being potentially most climate sensitive: agriculture, energy, salmon, urban stormwater infrastructure, forests, human health, coasts, and water resources. Most of these sectors are sensitive in one way or another to water availability. While water is generally abundant in the state under current climate conditions, its availability is highly variable in space and time, and these variations are expected to change as the climate warms. Here we summarize the results of the WACCIA and identify uncertainties and common mechanisms that relate many of the impacts. We also address cross-sectoral sensitivities, vulnerabilities, and adaptation strategies.     

Practitioner training for building capacity in ICZM

Capacity building has been a much promoted principle of Integrated Coastal Zone Management (ICZM) since its advent beginning in the 1970’s. Although the concept of capacity building includes human resource development, organizational development and institutional and legal framework development, in practice it has often become focussed on the transfer of technical knowledge and procedures to managers and decision makers. The effect of this is often to emphasise and promote sectoral approaches rather than a holistic one as advocated by ICZM. Experiences gained during the EU Intereg IIIB COREPOINT project led to the development of a training programme that progressively reduced its formal lecture-style content and increased opportunity for discussion and delegate participation. It also produced a more uniform and systematic style and structure to presentations, in particular the case studies illustrating the eight EU ICZM principles of best practice, and embedded the ICZM principles and European perspectives of coastal management within the context of the work environment.This paper reviews methods for practitioner-oriented capacity building, and details the evolution of a training course to sensitise and familiarise coastal practitioners with the principles and practices of ICZM, working from local to national to trans-national scales. The lessons learnt from the ICZM capacity development in COREPOINT are identified and it is suggested that these are relevant and applicable to many other ICZM initiatives.     

Proterozoic low-sulfidation epithermal Au-Ag mineralization in the Mallery Lake area, Nunavut, Canada

The Mallery Lake area contains pristine examples of ancient precious metal-bearing low-sulfidation epithermal deposits. The deposits are hosted by rhyolitic flows of the Early Proterozoic Pitz Formation, but are themselves apparently of Middle Proterozoic age. Gold mineralization occurs in stockwork quartz veins that cut the rhyolites, and highest gold grades (up to 24 g/t over 30 cm) occur in the Chalcedonic Stockwork Zone. Quartz veining occurs in two main types: barren A veins, characterized by fine- to coarse-grained comb quartz, with fluorite, calcite, and/or adularia; and mineralized B veins, characterized by banded chalcedonic silica and fine-grained quartz, locally intergrown with fine-grained gold or electrum. A third type of quartz vein (C), which crosscuts B veins at one locality, is characterized by microcrystalline quartz intergrown with fine-grained hematite and rare electrum. Fluid inclusions in the veins occur in two distinct assemblages. Assemblage 1 inclusions represent a moderate temperature (Th=150 to 220 °C), low salinity (~1 eq. wt% NaCl, with trace CO₂), locally boiling fluid; this fluid type is found in both A and B veins and is thought to have been responsible for Au-Ag transport and deposition. Assemblage 2 inclusions represent a lower temperature (Th=90 to 150 °C), high salinity calcic brine (23 to 31 wt% CaCl₂-NaCl), which occurs as primary inclusions only in the barren A veins. Assemblage 1 and 2 inclusions occur in alternating quartz growth bands in the A-type veins, where they appear to represent alternating fluxes of dilute fluid and local saline groundwater. No workable primary fluid inclusions were observed in the C veins. The A-vein quartz yields '¹⁸O values from 8.3 to 14.5‰ (average=10.9ǃ.7‰ [1C], n=30), whereas '¹⁸O values for B-vein quartz range from 11.2 to 14.0‰ (average=13.0ǂ.9‰, n=12). Calculated '¹⁸O_H2O values for the dilute mineralizing fluid from B veins range from -2.6 to 0.2‰ (average=-0.8ǂ.9‰, n=12) and are consistent with a dominantly meteoric origin. No values could be calculated for the brine, however, because all A-vein quartz samples contain mixed fluid inclusion populations. However, the fact that A-vein quartz samples extend to lower '¹⁸O values than the B veins suggests that the brine had a lighter isotopic signature relative to the dilute fluid. Hydrogen isotopic ratios of fluid inclusion waters extracted from eleven quartz samples of both vein types range from 'D_FI=-56 to -134‰, but show no particular correlation with vein type. In most respects, the mineralogical and fluid characteristics of the Mallery Lake system are comparable to those of Phanerozoic low-sulfidation deposits, and although the presence of high salinity brines is unusual in such deposits, it is not unknown (e.g., Creede, Colorado). In addition, one of the few other examples of well-preserved, Precambrian, low-sulfidation epithermal deposits, from the Central Pilbara tectonic zone, Australia, contains a similarly bimodal fluid assemblage. The significance of these saline brines is not clear, but from this study we infer that they were not directly involved with Au-Ag transport or deposition.     

Air Quality,Climate, and Policy: A Case Study of Ozone Pollution in Tucson,Arizona

This article addresses the need to better understand the complex interactions between climate, human activities, vegetation responses, and surface ozone so that more informed air‐quality policy recommendations can be made. The impacts of intraseasonal climate variations on ozone levels in Tucson, Arizona from April through September of 1995 to 1998 are determined by relating variations in ozone levels to variations in atmospheric conditions and emissions of ozone's precursor chemicals, volatile organic compounds (VOCs) and nitrogen oxides (NO_x), and by determining month‐specific atmospheric conditions that are conducive to elevated ozone levels. Results show that the transport of ozone and its precursor chemicals within the Tucson area causes the highest ozone levels to be measured at a downwind monitor. The highest ozone levels occur in August, due in part to the presence of the North American monsoon. Atmospheric conditions conducive to elevated ozone concentrations differ substantially between the arid foresummer (May and June) and the core monsoon months ( July and August). Transport of pollution from Phoenix may have a substantial impact on elevated ozone concentrations during April, May, and June, while El Paso/Ciudad Juarez –derived pollution may contribute significantly to elevated ozone concentrations in August and September. Two broad policy implications derive from this work. Regional pollutant transport, both within the U.S. and between the U.S. and Mexico, is a potential issue that needs to be examined more intensively in future studies. In addition, spatiotemporal variations in sensitivities of ozone production require the adoption of both NO_x and VOC control measures to reduce ozone levels in the Tucson area.     

Reply to “Comments on ‘Poles of rotation’”

Analysis of published data on sea floor spreading for the different oceans demonstrates a close correlation between interruptions of spreading at sea and compressive periods on land and between periods of spreading activity and periods of “no compression” of the orogenic regions. The evolution of both orogenic and oceanic areas appears to be rhythmic. The model is generalized to a dynamic model for the Earth's crust in which periods of global compression and extension follow alternately. Such a model fits better the geological evidences from orogenic regions than the present model for sea floor spreading which postulates an expansion in the mid ocean ridges and a compression along the continental margins underthrusted by oceanic crust.     

X-ray diffraction study of the displacive phase transition in anorthoclase,grain-size effects and surface relaxations

The temperature evolution of the displacive order parameter of hypersolvus, Al-Si disordered alkali feldspars with composition Or₃₁ and Or₂₀ was measured using X-ray powder diffractometry. The monoclinic — triclinic transition shows second-order behaviour and bilinear order parameter-strain coupling. The transition temperatures are 443 K (Or₃₁) and 750 K (Or₂₀). Temperature evolution of the peak width, Γ, of the 132 reflection was found to depend on the grain size of the sample with an anomalous increase of Γ at T _c in fine-grained material. This effect has been rationalised in terms of surface relaxations occuring as T approaches T _c . No anomalous line broadening occurs in coarse-grained material.     

Rates of continental erosion and mountain building

The first objective of this work was to obtain values for the rates at which continental erosion can smooth out or remove the topographic expression produced by orogeny. The dominant part is played by mechanical erosion, which acts most strongly in regions of large topographic expression. Chemical erosion depends strongly on precipitation or runoff in individual river drainage basins, but because most continents have very similar average rainfall, chemical erosion is fairly uniform for continental sized areas, and will succeed in planing down all continents to a level peneplain if given enough time. The exception to this rule is Australia, which has a very low chemical erosion rate because of its dryness. The time constants for mechanical and chemical erosion so obtained vary between about 30 and 300 My depending on the continent and the assumptions made. Mountain building occurs throughout the geological time-scale, but at a non-uniform rate. Although there will not be a balance between erosion and mountain building over a short time-scale, due to the non-uniform rate of mountain building, the long-term situation must be that the two phenomena should balance out. It is shown that the freeboard of continents will respond to the long-term balance between mountain building and erosion. An expression has been derived for the average continental elevation in which the rate of mountain building depends on the rate of radiogenic heat production within the earth. It is shown that relatively small changes in average elevation above sea level of a few hundred metres are predicted to have occurred since the beginning of the Proterozoic. As mountain building is predicted to decrease on average with time, because of the reduction in internal heat generation, and as erosion is dependent on the average elevation, this average elevation will decrease slowly through time, the opposite of what some workers have predicted. A more complicated model of mountain building is then investigated, in which one component of mountain building has a sinusoidal signal. The oscillations in average elevation depend on the period of the sinusoid, being smaller for shorter periods. Finally, an average continental elevation is derived using a list of real orogenic events. Although this list of orogenies is incomplete, there is some indication that the actual continental elevation as seen in the flooding history of the continents is similar to that derived in this paper.     

A development of the lichenometric method applied to the dating of glacially influenced debris flows in southern chile

Lichenometry is a dating technique that has problems relating to questionable assumptions. The development of a size frequency approach, previously used in attempts to resolve some of the problems, is described and applied to the dating of four debris flows marginal to the San Rafael Glacier in Southern Chile. This study provides examples of the development's application, its problems and directions for further work. The size frequency approach, based on new assumptions, uses parameters derived from population size frequency distributions of the lichen species Placopsis patagonica to provide relative and absolute dating for rock surfaces. Changes in the shapes of distributions suggest the relative age of populations. Absolute dating is based on a curve (spanning a 24 year time period) derived from mean diameter size/age correlations. A stratified random sampling design permits the use of inferential statistics. Standard deviations and confidence intervals show error margins, the degree of relatedness between neighbouring populations, and populations that are anomalous. One-way analysis of variance is used to indicate where populations may safely be grouped. The size frequency approach appears to be particularly suitable for use on unstable debris flows where secondary movements are common. The approach also demonstrates that lichen growth and colonization are sensitive to aspect differences and other variations in microhabitat.