LIMITATIONS OF USING A COARSE RESOLUTION MODEL TO ASSESS THE IMPACT OF CLIMATE CHANGE ON SEA ICE IN HUDSON BAY

The simulation of Sea-ice in a coarse resolution ocean general circulation model is examined in Hudson Bay and surrounding waters. Sea-ice distribution and duration compared well to climatological values, although ice thickness is undersimulated as it is in other modelling work. In Hudson Bay ice thickness variation was dominated by the atmospheric forcing as shown by the symmetric response of ice thickness to warming and cooling scenarios. Below ice heat fluxes play a more significant role in Foxe Basin and Baffin Bay where they mitigate air-ice heat loss by as much as 40 percent, thus limiting ice thickness and duration. Below ice heat flux reduces by 23 percent for the region of study (Hudson Bay, Foxe Basin, Baffin Bay, and Labrador Sea) for a global 3°C cooling and increases by 9 percent for a 3°C global warming. This asymmetric response is attributed to the ocean's asymmetric response to warming and cooling scenarios. In so much as Hudson Bay is dominated by atmospheric forcing rather than under ice heat as these results indicate, coarse resolution models may be useful in assessing the impact of change. However the necessary reconfiguration of the model grid render results from Foxe Basin and Hudson Strait less credible. On étudie la simulation de glace marine dans un modèle de circulation océanique générale à faible résolution dans la baie d'Hudson et dans les eaux avoisinantes. La distribution et la durée de la glace marine correspondent bien aux valeurs climatologiques, bien que l'épaisseur de la glace soit sous-simulée comme c'est le cas dans d'autres travaux de modélisation. Dans la baie d'Hudson, la variation de l'epaisseur de la glace est dominée par le forçage atmosphérique, comme on peut le voir d'après la réponse symétrique de l'épaisseur de la glace suivant les scénarios de réchauffement et de refroidissement. Les flux de chaleur sous la glace jouent un rôle plus important dans le bassin de Foxe et la baie Baffin, où ils permettent une réduction des pertes de chaleur air-glace allant jusqu'à 40 pour cent, limitant ainsi l'épaisseur de la glace et la durée. Le flux de chaleur sous la glace diminue de 23 pour cent dans la région étudiée (baie d'Hudson, bassin de Foxe, baie Baffin et mer du Labrador) pour un refroidissement global de 3C et augmente de 9 pour cent pour un réchauffement global de 3C. On attribue cette réponse asymétrique à la réponse asymétrique de l'océan aux scénarios de refroidissement et de réchauffement. Dans la mesure où, comme l'indiquent ces résultats, la baie d'Hudson est dominée par le forçage atmosphérique plutôt que par la chaleur sous la glace, des modèles à faible résolution peuvent être utiles pour évaluer l'impact des changements. Cependant, la reconfiguration nécessaire de la grille du modèle atténue la crédibilité des résultats obtenus dans le Bassin de Foxe et le détroit d'Hudson.     

MEASURING SUMMER SEA ICE SEVERITY IN EASTERN HUDSON BAY 1751–1870

The log-books of the Hudson's Bay Company supply ships are the sources from which are derived annual indices of summer sea ice severity in eastern Hudson Bay in the period 1751–1870. The indices are based on two properties of the daily ice conditions described in the log-books: lateness of occurrence and severity of ice. The annual ice index is obtained by comparing the ice conditions in each year from 1751 to 1870 with those in 1969. This year experienced the most severe late summer ice in this region during the period of present-day ice observations .
Les livres de bord des bateaux d'approvisionnement de la Compagnie de la Bale d'Hudson constituent les sources desquelles sont derives les indices annuels de sévérité de la glace marine estivale, dans la partie est de la Baie d'Hudson, pour la période 1751–1870. Ces indices de la glace sont établis à partir de deux propriétés des conditions quotidiennes de la glace, telles qu'elles sont décrites dans les livres de bord. Ces propriétés sont la tardiveté d'apparition et la sévérité de la glace. On obtient l'indice annuel de la glace en comparant les conditions de la glace pour chaque année de la période 1751–1870 avec les conditions de la glace en 1969. Cette année se charactérise par la glace d'été tardive la plus sévére dans cette région au cour de la période contemporaine d'observations de la glace .     

Late Glacial Origin of the Sandbanks, Webb Bay, Labrador

The Sandbanks of Webb Bay, Labrador owe their origin to ice marginal conditions during the last stages of deglaciation of this section of the Labrador coast. Several phases in their evolution are recognized. Phase 1 was characterized by disintegration of the remnants of Webb Bay and Ado's Brook valley ice masses into separate local bodies with ice marginal runoff in an eastern direction. During Phase 2 the first and highest ice-dammed lake formed. Eastward ice marginal flow continued into Phase 3, when a large system of kame terraces (altitude 360 feet) formed beside the receding Webb Bay Ice. They led to new and lower ice marginal lakes in the eastern part of the Sandbanks. Phase 4 was dominated by the construction of a more extensive system of kame terraces almost 100 feet lower than those formed in Phase 3. Locally, minor moraines helped to direct runoff and control development of these newer kame terraces. In Phase 5, meltwater from the ice and runoff from the deglaciated highlands filled a large marginal lake (altitude 230 feet), which may have contributed to subglacial drainage down Port Manvers Run. Phase 6, the last of the glacial conditions associated with formation of the Sandbanks, was introduced by withdrawal of ice far enough so that the eustatically rising sea level was able to reach part of the Sandbanks. A terrace at 135 feet above sea level is believed to be the local upper marine limit. Stagnant ice still covered the floor of Hummock Valley at the western end of the Sandbanks at this time. Subsequently isostatic adjustment has lifted the last glacio-fluvial and some of the glacio-marine features above sea level.     

DAMMING JAMES BAY: I. POTENTIAL IMPACTS ON COASTAL CLIMATE AND THE WATER BALANCE

The proposed grand Canal project calls for the damming of James Bay and the diversion of its water southward. This first part of a two-part study models some potential impacts on the climate, water balance, and growth patterns in the James Bay coastal zone. Use is made of a linear relationship of Bowen ratio and temperature, developed from studies of coastal wetlands in southern and northwestern James Bay and central Hudson Bay. It is hypothesized that changing James Bay into a fresh-water lake and disrupting its coastal currents would result in a delayed Bay ice melt of unknown length in the spring. Allowing a delay to vary between 0 and 30 days results in the prediction of lesser evaporation and greater water surplus. These differences in magnitude increase with the length of delayed melt, but in all cases are most strongly evident during the peak of the growing season. Colder and wetter conditions would have a strong ecological impact on all coastal areas of western and southern James Bay. In the northwest this could change the species composition of coastal flora, cause forests to retreat from the coast, and result in the growth of permafrost there.     

The geological methane budget at Continental Margins and its influence on climate change

Geological methane, generated by microbial decay and the thermogenic breakdown of organic matter, migrates towards the surface (seabed) to be trapped in reservoirs, sequestered by gas hydrates or escape through natural gas seeps or mud volcanoes (via ebullition). The total annual geological contribution to the atmosphere is estimated as 16–40 Terragrammes (Tg) methane; much of this natural flux is ‘fossil’ in origin. Emissions are affected by surface conditions (particularly the extent of ice sheets and permafrost), eustatic sea‐level and ocean bottom‐water temperatures. However, the different reservoirs and pathways are affected in different ways. Consequently, geological sources provide both positive and negative feedback to global warming and global cooling. Gas hydrates are not the only geological contributors to feedback. It is suggested that, together, these geological sources and reservoirs influence the direction and speed of global climate change, and constrain the extremes of climate.     

Late Weichselian deglaciation and sea level history of St Jonsfjorden,Spitsbergen: A contribution to ice sheet reconstruction

The elevation and age of surveyed shorelines in St Jonsfjorden, western Spitsbergen, provide a chronology for Late Weichselian deglaciation and a proxy for former ice thickness. Support is provided for previous reports of two sets of shorelines on NW Spitsbergen, the oldest (at 60 m in St Jonsfjorden) dating to a pre‐late Weichselian glaciation and the youngest documenting postglacial rebound. The remarkable survival of the older shorelines suggests that a large area of NW Spitsbergen was either covered by protective, cold‐based ice or was subject to only local glaciation during the late Weichselian even though glacier ice extended to the shelf edge in the Isfjorden Trough. A marine limit of 46 m at the mouth of St Jonsfjorden is compatible with the regional late Weichselian marine limit (LWML) dated to ～13 ka BP. A partial relative sea level curve and equidistant shoreline diagram are produced for St Jonsfjorden and used in conjunction with relative sea level curves based on data from previous studies to produce an isobase map for 9 ka BP. The curves indicate that western sites were subject to initial slow emergence followed by rapid emergence between 10 ka and 8.2 ka BP, trends characteristic of areas affected by a full glacial sea or at least subject to early break up of a thin or discontinuous glacier ice cover. A step in the 9 ka BP shoreline long profile over the western end of the peninsula separating Isfjorden and van Mijenfjorden suggests that Holocene neotectonics may have produced anomalously high rebound rates in that area.     

Decadal-scale sea ice changes in the Canadian Arctic and their impacts on humans during the past 4,000 years

Abstract

Climate warming of >1.5°C over three decades has diminished Arctic sea ice and forced drastic changes on Inuit people of the Canadian Arctic. Discontinuities in archaeological records also suggest that climatic changes may have caused site abandonment and life style shifts in Paleo- and Neo-eskimo societies. We therefore examine the decadal-scale palaeoclimatic changes recorded by quantitative palynological data in marine records from Coburg Polynya, near Palaeo- and Neo-eskimo settlements on the North Devon Lowlands, and from the North Water Polynya between Canada and Northwest Greenland. Palaeotransfer functions from dinoflagellate cyst assemblages provide quantitative estimates of changes in sea surface temperature (SST) and sea ice cover (SIC) with the accuracy of historical measurements.

Both sites record temperature variations of 2–4°C corresponding to changes in hunting modes and occupation-abandonment cycles on Devon and Ellesmere Islands. Our data show that from ～6500 to 2600 BP, there were large oscillations in summer SST from 2–4°C cooler than present to 6°C warmer and SIC ranged from 2 months more sea ice to 4 months more open water. The warmer interval corresponds to the period of pre-Dorset cultures that hunted muskox and caribou. Subsequent marine-based Dorset and Neo-eskimo cultures correspond to progressively cooler intervals with expanded sea ice cover. The warming took ～50–100 years and lasted ～300 years before replacement by colder intervals lasting ～200–500 years. These climate oscillations are more rapid than the archaeological cultural changes, but are of similar length to successive Palaeoeskimo occupations in the Nares Strait region.     

SEASONAL and ANNUAL VARIATIONS IN ICE COVER IN BAFFIN BAY and NORTHERN DAVIS STRAIT

The sea ice cover in Baffin Bay and northern Davis Strait is at a maximum in March and at a minimum in September. It depletes rapidly in July and August and grows rapidly during October and November. More annual variations were noticed during periods of ice cover depletion than during ice cover growth periods. The paper presents a sea ice forecast model which is based on annual ice cover depletion and growth data 1968-79 and which should be useful for planning navigation and drilling operations.
Le couvert de glace dans la baie de Baffin et le nord du détroit de Davis atteint son maximum en mars et est réduit à son minimum en septembre. II régresse rapidement en juillet et en aot et crot rapidement en octobre et en novembre. Plus de variations annuelles ont été observées pour les périodes de diminution du couvert de glace que pour les periodes de croissance de ce dernier. Cet article présente un modèle de prévision du couvert de glace lequel est basé sur les donnees relatives à la croissance et à la régression du couvert de glace pour la période 1968-79. Ce modèle devrait ětre utile dans la planification de la navigation et des opérations de forage.     

Sealing,whaling and caribou revisited: additional insights from the skeletal isotope chemistry of eastern Arctic foragers

Research reported here is the second phase of a bone collagen stable isotope and radiocarbon study of eastern Arctic diets. Seventy-five directly dated burials from the Native Point Sadlermiut mortuary collection and two Thule sites, Kamarvik and Silumiut in northwest Hudson Bay, were added to an existing data set of 81 individuals. Thule foragers dated to a 2σ range of AD 1047–1700 and subsisted on diets comprised of ca. 80% marine taxa, primarily ringed seal and bowhead whale. The Native Point Sadlermiut dated later in time, AD 1289–1896, and relied more heavily on high tropic level marine taxa, ringed seal and seabirds. Three dietary trends are apparent coincident with Neo-Boreal cooling (AD 1400). In addition, both Thule sites were abandoned at commencement of the Little Ice Age (AD 1600), which coincides with European contact, raising intriguing questions about the effects of climate change on high latitude foraging strategies and the possibility that epidemic disease was introduced in the Hudson Bay region as early as 1613.     

A 6000 Year‐old Fossil Dugong from Botany Bay: Inferences about Changes in Sydney's Climate,Sea Levels and Waterways

The excavation in the 1890s of a skeleton of the warm‐water marine mammal Dugong dugon, associated with Aboriginal artefacts, from a Botany Bay salt marsh, marked the beginning of speculation about climate and sea level change in Australia over the period of human occupation. The dugong bones have recently been dated, giving a conventional ¹⁴C age of 5520±70 years BP, which is consistent with three older ¹⁴C dates for a layer of buried trees that underlies much of the north Botany sediments. The carefully drawn cross‐sections of depositional strata produced by the original discoverers allow further interpretation of the pattern of Holocene sea‐level fluctuations in the Sydney region. Layers of estuarine sediment, such as the one containing the dugong skeleton, are inter‐bedded with peat layers containing in situ roots and stumps, suggesting that the site alternated between sub‐aerial exposure and submergence throughout the Holocene. The presence of the dugong is suggestive of warmer conditions, and its inland location indicates a more extensive Botany Bay in the recent past. This is in agreement with other work from southern New South Wales describing both warm‐water marine species and higher sea levels several thousand years ago.

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Manufacturing (co)agglomeration in a transition country: Evidence from Russia

We document the geographic concentration patterns of Russian manufacturing using detailed microgeographic data. About 80% of three-digit industries are significantly agglomerated, and a similar share of three-digit industry pairs is significantly coagglomerated. Industry pairs with stronger buyer–supplier links—as measured using Russian input–output tables—tend to be slightly more coagglomerated. This result is robust to instrumental variable estimation using either Canadian or US instruments. Using Canadian ad valorem transport costs as a proxy for transport costs in Russia, we further find that industries with higher transport costs are more dispersed, and industry pairs with higher transport costs are less coagglomerated.     

Reviews/Comptes rendus

Development Regions in the Soviet Union, Eastern Europe, and Canada , edited by A ndrew F. B urghardt
London School of Economics & Political Science and School of Slavonic Studies, University of London
Indians in the Fur Trade: Their Role as Trappers, Hunters, and Middlemen in the Lands Southwest of Hudson Bay 1660-1870 , by A rthur J. R ay
Environmental Data from Historical Documents by Content Analysis: Freeze-up and Break-up of Estuaries on Hudson Bay, 1714-1871 , by D.W. M oodie and A.J.W. C atchpole
Techniques in Pedology , by R ichard T. S mith and K enneth A tkinson
La Crise Urbaine: A Challenge to Geographers , edited by R.A. R oberge
Urban Home steading , by J ames W. H ughes and K enneth D. B leakly , Jr.     

An exploration of regional climate change scenarios for Scotland

Based on a high resolution regional climate model (RCM) experiment, a climate change scenario for Scotland for the end of this century is constructed with the aim of exploring the added value of utilising a regional rather than a global model (GCM) for climate change scenario construction. Spatial variations in regional seasonal average temperature and precipitation change are analysed and the local response of ‘extreme’ weather events to climate warming is assessed using daily model output. The analyses suggest that in comparison with the GCM, the RCM does not provide fundamentally different patterns of seasonal climate change and daily weather response over Scotland, although it does capture more subtle spatial variations in these changes. The RCM also simulates more realistic daily weather events than the GCM, although the relative changes in the frequencies of daily extremes are not greatly different. However, with the limited length of the single model simulation analysed here, it is not easy to establish how robust and significant are the sub‐national patterns of climate response across Scotland. To improve the quality and comprehensiveness of regional climate change scenario information, a number of research issues remain to be addressed.     

Dietary evenness,prey choice,and human–environment interactions

Although measures of evenness of archaeological faunas are increasingly used in zooarchaeological analyses, the widely accepted hypothesis that increasing evenness should indicate increasing dietary breadth has not been tested. In this paper, I examine three factors that can contribute to changing evenness values—changing encounter rates with high-ranked prey types, changing diet breadth, and similarity between the return rates of the highest-ranked resources—and discuss ways of controlling the latter two factors. I then test the “evenness hypothesis” using ethnographic data collected by Smith [E.A. Smith, Evolutionary Ecology and the Analysis of Human Foraging Behavior: An Inuit Example from the East Coast of Hudson Bay, Ph.D. thesis, Cornell University, 1980, E.A. Smith, Inujjamiut Foraging Strategies: Evolutionary Ecology of an Arctic Hunting Economy, Aldine de Gruyter, Hawthorne, NY, 1991] in Inukjuak, northern Canada. Although the results support the evenness hypothesis, they also show that the nature of archaeological data may make evenness measures difficult to use accurately. Evenness can be used to understand changing prehistoric encounter rates with prey, but many conditions must be met for it to do so.     

Science and reality: Arthur Dobbs and the eighteenth-century geography of Rupert's Land

In 1670, the Hudson's Bay Company was granted proprietary rights to Rupert's Land, a vaguely defined territory that came to be equated with the drainage basin of Hudson Bay. This paper is concerned with the geography of these lands that developed in the minds of Englishmen in the course of the eighteenth century. Since only slight and fragmentary information was available in England about these territories, there was created at this time a hypothetical physical geography of the Company's lands. This was based largely on the opinions of Arthur Dobbs, whose book in 1744 was the first devoted to the Company and its territories. Dobb's views were not opposed by the Hudson's Bay Company. Indeed, they were well grounded in the scientific thinking of the time, so that what we now regard as having been speculative and grossly exaggerated, gained acceptance in England as geographical reality in the latter half of the eighteenth century.     

Discrete Element Modeling of Stone Masonry Walls With Varying Core Conditions: Prince of Wales Fort Case Study

The Prince of Wales Fort was constructed in the 18th century as a Vauban style stone masonry fortification where the Churchill River flows into Hudson’s Bay, across the river from Churchill, Manitoba, Canada. Since completion the fort has been exposed to harsh weather conditions, which have led to significant deterioration and deformations in the walls, with some cases of localized collapse. Recently, an increase in the rate of degradation has made preventative conservation an issue of interest. For this conservation to be possible, an understanding of the cause of failure of the walls is first required. Discrete element modeling (DEM) using the non-smooth contact dynamics (NSCD) method utilized in the Program LMGC90 has been used as a first step in understanding the failure mechanism of the wall system. The results of the modeling show that the rubble core of the walls can transition from stability to instability as the cohesion between the stones is altered. Grouting the core will alter the bond between stones, increasing the stability of the core, and is thus one possible conservation method.     

Climate change resilience in the Canadian Arctic: The need for collaboration in the face of a changing landscape

Human-induced changes to global climate have become increasingly difficult to ignore in recent years. As the frequency and severity of extreme weather events increases, the impacts on both natural and human systems are becoming difficult to manage with the current policies. In Canada, one of the most vulnerable regions to climate change is the Arctic, where temperatures are rising at a rate two to three times that of the global average. Warmer seasonal temperatures have led to melting permafrost and increased variability in sea ice conditions, which has contributed to a rise in coastal erosion. The ongoing resilience of Arctic communities will depend heavily on their ability to implement successful long-term adaptation policies. The development and implementation of any action on climate change adaptation should involve collaboration with local stakeholders in order to reflect the views and experience of those living in the Arctic.     

The Impact of Climate Change on an Archaeological Site in the Arctic

Climate change may accelerate the degradation of archaeological sites in the Arctic and lead to a loss of important historical information. This study assesses the current preservation conditions and the processes controlling the physical and chemical stability of the Qajaa kitchen midden in western Greenland. Currently, the site is well protected by low ground temperatures, permafrost and a high water/ice content, keeping the deposits anoxic. Based on 5 years of monitoring data, degradation experiments and model simulation, our results suggest that the combined effects of permafrost thaw, thermal and hydrological erosion and oxygen exposure may lead to substantial loss of archaeological evidence before the end of the 21st century.     

The national security implications of solar geoengineering: an Australian perspective

ABSTRACT

Given current emissions trends an increase in global temperatures in excess of 2°C is highly likely in the coming century. In this context, it seems increasingly probable that states may consider solar geoengineering as a stop-gap climate response. Solar geoengineering refers to measures that aim to alleviate some measure of global warming by intentionally increasing the amount of the sun’s energy that is reflected into space. Currently the two most discussed solar geoengineering techniques involve either marine cloud brightening or dispersing aerosols in the stratosphere. These techniques could be relatively inexpensive, are within the technological capacities (after a brief period of development) of technologically-advanced countries, and could have an almost immediate impact on temperatures. Yet, while solar geoengineering might potentially be utilised to manage some climate-linked security threats, it itself would create new security challenges. Consequently, this paper explores potential international security implications for Australia if a regional state, or group of states, initiates a solar geoengineering program. We conclude that since solar geoengineering is unlikely to become a first-order international issue, disputation over solar geoengineering will likely reflect, or act as a proxy for, wider patterns of state interaction. However, scenarios in which China and the United States take different positions, or in which there are divisions among regional powers, such as Indonesia, Malaysia, India and Singapore would pose the greatest threat to Australia’s national security.     

Inferring Human Behaviors from Isotopic Analyses of Rat Diet: a Critical Review and Historical Application

Rat (Rattus spp.) bone collagen stable isotope values are often assumed to reflect an average of food stuffs that were available to archaeological populations. This paper considers the feasibility of using stable isotope evidence from rat remains as a source of proxy information for human food-related social, economic, and sensorial behaviors. First, a literature review of archaeological and modern ecological rat isotope work reveals that, while rat dietary signatures are often a reasonable proxy for human food waste, they will not always record an unbiased average of foods which are available in a given environment. Second, an overview of ethological, biological, and environmental factors that can influence rat diets is given from the perspective of archaeological bone chemistry, to help identify factors that require explicit and critical consideration when rat stable isotope data is taken as a proxy for human food-related behaviors. Finally, rat stable isotope values are considered to provide new evidence about the social and economic responses of an important historical English fishing community at Ferryland (CgAf-02) to conflict and political turmoil at the turn of the eighteenth century. These results also highlight how information on rat diets can provide a counterpoint to other common faunal isotope approaches that focus on dogs and pigs as a proxy for human dietary behaviors.