Can glacial erosion limit the extent of glaciation?

In southern South America, the maximum areal extent of ice during the Quaternary Period, the Greatest Patagonian Glaciation (GPG, [Mercer, J.H., 1983. Cenozoic glaciation in the southern hemisphere. Annual Reviews of Earth and Planetary Science 11, 99–132.]), occurred at 1.1 Ma and subsequent glaciations were overall less extensive. The GPG preceded global minimum temperatures and maximal volume of ice, which occurred in the last ~ 800 kyr, as recorded in the marine δ¹⁸O record. Significant modification of the drainage morphology of the southern Andes from a non-glaciated to glaciated landscape occurred throughout the Quaternary Period. We infer a non-climatic relationship between glacial modification of the mountains and the decreasing extent of ice and we discuss processes of landscape development that could have caused the trend. Specifically, these include modification of valleys, such as development from a V- to a U-shape, and lowering of mass-accumulation areas. Such changes would strongly affect glacial dynamics, the mass balance profile and mass-flux during succeeding glaciations, especially for low-gradient outlet glaciers occupying low areas. Other areas around Earth (at least where ice has been warm-based) also may exhibit a non-random trend of decreasing extent of ice with time, ultimately because of glacial erosion in the Quaternary Period.     

Mass Balance of the Greenland Ice Sheet: Can Modern Observation Methods Reduce the Uncertainty?

The future contribution to sea level change from the large ice sheets in Greenland and Antarctica is composed of two terms: (i) a background trend determined by the past climate and dynamic history of the ice sheets on a range of time scales (decadal, millennial or even longer); and (ii) a rise/fall related to future climate change, whether due to anthropogenic effects or natural climate variability. The accelerating development of remote sensing techniques for monitoring ice sheet behaviour, and the use of high-resolution general circulation models to estimate temperature and precipitation changes are likely to result in improved estimates of the sensitivity of ice sheet mass balance to climate change and thereby to narrow down the uncertainty of contribution (ii). Contribution (i) is much more difficult to assess, because the mass balance displays large temporal variability on year-to-year and even on decadal time scales that masks the long-term trend. So, although modern remote sensing techniques enable accurate measurement of ice sheet surface elevation change, the mass changes derived from such measurements, even if performed over a period of several years, might just reflect a statistical fluctuation around the long-term background trend, which we must know in order to assess the future ice sheet contribution to sea level change on century and longer time scales. The measured volume changes must therefore be evaluated on the background of short- and long-term accumulation rates (e.g. determined from ice cores and high-resolution ice radar) and dynamic model studies of ice sheet evolution on century, millennial and longer time scales. The problems are illustrated by using the Greenland ice sheet as an example.     

Part of the action, or 'going native'? Learning to cope with the 'politics of integration'

Summary Despite continuing work within feminist research on issues of political commitment and critical forms of engagement, and an increasing desire within geography to effect social change through our privileged positions as academics, active collaboration with groups involved in social action continues to be fraught with ambiguity and anxiety. In this paper, I consider the potential role of the 'researcher as activist' through documentation of my interaction and repositioning of identities while becoming involved in credit union development in Kingston upon Hull. I hope to illustrate how the maintenance of a critical, multi-positioned (and repositioned) identity can be seen as a beneficial, reflexive learning experience for researchers operating within ethnography, and for the research itself.     

Can designation without regulation preserve land in the face of urbanization? A case study of ZNIEFFs in the Paris region

Preservation through legal protection of natural areas is costly and limited in its extent. A much cheaper strategy to preserve natural areas could be to simply identify areas of ecological interest and let it be known. A survey was launched in France to identify such areas (called ZNIEFF) in the early 1980s. Since then, municipalities have had to account for ZNIEFFs in their formal land planning schemes, though they are not under any obligation to protect them. In this study, we tested the effectiveness of ZNIEFFs as a conservation tool in an area of high growth near Paris. Using GAM modeling, we compared the rate of urbanization inside and outside ZNIEFFs in the 17 years following designation, accounting for the share of farmland, the overall rate of urbanization and ZNIEFF proportion in the municipalities, and also accounting for demography and physical constraints (hydromorphy and slope). Overall, there was less urbanization inside ZNIEFFs, but this varied depending on the context. Surprisingly, they were better preserved in areas of more intense urbanization. This effect was increased if farmland area was already reduced (<30% of the municipality area). In contrast, when farmland was still predominant and urbanization rates were lower, ZNIEFFs tended to be more urbanized than the areas outside. This shows that the value of remnant natural areas varies considerably, perhaps as a function of the value attributed to farmland.     

Can phytoliths provide an insight into past vegetation of the Middle Kalahari palaeolakes during the late Quaternary?

The Middle Kalahari is characterised by significant regional scale geomorphic activity and landscape change during the late Quaternary period. Very little however, is known about vegetation dynamics over this period due in part to the absence of well-preserved organic records. Here we test the application of phytolith analyses to sandy shoreline deposits of megalake Makgadikgadi, one of the sumps of the Okavango delta, routinely sampled and dated as part of a separate systematic geomorphological analysis. We confirm the presence of both an abundant and diverse assemblage of diagnostic phytoliths within these sand-dominated samples. The phytolith record reveals significant differences in the savanna vegetation through time with the composition of shoreline vegetation during different lake high-stand events was found to vary. Lake high stands are characterised by a coherently grassland dominated signal as well as a general trend towards more mesic and C₃ prominent taxa during lake events after ∼40 ka. We suggest that phytolith analyses, whilst far from a perfect proxy, provide the potential to offer an important insight into long-term changes in Kalahari savanna, critical for understanding the response of regional vegetation to climatic and hydrological change both in the past and under future climate change scenarios.     

Can the narrowing of the Lower Yellow River by regulation result in non-siltation and even channel scouring?

This study considered whether the narrowing of the upper (broad and wandering) reaches of the Lower Yellow River could result in a reduction in sedimentation and even an increase in channel erosion in both the upper and the lower (narrow and meandering) reaches. Analysis of field data and numerical modeling results both justify the proposal to narrow the channel. A positive correlation was found between channel eroded-area and the channel width. Therefore narrowing under conditions of low flow will reduce the amount of erosion in the reach, which, in turn, will reduce the amount of sediment transported into the lower channel. This will reduce the amount of siltation in the lower reaches of the river. However, narrowing under conditions of high flow with a low concentration of sediment will reduce both the extent of flood attenuation along the narrowed channel and the amount of lateral channel bank collapse, which results in increased flows and less sedimentation in the lower channel, leading to increased erosion. When flows with a high concentration of sediment are released from the Xiaolangdi Reservoir, both the lower narrow channel and the upper channel can transport a large amount of the sediment load. It is concluded that the narrowing of the upper broad channel will result in a reduction in sedimentation, or even in channel erosion, in both the upper and the lower channels if the reservoir is operated such that the volume of sediment added during low flows is balanced by the volume eroded during high flows with a low concentration of sediment.     

Can a Simulated Flood Experience Improve Social Resilience to Disasters?

The increase of extreme meteorological phenomena, along with continuous population growth, has led to a rising number of flooding disasters. Therefore, there is an urgent need to develop better risk reduction strategies, among which is increased social resilience. Experiencing a disaster is recognized as a factor that positively influences overall community resilience, with particular effects on social resilience; it appears to be more influential than school education. It also has many negative effects, though. Previous studies underline that citizens do not distinguish between different types of experiences. Thus, we investigated whether a simulated experience of a flood can improve social resilience, without being hampered by negative repercussions. The study was executed in five municipalities in three Italian regions involved in the European project LIFE PRIMES, which planned simulation activities for each studied area. Data, collected through the administration of anonymous questionnaires before and after a flood drill, were processed by applying a multicriteria decision analysis tool (PROMETHEE). Results show that the drill significantly augmented perceived social resilience in the smaller studied communities but not in the larger ones, a fact that should be further investigated. Key Words: multicriteria decision analysis, simulated flood experience, social resilience to disasters.     

How many Stakes are Required to Measure the Mass Balance of a Glacier?

Glacier mass balance is estimated for South Cascade Glacier and Maclure Glacier using a one-dimensional regression of mass balance with altitude as an alternative to the traditional approach of contouring mass balance values. One attractive feature of regression is that it can be applied to sparse data sets where contouring is not possible and can provide an objective error of the resulting estimate. Regression methods yielded mass balance values equivalent to contouring methods. The effect of the number of mass balance measurements on the final value for the glacier showed that sample sizes as small as five stakes provided reasonable estimates, although the error estimates were greater than for larger sample sizes. Different spatial patterns of measurement locations showed no appreciable influence on the final value as long as different surface altitudes were intermittently sampled over the altitude range of the glacier. Two different regression equations were examined, a quadratic, and a piecewise linear spline, and comparison of results showed little sensitivity to the type of equation. These results point to the dominant effect of the gradient of mass balance with altitude of alpine glaciers compared to transverse variations. The number of mass balance measurements required to determine the glacier balance appears to be scale invariant for small glaciers and five to ten stakes are sufficient.     

Singapore in the 1990s. Can population policies reverse the demographic transition?

Singapore experienced an extraordinary demographic transition from a population growth of over 4% per year in the late 1950s to around 1.6% in the 1990s and below replacement fertility since 1986. In 1987 official government policy shifted to measures for increasing fertility. This paper explores whether Singapore's pronatalist policies can reverse the demographic transition. The present policies aim to selectively increase fertility among the well educated. By 1987 the slogan switched from "stop at two" to "have three, if you can afford it." The policy included tax relief for a third child and other measures to encourage a third child. The policies are expected to have a different influence on society according to one's education, income, and family size. The government target is to selectively increase population by 40% over 25 years. Singapore's transition may follow the theory that low fertility is attained in societies where kin relationships are less important than personal educational achievements. The three ethnic groups responded differently to educational and fertility policies. The Chinese acquired the best education and attained the lowest fertility. The Chinese, who comprised 76% of total population in 1986, continued to have low fertility, while increases occurred among the Malays and the Indians. Future trends are considered difficult to predict. A survey conducted in 1992 in Ang Mo Kio among 489 reproductive age respondents revealed that Malays had the earliest marriage and first births before the age of 25 years (75% of Malays and 50% of Indians). The Chinese had their first child at 25 years or older. Without controls for the age of the mother, a strong statistically significant association was found between ethnic group and age at marriage and age at first birth. The relationship was not supported for current fertility. A comparison of women married for 5 years or less and 5 years or more revealed that women in recent marriages showed a greater likelihood of postponing marriage and childbirth for all ethnic groups. Since 1987, third order births as a percentage of all births increased from 21.47% before 1987 to 23.11% during 1987-92, which only suggests the favorable impact of the pronatalist policy. Educational changes are likely to become more influential in affecting choice of family size.     

“Where to put the spare cash?” Subprime urbanization and the geographies of the financial crisis in the Global South

This article investigates the geographies of subprime urbanization, and by extension, the displacement of 2007–08 financial crisis to the Global South. Previous research examined the formative ways that technological innovations enabled mortgages to deterritorialize and circulate on secondary markets. Less is known about how cities with underdeveloped financial systems and housing markets have been impacted. The case of Tangier, Morocco, is used to argue that the geography of the crisis must be understood as a particular mode of urbanization, subprime urbanization, predicated upon the creation and exploitation of housing submarkets into new geographical frontiers. Subprime urbanization emerged in Tangier in response to the historic contradictions of regional disinvestment in northern Morocco. Weak financial inclusion for local low-income homebuyers led State bureaucrats to increasingly use housing policy to encourage European investment into Moroccan property markets, thereby transforming policy away from improving homeownership access and inclusion toward an urban model centered on the logics of international property speculation.     

The American whale oil industry: A look back to the future of the American petroleum industry?

The American whaling industry rose from humble beginnings off Long island to become an international giant. In its peak year, 1846, 735 ships and 70,000 people served the industry. As whale stocks and reserves decreased, whalers were forced to go farther and farther from their New England home ports. Voyages became longer, and risks on required return-on-investment became higher. The easy money of Atlantic and Pacific whaling was no more: the only remaining profitable ventures were to Arctic and Antarctic waters. Many ships returned empty, if at all. in 1871, most of the Arctic whaling fleet was crushed by early winter ice and lost. This calamity, in conjunction with the long-term diminishing whale stocks, the diversion of investment capital to more profitable ventures, and the discovery, development, and refinement of abundant petroleum crude oil, struck the death blow to the American whaling industry. By 1890, only 200 whaling vessels were at work, and by 1971, no American commercial whaling ship sailed the world's oceans.It is apparent that no single event caused the final, rapid decline. However, a single calamity, in an already stressed industry, that was self-insured and commercially interlinked, precipitated the end. Today's American petroleum industry, although adopting some principles of the American whaling industry, also has embraced other activities such as work process reengineering and customer alliances, which may preempt, or postpone, a similar catastrophic demise.     

Modelling population retention in Australia’s Northern Territory – how do current forms of migration contribute to population turnover and retention?

ABSTRACT

In the past, population growth in Australia's Northern Territory, as in other peripheral parts of high-income countries, has been driven by internal labour migration and migration from outside of Australia. These have been contributing to the high population turnover experienced in peripheral areas. Since 2010, the Northern Territory has experienced low (and even negative) population growth, and public policy is currently focused on migration as a lever to reverse this trend. However, the extent to which the characteristics of migrants influence the potential for longer-term population growth is poorly understood. This paper uses a new method to analyse the contributions of various types of migrants to both population turnover and retention. Two major sets of findings emerge: First, the significance of separating newer in-migrants from longer-term residents when analysing migration patterns; and secondly, the contribution of age, gender, Indigenous status, international origin, wages and industry of employment to the Northern Territory's population turnover. The research suggests that current forms of migration favour people who are likely to stay for only short periods, and have high wage demands. The main policy inference is that long-term population growth will likely not eventuate unless new forms of migration can be stimulated.     

How to Include Ignorance into Hydrocarbon-Resource Assessments? A Case Study Applied to the Presence of Source Rock at the Argentine Deep Water Margin

The underexplored deep Argentine continental margin may be a prospective area for hydrocarbon resources. This study quantifies the degree of certainty about a fundamental part in a petroleum system, the presence of source rocks. Probability theory and, in particular, Bayesian networks provide powerful assessment tools based on incomplete knowledge. However, they should not be applied uncritically in cases where necessary assumptions like independence are not fulfilled or prior probabilities are not known. We discuss the difference between a low probability and the ignorance of a hypothesis, and apply an alternative method to the assessment of source rock presence. The results of this probabilistic argumentation system coincide with the intuitive judgement, stating that there is a quantifiable evidence for a source rock, but no evidence against it.     

Does prolonged illness contribute to adaptive land use practices among subsistence agricultural households in rural Mozambique?

The environmental effects of disease are broadly recognized but still not fully understood. The impact of health on economic development has been well-documented, as have how changes in land cover can contribute to poor health. However, little is known about how changes in health may impact land use and land cover. Fallowing has long been regarded as an advanced, sustainable land use decision employed by subsistence agriculturalists. In the presence of a prolonged illness, however, subsistence agriculturalists may also potentially use fallowing as a coping mechanism. In this paper we seek to understand the extent to which fallowing is used as a coping strategy by households facing a prolonged illness. If illness threatens a household's labor supply, it could affect their ability to cultivate all of their land and may impact food security and general economic well-being. Additionally, it may also impact the actual landscape, as previously agricultural land may revert to a transitional state or land abandonment. This study employs mixed methods to determine if unhealthy agricultural households use fallowing as a coping strategy, identifies whether or not unhealthy fallowing households are more vulnerable agriculturally and economically than their healthier fallowing counterparts, and examines whether there is a land cover effect that can be detected using Landsat TM/ETM + satellite imagery.     

How to Earn the Status of Honest Broker? Scientists’ Roles Facilitating the Political Water Supply Decision-Making Process

“Honest broker” refers to scientists facilitating complex political decisions from a neutral position, aiming to expand the scope of choice available instead of advocating a certain policy. This article reflects on the experiences of three scientists acting as honest brokers while carrying out a multicriteria evaluation to help politicians choose the water supply option for the city of Oulu, Finland. The process was considered successful and many politicians said that they have never before been that well informed when making a decision. The case primarily shows that besides the common knowledge brokerage roles targeting knowledge exchange, the honest brokerage approach relates more to managing social relationships and balancing political games and rapidly evolving discussions. Trustful relationships increased the perceived credibility of the brokers and ensured two-way communication. On the other hand, the brokers faced ethical dilemmas and difficulties of staying impartial while finding out confidential information related to political strategies.     

Can sheep replace indigenous antelope as seed dispersers in the Kalahari?

The Southern Kalahari Duneveld is an arid savannah, which has been used for permanent stock farming since around 1900. Farming with high numbers of animals has led to changes in the vegetation which have been associated with excessive grazing and trampling. To determine whether altered seed dispersal could be an alternative or additional explanation, we investigated how replacing antelope with sheep affects seed dispersal. We determined the dispersal potentials of plant species by various vectors using standardized experiments and studied the variation of dispersal potential along a grazing intensity gradient and among different habitats.Wind dispersal potential was low, but diaspores of many plant species were well adapted to dispersal by water. Biotic long-distance dispersal potentials were relatively high and varied between sheep and antelope: the species of plants dispersed differed, as did the number of seeds transported and the time of year that seeds were dispersed in.The importance of zoochory and the differences found between antelope and sheep dispersal suggest that dispersal is affected by a change of animal type. Thus, sheep can not replace antelope as seed dispersers. Therefore, sustainable grazing management or restoration efforts should benefit from seed input of sensitive species where antelope are rare.