No abstract

The higher temperatures of climate change may result in a fall in Great Lakes water levels. For vessels carrying imports into and exports out of the Great Lakes lower lake levels will lead to restrictions on vessel drafts and reductions in vessel cargos, increasing the number of trips and the cost of moving cargo. Estimates of these impacts are derived from simulations of a recent year's international cargo movements, comparing a base case with no climate change to various climate change scenarios. The impacts vary from a 5% increase in vessel variable operating costs for a climate change scenario representing the possible climate in 2030 to over 22% for a scenario representing a doubling of atmospheric carbon dioxide. Impacts vary by commodity and route. For years of naturally occurring low water the impacts are up to 13% higher for even the most moderate climate change scenario. Climate change may also result in a shorter time of ice cover leading to an extension of the navigation season. Climate change is also expected to increase the threat of damage from aquatic invasive species, possibly leading to further requirements for ships to undertake preventive measures.

Abstract:The decrease in water depths facing commercial navigation in the Great Lakes-St. Lawrence River system is likely the greatest potential impact of climate change on freight transportation in Canada. This water transportation system is an effi cient means of transporting bulk and other commodities through a heavily industrialized part of North America. Great Lakes vessels, however, often have to limit their loads to maintain minimum under-keel clearances when water depths are restricted in harbours and connecting channels. Climate change due to increasing atmospheric concentrations of greenhouse gases is expected to bring about lower water levels and further reduced depths in the Great Lakes, with consequent reductions in vessel cargo capacities and increases in shipping costs. The lower water levels predicted as a result of a doubling of the atmospheric concentration of carbon dioxide could increase annual transportation costs by 29 percent, more moderate climate change could result in a 13 percent increase in annual shipping costs, based on current prices. The impacts vary between commodities and routes.Résumé : Les coûts plus élevés auxquels fait face l'industrie du transport des marchandises dans le réseau fl uvial des Grands Lacs-Saint-Laurent ont été considérés comme étant le plus grand problème éventuel attribuable au changement climatique pour le transport des marchandises au Canada. Ce système de transport par eau constitue un moyen effi cace de transporter des cargaisons en vrac et autres produits de base en passant par une région fortement industrialisée de l'Amérique du Nord, ainsi qu'à destination et en provenance des marchés d'outre-mer. Le chargement des navires dans les Grands Lacs est souvent limité par les profondeurs d'eau des ports et des chenaux de communication, ce qui se traduit fréquemment par des profondeurs d'eau sous quille minimes. On prévoit que le changement climatique, en raison de la hausse des concentrations atmosphériques des gaz à effet de serre, entraînera une baisse des niveaux d'eau dans les Grands Lacs, qui à son tour donnera lieu à une réduction conséquente des capacités de cargaison et à une hausse des coûts d'expédition. Les niveaux d'eau plus bas prédits du fait des concentrations atmosphériques deux fois plus élevées de dioxyde de carbone pourraient entraîner une hausse de 29 pour cent des coûts de transport annuels. Un changement climatique plus modéré pourrait se traduire quant à lui par une hausse de 13 pour cent des coûts d'expédition, par rapport aux prix actuels. Les incidences varieront d'un type de marchandises et d'un itinéraire à l'autre. 270Canadian Water Resources Journal/Revue canadienne des ressources hydriques

elderly. The human capital model of migration is not applicable to the elderly. For couples both the characteristics of the primary household maintainer and the characteristics of the spouse or common-law partner are determinants of the couple's migration, underlining the importance of modelling migration as a household move. Single-person households often, but not always, show results similar to those for couples. When male and female single-person households are compared, migration determinants usually have a stronger effect on females then on males. ABSTRACTThe elderly, already a significant component of internal migration in Canada, will be an increasingly important element of future internal migration. Using census data on households, the flows and determinants of elderly migration are examined and compared with younger groups. Few migrate as individuals, most moves are multiple-person moves, and the household, particularly the family, is the appropriate unit of analysis. In 1996 over 88% of those who migrated in the previous five years were members of households of two or more persons. The elderly are compared with the near-elderly and those likely to be in the labour force, using the age of the primary household maintainer, a person named by each household, to classify households. The elderly are households with a primary household maintainer 65 years of age or over, the nearelderly have a primary household maintainer of 55 to 64 years, and independent decisionmakers, the major component of the labour force, have a primary household maintainer aged 25 to 54. Significant differences are found between the groups. The elderly have a lower rate of migration and their migration determinants and destinations are less driven by employment considerations. While education, for example, is a consistently-found determinant of migration for those in the labour force, it is much less significant for the

No abstract