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11.
Arild Holt-Jensen 《GeoJournal》1996,39(2):211-219
The article compares the national energy policies of the countries around the North Sea and the recent development in energy consumption and production. In Northern Europe only Norway has a large energy surplus for export, and it continues to stand outside the EU after its second “No” to membership in the 1994-referendum. Will this mean reduced production to conserve the resources? Are energy policies in the countries around the North Sea determined by the longterm national interests? The conclusion is made that in the initial phases the offshore petroleum developments were, to a larger extent, determined by strictly national interests and policies rather than by the international market and the interests of the companies. At present, however, by the shear weight in the national economies, the companies and the market forces have obtained the leading role. 相似文献
12.
Arild Underdal 《Global Environmental Change》2010,20(3):386-393
Some important processes of environmental change – including those of climate change and loss of biodiversity – share three characteristics that make them extremely demanding challenges of governance. First, time-lags between human action and environmental effect are very long, often extending beyond one human generation. Second, problems are embedded in highly complex systems that are not well understood. Third, these problems involve global collective goods of a type that links them to a wide range of human activities and leaves them beyond the scope of unilateral solutions. Social science research offers two essentially different models of collective response to severe challenges. One portrays effective response as collective action through central leadership and contraction of power. The other conceives of societal response as involving a variety of local activities undertaken by subunits of a complex and decentralised system. I argue that both models have considerable merit, but also that they respond to different types of challenges. Therefore, useful insights can be gained by specifying more precisely the circumstances under which each model applies. 相似文献
13.
The causes of land-use and land-cover change: moving beyond the myths 总被引:39,自引:0,他引:39
Eric F. Lambin B. L. Turner Helmut J. Geist Samuel B. Agbola Arild Angelsen John W. Bruce Oliver T. Coomes Rodolfo Dirzo Günther Fischer Carl Folke P. S. George Katherine Homewood Jacques Imbernon Rik Leemans Xiubin Li Emilio F. Moran Michael Mortimore P. S. Ramakrishnan John F. Richards Helle Sknes Will Steffen Glenn D. Stone Uno Svedin Tom A. Veldkamp Coleen Vogel Jianchu Xu 《Global Environmental Change》2001,11(4)
Common understanding of the causes of land-use and land-cover change is dominated by simplifications which, in turn, underlie many environment-development policies. This article tracks some of the major myths on driving forces of land-cover change and proposes alternative pathways of change that are better supported by case study evidence. Cases reviewed support the conclusion that neither population nor poverty alone constitute the sole and major underlying causes of land-cover change worldwide. Rather, peoples’ responses to economic opportunities, as mediated by institutional factors, drive land-cover changes. Opportunities and constraints for new land uses are created by local as well as national markets and policies. Global forces become the main determinants of land-use change, as they amplify or attenuate local factors. 相似文献
14.
ABSTRACTThe article presents the changes in the discipline of geography over 60 years as experienced both in fieldwork and in practice by a Norwegian geographer. Based on diaries and collections of memoirs, the author, Arild Holt-Jensen, presents his life story and how it has been impacted by people, places and special events. His intention is to show how geography and his own work reflect social, political and intellectual changes since the late 1950s. Initially, a regional geography approach was adopted in the fieldwork for his master’s thesis but the approach was challenged by new ideas and methods from both the spatial science school and model thinking. As a young lecturer in 1968, the author was shocked by the positivism debate and critical philosophy, and his spatial science and quantitative approach in his PhD project had to be adapted. His political engagement and interest in planning led him to research social exclusion in European neighbourhoods. His need to trace the identity of geography as a discipline resulted in a textbook that throughout the years has been updated by following up on research trends to the present. Thus, the book and the article show Holt-Jensen’s shifts in disciplinary identity and research practice. 相似文献
15.
The physical and biological environment of the Barents Sea is characterised by large variability on a wide range of scales.
Results from a numerical ocean model, SINMOD, are presented showing that the physical variability is partly forced by changes
in annual net ice import. The mean contribution from ice import in the simulation period (1979–2007) is about 40% of the total
amount of ice melted each year. The annual ice import into the Barents Sea varies between 143 and 1,236 km3, and this causes a substantial variability in the amount of annual ice melt in the Barents Sea. This in turn impacts the
freshwater content. The simulated freshwater contribution from ice is 0.02 Sv on average and 0.04 Sv at maximum. When mixed
into a mean net Atlantic Water (AW) inflow of 1.1 Sv with a salinity of 35.1, this freshwater addition decreases the salinity
of the modified AW to 34.4 and 33.9 for the mean and maximum freshwater fluxes, respectively. Ice import may thus be important
for the Barents Sea production of Arctic Ocean halocline water which has salinity of about 34.5. The changes in the ice melt
the following summer due to ice import also affect the formation of dense water in the Barents Sea by changing stratification,
altering the vertical mixing rates and affecting heat loss from the warm AW. The model results thus indicate that ice import
from the Arctic has a great impact on water mass modification in the Barents Sea which in turn impacts the ventilation of
the Arctic Ocean. 相似文献
16.
Arild Gulbrandsen 《Planetary and Space Science》1973,21(4):703-707
An analysis on the variation of coronal λ5303 intensity relative to the solar magnetic sector boundaries is presented. The location of the boundaries has been extrapolated from the observed interplanetary sector structure. The results indicate that in the years 1962–1964 the solar activity is in general high to the west and low to the east of a solar sector boundary. Such a distribution of solar activity contradicts with the one assumed up to now. Nevertheless, this distribution is in general in agreement with results of investigations on the correlation between solar and geomagnetic activity. 相似文献
17.
Arild Gulbrandsen 《Planetary and Space Science》1975,23(1):143-149
The solar M-region problem is briefly reviewed. The Mustel and the Allen-Saemundsson M-region schools are discussed in the light of (a) recent results on coronal structures and solar wind variations, and (b) statistical analyses of coronal-geomagnetic correlations. From this discussion it is suggested that the M-regions should be identified with the central portion of magnetically open solar regions, or coronal holes. With reference to the papers by Gulbrandsen (1973b, 1974), it is concluded that such an identification is in fact favoured by the great majority of analyses published on the M-region problem during the last 40 yr.It is assumed that historically, the M-region conflict has evolved from the scientific pecularity that geomagnetic phenomena which are actually related to magnetically open structures, were generally not studied in relation to such structures, but to closed magnetic configurations. 相似文献
18.
Whole rock abundances of Sc, Co and total Fe are presented for the Fen carbonatite complex. Average Sc and Co abundances are as follows: urtites (Sc = 1.8 ppm; Co. 5.5 ppm), ijolites (6.6; 25), silicocarbonatites (3.2; 12.2), søvites (3.5, 8.6), damtjernites (24; 57), vipetoites (5.2, 36), rauhaugites (15, 26), rødberg (61, 28). With in the ijolite-søvite series Sc decreases with degree of differentiation due to removal of pyroxene and garnet. In the damtjernite-rødberg series Sc increases with differentiation due to concentration by volatiles involved in the metasomatic conversion of damtjernite to rødberg. Data for the ijolite-søvite series is opposite to trends for this series found in the Oka carbonatite complex. 相似文献
19.
Determination of rare earth element (REE) abundances in rocks of the Fen complex has shown that within rocks of the first magmatic series REE abundances increase in the order urtiteFen magmas are discussed and it is considered that parental magmas had relatively high La/Yb ratios (40–60). Utilizing petrological evidence from other alkaline complexes coupled with experimental studies it is considered that the parental magma was a carbonated nephelinite produced by limited (<10%) partial melting of the mantle. All the Fen rocks are placed in a petrogentic scheme in which a carbonated nephelinite magma undergoes liquid immiscibility, differentiation and volatile transport. 相似文献
20.