排序方式： 共有20条查询结果，搜索用时 281 毫秒
11.
Suraje Dessai W. Neil Adger Mike Hulme John Turnpenny Jonathan Köhler Rachel Warren 《Climatic change》2004,64(1-2):11-25
Understanding what constitutes dangerous climate change is of critical importance for future concerted action (Schneider, 2001, 2002). To date separate scientific and policy discourses have proceeded with competing and somewhat arbitrary definitions of danger based on a variety of assumptions and assessments generally undertaken by `experts'. We argue that it is not possible to make progress on defining dangerous climate change, or in developing sustainable responses to this global problem, without recognising the central role played by social or individual perceptions of danger. There are therefore at least two contrasting perspectives on dangerous climate change, what we term `external' and `internal' definitions of risk. External definitions are usually based on scientific risk analysis, performed by experts, of system characteristics of the physical or social world. Internal definitions of danger recognise that to be real, danger has to be either experienced or perceived – it is the individual or collective experience or perception of insecurity or lack of safety that constitutes the danger. A robust policy response must appreciate both external and internal definitions of danger. 相似文献
12.
13.
A late-stage rift-related tholeiite-alkalic suite of igneous intrusions cut the Deccan Traps lavas at the western Indian continental margin. The suite comprises intrusives that can be grouped into ten lithotypes on the basis of their mutual relationships. Tholeiitic types predate the alkaline rocks and greatly predominate, however, the alkaline members exhibit more diversity in mineralogy and chemistry, and are amongst the rare magmatic rocks from the Deccan that host both mantle and lower crustal xenoliths. The mineralogy of most rock types is dominated by clinopyroxene. The diversity of the alkaline rocks could be mainly accounted for by fractional crystallization and mixing between evolved and primitive melts under varying P-T conditions. Sodic and potassic lamprophyres are amongst the most primitive samples with high Mg #, FeO/MgO < 1, high Cr and also with relatively high Ba, Sr, Zr and Nb. They are the most deeply derived magmas within the Deccan Traps as is evident from the mantle and lower crustal xenoliths entrained by them. They possibly represent low degree melts of incompatible element-enriched mantle source rocks. The nephelinites are strongly porphyritic and despite their high Mg #s can be regarded as evolved magmas that have been responsible for the formation of the tephriphonolite daughter. The nephelinites have undergone contamination by lower crustal granulites. The composite intrusions of microdiorites with their complexly zoned mineralogy dominated by plagioclase and amphiboles/micas represent hybrid rocks that have resulted from mixing between tholeiitic and trachytic melts partly at depth and partly at shallow crustal levels. 相似文献
14.
Depositional environment of mudflats and mangroves and bioavailability of selected metals within mudflats in a tropical estuary 总被引：1，自引：1，他引：0
M. C. Fernandes G. N. Nayak A. Pande S. P. Volvoikar D. R. G. Dessai 《Environmental Earth Sciences》2014,72(6):1861-1875
Four sediment cores representing adjacent mudflat and mangrove sub-environments of middle estuary (Shastri) were analyzed for sand, silt, clay, and organic carbon. Total metal concentration of iron (Fe), manganese (Mn), nickel (Ni), zinc (Zn), chromium (Cr), copper (Cu), cobalt (Co), and lead (Pb) and chemical speciation of Fe, Mn, and Co on selected samples was also carried out on mudflat cores. The sediments in the upper middle estuary were found to be deposited under highly varying hydrodynamic energy conditions; whereas lower middle estuary experienced relatively stable hydrodynamic energy conditions with time. The tributary joining the river near the upper middle estuary is found to be responsible for the addition of enhanced organic carbon and metal concentrations. Speciation study indicated Fe and Co are from natural lithogenic origin while Mn is derived from anthropogenic sources. Higher Mn and Co than apparent effects threshold can pose a high risk of toxicity to organisms associated with these sediments. 相似文献
15.
16.
Suraje Dessai 《Climate Policy》2003,3(3):295-302
The Special Climate Change (SCC) fund was established by the Marrakesh Accords under the United Nations Framework Convention on Climate Change. This fund will finance climate change activities in the areas of: adaptation, technology transfer, certain specific sectors, and activities to assist oil-exporting countries diversify their economies. These activities are to be complementary to those funded by the Global Environment Facility and by bilateral and multilateral funding. This paper describes the origins of the SCC fund and proposes a framework for the prioritisation of its activities. The fund has a complicated history that is intrinsically linked to numerous Convention issues, which explains the range of activities included in it. The framework proposed is based on certain principles: sound scientific knowledge, the ultimate objective of the Convention, “common but differentiated responsibilities and respective capabilities” and the status of the climate negotiations. This appraisal suggests that the fund should prioritise adaptation, followed by mitigation and finally economic diversification. 相似文献
17.
18.
The geology of Goa Group: Revisited 总被引：1，自引：0，他引：1
A. G. Dessai 《Journal of the Geological Society of India》2011,78(3):233-242
The supracrustals that constitute the Goa Group of Gokul et al. (1985) can be divided into two lithostratigraphic sequences
namely the Barcem Group and the Ponda Group. The former comprises predominantly greenstones (metabasalts) and rests on a basement
of the 3300–3400 Ma Anmode Ghat trodhjemite gneiss with a crudely developed quartz-pebble conglomerate at the base, and shows
lithological similarities with the lower part of the Bababudan Group. The younger sequence is dominated by clastics, and is
assigned to a new stratigraphic group formally termed the Ponda Group which is equivalent to the Chitradurga Group of the
Dharwar Supergroup. This group rests on a basement of the 2700–2900 Ma Chandranath granite gneiss with a distinct unconformity
marked by a polymict, granite-clast metaconglomerate. The conglomerate displays many similarities with the Talya conglomerate
that occurs at the base of the Chitradurga Group. It is overlain by a psamolitic sequence which is followed in ascending order
by the chemogenic sediments that host the BIF and by the deep water turbidite sequence (argillite-graywacke association) with
intercalations of mafic volcanics. The supracrustal sequence is intruded by the Bondla layered mafic-ultramafic complex along
a major shear zone (NW-SE) that largely controls the course of the northwesterly flowing tributary of River Mandovi. The late
intrusive, Canacona potassic granite marks the culmination of the sedimentation in the Shimoga-Goa basin. 相似文献
19.
The aim of this study is to understand the various sources and factors controlling the abundance and distribution of the metals through the analyses of selected metals (iron, manganese, chromium, copper, zinc and cobalt), sand, silt, clay, organic carbon and magnetic susceptibility of the surface sediments of Zuari estuary in three different seasons. Total suspended matter (TSM) concentration and salinity of near surface and bottom waters were also measured. The study undertaken for three seasons, based on 18 selected stations all along the estuary, indicated that the concentration of most of the metals were comparatively higher during pre-monsoon than in monsoon and post-monsoon seasons. Further, along the length of the estuary, high concentrations were observed at lower middle and lower estuary and also at few stations at the upstream end. Salinity, distribution of TSM, size of the sediment, organic matter, geomorphological setup, fresh water input from land and release of industrial waste within the estuary played a role in distribution and concentration of metals. Magnetic measurements indicated the dominance of haematite like minerals and helped in understanding the source and depositional processes. 相似文献
20.
Are there social limits to adaptation to climate change? 总被引：1，自引：0，他引：1
W. Neil Adger Suraje Dessai Marisa Goulden Mike Hulme Irene Lorenzoni Donald R. Nelson Lars Otto Naess Johanna Wolf Anita Wreford 《Climatic change》2009,93(3-4):335-354
While there is a recognised need to adapt to changing climatic conditions, there is an emerging discourse of limits to such adaptation. Limits are traditionally analysed as a set of immutable thresholds in biological, economic or technological parameters. This paper contends that limits to adaptation are endogenous to society and hence contingent on ethics, knowledge, attitudes to risk and culture. We review insights from history, sociology and psychology of risk, economics and political science to develop four propositions concerning limits to adaptation. First, any limits to adaptation depend on the ultimate goals of adaptation underpinned by diverse values. Second, adaptation need not be limited by uncertainty around future foresight of risk. Third, social and individual factors limit adaptation action. Fourth, systematic undervaluation of loss of places and culture disguises real, experienced but subjective limits to adaptation. We conclude that these issues of values and ethics, risk, knowledge and culture construct societal limits to adaptation, but that these limits are mutable. 相似文献