共查询到20条相似文献，搜索用时 781 毫秒
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D.T. Patterson J.K. Westbrook R.J.V. Joyce† P.D. Lingren J. Rogasik 《Climatic change》1999,43(4):711-727
The geographic distribution, vigor, virulence, and agricultural impact of weeds, insects, and plant pathogens will be affected by climatic changes accompanying the global "greenhouse effect." Weed/crop competitive interactions, particularly among species differing in photosynthetic pathway (C3 v C4), may be altered, with the C3 species favored by increasing CO2. Physiological and biochemical changes induced in host crop plants by rising CO2 may affect feeding patterns of pest insects. Compilation of climatic thresholds for phenological development of pest insects reveals the potential for shifts in pest behavior induced by global warming and other climatic change. Generation times may be reduced, enabling more rapid population increases to occur. Poleward migration may be accelerated during the crop season. The epidemiology of plant diseases also will be altered. Prediction of disease outbreaks will be more difficult in periods of rapidly changing climate and unstable weather. Environmental instability and increased incidence of extreme weather may reduce the effectiveness of pesticides on targeted pests or result in more injury to non-target organisms. Biological control may be affected either negatively or positively. Overall, the challenge to agriculture from pests probably will increase. 相似文献
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Governance,complexity, and resilience 总被引：1，自引：0，他引：1
Andreas Duit Victor Galaz Katarina Eckerberg Jonas Ebbesson 《Global Environmental Change》2010,20(3):363-368
This special issue brings together prominent scholars to explore novel multilevel governance challenges posed by the behavior of dynamic and complex social-ecological systems. Here we expand and investigate the emerging notion of “resilience” as a perspective for understanding how societies can cope with, and develop from, disturbances and change. As the contributions to the special issue illustrate, resilience thinking in its current form contains substantial normative and conceptual difficulties for the analysis of social systems. However, a resilience approach to governance issues also shows a great deal of promise as it enables a more refined understanding of the dynamics of rapid, interlinked and multiscale change. This potential should not be underestimated as institutions and decision-makers try to deal with converging trends of global interconnectedness and increasing pressure on social-ecological systems. 相似文献
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By C. S. ZEREFOS K. ELEFTHERATOS C. MELETI S. KAZADZIS A. ROMANOU C. ICHOKU G. TSELIOUDIS A. BAIS 《Tellus. Series B, Chemical and physical meteorology》2009,61(4):657-665
This work presents evidence that ultraviolet (UV)-A solar irradiances show increasing trends at Thessaloniki, Greece, where air quality has been improving because of air pollution abatement strategies. In contrast, over Beijing, China, where air quality measures were taken later, solar brightening was delayed. It is shown that until the early 1990s, UV-A irradiances over Thessaloniki show a downward trend of –0.5% yr−1 , which reverses sign and becomes positive in the last decade (+0.8% yr−1 ). This brightening is related to a decreasing trend in local aerosol amounts. Both the negative rate of change (dimming) and the positive rate of change (brightening) are amplified in the UV-A solar irradiances, compared with the total solar irradiance, by a factor of 2.6. Satellite derived short-wave radiation over Beijing showed negative changes of –0.4% (1984–1991) and –0.1% yr−1 during 1994–2006. The negative trend in solar radiation continued even during 2000–2006. Satellite-derived aerosol optical depth (AOD) increased by +1.0% yr−1 during 2000–2006, in agreement with in situ measurements of increasing AOD. Therefore, a statistically significant change from dimming to brightening in Beijing could not be seen in the last decade, but it is expected to occur in the near future. 相似文献
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Linking vulnerability, adaptation, and resilience science to practice: Pathways, players, and partnerships 总被引：7，自引：1，他引：7
Coleen Vogel Susanne C. Moser Roger E. Kasperson Geoffrey D. Dabelko 《Global Environmental Change》2007,17(3-4):349-364
Vulnerability, adaptation and resilience are concepts that are finding increasing currency in several fields of research as well as in various policy and practitioner communities engaged in global environmental change science, climate change, sustainability science, disaster risk-reduction and famine interventions. As scientists and practitioners increasingly work together in this arena a number of questions are emerging: What is credible, salient and legitimate knowledge, how is this knowledge generated and how is it used in decision making? Drawing on important science in this field, and including a case study from southern Africa, we suggest an alternative mode of interaction to the usual one-way interaction between science and practice often used. In this alternative approach, different experts, risk-bearers, and local communities are involved and knowledge and practice is contested, co-produced and reflected upon. Despite some successes in the use and negotiation of such knowledge for ‘real’ world issues, a number of problems persist that require further investigation including the difficulties of developing consensus on the methodologies used by a range of stakeholders usually across a wide region (as the case study of southern Africa shows, particularly in determining and identifying vulnerable groups, sectors, and systems); slow delivery of products that could enhance resilience to change that reflects not only a lack of data, and need for scientific credibility, but also the time-consuming process of coming to a negotiated understanding in science–practice interactions and, finally, the need to clarify the role of ‘external’ agencies, stakeholders, and scientists at the outset of the dialogue process and subsequent interactions. Such factors, we argue, all hinder the use of vulnerability and resilience ‘knowledge’ that is being generated and will require much more detailed investigation by both producers and users of such knowledge. 相似文献
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Inequalities, institutions, and forest commons 总被引：1，自引：0，他引：1
Krister AnderssonArun Agrawal 《Global Environmental Change》2011,21(3):866-875
This paper contributes to a growing literature on the commons that examines the relationship between inequality and commons outcomes. Our analysis of evidence on forest commons outcomes in 228 cases from South Asia (India and Nepal), East Africa (Kenya and Uganda) and Latin America (Mexico and Bolivia) suggests that local governance and collective action matter in shaping how socioeconomic inequalities affect forest conditions. In particular, we find that both inter-group and intra-group economic inequalities have consistently negative effects on forest outcomes, but that effectively functioning local institutions for collective action dampen the negative effect of inter-group inequality on forest outcomes. 相似文献
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The present study aims at the assessment of six satellite rainfall estimates (SREs) in Pakistan. For each assessed products, both real-time (RT) and post adjusted (Adj) versions are considered to highlight their potential benefits in the rainfall estimation at annual, monthly, and daily temporal scales. Three geomorphological climatic zones, i.e., plain, mountainous, and glacial are taken under considerations for the determination of relative potentials of these SREs over Pakistan at global and regional scales. All SREs, in general, have well captured the annual north-south rainfall decreasing patterns and rainfall amounts over the typical arid regions of the country. Regarding the zonal approach, the performance of all SREs has remained good over mountainous region comparative to arid regions. This poor performance in accurate rainfall estimation of all the six SREs over arid regions has made their use questionable in these regions. Over glacier region, all SREs have highly overestimated the rainfall. One possible cause of this overestimation may be due to the low surface temperature and radiation absorption over snow and ice cover, resulting in their misidentification with rainy clouds as daily false alarm ratio has increased from mountainous to glacial regions. Among RT products, CMORPH-RT is the most biased product. The Bias was almost removed on CMORPH-Adj thanks to the gauge adjustment. On a general way, all Adj versions outperformed their respective RT versions at all considered temporal scales and have confirmed the positive effects of gauge adjustment. CMORPH-Adj and TMPA-Adj have shown the best agreement with in situ data in terms of Bias, RMSE, and CC over the entire study area. 相似文献
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Assessments of the benefits of climate change mitigation—and thus of the appropriate stringency of greenhouse gas emissions abatement—depend upon ethical, legal, and political economic considerations. Global climate change mitigation is often represented as a repeated prisoners’ dilemma in which the net benefits of sustained global cooperation exceed the net benefits of uncooperative unilateral action for any given actor. Global cooperation can be motivated either by circumspection—a decision to account for the damages one’s own actions inflict upon others—or by the expectation of reciprocity from others. If the marginal global benefits of abatement are approximately constant in total abatement, the domestically optimal price approaches the global cooperative optimum linearly with increasing circumspection and reciprocity. Approximately constant marginal benefits are expected if climate damages are quadratic in temperature and if the airborne fraction of carbon emissions is constant. If, on the other hand, damages increase with temperature faster than quadratically or carbon sinks weaken significantly with increasing CO2 concentrations, marginal benefits will decline with abatement. In this case, the approach to the global optimum is concave and less than full circumspection and/or reciprocity can lead to optimal domestic abatement close to the global optimum. 相似文献
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《大气与海洋》2013,51(1):117-138
Abstract Dynamics affects the distribution and abundance of stratospheric ozone directly through transport of ozone itself and indirectly through its effect on ozone chemistry via temperature and transport of other chemical species. Dynamical processes must be considered in order to understand past ozone changes, especially in the northern hemisphere where there appears to be significant low‐frequency variability which can look “trend‐like” on decadal time scales. A major challenge is to quantify the predictable, or deterministic, component of past ozone changes. Over the coming century, changes in climate will affect the expected recovery of ozone. For policy reasons it is important to be able to distinguish and separately attribute the effects of ozone‐depleting substances and greenhouse gases on both ozone and climate. While the radiative‐chemical effects can be relatively easily identified, this is not so evident for dynamics — yet dynamical changes (e.g., changes in the Brewer‐Dobson circulation) could have a first‐order effect on ozone over particular regions. Understanding the predictability and robustness of such dynamical changes represents another major challenge. Chemistry‐climate models have recently emerged as useful tools for addressing these questions, as they provide a self‐consistent representation of dynamical aspects of climate and their coupling to ozone chemistry. We can expect such models to play an increasingly central role in the study of ozone and climate in the future, analogous to the central role of global climate models in the study of tropospheric climate change. 相似文献
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The workshop focused on methodologies to assess the impacts of climate change on terrestrial and aquatic ecosystems and their socioeconomic consequences. It did not deal in any detail with the other components (i.e., models designed to estimate changes in atmospheric concentrations of greenhouse gases or in climatic factors) of an integrated assessment shown in Figure 2 of the introduction. This final chapter discusses some of the issues addressed during the San Diego workshop and highlights a few of the major findings of the papers. Issues discussed below include limitations of past modeling efforts and impediments to developing better models of the impacts of climate change on forest, grassland, and water resources; suggestions for future research both to develop better data and models and to employ existing data and modeling capabilities to improve the usefulness of climate impact assessments for policy purposes; and the need for developing a common assessment framework.The views expressed here are those of the authors and do not necessarily reflect those of their institutions or the other participants in the February 28 to March 3, 1993 workshop held in San Diego, California. 相似文献
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Vincent J. Schaefer 《Meteorology and Atmospheric Physics》1955,8(3):265-282
Summary More than 70% of forest fires in the northwestern United States are caused by lightening. The Project Skyfire is an attempt to learn more about the atmospheric conditions leading to thunderstorms in this area and to investigate the possibilities of an artificial influence on their development by cloud seeding. The experiences gained with the training of amateur observers as well as the first scientific results of the project are briefly discussed. During the first year of observations, for instance, there was found to exist an intimate relationship between a certain type of fast moving thunderstorms and the intensity and position of the jet stream. Finally, the great economical value of researches in the field of applied meteorology is stressed.
With 7 Figures.
The Munitalp Foundation, Inc. 相似文献
Zusammenfassung Über 70% der Waldbrände im Nordwesten der Vereinigten Staaten werden durch Blitze entzündet. Das Project Skyfire hat es sich zum Ziel gesetzt, die atmosphärischen Bedingungen, welche zur Bildung von Gewittern in diesem Gebiet führen, zu untersuchen und die Möglichkeiten einer künstlichen Beeinflussung durch seeding zu erforschen. Die gesammelten Erfahrungen mit der Schulung von Amateur-Beobachtern, sowie die bisherigen wissenschaftlichen Ergebnisse werden kurz diskutiert. Schon im ersten Jahr der Beobachtungen ergaben sich interessante Zusammenhänge zwischen einer bestimmten Art von rasch ziehenden Gewittern und dem Jet-Stream. Schließlich wird auf den weitreichenden wirtschaftlichen Nutzen großzügiger Forschungen auf dem Gebiet der angewandten Meteorologie hingewiesen.
Résumé Plus de 70% des incendies de forêts dans le Nord-Ouest des Etats-Unis sont dûs à la foudre. Le «Project Skyfire» a pour but d'étudier les conditions atmosphériques conduisant dans ces régions à la formation d'orages ainsi que les possibilités d'agir sur cette formation au moyen d'inséminations artificielles. On discute brièvement les expériences faites en instruisant des observateurs amateurs ainsi que les résultats scientifiques. Dès la première année de recherches, on a constaté d'intéressantes relations entre un certain type d'orages rapides et le jet stream. Enfin on attire l'attention sur le grand intérêt économique d'études étendues dans le domaine de la métérologie appliquée.
With 7 Figures.
The Munitalp Foundation, Inc. 相似文献
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《Global Environmental Change》2001,11(2):119-131
In recent years there has been a movement by administrators and policymakers across the country to reorganize and reinvent government to improve program efficiencies, to harness resources outside government in the service of public policy goals, and to better facilitate the input of affected interests and the general public. Central to this effort are innovative, decentralized institutional arrangements which delegate significant authority either to private citizens, program managers within existing bureaucracy, or market-based mechanisms. Ecosystem- and watershed-based management, which seek to both prevent pollution and sustain development, are in the vanguard of this movement. This paper examines this trend toward decentralizing environmental policy and the use of ecosystem management from the perspective of the public. Planning and implementation of devolved environmental policy will require the support of local stakeholders and citizens. Using data from a national public opinion survey conducted during the summer of 1998, the paper examines factors associated with public acceptability of ecosystem management and the preferred level of government and citizen participation that should be involved in the implementation of such management strategies. 相似文献
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大气中硝酸盐、硫酸盐、铵和钙的浓度 总被引：2，自引：0，他引：2
1985年10月,在中国的三个不同地点用太氟龙和尼龙滤膜采样系统观测了硝酸根、硫酸根、铵和钙的浓度。平均而言,硫酸根的摩尔浓度与硝酸根的摩尔浓度之比不到2。考虑到中国燃煤大量排放SO_2这一事实,这一低比值有点出乎预料。在北京钙是最重要的阳离子,而在华北山区的兴隆天文观测站和南方城市长沙气溶胶中铵离子多于钙离子。在北风条件下,兴隆的硫酸根和硝酸根浓度与文献中报道的欧洲和北美的本底值接近。因此,兴隆天文观测站是研究亚洲大陆本底空气的理想地点。 相似文献
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