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1.
Tropical rain forests are dynamic and continually regenerating by growth of seedlings up from the forest floor into canopy gaps that form on a cycle of usually a century of more in length. Changes in seedling establishment, survival, and release in gaps could thus change canopy species composition for a long time. Of likely climatic changes, evidence is presented that cyclone occurrence and increased rainfall seasonality could have important effects on seedling ecology. These forests and their species have lived through big Pleistocene and Holocene climatic changes, but today they are fragmented by human impact and so have less resilience to future climatic change. Management to accommodate climatic change should aim to reduce fragmentation and also canopy opening during logging operations. These are the same practices as advocated for biodiversity conservation. Tropical seasonal forests are also likely to be altered by expected climatic change, and also mainly at their regeneration stage.  相似文献   

2.
在气候影响研究中引入随机天气发生器的方法和不确定性   总被引：1，自引：0，他引：1  
通过采用不同的随机天气发生器生成一定气候背景下各种气候变率情景，许多学者在最近的研究中已经认识到气候变率对农作物生长发育影响的重要性。传统的气候影响评估方法直接以大气环流模式的模拟试验结果作为未来气候情景，这样不可能理解如上的重要性。本文着重评述将随机天气发生器应用于气候变化影响研究的一般方法框架，以及作者的具体个例研究方法。文中最后分析了目前该领域研究中还存在的一些不确定性。 在当前的气候变化影响研究中，有不同的方法用来研制一种称为WGEN的典型随机天气发生器的参数化方案及其随机试验方法。不同的研究者也有不同的参数调控方法。通常的思路是通过气候控制试验和2×CO2试验之间的气候变量平均值和方差的变化来扰动随机天气发生器的参数，以生成未来逐日气候变化情景。本文作者根据短期气候预测模式的输出产品建立了一套WGEN的参数化方案及其随机试验方法，并且在时间和空间两个尺度上检验和评估了此参数化方案下WGEN的模拟能力。另外，作者由未来降水的变化，调试随机天气发生器参数，生成了气候变率变化情景。这些参数调节可以产生各种不同类型和定性大小的气候变率变化，用于气候影响评估的敏感性分析。通过如上方法，作为一个个例，文中评估了未来气候变率变化  相似文献   

3.
Globally, youth voices and their experiences, observations, and perceptions about climatic and environmental change and variability are relatively absent in the published literature to date. To address this gap, the goal of this research was to explore the observations and perceptions of climate change held by youth (12–25 years old) in the Inuit community of Rigolet, Nunatsiavut, Canada. Twenty in-depth interviews were conducted with youth in Rigolet to gather data about climatic and environmental changes young people have observed, and the subsequent impacts of these changes on their lives, culture, and community. Youth reported observing and experiencing climatic and environmental changes throughout their lives, with reported impacts falling within five main themes: changing travel conditions and access to hunting; challenges to Inuit culture; a concern for Elder and senior well-being; strong climate-related emotional responses; and youth-identified potential adaptation strategies. More broadly, this research demonstrated that young people have valuable knowledge and perspectives to offer. In particular, researchers, community leaders, and policy makers are encouraged to meaningfully engage youth as crucial stakeholders in future climate change work, research, dialogue, and policy.  相似文献   

4.
Abstract

Summertime energy budgets of contiguous wetland tundra and forest near Churchill, Manitoba along the coast of Hudson Bay were measured over a five year period, 1989–1993. An examination of differences in energy budgets between the two sites showed that net radiation was similar in all years. Soil heat flux was greater at the tundra site in most, but not all, years. However, sensible heat flux was always larger at the forest site and latent heat flux was always greater at the tundra site. Mean daily Bowen ratios at both sites were less than unity in all years. Average Bowen ratios for the five years were 0.45 for tundra and 0.66 for forest. Wind direction is used as an analogue for changing climatic conditions where onshore winds are cooler and moister than offshore winds. Sensible and latent heat fluxes at both sites varied significantly between onshore and offshore wind regimes. However, differences between onshore and offshore fluxes at the tundra site were larger than for the forest. Thus, Bowen ratios also varied more at the tundra site. We have plotted the ratio of tundra‐to‐forest Bowen ratios as a measure of the relative sensitivity of energy partitioning to climatic change. The ratio decreases with increasing vapour pressure deficit (and increasing air temperature). We interpret these results as suggesting that energy partitioning over the wetland tundra is more sensitive to changes in climate than the treeline forest environment. Thus, as the climate warms and becomes drier, more additional energy goes into evaporation of water from the wetland tundra than from the forest.  相似文献   

5.
Adaptation in Canadian Agriculture to Climatic Variability and Change   总被引：3，自引：0，他引：3  
The effects of climatic variability and change on Canadian agriculture have become an important research field since the early 1980s. In this paper, we seek to synthesize this research, focusing on agricultural adaptation, a purposeful proactive or reactive response to changes associated with climate, and influenced by many factors. A distinctive feature of methods used in research on adaptation in Canadian agriculture is the focus on the important role of human agency. Many individual farmers perceive they are well adapted to climate, because of their extensive 'technological' tool-kit, giving them confidence in dealing with climatic change. In many regions, little concern is expressed over climatic change, except where there are particular types of climatic vulnerability. Farmers respond to biophysical factors, including climate, as they interact with a complex of human factors. Several of these, notably institutional and political ones, have tended to diminish the farm-level risks stemming from climatic variability and change, but may well increase the long term vulnerability of Canadian agriculture. Notwithstanding the technological and management adaptation measures available to producers, Canadian agriculture remains vulnerable to climatic variability and to climate change.  相似文献   

6.
Concern over changes in global climate caused by growing atmospheric concentrations of carbon dioxide and other trace gases has increased in recent years as our understanding of atmospheric dynamics and global climate systems has improved. Yet despite a growing understanding of climatic processes, many of the effects of human-induced climatic changes are still poorly understood. Major alterations in regional hydrologic cycles and subsequent changes in regional water availability may be the most important effects of such climatic changes. Unfortunately, these are among the least well-understood impact. Water-balance modeling techniques - modified for assessing climatic impacts - were developed and tested for a major watershed in northern California using climate-change scenarios from both state-of-the-art general circulation models and from a series of hypothetical scenarios. Results of this research suggest strongly that plausible changes in temperature and precipitation caused by increases in atmospheric trace-gas concentrations could have major impacts on both the timing and magnitude of runoff and soil moisture in important agricultural areas. Of particular importance are predicted patterns of summer soil-moisture drying that are consistent across the entire range of tested scenarios. The decreases in summer soil moisture range from 8 to 44%. In addition, consistent changes were observed in the timing of runoff-specifically dramatic increases in winter runoff and decreases in summer runoff. These hydrologic results raise the possibility of major environmental and socioeconomic difficulties and they will have significant implications for future water-resource planning and management.  相似文献   

7.
This study evaluates the effects of climate change on agriculture in Northern Norway. It is based on downscaled climate projections for six different municipalities combined with interviews with farmers, advisors and administrative personnel in these municipalities. The projections document large climatic differences both between and within the different municipalities. The main predicted climatic changes include increasing temperatures and precipitation as well as increased frequency of certain types of extreme weather events. Despite challenges such as unstable winters, increased autumn precipitation and possibly more weeds and diseases, a prolongation of the current short growth season together with higher growth temperatures can give new opportunities for agriculture here. The impacts are expected to differ both within and between municipalities and will require tailored adaptive strategies. Most of these however should pose no difficulty implementing, having an agronomical basis that farmers are accustomed to cope with.  相似文献   

8.
Summer tourism is one of the most important contributors to the European GDP especially for the southern countries and is highly dependent on the climatic conditions. Changes in average climatic conditions, along with the potential subsequent changes in the physical environment, will pose stress on the favorability of the climate of European destinations for tourism and recreational activities. Here, we study the vulnerability of summer-oriented tourism due to a global temperature increase by 2 °C relative to the preindustrial era. We use a well-defined framework of exposure, sensitivity, and adaptive capacity indicators for a set of plausible climate (RCPs) and socioeconomic (SSPs) combinations. Our result shows that a 2 °C global warming will pose substantial changes to the vulnerability of the European tourism sector. Despite the general increase in exposure, the vulnerability of summer tourism is highly depended on the socioeconomic developments (SSPs). Although exposure is higher for most of the popular southern European destinations like Spain, France, South Italy, southernmost Greece, and Cyprus, they are expected to be less vulnerable than others, under specific SSPs, due to their higher capacity to adapt to a different climate. The capacity to adapt is lower for higher emission scenarios. Substantial changes are also apparent at the subnational level. Countries like France are foreseen to experience very diverse impacts and vulnerabilities within their own territories that will have consequences in terms of domestic tourism. The dynamics of these changes are expected to alter the state of the current European tourism regime.  相似文献   

9.
A physical model was developed for describing the thermal environment of ponded shallow water as a model for rice fields in relation to climatic conditions. The model was used to assess probable effects of CO2-induced warming on the thermal conditions of ponded shallow water. It was assumed that an altered equilibrium climate was produced by atmospheric CO2 which was twice that of present levels. The 1951–80 climatic means of Japan were used as baseline data. Water temperature and energy balance characteristics predicted from the model were compared between both climates. The most notable results were that water temperature under CO2 doubling rose 2 to 4 °C. These increases in temperature would induce a remarkable northward shift of the 15 °C isotherm which characterizes the isochrone of safe transplanting dates for rice seedlings. CO2-warming would have a considerable influence on the energy balance characteristics, intensifying the evaporation rate from the water surface. Changes in thermal conditions of rice fields due to CO2-induced climatic warming are, therefore, expected to bring about significant effects on aquatic environments and the life forms they support.  相似文献   

10.
Agriculture appears to be one of the human activities most vulnerable to climatic changes due to its large dependence on environmental conditions. However, the diversity of Brazilian environmental conditions could be of great advantage to adapting this sector to new climatic conditions, which should be assessed as in this study on shifting Arabica coffee cultivation to the extreme south of the country. The methodology applied is the same the one used to define climatic risks in current productive regions of Brazil and their vulnerability to climatic change predicted by IPCC reports. The basic climatic parameters applied were frost probability and annual average temperature, since annual water deficit did not prove to be a restricting factor for Arabica coffee cultivation in the study area. The climatic conditions suitable for coffee production are: annual average temperature between 18??C and 22??C, annual water deficit less than 100?mm and frost probability (risk of lowest annual temperature less than 1??C) less than 25%. An area is said to have ??low climatic risks?? for coffee production when these three climatic conditions are met. Current climatic conditions were used and simulations of four temperature increases between 1??C and 4??C were also performed. The results indicated a substantial increase in the size of low climatic risks areas for the production of Arabica coffee in the extreme south of Brazil, mainly for mean temperature increases of 3??C in the study area in relation to present conditions. Increases of 2??C and 4??C were also favorable, but not as good as those obtained for 3??C. It should be underscored that areas with low climatic risks will be able to be found mainly in the extreme south of the study region, the border with Uruguay and North of Argentina.  相似文献   

11.
Climate change is complicating the variables that Alaskans consider when planning for the future. Communities, agencies and other entities have begun to grapple with both the information that they need to adapt to a changing climate and how the processes and practices of science should change to make science more useful. We reviewed sixty-three documents that expressed practical research needs related to climate change in Alaska. Documents nearly unanimously expressed that science, as it is currently practiced, is inadequate to meet the challenges of climate change. They call for processes that are more transparent, collaborative, and accessible. They recommend changed practices including maintaining accessible data-sharing archives, building networks for knowledge sharing, and creating place-based long-term partnerships with communities. They advocate integrating local knowledge, but infrequently address the complexities of how this is best accomplished. They also suggest the need for improved training in interdisciplinary research and changes in the incentive structure of research institutions. This review complements the climate-change literature by providing concrete suggestions about how to increase the utility of science from a region that is experiencing some of the most dramatic climatic change on the planet.  相似文献   

12.
针对某一个气候要素，将我区100个气象观测站分为若干个气候区，分别对每一个气候区的气候要素和高度、经度、纬度、坡度、坡向5项地理信息要素进行分析，发现其相关关系，建立非线性回归方程，然后在新疆地图上确定一个与行政区划无关的范围，认为该范围内所有网格点上的气候要素与地理信息要素也具有同样的对应关系，进行小网格气候要素推算。  相似文献   

13.
Outputs from a 10,000-year simulation with a coupled global climatic model for present climatic conditions have been used to investigate the behaviour of the Pacific Decadal Oscillation (PDO), the North Pacific Oscillation (NPO) and related phenomena. The analysis reveals a wide range of temporal variability for these Oscillations, suggesting that observations to date provide only a limited sample of possible outcomes. In addition, the simulation suggests that the current observed phase relation between the PDO and NPO may not be typical of longer-term variability. Climatic jumps appear to be a ubiquitous feature of climatic variability, and while, as observed, the most common interval between such jumps is about 20 years, intervals of up to 100 years occur in the simulation. The probability density functions of the PDO and NPO are very close to Gaussian, with the PDO being represented by an auto-regressive function of order one, while the NPO consisted of white noise. An FFT analysis of PC1 of the PDO revealed periodicities concentrated near 10 years, while for the NPO the principal periodicities were decadal to bidecadal. Global distributions of the distributions of the correlations between PC1 or the NPO and selected climatic variables were similar, and in agreement with observations. These correlations highlight the inter-relationships between these two Oscillations. The above correlations were not necessarily stable in time for a given geographical point, with transitions occurring between positive and negative extremes. Climatic jumps were identified with transitions of both the PDO and NPO, with magnitudes of importance as regards climatic perturbations. Spatial patterns of the changes associated with such jumps have global scales, and the need to consider the implications of these jumps in regard to greenhouse induced climatic change is noted.  相似文献   

14.
Climate Change and Global Wine Quality   总被引：10，自引：0，他引：10  
From 1950 to 1999 the majority of the world's highest quality wine-producing regions experienced growing season warming trends. Vintage quality ratings during this same time period increased significantly while year-to-year variation declined. While improved winemaking knowledge and husbandry practices contributed to the better vintages it was shown that climate had, and will likely always have, a significant role in quality variations. This study revealed that the impacts of climate change are not likely to be uniform across all varieties and regions. Currently, many European regions appear to be at or near their optimum growing season temperatures, while the relationships are less defined in the New World viticulture regions. For future climates, model output for global wine producing regions predicts an average warming of 2 ∘C in the next 50 yr. For regions producing high-quality grapes at the margins of their climatic limits, these results suggest that future climate change will exceed a climatic threshold such that the ripening of balanced fruit required for existing varieties and wine styles will become progressively more difficult. In other regions, historical and predicted climate changes could push some regions into more optimal climatic regimes for the production of current varietals. In addition, the warmer conditions could lead to more poleward locations potentially becoming more conducive to grape growing and wine production.  相似文献   

15.
Roy Darwin 《Climatic change》1999,41(3-4):371-411
During the past few years two new methods, each based on the analogous region concept, have been developed to account for farmer adaptation in response to global climatic change. The first, called 'Ricardian' by Mendelsohn, Nordhaus, and Shaw (1994), econometrically estimates the impact of climatic and other variables on the value of farm real estate. Under some conditions, estimates of climate-induced changes in farm real estate capture first-round adaptations by farmers and represent the economic value of climatic change on agriculture. The second method, promulgated by Darwin et al. (1994) in the Future Agricultural Resources Model (FARM), uses a geographic information system to empirically link climatically derived land classes with other inputs and agricultural outputs in an economic model of the world. FARM provides estimates of economic impacts that fully account for all responses by economic agents under global climate change as well as estimates of Ricardian rents. The primary objective of this analysis is to evaluate how well changes in Ricardian rents measure agricultural or other effects of climatic change after all economic agents around the world have responded. Results indicate that changes in Ricardian rents on agricultural land are poor quantitative, but good qualitative, measures of how global climatic change is likely to affect the welfare of agricultural landowners, if one recognizes that increases in Ricardian rents actually indicate losses in landowner welfare and vice versa. Results also indicate that regional changes in Ricardian rents on all land are good qualitative measures of changes in regional welfare. They are poor quantitative welfare measures because they systematically overestimate both benefits and losses and are on average upwardly biased because inflated benefits are larger than exaggerated losses. Results also indicate that, when based on existing land-use patterns, changes in Ricardian rents on all the world's land are poor quantitative and qualitative measures of changes in world welfare. Despite these shortcomings, changes in Ricardian rents can provide useful information when other measures are not available. In this analysis, for example, estimated changes in Ricardian rents on all land indicate that climatic change would likely have detrimental effects in Latin America and Africa, beneficial effects in the former Soviet Union, and either detrimental or beneficial impacts in eastern and northern Europe and western and southern Asia. This is consistent with previous studies showing that climatic change would likely have detrimental, beneficial, and mixed effects on economic welfare in, respectively, equatorial, high latitude, and temperate areas. Estimated changes in Ricardian rents also indicate that aggregating Africa, Latin America, the former Soviet Union, eastern and northern Europe, and western and southern Asia into one region causes FARM's economic model to generate upwardly biased changes in world welfare. Modified results from scenarios with moderately flexible land-use change and which account for current land-use patterns indicate that world welfare may increase if the average surface land temperature does not increase by more than 1.0 or 2.0°C. If the average surface land temperature increases by 3.0°C or more, however, then world welfare may decline.  相似文献   

16.
Climatic Change, Wars and Dynastic Cycles in China Over the Last Millennium   总被引：1，自引：0，他引：1  
In recent years, the phenomenon of global warming and its implications for the future of the human race have been intensively studied. In contrast, few quantitative studies have been attempted on the notable effects of past climatic changes upon human societies. This study explored the relationship between climatic change and war in China by comparing high-resolution paleo-climatic reconstructions with known war incidences in China in the last millennium. War frequencies showed a cyclic pattern that closely followed the global paleo-temperature changes. Strong and significant correlations were found between climatic change, war occurrence, harvest level, population size and dynastic transition. During cold phases, China suffered more often from frequent wars, population decline and dynastic changes. The quantitative analyses suggested that the reduction of thermal energy input during a cold phase would lower the land carrying capacity in the traditional agrarian society, and the population size, with significant accretions accrued in the previous warm phase, could not be sustained by the shrinking resource base. The stressed human-nature relationship generated a ‘push force’, leading to more frequent wars between states, regions and tribes, which could lead to the collapse of dynasties and collapses of human population size. War frequencies varied according to geographical locations (North, Central and South China) due to spatial variations in the physical environment and hence differential response to climatic change. Moreover, war occurrences demonstrated an obvious time lag after an episode of temperature fall, and the three geographical regions experienced different length of time lags. This research also shows that human population increases and collapses were correlated with the climatic phases and the social instabilities that were induced by climate changes during the last millennium. The findings proposed a new interpretation of human-nature relationship in the past, with implications for the impacts of anomalous global warming on future human conflicts.  相似文献   

17.
The line that marks the boundary between the boreal forest and the tundra regions is a relatively abrupt line in central Canada and appears to reflect a clearly defined climate boundary. Research suggests that relatively small changes in the climatic conditions should result in a movement of the treeline. Such a movement was apparently reported in 1772 by Samuel Hearne based upon the observations of generations of Indians who had lived in the area. A map of his voyages indicates a tree limit that was further west in the north/south section of western Canada and further south in the east/west section of central Canada. This location and subsequent movement appears to be logical in relation to the climatic conditions that occurred in the region as a result of the Little Ice Age and the warmer conditions thereafter.  相似文献   

18.
California mountain streams provide critical water resources for human supplies and aquatic ecosystems, and have been affected by climatic changes to varying degrees, often within close proximity. The objective of this study is to examine stream flow timing changes and their climatic drivers through 2009, identify sub-regional patterns in response and sensitivity, and explore whether the differences in the sensitivity of a stream to climatic changes can be partially explained through the physical characteristics of a watershed. To this end, changes in streamflow timing for each watershed were assessed through several runoff timing measures, and overall sensitivity to historic climatic changes through a composite sensitivity index. Elevation, aspect, slope, geology, and landcover distributions, as well as climate information were assembled for each watershed; and were analyzed in conjunction with the sensitivity index. Results showed that the basins most sensitive to climatic changes are on the western Sierra Nevada slopes, while eastern and southern Sierra Nevada, as well as Klamath mountain watersheds exhibit little or no response to climatic shifts to date. Basin sensitivity was not found to be connected to any individual physical watershed characteristic other than elevation. However, it is suggested that basin-to-basin differences in sensitivity, observed in spite of regional-scale warming and similar watershed elevations, can be explained by differences in elevation ranges and combinations of physical watershed characteristics. Results about stream differences in climate sensitivity could aid in prioritizing stream preservation efforts.  相似文献   

19.
This study assesses the possible impact of climatic change on Saudi Arabia's agriculture and water supplies using climatic change scenarios from GCMs (General Circulation Models) and related research. The resulting assessment indicates that an increase in temperature and decrease in precipitation could have a major negative impact on agriculture and water supplies in Saudi Arabia. To find signs of climatic change in Saudi Arabia a preliminaryassessment of systematic changes in temperature and precipitation was made, based on the records of four Saudi weather stations. The analysis of this data, which dates back to 1961, shows no discernable signs of climatic change during the study period. Such data is, however, limited both spatially and temporally and cannot provide conclusive evidence to confirm climatic changes projected by GCMs. Nevertheless, in the light of recent climatic conditions and rapid population growth, Saudi decision-makers are urged to adopt a `no regret' policy. Ideally, such a policy would include measures to avoid future environmental or socioeconomic problems that may occur in the event of significant climatic change.  相似文献   

20.
Globalization,Pacific Islands,and the paradox of resilience   总被引：1，自引：0，他引：1  
On April 2nd, 2007 a 12 m tsunami struck Simbo, a relatively remote island in Western Province, Solomon Islands. Although Simbo's population continues to depend on their own food production and small-scale governance regimes regulate access to resources, the island's way of life over the last century has increasingly been affected by processes associated with globalization. In this context of a rapidly globalizing world, this article examines the island's resilience and vulnerability to the tsunami and the adaptive capacities that enabled the response and recovery. The tsunami completely destroyed two villages and damaged fringing coral reefs, but casualties were low and social–ecological rebound relatively brisk. By combining social science methods (household surveys, focus group and ethnographic interviews) and underwater reef surveys we identify a number of countervailing challenges and opportunities presented by globalization that both nurture and suppress the island's resilience to high amplitude, low-frequency disturbances like tsunamis. Analysis suggests that certain adaptive capacities that sustain general system resilience come at the cost of more vulnerability to low-probability hazards. We discuss how communities undergoing increasingly complex processes of change must negotiate these kinds of trade-offs as they manage resilience at multiple spatial and temporal scales. Understanding the shifting dynamics of resilience may be critical for Pacific Island communities who seek to leverage globalization in their favor as they adapt to current social–ecological change and prepare for future large-scale ecological disturbances.  相似文献   

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