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Bangladesh is a small country of South Asia which is considered as one of the most vulnerable countries in the world to climate change and it is affected by severe weather and climate events. In th...

While studies increasingly document long-term change in community composition, whether long-term change occurs gradually or via rapid reorganization events remains unclear. We used Latent Dirichlet Allocation (LDA) and a change-point model to examine the long-term dynamics of a desert rodent community undergoing compositional change over a 38-yr span. Our approach detected three rapid reorganization events, where changes in the relative abundances of dominant and rare species occurred, and a separate period of increased variance in the structure of the community. These events coincided with time periods, possibly related to climate events, where the total abundance of rodents was extremely low. There are a variety of processes that could link low abundance events with a higher probability of rapid ecological transitions, including higher importance of stochastic processes (i.e., competitive interactions or priority effects) and the removal of structuring effects of competitive dominants or incumbent species. Continued study of the dynamics of community change will provide important information not only on the processes structuring communities, but will also provide guidance for forecasting how communities will undergo change in the future.

It is recognized that biodiversity changes across the planet latitudinally; however, the timing of and reasons for diversity loss at higher latitudes are not well understood. Meseguer and Condamine investigate phylogenies and fossil evidence of reptilian species and determine that global warming and cooling events allowed asymmetric extinction and dispersion across latitudes, suggesting a hypothesis where climate profoundly shapes the latitudinal diversity gradient in certain taxa.

The Last Termination (19 000–11 000 a BP) with its rapid and distinct climate shifts provides a perfect laboratory to study the nature and regional impact of climate variability. The sedimentary succession from the ancient lake at Hässeldala Port in southern Sweden with its distinct Lateglacial/early Holocene stratigraphy (>14.1–9.5 cal. ka BP) is one of the few chronologically well‐constrained, multi‐proxy sites in Europe that capture a variety of local and regional climatic and environmental signals. Here we present Hässeldala's multi‐proxy records (lithology, geochemistry, pollen, diatoms, chironomids, biomarkers, hydrogen isotopes) in a refined age model and place the observed changes in lake status, catchment vegetation, summer temperatures and hydroclimate in a wider regional context. Reconstructed mean July temperatures increased between c. 14.1 and c. 13.1 cal. ka BP and subsequently declined. This latter cooling coincided with drier hydroclimatic conditions that were probably associated with a freshening of the Nordic Seas and started a few hundred years before the onset of Greenland Stadial 1 (c. 12.9 cal. ka BP). Our proxies suggest a further shift towards colder and drier conditions as late as c. 12.7 cal. ka BP, which was followed by the establishment of a stadial climate regime (c. 12.5–11.8 cal. ka BP). The onset of warmer and wetter conditions preceded the Holocene warming over Greenland by c. 200 years. Hässeldala's proxies thus highlight the complexity of environmental and hydrological responses across abrupt climate transitions in northern Europe.

While business tends to be seen as a substantial factor in causing climate change, climate-induced physical changes can also pose major challenges to firms in return. Firms can reduce their vulnerability to these changes by defining and implementing an adaptation strategy. Based on an empirical analysis of the oil and gas industry, this paper examines how the way firms interpret climate events in terms of awareness and vulnerability informs their measures to adapt to climate-induced physical change. In the empirical analysis, the paper derives four types of adaptation behaviour ? pre-emptive, reactive, continuous, and deferred adaptation ? that correspond with different degrees of awareness and vulnerability. The paper concludes with implications for management practice and policymakers.

Understanding the influence of climatic variations on forest decline is a major challenge for scientists investigating global changes. Although reductions in tree growth have previously been associated with forest decline, comprehensive efforts to understand these relationships are rare. Based on ring‐width variations, we determine the influence of climatic fluctuations on the onset and temporal evolution of Nothofagus pumilio forest decline in the Patagonian Andes. Basal area increment (BAI) data from 294 Nothofagus trees at 11 stands in a 500‐km latitudinal transect along the forest–steppe ecotone were used to identify the dominant patterns of regional growth. Three Regional dominant patterns, showing common variations in BAI, were derived. Two BAI patterns show high rates of growth from early to mid‐20th century, followed by sustained negative trends over the last 3–6 decades, whereas the third pattern is characterized by a positive trend since the 1960s. Tipping points in growth trends of the first two patterns are associated with two extreme dry–warm climate events in spring–summer of 1942–1943/1943–1944/1944–1945 and 1978–1979. Both severe droughts were preceded by up to 10 yr of wet periods that promoted above‐average tree growth. We concluded that severe droughts occurring after wet periods trigger the decline of large, dominant N. pumilio trees with high rates of growth. The coincidence between major changes in regional growth with two of the most severe droughts in the instrumental records shows that climatic variations over northern Patagonia synchronize the beginning of forest decline at a regional scale. As these dry–mesic N. pumilio sites will face more severe droughts in the 21st century, as suggested by future climate scenarios, the areas affected by forest decline would increase substantially.

In recent years, Costa Rica has faced various natural hazards and experienced increasing economic loss from numerous small-scale local climate events. This growing trend of losses is triggered by, among other factors, global climate change. In order to meet the challenge of reducing local vulnerabilities, it is necessary to incorporate the potential impacts of climate change into DRM planning. The present study identifies opportunities and challenges for improving incorporation of climate change impacts into DRM planning at the local level in Costa Rica by applying a checklist to 17 municipalities. The study found overall unsatisfactory progress in DRM planning at the municipality level. However, results indicated that local governments' experiences and small actions related to climate change, based on their own needs and taken independently of the national policy priorities, are a key element in improving DRM at the local level. This study also identifies four challenges to further improving local level DRM.

Several large abrupt climate fluctuations during the last glacial have been recorded in Greenland ice cores and archives from other regions. Often these Dansgaard-Oeschger events are assumed to have been synchronous over wide areas, and then used as tie-points to link chronologies between the proxy archives. However, it has not yet been tested independently whether or not these events were indeed synchronous over large areas. Here, we compare Dansgaard-Oeschger-type events in a well-dated record from southeastern France with those in Greenland ice cores. Instead of assuming simultaneous climate events between both archives, we keep their age models independent. Even these well-dated archives possess large chronological uncertainties that prevent us from inferring synchronous climate events at decadal to multi-centennial time scales. If possible, comparisons between proxy archives should be based on independent, non-tuned time-scales. Copyright # 2009 John Wiley & Sons, Ltd.

Uncertainties in historical climate records constrain our understanding of natural variability of climate, but estimation of these uncertainties enables us to place recent climate events and extremes into a realistic historical perspective. Uncertainties in Central England temperature (CET) since 1878 have already been estimated; here we estimate uncertainties back to the start of the record in 1659, using Manley's publications and more recently developed techniques for estimating spatial sampling errors. Estimated monthly standard errors are of the order of 0.5 °C up to the 1720s, but 0.3 °C subsequently when more observing sites were used. Corresponding annual standard errors are up to nearly 0.4 °C in the earliest years but around 0.15 °C after the 1720s. Daily standard errors from 1772, when the daily series begins, up to 1877 are of the order of 1 °C because only a single site was used at any one time. Inter-diurnal variability in the daily CET record appears greater before 1878 than subsequently, partly because the sites were in the Midlands or southern England where day-to-day temperature variability exceeds that in the Lancashire part of Manley's CET. Copyright © 2009 Royal Meteorological Society

Mean July and January temperatures are reconstructed from radiocarbon-dated fossil beetle assemblages from late-glacial sites in the Maritimes Region of eastern Canada. Fossil-bearing sediments date from 12700 14C yr BP (14950 cal yr BP) to younger than 10800 14C yr BP (12730 cal yr BP), spanning a period which includes stratigraphic, palynological, chironomid and coleopteran evidence for a climatic deterioration during the Younger Dryas in North America. Mutual Climatic Range data suggest several ‘events’ in the coleopteran record from the Maritimes that appear similar to climate events recorded in the GRIP ice-core record, including the (Younger Dryas) cooling event from GI-1a to GS-1 beginning c. 12650 GRIP yr BP Some of the major temperature oscillations of Greenland Interstadial 1 may also be reflected in the coleopteran record of the Maritimes.

There is much talk about current global warming, but that is not the main subject under discussion here. There is fairly general agreement on climate changes through geological time, and the cause or causes are becoming clearer. In this Feature, a simple backward look is given to climate events, particularly climatic cycles, in geological time, to help get in perspective some of the predictions for our near future.

Global climates have been changing, sometimes rapidly and dramatically, throughout the evolutionary history of amphibians. Therefore, existing amphibian species have been derived from those that have survived major climatic disturbances. Although recent global climate change has resulted in warming in many regions, temperatures in some areas to date have not changed measurably, or have even cooled. Declines of some amphibian populations have been correlated with climate events, but demonstrations of direct causal relationships need further research. Data are available indicating some indirect effect of climate change on the initiation of breeding activities of some amphibians that occur earlier than in previous springs, but the costs and benefits of these changes are just beginning to be investigated. Climate may also play an indirect role in facilitating epidemics of infectious disease. Regardless of the role that climate changes may have played in past and current amphibian declines, future shifts in climate, should they prove as dramatic as predicted, will certainly pose challenges for surviving amphibian populations and for successful recovery efforts of species that have suffered declines.

This paper examines the commonly used assumption that decision-makers possess accurate prior probability information about climate events that affect their well-being, and illustrates the impact of that assumption on the valuation of prediction information. A survey of large producers in the Mid-western United States is used to recover their prior beliefs about climate variables. It is found that producers systematically misrepresent the probabilities of climate events that materially affect their well-being. In particular, the most common form of the miscalibration between actual and subjective probabilities is to overstate the likelihood of adverse events and understate the likelihood of favourable events. As a result, common methods for valuing prediction information are likely to understate the true value when recipients begin with less accurate prior beliefs. Copyright © 2000 Royal Meteorological Society

Meteorological factors are associated with most of the interannual variability in primary production at both Castle Lake, California (4 l”N, 122%‘) and Lake Tahoe, California-Nevada (39”N, 12O”W). At Castle Lake, extreme values of annual primary production, either much higher or lower than the long-term average, are likely to occur during the phenomenon of El Nifio/Southern Oscillation. Two plausible pathways for the impacts of these large-scale climate events at Castle Lake were identified: winter snowfall, acting through its effect on the snow-ice pack and timing of the spring thaw; and total precipitation, acting through its effect on outwash rates. In contrast, no influence of large-scale climate events is apparent at Lake Tahoe, but a plausible pathway involving the impact of synoptic-scale phenomena on interannual variation was identified: local weather events occurring in the late winter-early spring period near the time of minima1 stratification, acting through their cl&t on the depth of spring mixing. The difference between the two lakes can be attributed to absence of an ice cover and long hydraulic retention time at Lake Tahoe. Timeseries models that incorporate meteorological information adequately forecast primary production at both lakes.