Combination Of Climate Change Research Articles

Changing structure of precipitation evolution during 1957–2013 in Yangtze River Delta, China

Based on the daily precipitation of 16 rain gauges in Yangtze River Delta (YRD), the spatial and temporal changing properties of precipitation structure during 1957–2013 are investigated in the view of consecutive rainy duration. The results show that: (1) increasing precipitation amount can be detected in YRD while rainy days exhibit decreasing tendency over the basin. So precipitation intensity has been increasing in the past 57 years. (2) During the past 57 years, the mean wet periods become shorter over most of YRD. Wet periods with short duration show upward occurrence and fractional contribution to annual precipitation. Being shorter, wet periods in Yangtze River Delta are characterized by intensified precipitation, which may result in high risk of flash flood. (3) Extreme precipitation events during 1957–2013 are more evidently associated with short wet periods and peak for 2-day duration both in occurrence and fractional contribution. (4) An combination of climate change and urbanization intensifies the change in the distribution of temporal evolution of precipitation structure towards the precipitation events with shorter duration and higher intensity. Therefore, these changing properties are of significance to understanding the impact of climate change and human interference on hydrological processes and the flood prevention in the future in Yantze River Delta.

Evolution of an Eocene-Oligocene saline lake depositional system and its controlling factors, Jianghan Basin, China

The Upper Eocene-Lower Oligocene Qianjiang Formation of the Jianghan Basin in central China consists of a 4 700-m-thick lacustrine succession, containing 1 800 m of halite deposits. The maximum thickness of the formation is 4 700 m, and includes 1 800 m of halite. We have identified eight third-order depositional sequences based on pinch-out and onlap stratigraphic patterns in 2-D and 3-D seismic data and well logs. The basin evolved from a deep to shallow under-filled lake during the Eocene-Oligocene interval. The main rock types are dark mudstones, halite, and siltstone/sandstone in the depocenter, and alternating mudstone and gypsum in shallower areas. The vertical succession indicates a strong sedimentary cyclicity. Depositional facies indicate the presence of two lake system types. Halite developed in a saline lake system, whereas clastic sediments were deposited in freshwater lake systems. The alternating sediment types indicate that the basin cycled repeatedly between saline and freshwater lake systems. This cyclicity was caused by availability of accommodation space that was controlled by a combination of climate change, tectonic subsidence and sediment supply; notably, the highest frequency cycles occurred at Milankovitch timescales controlled by the Earth’s orbital variations. The cyclic halite plays an important role in generating and preserving oil in the Qianjiang Formation of the Qianjiang depression.

Reconfiguring agriculture through the relocation of production systems for water, environment and food security under climate change

SUMMARYThe prospect of climate change has revived both fears of food insecurity and its corollary, market opportunities for agricultural production. In Australia, with its long history of state-sponsored agricultural development, there is renewed interest in the agricultural development of tropical and sub-tropical northern regions. Climate projections suggest that there will be less water available to the main irrigation systems of the eastern central and southern regions of Australia, while net rainfall could be sustained or even increase in the northern areas. Hence, there could be more intensive use of northern agricultural areas, with the relocation of some production of economically important commodities such as vegetables, rice and cotton. The problem is that the expansion of cropping in northern Australia has been constrained by agronomic and economic considerations.The present paper examines the economics, at both farm and regional level, of relocating some cotton production from the east-central irrigation areas to the north where there is an existing irrigation scheme together with some industry and individual interest in such relocation. Integrated modelling and expert knowledge are used to examine this example of prospective climate change adaptation. Farm-level simulations show that without adaptation, overall gross margins will decrease under a combination of climate change and reduction in water availability. A dynamic regional Computable General Equilibrium model is used to explore two scenarios of relocating cotton production from south east Queensland, to sugar-dominated areas in northern Queensland. Overall, an increase in real economic output and real income was realized when some cotton production was relocated to sugar cane fallow land/new land. There were, however, large negative effects on regional economies where cotton production displaced sugar cane. It is concluded that even excluding the agronomic uncertainties, which are not examined here, there is unlikely to be significant market-driven relocation of cotton production.

Response of Swiss forests to management and climate change in the last 60 years

Forest vegetation is forecasted to shift upslope several hundred metres by 2100 due to climate warming. However, only a small number of detailed assessments in selected regions have confirmed a climate response on the part of forest vegetation. This study aimed to analyse the relative contributions of temperature and other factors to range shifts in forest vegetation by comparing old and revisited releves in Swiss forests. In order to investigate such range shifts, we revisited 451 releve plots in forests in all parts of Switzerland. Collected data comprise two independent samples, one dating from the 1950s (age 60 sample) on 126 plots and the other dating from the 1990s (age 15 sample) on 325 plots. We defined an indicator value for elevation to estimate the upslope and downslope range shifts of forest species. The influence of different site factors on range shifts was assessed by variance partitioning using Landolt’s (2010) averaged species indicator values. Vegetation changes were analysed by balancing both increasing and decreasing frequencies of plant species. Our findings show significant differences between the two survey periods, where the averaged species indicator for elevation varied greatly in both the age-60 and the age-15 samples. In addition, a significant upslope shift in the herbaceous forest layer (herbs and tree regeneration) of about 10 m per decade since the mid-twentieth century is evident. Downslope shifts were detected in the shrub/tree layer at lower elevations, which may be explained by factors other than climate warming. To date, the impact of global warming on tree species composition in Swiss forests has been weaker in comparison to the effects arising from forest management and land use change. Understorey vegetation, however, shows a strong signal of upslope shift that may be explained most adequately by a combination of climate change and other factors.

The effects of interannual climate variability on the moraine record

Research Article| January 01, 2014 The effects of interannual climate variability on the moraine record Leif S. Anderson; Leif S. Anderson 1Institute of Arctic and Alpine Research, and Department of Geological Sciences, University of Colorado, Campus Box 450, Boulder, Colorado 80309, USA Search for other works by this author on: GSW Google Scholar Gerard H. Roe; Gerard H. Roe 2Department of Earth and Space Sciences, University of Washington, 4000 15th Avenue NE, Seattle, Washington 98195, USA Search for other works by this author on: GSW Google Scholar Robert S. Anderson Robert S. Anderson 1Institute of Arctic and Alpine Research, and Department of Geological Sciences, University of Colorado, Campus Box 450, Boulder, Colorado 80309, USA Search for other works by this author on: GSW Google Scholar Geology (2014) 42 (1): 55–58. https://doi.org/10.1130/G34791.1 Article history received: 20 May 2013 rev-recd: 15 Sep 2013 accepted: 19 Sep 2013 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Leif S. Anderson, Gerard H. Roe, Robert S. Anderson; The effects of interannual climate variability on the moraine record. Geology 2014;; 42 (1): 55–58. doi: https://doi.org/10.1130/G34791.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Valley glacier moraines are commonly used to infer past mean annual precipitation and mean melt-season temperature. However, recent research has demonstrated that, even in steady climates, multi-decadal, kilometer-scale fluctuations in glacier length occur in response to stochastic, year-to-year variability in mass balance. When interpreting moraine sequences it is important to include the effect of interannual weather variability on glacier length; moraines record advances that are forced either by interannual variability or by a combination of climate change and interannual variability. We address this issue for the Last Glacial Maximum (LGM) glaciers of the Colorado Front Range, United States. Using a linear glacier model that allows thorough exploration of parameter uncertainties, supplemented by a shallow-ice flowline model, our analyses suggest that (1) glacial standstills longer than 50 years were unlikely; (2) mean glacier lengths are ∼10%–15% up-valley from maximum glacier lengths; and (3) individual LGM terminal moraines were formed by a combination of a climate change and interannual variability–forced advances. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Introduction to the special virtual issue on climate change

This special virtual issue of Plant Ecology draws together 14 papers on climate change published in the journal over the past 5 years. It encompasses a range of ecosystems and species, and issues relating to potential climate change effects on plants and plant communities. The potential impacts of global climate change on the distribution of species, and the distribution, structure and function of communities in the 21st century have been the subject of an everincreasing scientific literature over the past two decades (Parry 2007). Recent global analyses show that anthropogenic climate change is already affecting species and ecosystems and will continue to do so, with changes in the phenology, distribution and abundance of plants and animals reported for marine, freshwater and terrestrial plants and animals. Measured changes are heavily biased in the directions predicted under global warming scenarios and include earlier timing of spring events such as flowering, bud burst and egg laying, and latitudinal and altitudinal shifts in species ranges (Parmesan 2006). The magnitude and rate of on-going climate change, combined with other stressors, may exceed the adaptive capacity of species and resilience of ecosystems. In addition, changing climate combined with current, and future altered, disturbance regimes may lead to exacerbated rates of range contraction and extinction in plant species unable to maintain contact with suitable habitat through dispersal (Westerling et al. 2011; Moritz et al. 2012). Changes to ecosystems may include impoverished species mixes, simplified ecosystem structure and function, and greater vulnerability to invasive species (Malcolm et al. 2006; Midgley and Thuiller 2007; Keeley and Brennan 2012). Three key conclusions from the 2007 International Panel on Climate Change (Parry 2007) highlight the threat that anthropogenic climate change poses for global plant biodiversity: (1) Resilience of many ecosystems is likely to be exceeded by the combination of climate change, associated disturbances (e.g. wildfire) and other global change drivers. (2) Increases in global temperature of more than 1.5–2.5 C and rising atmospheric CO2 concentrations are projected to cause major changes in ecosystem structure, function and species interactions. (3) 2–30 % of plant species globally are at increased risk of extinction. Many studies on the potential impacts of climate change on plant and animal species have used bioclimatic envelope models which predict the future distribution of species using the correlation of their present range to present-day climate parameters, and the future geographic distribution of these climates based on a range of possible climate futures as described in various GCMs (e.g. Thuiller et al. 2005). Pearson and Dawson (2003) have highlighted the shortcomings of this approach as it ignores factors N. J. Enright (&) Murdoch University School of Veterinary and Life Sciences, Murdoch, Australia e-mail: N.Enright@murdoch.edu.au

The definition of urban stormwater tolerance threshold and its conceptual estimation: an example from Taiwan

The combination of climate change and urbanization is worsening urban flooding problems. Estimating the amount of rainfall that a city can tolerate without flooding is a fundamental task that is difficult to perform, although large amounts of resources are invested in urban flood control. The purpose of this study is to determine the tolerance threshold for stormwater in a city. Based on hydrometeorological characteristics and existing flood control facilities, the urban adaptive water capacity is analyzed to determine the critical rainfall loading. Different critical levels are defined. The low critical point represents the beginning of the water accumulation, while the intermediate and high critical points are defined as flooding with heights of 300 and 600 cm, respectively, in low-lying areas. This study adopts a simple conceptual method to illustrate the critical levels instead of applying complex hydrologic and hydraulic modeling, which require high-resolution spatial data. Three cities and one township in Taiwan are used as urban case studies and to verify the conceptual method. As the capital, Taipei City utilizes the highest flood control engineering technology of our case studies; it is also the site in which the lowest rainfall thresholds cause the accumulation of water to reach the intermediate and high critical points because its small ‘internal water areas’ increase the height of floods rapidly. Conversely, Taichung City has a large internal water area that can disperse accumulating waters without increasing flood height. The estimations of urban storm tolerance thresholds increase the understanding of the limitations of water protection facilities. These estimations may be combined with rainfall forecasts to increase early warning functions and provide a reference point for subsequent planning related to urban flood adaptation strategies.

The combined effects of land‐use legacies and novel fire regimes on bird distributions in the Mediterranean

AbstractAimWe investigate first whether fire regimes resulting from the combination of climate change and fire‐fighting policy may affect species distributions in Mediterranean landscapes, and second to what extent distributional dynamics may be constrained by the spatial legacy of historical land use.LocationCatalonia (north‐eastern Spain).MethodsWe modelled the distributional responses of 64 forest and open‐habitat bird species to nine fire‐regime scenarios, defined by combining different levels of climate change and fire suppression efficiency. A fire‐succession model was used to stochastically simulate land‐cover changes between 2000 and 2050 under these scenarios. We used species distribution models to predict habitat suitability and occupancy dynamics under either no dispersal or full dispersal assumptions.ResultsUnder many simulated scenarios, the succession from shrubland to forest dominated over the creation of new low‐vegetation areas derived from wildfires. Consequently, open‐habitat specialists were the group most affected by losses of suitable habitat. Fire regimes obtained under scenarios including high fire suppression efficiency resulted in a larger number of bird species experiencing reductions in their distribution area.Main conclusionsAnthropogenic factors, such as historical land‐use change and fire suppression, can drive regional distribution dynamics in directions opposite to those expected from climatic trends. This raises the question of what drivers and interactions should be given priority in the prediction of biodiversity responses to global change at the regional scale.

Climate change and the Baltic Sea action plan: Model simulations on the future of the western Baltic Sea

In this study we apply the model ERGOM to simulate the consequences of Climate Change as well as the combination of Climate Change with nutrient load reductions according to the Baltic Sea Action Plan (BSAP) on the Baltic Sea ecosystem.According to the simulations, Climate Change will cause an increase of the water temperature up to 3K and a salinity decrease of 1.5PSU until 2100. However, the implementation of the BSAP will have much stronger effects on the ecosystem. The model suggests that the western Baltic Sea will shift from a nitrogen (N) towards a phosphorus (P) limited system. As a consequence, N-fixation will strongly decrease. The same applies to nutrient-concentrations in winter, denitrification as well as detritus and chlorophyll concentrations in summer. The availability of N in summer, the Secchi depth and the oxygen saturation will increase. Our simulations suggest that the full implementation of the BSAP will cause imbalances in the Baltic Sea over decades before a new system state will be reached. Our results indicate that the Secchi depth alone is not a suitable indicator for the state of eutrophication. Concerning the Water Framework Directive (WFD), Climate Change might alter gradients and concentrations, e.g. of salinity, and in return this might require a re-definition of the WFD typology or a spatial shift of the surface water types, e.g. in Germany. The western Baltic Sea is strongly controlled by regional nutrient loads. Climate Change has only a limited effect on loads in the western Baltic. A re-definition of reference conditions and a good status because of Climate Change seems not necessary.

Effects of climate change and elevated atmospheric CO2 on soil organic carbon: a response equation

Climate change, such as warming and precipitation change, as well as elevated CO2 can affect soil organic carbon (SOC) dynamics and cause changes in soil carbon sequestration. In this study, we introduced a response equation, relating the relative change of SOC to the relative changes of annual average temperature, annual precipitation, and atmospheric CO2 concentration, as well as their inter-products. Using Nelson Farm as a case study, based on simulations of CENTURY model and multiple regressions, we examined the response equation for three vegetation covers (i.e., soybean, corn, and grass) and scenarios with different soil erosion rates and initial SOC contents. The response equation fit the simulation results very well with high adjusted coefficients of determination (R 2) (0.982 to 0.990). The results showed that the SOC was negatively related to the annual average temperature, positively related to the annual precipitation, and positively related to the elevated CO2 for all the vegetation covers (p < 0.001). The SOC was also significantly impacted by the interaction effects between elevated CO2 and warming or precipitation change (p < 0.001). The general form of the response equations for the different vegetation covers, soil erosion rates, and initial SOC contents was the same although the parameters varied with the different conditions. Based on the response equation, “cutoff surfaces” were defined to clearly quantify the synthesis effects of any possible combination of climate change and elevated CO2 on the SOC, and the SOC sequestration potential was assessed under climate change and elevated CO2 for different vegetations. Compared with the empirical models in the literature, this response equation provides a simple yet but robust method to represent the relationship between the SOC relative change vs. the relative changes of atmospheric temperature, precipitation, and atmospheric CO2 concentration.

Vulnerability of cloud forest reserves in Mexico to climate change

Tropical montane cloud forests are among the most vulnerable terrestrial ecosystems to climate change(1-3) owing to their restricted climatic requirements and their narrow and fragmented distribution(4). Although 12% of Mexican cloud forest is protected, it is not known whether reserves will ensure the persistence of the ecosystem and its endemic species under climate change. Here, we show that 68% of Mexico's cloud forest could vanish by 2080 because of climate change and more than 90% of cloud forest that is protected at present will not be climatically suitable for that ecosystem in 2080. Moreover, if we assume unprotected forests are cleared, 99% of the entire ecosystem could be lost through a combination of climate change and habitat loss, resulting in the extinction of about 70% of endemic cloud forest vertebrate species. Immediate action is required to minimize this loss-expansion of the protected-area estate in areas of low climate vulnerability is an urgent priority. Our analysis indicates that one key area for immediate protection is the Sierra de Juarez in Oaxaca. This area supports many endemic species and is expected to retain relatively large fragments of cloud forest despite rapid climate change.

Impact of Holocene climate changes on alpine and treeline vegetation at Sanetsch Pass, Bernese Alps, Switzerland

In order to infer reactions of treeline and alpine vegetation to climatic change, past vegetation changes are reconstructed on the basis of pollen, macrofossil and charcoal analysis. The sampled sediment cores originate from the small pond Emines, located at the Sanetsch Pass (connecting the Valais and Bern, Switzerland) at an altitude of 2288ma.s.l. Today's treeline is at ca. 2200ma.s.l. in the area, though due to special pass (saddle) conditions it is locally depressed to ca. 2060ma.s.l. Our results reveal that the area around Emines was covered by treeless alpine vegetation during most of the past 12,000years. Single individuals of Betula, Larix decidua and possibly Pinus cembra occurred during the Holocene. Major centennial to millennial-scale responses of treeline vegetation to climatic changes are evident. However, alpine vegetation composition remained rather stable between 11,500 and 6000cal. BP, showing that Holocene climatic changes of +/−1°C hardly influenced the local vegetation at Emines. The rapid warming of 3–4°C at the Late Glacial/Holocene transition (11,600cal.BP) caused significant altitudinal displacements of alpine species that were additionally affected by the rapid upward movement of trees and shrubs. Since the beginning of the Neolithic, vegetation changes at Sanetsch Pass resulted from a combination of climate change and human impact. Anthropogenic fire increase and land-use change combined with a natural change from subcontinental to more oceanic climate during the second half of the Holocene led to the disappearance of P. cembra in the study area, but favoured the occurrence of Picea abies and Alnus viridis. The mid- to late-Holocene decline of Abies alba was primarily a consequence of human impact, since this mesic species should have benefitted from a shift to more oceanic conditions. Future alpine vegetation changes will be a function of the amplitude and rapidity of global warming as well as human land use. Our results imply that alpine vegetation at our treeline pass site was never replaced by forests since the last ice-age. This may change in the future if anticipated climate change will induce upslope migration of trees. The results of this study emphasise the necessity of climate change mitigation in order to prevent biodiversity losses as a consequence of unprecedented community and species displacement in response to climatic change.

Simulating fire regimes in the Amazon in response to climate change and deforestation

Fires in tropical forests release globally significant amounts of carbon to the atmosphere and may increase in importance as a result of climate change. Despite the striking impacts of fire on tropical ecosystems, the paucity of robust spatial models of forest fire still hampers our ability to simulate tropical forest fire regimes today and in the future. Here we present a probabilistic model of human-induced fire occurrence for the Amazon that integrates the effects of a series of anthropogenic factors with climatic conditions described by vapor pressure deficit. The model was calibrated using NOAA-12 night satellite hot pixels for 2003 and validated for the years 2002, 2004, and 2005. Assessment of the fire risk map yielded fitness values > 85% for all months from 2002 to 2005. Simulated fires exhibited high overlap with NOAA-12 hot pixels regarding both spatial and temporal distributions, showing a spatial fit of 50% within a radius of 11 km and a maximum yearly frequency deviation of 15%. We applied this model to simulate fire regimes in the Amazon until 2050 using IPCC's A2 scenario climate data from the Hadley Centre model and a business-as-usual (BAU) scenario of deforestation and road expansion from SimAmazonia. Results show that the combination of these scenarios may double forest fire occurrence outside protected areas (PAs) in years of extreme drought, expanding the risk of fire even to the northwestern Amazon by midcentury. In particular, forest fires may increase substantially across southern and southwestern Amazon, especially along the highways slated for paving and in agricultural zones. Committed emissions from Amazon forest fires and deforestation under a scenario of global warming and uncurbed deforestation may amount to 21 +/- 4 Pg of carbon by 2050. BAU deforestation may increase fires occurrence outside PAs by 19% over the next four decades, while climate change alone may account for a 12% increase. In turn, the combination of climate change and deforestation would boost fire occurrence outside PAs by half during this period. Our modeling results, therefore, confirm the synergy between the two Ds of REDD (Reducing Emissions from Deforestation and Forest Degradation in Developing Countries).

Maintaining northern peatland ecosystems in a changing climate: effects of soil moisture, drainage and drain blocking on craneflies

AbstractThe capacity of peatlands in the northern hemisphere to provide carbon storage, maintain water quality and support northern biodiversity is threatened by a combination of climate change and inappropriate land management. Historical drainage and increasing temperatures threaten the maintenance of the high water tables required for effective peatland functioning, and there is an urgent need to develop appropriate adaptation strategies. Here we use a large‐scale replicated experimental design to test the effects of artificial drainage and drain blocking upon soil moisture and cranefly (Diptera: Tipulidae) abundance. Craneflies constitute a key component of peatland biological communities; they are important herbivores and a major prey item for breeding birds. However, they are also susceptible to drought, so are at risk from future climate change. We found that cranefly abundance increased with soil moisture, in a wedge‐shaped relationship; high soil moisture is a necessary condition for high cranefly abundance. Blocking drains increased both soil moisture (by 0.06 m3 m−3 in 2009 and 0.23 m3 m−3 in 2010) and cranefly abundance (1.3‐fold in 2009, 4.5‐fold in 2010), but the strength and significance of the effects varied between years. The benefits of restoring ecosystem moisture levels are likely to be greatest during dry years and at dry sites. This study provides some of the first evidence that adaptation management can potentially reduce some of the negative effects of climate change on vulnerable peatland systems. Management to maintain or increase soil moisture in peatlands can therefore be expected to increase populations of craneflies and their avian predators (which are of conservation and economic interest), but also increase the resilience of the ecosystem to future warming and increasingly frequent droughts, and improve carbon storage and water quality.

Climate Change and Asia’s Coastal Urban Cities

The scientific literature has documented the growing risks of flooding posed for Asia’s coastal cities by the combination of climate change, as reflected in sea level rise and intensified storms and storm surges, and ongoing urban growth in low-lying coastal zones. These issues were already elaborated in the 2007 IPCC (IPCC, 2007) reports but recent studies indicate that climate change, sea level rise and the sinking of the deltas on which most Asian mega urban regions have arisen, are all occurring at much faster rates than earlier projected and therefore pose even greater risks than previously indicated. Global warming appears to be accelerating and may increase to 4° C or more by the end of this century, twice the earlier IPCC projections. The sea level is now expected to rise by one meter or more by 2100; two or three times the earlier projections. The recent typhoons and rains striking Southeast Asia have been the most intense in decades as would be expected as a result of global warming. At the same time, Asia’s urban population is increasing at the rate of 140,000 per day, with much of this growth occurring in low-lying coastal regions and on deltas characterized by land subsidence that is further contributing to flooding risks. While these risks and vulnerabilities have been increasingly detailed in the scientific literature, recognition and effective responses on the part of the urban planning and policy community have been slow to develop. Barriers to adaptation, policy formation and response are reviewed and possible steps forward are outlined.

Introduction to Environmental and Economic Consequences of Hypoxia

Low dissolved oxygen environments (known as hypoxic or dead zones) occur in a wide range of aquatic systems and vary in frequency, seasonality and persistence. While there have always been naturally occurring hypoxic habitats, anthropogenic activities related primarily to organic and nutrient enrichment related to sewage/industrial discharges and land runoff have led to increases in hypoxia and anoxia in both freshwater and marine systems. As a result, over the last 50 years there has been a rapid rise in the areas affected by hypoxia. The future status of hypoxia and its consequences for the environment, society and economies will depend on a combination of climate change (primarily from warming, and altered patterns for wind, currents and precipitation) and land-use change (primarily from expanded human population, agriculture and nutrient loadings). The overall forecast is for hypoxia to worsen, with increased occurrence, frequency, intensity and duration. The consequences of eutrophication-induced hypoxia can be reversed if long-term, broad-scale and persistent efforts to reduce nutrient loads are developed and implemented.

Combined effects of climate and land‐use change on the future of humid tropical forests

AbstractNew deforestation and selective logging data and climate change projections suggest that biodiversity refugia in humid tropical forests may change more extensively than previously reported. However, the relative impacts from climate change and land use vary by region. In the Amazon, a combination of climate change and land use renders up to 81% of the region susceptible to rapid vegetation change. In the Congo, logging and climate change could negatively affect the biodiversity in 35–74% of the basin. Climate‐driven changes may play a smaller role in Asia‐Oceania compared to that of Latin America or Africa, but land use renders 60–77% of Asia‐Oceania susceptible to major biodiversity changes. By 2100, only 18–45% of the biome will remain intact. The results provide new input on the geography of projected climate change relative to ongoing land‐use change to better determine where biological conservation might be most effective in this century.

Reconstruction of lake-level and climate changes in Lake Qarun, Egypt, during the last 7000 years

Sediment cores from Lake Qarun provide a record of mid-late Holocene climatic changes in Northern and Eastern Africa as well as environmental changes due to the activities of ancient Egyptians. We used sedimentological, mineralogical, and geochemical analyses of the cores to investigate long-term variations in lake level due to changing hydrologic inputs. An age model based on three paired 14C and paleomagnetic measurements suggests that the base of the sediment cores is as old as ∼ 5000 B.C.E. Geochemical analyses indicated that lake sediments were derived from Nile floods with an admixture of Saharan sand. Laminated endogenic carbonate-rich clayey silt lithofacies with benthic diatoms are indicative of relatively low lake levels, saline waters and dry conditions; massive lithofacies with planktonic diatom species are indicative of relatively high lake levels, fresh waters and humid conditions. Faintly laminated clayey silt lithofacies suggest intermediate conditions. Variations in lithology as well as diatom composition suggest that the lake level has varied from relatively high levels in its early history to lower levels in later years although there have been numerous cycles in water level over the past 7000 years. A combination of climate changes in the source area of the Nile River as a result of monsoon dynamics; climatic changes in the setting area of the Lake Qarun; and human activities through the dynasties in Egypt produced these variations in lake level.

ESR and U-series analyses of faunal material from Cuddie Springs, NSW, Australia: implications for the timing of the extinction of the Australian megafauna

The timing and cause of late Pleistocene faunal extinctions in Australia are subjects of a debate that has become polarised by two vigorously defended views. One contends that the late Pleistocene extinction was a short event caused by humans colonising the Australian continent, whereas the other promotes a gradual demise of the fauna, over a period of at least 10–20 ka, due to a combination of climatic changes and ecological pressures by humans. Cuddie Springs is central to this debate as it is the only site known in continental Australia where archaeological and megafauna remains co-occur. We have analysed more than 60 bones and teeth from the site by laser ablation ICP-MS to determine U, and Th concentrations and distributions, and those with sufficiently high U concentrations were analysed for U-series isotopes. Twenty-nine teeth were analysed by ESR. These new results, as well as previously published geochronological data, contradict the hypothesis that the clastic sediments of Stratigraphic Unit 6 (SU6) are in primary context with the faunal, archaeological and other materials found in SU6, and that all have ages consistent with the optically stimulated luminescence (OSL) estimates of 30–36 ka. These young OSL results were used to argue for a relatively recent age of the extinct fauna. Our results imply that SU6 is either significantly older than the OSL results, or that a large fraction of the faunal material and the charcoal found in SU6 was derived from older, lateral deposits. Our U and Th laser ablation ICPMS results as well as the REE profiles reported by Trueman et al. [2008. Comparing rates of recystallisation and the potential for preservation of biomolecules from the distribution of trace elements in fossil bones. C.R. Palevol. General Paleontology (Taphonomy and Fossilization) 7, 145–158] contradict the interpretation of previously reported rare earth element compositions of bones, and the argument based thereon for the primary context of faunal material and clastic sediments in SU6 layers.

An assessment of long-term trends in hydrologic components and implications for water levels in Lake Superior

The combination of climate change and natural periodicities in meteorological variables are demonstrating significant impacts on the water resources of Lake Superior within the Laurentian Great Lakes system of North America. Statistical analyses of long-term records are used to demonstrate how changes over time may be interpreted very differently, depending upon the timeframe over which the analyses are made. Non-linear regression modelling shows that, while increasing trends in overland and overlake precipitation, flows and runoff occurred during the first decades of the twentieth century, very different trends are apparent for the period 1970–2005. For this latter period, increasing rates of air overlake temperature and lake evaporation are occurring but all other parameters are demonstrating decreasing trends. The result is a decline in water levels in Lake Superior at the rate of approximately 1 cm per year over the last 35 years. The results are used to show that to avoid decreasing water levels in Lake Superior, the discharge through St Mary's River must be decreased to approximately one-half the long-term annual average, the results of which will have dramatic implications for ships' cargo levels and hydroelectric energy generation.