Preface"11th Plinius Conference on Mediterranean Storms"

The EGU Plinius Conference on Mediterranean Storms was established in 1999 within the framework of the Interdisciplinary Working Group on Natural Hazards (IWG-NH) of the former European Geophysical Society (EGS)- since 2002,European Geosciences Union (EGU). Since its advent, the Plinius Conference series has provided a crucial interdisciplinary forum for improving our understanding of hazardous storms over the Mediterranean basin that are capable of producing strong winds, heavy rains, explosive landslides, devastating flash floods and other related extremes ...

Fluctuaciones de la extension del casquete glacial de la isla de Livingston (Shetland del sur) desde 1956 hasta 1996.

A partir de documentos cartográficos e imágenes de satélite se constata un 4,31% de reducción de extensión del casquete glacial de la isla Livingston desde 1956 hasta 1996. Se detecta la influencia de factores locales, fundamentalmente de tipo topogr á fico, que condicionan los avances y retrocesos del frente glacial en los diferentes sectores de la costa y se establece un modelo simple en el que se relaciona la reducción del conjunto del casquete con el calentamiento atmosférico experimentado en los últimos decenios en la zona de la Península Antártica.

Alkaloids and acetogenins in Annonaceae development: biological considerations

Chemical studies of the plant family Annonaceae have intensified in the last several decades due to the discovery of annonaceous molecules with medicinal potential (e.g., benzylisoquinoline alkaloids and acetogenins). Approximately 500 alkaloids have been identified in 138 Annonaceae species in 43 genera. In addition, until 2004, 593 annonaceous acetogenins (ACGs) had been identified, from 51 species in 13 genera.This suggests that plants from this family allocate important resources to the biosynthesis of these compounds. Despite the diversity of these molecules, their biological roles, including their physiological and/or ecological functions, are not well understood. In this study, it was provided new data describing the variety and distribution of certain alkaloids and ACGs in annonaceous plants in distinct stages of development. The potential relationships among some of these compounds and the seasonally climatic changes occurring in the plant habitat are also discussed. These data will improve our understanding of the secondary metabolism of these pharmacologically important molecules and their expression patterns during development, which will help to determine the optimal growth conditions and harvest times for their production.

Evidence for the influence of the North Atlantic Oscillation on the total ozone column at northern low latitudes and midlatitudes during winter and summer seasons.

The strong influence of the winter North Atlantic Oscillation (NAO) on the total ozone column (TOC) in the Northern Hemisphere has been reported in a number of previous studies. In this study we show that this influence is not restricted to the winter season but is also significant in summer. Especially interesting effects of the summer NAO (SNAO) on the TOC are observed over the eastern Mediterranean region, where a strongly positive SNAO index is related to the creation of a geopotential height-negative anomaly over Greece with maximum amplitude at 200 hPa. Another anomaly was observed west of the Iberian Peninsula with similar effects on the TOC. Analyzing 26 years of Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI) data from the equator to midlatitudes (60°) in the Northern Hemisphere, we demonstrate that the SNAO accounts for up to 30% of the TOC variability with a strong latitudinal and longitudinal dependence. Additionally, we obtain significant correlations between the NAO index and the thermal tropopause pressure and also with the geopotential heights at 200 and 500 hPa. Finally, some indirect connections between NAO and the TOC through teleconnections are also discussed.

Phylogeny and biogeography of Primula sect. Armerina: implications for plant evolution under climate change and the uplift of the Qinghai-Tibet Plateau.

BACKGROUND: The historical orogenesis and associated climatic changes of mountain areas have been suggested to partly account for the occurrence of high levels of biodiversity and endemism. However, their effects on dispersal, differentiation and evolution of many groups of plants are still unknown. In this study, we examined the detailed diversification history of Primula sect. Armerina, and used biogeographic analysis and macro-evolutionary modeling to investigate a series of different questions concerning the evolution of the geographical and ecological distribution of the species in this section. RESULTS: We sequenced five chloroplast and one nuclear genes for species of Primula sect. Armerina. Neither chloroplast nor nuclear trees support the monophyly of the section. The major incongruences between the two trees occur among closely related species and may be explained by hybridization. Our dating analyses based on the chloroplast dataset suggest that this section began to diverge from its relatives around 3.55 million years ago, largely coinciding with the last major uplift of the Qinghai-Tibet Plateau (QTP). Biogeographic analysis supports the origin of the section in the Himalayan Mountains and dispersal from the Himalayas to Northeastern QTP, Western QTP and Hengduan Mountains. Furthermore, evolutionary models of ecological niches show that the two P. fasciculata clades have significantly different climatic niche optima and rates of niche evolution, indicating niche evolution under climatic changes and further providing evidence for explaining their biogeographic patterns. CONCLUSION: Our results support the hypothesis that geologic and climatic events play important roles in driving biological diversification of organisms in the QTP area. The Pliocene uplift of the QTP and following climatic changes most likely promoted both the inter- and intraspecific divergence of Primula sect. Armerina. This study also illustrates how niche evolution under climatic changes influences biogeographic patterns.

Cambio climático y diversidad de la flora vascular en las montañas tabulares de Guayana.

Una de las posibles consecuencias del calentamiento global es la extinción de especies de alta montaña por migración ascendente de las condiciones ambientales y pérdida de hábitat, fenómeno que, por el momento, ha sido considerado únicamente en montañas templadas y boreales. Este trabajo analiza la misma situación en montañas tropicales y estima el grado de amenaza de la flora vascular de las cimas de las montañas neotropicales de Guayana, al norte de Sudamérica. Del estudio basado en una muestra de 83 especies, entre aproximadamente el 8 y el 33% de las mismas se encuentran en peligro de extinguirse debido a la desaparición de su hábitat. La mayoría de estas especies son endémicas de Guayana, por lo que su desaparición afectaría a la biodiversidad global.

Emerging environmental and weather challenges in outdoor sports

Given the climatic changes around the world and the growing outdoor sports participation, existing guidelines and recommendations for exercising in naturally challenging environments such as heat, cold or altitude, exhibit potential shortcomings. Continuous efforts from sport sciences and exercise physiology communities aim at minimizing the risks of environmental-related illnesses during outdoor sports practices. Despite this, the use of simple weather indices does not permit an accurate estimation of the likelihood of facing thermal illnesses. This provides a critical foundation to modify available human comfort modeling and to integrate bio-meteorological data in order to improve the current guidelines. Although it requires further refinement, there is no doubt that standardizing the recently developed Universal Thermal Climate Index approach and its application in the field of sport sciences and exercise physiology may help to improve the appropriateness of the current guidelines for outdoor, recreational and competitive sports participation. This review first summarizes the main environmental-related risk factors that are susceptible to increase with recent climate changes when exercising outside and offers recommendations to combat them appropriately. Secondly, we briefly address the recent development of thermal stress models to assess the thermal comfort and physiological responses when practicing outdoor activities in challenging environments.

Estimating 750 years of temperature variations and uncertainties in the Pyrenees by tree-ring reconstructions and climate simulations.

Past temperature variations are usually inferred from proxy data or estimated using general circulation models. Comparisons between climate estimations derived from proxy records and from model simulations help to better understand mechanisms driving climate variations, and also offer the possibility to identify deficiencies in both approaches. This paper presents regional temperature reconstructions based on tree-ring maximum density series in the Pyrenees, and compares them with the output of global simulations for this region and with regional climate model simulations conducted for the target region. An ensemble of 24 reconstructions of May-to-September regional mean temperature was derived from 22 maximum density tree-ring site chronologies distributed over the larger Pyrenees area. Four different tree-ring series standardization procedures were applied, combining two detrending methods: 300-yr spline and the regional curve standardization (RCS). Additionally, different methodological variants for the regional chronology were generated by using three different aggregation methods. Calibration verification trials were performed in split periods and using two methods: regression and a simple variance matching. The resulting set of temperature reconstructions was compared with climate simulations performed with global (ECHO-G) and regional (MM5) climate models. The 24 variants of May-to-September temperature reconstructions reveal a generally coherent pattern of inter-annual to multi-centennial temperature variations in the Pyrenees region for the last 750 yr. However, some reconstructions display a marked positive trend for the entire length of the reconstruction, pointing out that the application of the RCS method to a suboptimal set of samples may lead to unreliable results. Climate model simulations agree with the tree-ring based reconstructions at multi-decadal time scales, suggesting solar variability and volcanism as the main factors controlling preindustrial mean temperature variations in the Pyrenees. Nevertheless, the comparison also highlights differences with the reconstructions, mainly in the amplitude of past temperature variations and in the 20th century trends. Neither proxy-based reconstructions nor model simulations are able to perfectly track the temperature variations of the instrumental record, suggesting that both approximations still need further improvements.

A look to the HyMeX program (Una mirada al programa HyMeX)

The international HyMeX (Hydrological Mediterranean Experiment) program aims to improve our understanding of the water cycle in the Mediterranean, using a multidisciplinary and multiscale approach and with emphasis on extreme events. This program will improve our understanding and our predictive ability of hydrometeorological hazards including their evolution within the next century. One of the most important results of the program will be its observational campaigns, which will greatly improve the data available, leading to significant scientific results. The interest of the program for the Spanish research groups is described, as the active participation of some of them in the design and execution of the observational activities. At the same time, due to its location, Spain is key to the program, being a good observation platform. HyMeX will enrich the work of the Spanish research groups, it will improve the predictive ability of the weather services, will help us to have a better understanding of the impacts of hydrometeorological extremes on our society and will lead to better strategies for adapting to climate change.

El canvi climàtic posa en perill el cafè i el cacau

PER A MOLTES PERSONES, beure cafè i menjar xocolata és un autèntic plaer. Tant les plantes de cafè com les de cacau es cultiven en unes zones molt concretes de la Terra, als cinturons tropicals, i en teoria representen una font de riquesa per als països productors. Tanmateix, la demanda creixent, combinada amb els efectes del canvi climàtic i les desigualtats econòmiques entre productors i consumidors, posen en perill aquests cultius. Així ho indiquen dos estudis publicats a la revista Plos One i un altre a Current Biology, que suggereixen que per mantenir la productivitat actual cal incrementar la diversitat genètica d"aquestes plantes i afavorir un model de comerç just.

Las entidades sub-nacionales en Norteamérica y la lucha contra el cambio climático: desarrollo normativo y vinculación de sistemas de comercio de derechos de emisión

[spa] Mientras que en Europa la interdependencia y la dimensión transfronteriza de las cuestiones ligadas al cambio climático ha facilitado una cierta"continentalización" de la gestión de este fenómeno, favorecida por el carácter intergubernamental de las medidas que se adoptan en el marco de la Unión Europea, al otro lado del Atlántico la transversalidad de este mismo fenómeno explica la necesidad de que, ante las limitaciones del marco regional, se pongan en marcha mecanismos que faciliten la intervención no sólo estatal sino también de las entidades sub-nacionales. En este sentido, la ausencia de la acción federal tanto en Estados Unidos como en Canadá ha comportado un mayor desarrollo de la acción de las entidades sub-nacionales, que han tomado el liderazgo en la lucha contra el cambio climático. Son estas medidas las que se han visualizado en el escenario internacional. Ello ha favorecido el establecimiento de mecanismos de coordinación de la acción de estas entidades sub-nacionales en el seno de redes transnacionales, que han ido adquiriendo una mayor relevancia en la implementación del Convenio Marco sobre el Cambio Climático y del Protocolo de Kyoto, particularmente en relación a uno de sus instrumentos, el comercio de los derechos de emisión de gases de efecto invernadero. En este contexto, la futura vinculación de los sistemas de comercio de derechos de emisión de gases de efecto invernadero en Norteamérica con el sistema de la Unión Europea presenta diversos retos de carácter material y formal.

Vulnerability of stream biota to climate change in mediterranean climate regions: a synthesis of ecological responses and conservation challenges

Freshwater species worldwide are experiencing dramatic declines partly attributable to ongoing climate change. It is expected that the future effects of climate change could be particularly severe in mediterranean climate (med-) regions, which host many endemic species already under great stress from the high level of human development. In this article, we review the climate and climate-induced changes in streams of med-regions and the responses of stream biota, focusing on both observed and anticipated ecological responses. We also discuss current knowledge gaps and conservation challenges. Expected climate alterations have already been observed in the last decades, and include: increased annual average air temperatures; decreased annual average precipitation; hydrologic alterations; and an increase in frequency, intensity and duration of extreme events, such as floods, droughts and fires. Recent observations, which are concordant with forecasts built, show stream biota of med-regions when facing climate changes tend to be displaced towards higher elevations and upper latitudes, communities tend to change their composition and homogenize, while some life-history traits seem to provide biota with resilience and resistance to adapt to the new conditions (as being short-lived, small, and resistant to low streamflow and desiccation). Nevertheless, such responses may be insufficient to cope with current and future environmental changes. Accurate forecasts of biotic changes and possible adaptations are difficult to obtain in med-regions mainly because of the difficulty of distinguishing disturbances due to natural variability from the effects of climate change, particularly regarding hydrology. Long-term studies are needed to disentangle such variability and improve knowledge regarding the ecological responses and the detection of early warning signals to climate change. Investments should focus on taxa beyond fish and macroinvertebrates, and in covering the less studied regions of Chile and South Africa. Scientists, policy makers and water managers must be involved in the climate change dialogue because the freshwater conservation concerns are huge.

Lipídios como Indicadores de Mudanças Climáticas no Passado 1: Biomarcadores Marinhos

The distribution and abundance of specific lipid biomarkers in marine sediments can play an important rule for the reconstruction of past climatic changes. Here, it is shown the use of a widely known paleo Sea Surface Temperature (SST) proxy based on the unsaturation ratio of a suite of long-chain C37 alkenones: the alkenone unsaturation index, U K37'. These compounds are biosynthesised by only a restricted group of prymnesiophyte algae, mostly notably the coccolithophorid Emiliania huxleyi. To ilustrate the importance of the U K37' index as a molecular tool, the correlation between the SST signal derived from the U K37' and other paleoclimatic records examined in a core from the North Atlantic is discussed.

The summer North Atlantic Oscillation in CMIP3 models and related uncertainties in projected summer drying in Europe

This paper discusses uncertainties in model projections of summer drying in the Euro-Mediterranean region related to errors and uncertainties in the simulation of the summer NAO (SNAO). The SNAO is the leading mode of summer SLP variability in the North Atlantic/European sector and modulates precipitation not only in the vicinity of the SLP dipole (northwest Europe) but also in the Mediterranean region. An analysis of CMIP3 models is conducted to determine the extent to which models reproduce the signature of the SNAO and its impact on precipitation and to assess the role of the SNAO in the projected precipitation reductions. Most models correctly simulate the spatial pattern of the SNAO and the dry anomalies in northwest Europe that accompany the positive phase. The models also capture the concurrent wet conditions in the Mediterranean, but the amplitude of this signal is too weak, especially in the east. This error is related to the poor simulation of the upper-level circulation response to a positive SNAO, namely the observed trough over the Balkans that creates potential instability and favors precipitation. The SNAO is generally projected to trend upwards in CMIP3 models, leading to a consistent signal of precipitation reduction in NW Europe, but the intensity of the trend varies greatly across models, resulting in large uncertainties in the magnitude of the projected drying. In the Mediterranean, because the simulated influence of the SNAO is too weak, no precipitation increase occurs even in the presence of a strong SNAO trend, reducing confidence in these projections.

Quantifying seasonality along a latitudinal gradient: from stream temperature to growth of invasive mosquitofish

Most ecosystems undergo substantial variation over the seasons, ranging from changes in abiotic features, such as temperature, light and precipitation, to changes in species abundance and composition. How seasonality varies along latitudinal gradients is not well known in freshwater ecosystems, despite being very important in predicting the effects of climate change and in helping to advance ecological understanding. Stream temperature is often well correlated with air temperature and influences many ecosystem features such as growth and metabolism of most aquatic organisms. We evaluated the degree of seasonality in ten river mouths along a latitudinal gradient for a set of variables, ranging from air and water temperatures, to physical and chemical properties of water and growth of an invasive fish species (eastern mosquitofish, Gambusia holbrooki ). Our results show that although most of the variation in air temperature was explained by latitude and season, this was not the case for water features, including temperature, in lowland Mediterranean streams, which depended less on season and much more on local factors. Similarly, although there was evidence of latitude-dependent seasonality in fish growth, the relationship was nonlinear and weak and the significant latitudinal differences in growth rates observed during winter were compensated later in the year and did not result in overall differences in size and growth. Our results suggest that although latitudinal differences in air temperature cascade through properties of freshwater ecosystems, local factors and complex interactions often override the water temperature variation with latitude and might therefore hinder projections of species distribution models and effects of climate change