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El litoral mallorquí s’enfronta a una situació d’alta vulnerabilitat davant l’increment del nivell de la mar, el qual causa impactes en les urbanitzacions costaneres que s’intensifiquen amb el temps. Els informes científics que aborden el canvi climàtic posen a la nostra disposició prediccions que ens permeten conèixer amb antelació els riscos als quals ens enfrontem com a societat. El treball es centra en la badia d’Alcúdia per ser la zona més desfavorable de Mallorca davant la pujada del nivell de la mar. A través de l’anàlisi de la matriu biofísica i històrica, i fruit de l’observació de les diferents solucions que s’estan implementant a escala global, se presenta una proposta d’adaptació per aquest indret. Amb aquest treball volem obrir el debat públic per repensar el nostre model territorial i traçar nous camins cap al futur assegurant la resiliència i estabilitat dels ecosistemes. El litoral mallorquín se enfrenta a una situación de alta vulnerabilidad ante el incremento del nivel del mar, el cual causa impactos en las urbanizaciones costeras que se intensifican con el tiempo. Los informes científicos que abordan el cambio climático ponen a nuestra disposición predicciones que nos permiten conocer con antelación los riesgos a los cuales nos enfrentamos como sociedad. El trabajo se centra en la bahía de Alcúdia por ser la zona más desfavorable de Mallorca ante la subida del nivel del mar. A través del análisis de la matriz biofísica e histórica, y fruto de la observación de las diferentes soluciones que se están implementando a escala global, se presenta una propuesta de adaptación para este lugar. Con este trabajo queremos abrir el debate público para repensar nuestro modelo territorial y trazar nuevos caminos hacia el futuro asegurando la resiliencia y estabilidad de los ecosistemas. The Mallorcan coastline faces a situation of high vulnerability due to the rise of sea level, which causes impacts on coastal developments that intensify over time. Scientific reports on climate change provide predictions that allow us to be aware in advance of the risks we face as a society. The work focuses on the Alcúdia Bay as the most unfavourable area of Mallorca in terms of sea level rise. Through the analysis of the biophysical and historical basis, and observing the different solutions implemented on a global scale, we present different proposals for adapting this area. The aim of this work is to open the public debate in order to rethink our territorial model and map out new paths for the future, ensuring the resilience and stability of ecosystems.

El aumento de la temperatura del planeta aboca a la humanidad a sufrir efectos muy graves o irreversibles. En este artículo publicado originalmente en la revista Telos de Fundación Telefónica, el autor alerta de la urgencia de revertir la situación.

Reproducció del document publicat a: https://theconversation.com/una-nueva-vida-para-el-co-asi-podemos-convertirlo-en-combustible-plastico-y-materiales-de-construccion-187570, Utilizar el dióxido de carbono para fabricar productos de uso masivo permite que este gas quede capturado y no sea emitido a la atmósfera.

[eng] Climate change has emerged as one of the greatest and most pervasive threats that our natural heritage will have to face in the coming decades. Together with other anthropogenic pressures such as pollution, overfishing or habitat degradation, climate change is causing enormous impacts on oceans, affecting all kind of marine communities and driving major losses to biodiversity. In this framework of global change, the Mediterranean Sea, which has been identified as one of the major hotspots of marine biodiversity, has also become a hotspot of climate change. Consequently, some of its most emblematic and ecologically important communities are now under threat. This is the case of the coralligenous assemblages, which are temperate benthic communities which stand out for their great structural complexity and exceptional biodiversity (they harbour approximately 10% of Mediterranean species). Most of the constituent species of these communities exhibit high longevity and slow population dynamics. Consequently, they are especially vulnerable to disturbances that increase adults mortality. In fact, thermal anomalies linked to ocean warming have impacted the coralligenous assemblages in several ways during last decades, triggering changes that go from the observed mass mortalities of benthic organisms to potential changes at the community and ecosystem levels. However, despite the increasing interest of the scientific community to conserve the coralligenous, how these benthic communities are responding to climate change at the community level is poorly understood. In this thesis, we have taken this leap by integrating responses from species to the ecosystem level, through populations and communities. In particular, we have combined field observations of ecological and environmental changes, aquaria experiments, ecological theory, and cutting-edge quantitative research to improve our understanding of the bio-ecological consequences of ocean warming for Mediterranean coralligenous assemblages. In the first three chapters, we gathered field and experimental data on sensitivity of several coralligenous species and populations to marine heatwaves (MHWs) by conducting a literature review on previous mass mortality events occurred in the Mediterranean and by carrying out scaled-up thermotolerance experiments. The results of Chapter 1 revealed contrasting patterns of sensitivity to MHWs among different coralligenous species and populations. The posterior multi-specific thermotolerance experiment (including corals, sponges and tunicates) conducted in Chapter 2 confirmed the high response diversity to warming among co-occurring species observed in the field. These results demonstrate that co-occurring species that are taxonomically and morpho- functionally similar can have contrasting thermotolerances. Moreover, the observed patterns suggest that coralligenous assemblages could have certain degree of insurance against MHWs, since the decline of sensitive species could potentially be compensated by other functionally similar species that are more resistant. The results of the multi- population thermal experiment conducted in Chapter 3 with 12 populations of the red gorgonian Paramuricea clavata (Risso, 1826) revealed that this species, which has a key habitat-forming role in coralligenous assemblages, is highly sensitive to thermal stress across its distributional range. Moreover, we found little local adaptation to average thermal regime and little acclimatization to local above-average warm temperatures prior to the experiment. These findings, which were obtained at a spatial scale never addressed before (> 2000 km) for P. clavata, question the adaptive potential of this species to climate change. In Chapter 4, we further explored the vulnerability of Mediterranean habitat- forming octocorals to climate change by exploring the long-term recovery capacity of Corallium rubrum (Linnaeus, 1758) and P. clavata from recurrent MHWs. We explored the long-term trajectories (15 years) of different populations that were firstly impacted by the 2003-MHW in terms of changes in biomass, density and size structure. We found that all impacted populations have followed collapse trajectories. These results further highlight the high vulnerability of these species to the ongoing climate change. Finally, we took the leap from species and populations to the community and ecosystem levels in Chapter 5, to explore if MHWs have driven changes in the functional community structure of coralligenous assemblages, which could imply changes for ecosystem functioning. Specifically, we conducted a multi-taxa, trait-based analysis and found that MHW are shifting the functional identity of coralligenous assemblages (i.e., dominant functional traits). Interestingly, the observed changes were driven primarily by the decline of a single functional group (habitat-forming octocorals), whose species are functionally unique. Consequently, by severely affecting habitat-forming octocorals, MHWs are leading to assemblages that are deficient in key functional traits, likely causing changes in ecosystem functioning. Overall, this thesis provides an integrated, long-term view of the interconnected responses to ocean warming found in coralligenous assemblages. The combined results of this thesis suggest that despite structural changes induced by climate change, most ecosystem functions count on certain degree of insurance against MHWs. However, some essential functions (e.g., 3D-habitat provision) could be highly compromised or even totally disappear, threatening the overall assemblage stability. Given the current climate change trends, identifying and preserving the mechanisms that maintain essential ecosystem functions and the overall ecosystem stability is critical. In this thesis, we have identified the general loss of arborescent octocorals as the greatest disruptive process for coralligenous assemblages. Therefore, the future trajectories of these emblematic Mediterranean communities will greatly depend on the design and implementation of measures that favour the conservation and adaptive management of these key habitat-forming species in the face of climate change.

Desde finales de la década de los años 70 del siglo pasado la temperatura global del aire en superficie está aumentando de un modo nítido. Una tendencia a la que los test al uso atribuyen significación estadística con un nivel de confianza muy alto.

Concerns about the unequal distribution of greenhouse gas emissions attributable to mobility are gaining increasing attention in scholarly analyses as well as in the public policy arena. The factors influencing the emissions of individuals are largely undocumented, but they are assumed to be the same for all, be they low or high emitters. We use a household travel survey conducted in the metropolitan area of Barcelona to differentiate the factors that result in different rates of emission. It shows that the top 10% of emitters produce 49% of total emissions while ‘non-daily’ emitters make up 38.5% of the sample. We adopt a quantile regression approach, which reveals significant socioeconomic differences between groups of emitters. Gender, income and home-municipality type are influential in accounting for CO 2 emissions for all groups. Educational level appears to be less significant, and occupation shows no significance at all. The study confirms the ineffective nature of toll policy design in the area. Overall, socioeconomic factors have different impacts on different emitting groups, but these characteristics do not impact equally across all the population. Quantile regression using mobility survey data gathered from various cities would provide useful evidence for improving the design of urban mobility policies.

El Consejo de Ministros aprobó en enero el acuerdo de Declaración ante la Emergencia Climática y Ambiental en España, mientras que el Congreso de los Diputados lo hizo en septiembre del año pasado. Ambas instituciones se suman al creciente número de administraciones públicas de todo el mundo –el Parlamento Europeo, gobiernos de estados y regionales, ayuntamientos, etc.– así como instituciones de todo tipo, entre ellas universidades, que aprobaron en 2019 declaraciones de emergencia climática.

Resoldre l’actual crisi climàtica és un dels grans reptes que la humanitat té plantejats. L’escalfament global ens situa en un punt d'inflexió, posa en qüestió el model socioeconòmic i fa paleses les desigualtats que aquest model comporta. Les causes d’aquesta crisi estan íntimament relacionades amb el model de desenvolupament capitalista que concep la natura com a recurs. A través d'aquest pensament que planteja la humanitat i el medi com a ens separats, es comprèn la Terra i tot el que en ella viu com a recursos apropiables i explotables i al voltant d'aquesta explotació s’ha creat un fals paradigma de creixement econòmic il·limitat, totalment incompatible amb un planeta finit. El creixement ha anat lligat a un model productiu occidental masculinitzat, que ha oblidat permanentment la seva contrapart, el principi femení, històricament associat a les dones per ser-ne les principals executores. La feminitat entesa com aquell compendi de valors creatius i no violents que manté la vida i s’encarrega de les tasques reproductives i les cures. Com a productes socialment construïts, la dicotomia masculí/femení o valors productius/valors reproductius, ens ajuda a enfocar en clau de gènere la crisi i a analitzar tant les seves causes, com també les conseqüències i els espais de solució. De la mateixa manera que diversos estudis evidencien que les dones pateixen més intensament les conseqüències del canvi climàtic, resulta il·lustratiu veure que els espais de solució com la UNFCCC es troben altament masculinitzats. No tan sols en relació al pensament predominant, sinó també pel nombre de dones que hi participen. Davant la impossibilitat que suposa resoldre una crisi causada pel productivisme masculí imperant mitjançant aquesta mateixa manera d'entendre el món, cal recuperar el principi femení de les cures i plantejar una forma alternativa de relacionar-nos

Permafrost warming has the potential to amplify global climate change, because when frozen sediments thaw it unlocks soil organic carbon. Yet to date, no globally consistent assessment of permafrost temperature change has been compiled. Here we use a global data set of permafrost temperature time series from the Global Terrestrial Network for Permafrost to evaluate temperature change across permafrost regions for the period since the International Polar Year (2007–2009). During the reference decade between 2007 and 2016, ground temperature near the depth of zero annual amplitude in the continuous permafrost zone increased by 0.39 ± 0.15 °C. Over the same period, discontinuous permafrost warmed by 0.20 ± 0.10 °C. Permafrost in mountains warmed by 0.19 ± 0.05 °C and in Antarctica by 0.37 ± 0.10 °C. Globally, permafrost temperature increased by 0.29 ± 0.12 °C. The observed trend follows the Arctic amplification of air temperature increase in the Northern Hemisphere. In the discontinuous zone, however, ground warming occurred due to increased snow thickness while air temperature remained statistically unchanged.

Bazairi, Hocein/0000-0002-1788-0580; Gattuso, Jean-Pierre/0000-0002-4533-4114; Gerovasileiou, Vasilis/0000-0002-9143-7480; Cerrano, Carlo/0000-0001-9580-5546; Turicchia, Eva/0000-0002-8952-9028; Topcu, Nur Eda/0000-0003-2734-2695; Ponti, Massimo/0000-0002-6521-1330; deudero, salud/0000-0001-5584-2801; Ledoux, Jean-Baptiste/0000-0001-8796-6163; Fraschetti, Simonetta/0000-0002-1780-1651; BERTOLINO, Marco/0000-0003-3233-303X; Duarte, Carlos M./0000-0002-1213-1361, WOS: 000499719400001, [No abstract available], postdoctoral contract Juan de la Cierva-Incorporacion [IJCI-2016-29329]; Ministerio de Ciencia, Innovacion y Universidades [PTA2015-10829-I]; Interreg Med Programme [MPA-Adapt 1MED15_3.2_M2_337]; European Regional Development Fund - Foundation Prince Albert II Monaco; European UnionEuropean Union (EU) [689518, FPU15/05457]; Spanish Ministry of EducationSpanish Government [UID/Multi/04423/2013]; FCT - Foundation for Science and TechnologyPortuguese Foundation for Science and Technology; European Regional Development Fund (ERDF)European Union (EU), MV-L was supported by a postdoctoral contract Juan de la Cierva-Incorporacion (IJCI-2016-29329) of Ministerio de Ciencia, Innovacion y Universidades. AI was supported by a Technical staff contract (PTA2015-10829-I) Ayudas Personal Tecnico de Apoyo of Ministerio de Economia y Competitividad (2015). Interreg Med Programme (grant number Project MPA-Adapt 1MED15_3.2_M2_337) 85% cofunded by the European Regional Development Fund, the MIMOSA project funded by the Foundation Prince Albert II Monaco and the European Union's Horizon 2020 research and innovation programme under grant agreement no 689518 (MERCES). DG-G was supported by an FPU grant (FPU15/05457) from the Spanish Ministry of Education. J-BL was partially supported by the Strategic Funding UID/Multi/04423/2013 through national funds provided by FCT - Foundation for Science and Technology and European Regional Development Fund (ERDF), in the framework of the programme PT2020.

Des de que l’any 1990 es va publicar el primer informe del Panell Intergovernamental del Canvi Climàtic (en anglès IPCC) quatre més han aparegut (els anys 1995, 2001, 2007 i 2014), els quals ens donen una visió de l’evolució en l’estat del coneixement sobre el canvi climàtic en les diferents etapes d’aquest període 1990-2014. A partir del contingut científic i de les conclusions més destacables recollides en aquests cinc informes, s’ha analitzat l’evolució del coneixement sobre el canvi climàtic, les polítiques i mesures proposades per a combatre’l. En poc més de 20 anys s’ha passat d’una exhaustiva descripció de les bases científiques de l’efecte hivernacle i del canvi climàtic en què es basava l’informe del 1990, amb moltes incerteses i en el què era científicament difícil atribuir a l’ésser humà com a unic responsable d’aquest canvi de clima, al darrer informe del 2014, el qual qualifica d’extremament probable amb un 95% de certesa de que l’escalfaent del planeta és d’origen antròpic, el qual pot esdevenir irreversible si no s’actua de forma urgent en la reducció de les emissions.

Màster Oficial d'Internacionalització, Facultat d'Economia i Empresa, Universitat de Barcelona, Curs: 2015-2016, Tutora: Aurèlia Mañé Estrada, In the second half of the 20th century scientists became increasingly aware of the effects that gases such as carbon dioxide and methane were having on the planet’s environment. Initially, concerns about the warming effects of gasses were countered by suggestions that human activity could have cooling effects on the environment through the use of aerosols. However, by the 1970’s scientific consensus had veered towards warming rather than cooling. In 1975, Wallace Broecker published a paper titled, Climate Change: Are we on the Brink of a Pronounced Global Warming? This paper is often credited with coining the term ‘global warming.’

8 páginas, 6 figuras, In the current global climate change scenario, stressors overlap in space and time, and knowledge on the effects of their interaction is highly needed to understand and predict the response and resilience of organisms. Corals, among many other benthic organisms, are affected by an increasing number of global change-related stressors including warming and invasive species. In this study, the cumulative effects between warming and invasive algae were experimentally assessed on the temperate reefbuilder coral Cladocora caespitosa. We first investigated the potential local adaptation to thermal stress in two distant populations subjected to contrasting thermal and necrosis histories. No significant differences were found between populations. Colonies from both populations suffered no necrosis after long-term exposure to temperatures up to 29°C. Second, we tested the effects of the interaction of both warming and the presence of invasive algae. The combined exposure triggered critical synergistic effects on photosynthetic efficiency and tissue necrosis. At the end of the experiment, over 90% of the colonies subjected to warming and invasive algae showed signs of necrosis. The results are of particular concern when considering the predicted increase of extreme climatic events and the spread of invasive species in the Mediterranean and other seas in the future., We thank the Secretaría General de Pesca (MAGRAMA) and the Columbretes Islands Marine Reserve staff for their logistic support. Support for this work was provided by a Ramon y Cajal research contract (RyC- 2011-08134) to C.L. and by a JAE-doc (FSE) to E.C. This study was funded by the Spanish Ministry of Economy and Innovation Smart project (CGL2012-32194).

Des de que l’any 1990 es va publicar el primer informe del Panell Intergovernamental del Canvi Climàtic (en anglès IPCC) quatre més han aparegut (els anys 1995, 2001, 2007 i 2014), els quals ens donen una visió de l’evolució en l’estat del coneixement sobre el canvi climàtic en les diferents etapes d’aquest període 1990-2014. A partir del contingut científic i de les conclusions més destacables recollides en aquests cinc informes, s’ha analitzat l’evolució del coneixement sobre el canvi climàtic, les polítiques i mesures proposades per a combatre’l. En poc més de 20 anys s’ha passat d’una exhaustiva descripció de les bases científiques de l’efecte hivernacle i del canvi climàtic en què es basava l’informe del 1990, amb moltes incerteses i en el què era científicament difícil atribuir a l’ésser humà com a unic responsable d’aquest canvi de clima, al darrer informe del 2014, el qual qualifica d’extremament probable amb un 95% de certesa de que l’escalfaent del planeta és d’origen antròpic, el qual pot esdevenir irreversible si no s’actua de forma urgent en la reducció de les emissions.

“Lake macroinvertebrates and the altitudinal gradient in the Pyrenees [Los macroinvertebrados lacustres y el gradiente altitudinal en los Pirineos]” is a thesis about freshwater macroinvertebrate communities inhabitting the littoral zone of the mountain lakes of the Pyrenees, and about the effect of altitude on the species composition, and richness, of these communities. The investigation is addressed by analysing the relative relevance of the environmental and spatial components of the altitudinal gradient on macroinvertebrate communities. This is performed by comparing different macroinvertebrate groups, which attain for different evolutionary histories and ecological idiosyncrasies, including different dispersal capabilities. The taxonomical resolution achieved in macroinvertebrate determinations is high, which allows for among-group comparisons at the species level. These comparisons can be used to test ecological theories of current usage. Mountain lakes are particularly useful to this purpose, as these ecological systems account for large environmental gradients related to altitude and, at the same time, the altitudinal ecological gradient includes spatial components that may be relevant in shaping macroinvertebrate community assemblages. The spatial component of altitude relates to the uneven distribution of lakes along altitude in mountain ranges, which implies different degrees of ecological isolation between lakes. Also, the littoral zone of mountain lakes is particularly suited for among-group comparisons because it is in the littoral zone where most freshwater macroinvertebrate biodiversity of lakes concentrates. In the Results section, the results obtained are presented first as a general overview of the distribution of main macroinvertebrate taxa across altitude. The influence of environmental variables related to altitude on distributions is explored, and the relative relevance of different environmental variables on macroinvertebrate communities is partialled out. Then, the effect of different environmental and spatial factors is analysed for each macroinvertebrate group, separately. The main taxa analysed in each of the chapters are, arranged by convenience, as follows: Oligochaeta, Chironomidae, Mollusca, Megaloptera, Trichoptera, Coleoptera, Hydracarina and Nematoda. In the Discussion section, altitudinal distributions are compared between groups, and differences observed in this regard between the main macroinvertebrate taxa are discussed. The effect of both environmental and spatial factors related to altitude is suggested. Then, species richness patterns are also compared between the main macroinvertebrate taxa. The relative contribution of environmental and spatial factors is, to some extent, disentangled. Finally, the effect of altitude on the similarity of communities is also compared between groups, de-composing this effect in environmental and spatial terms. The following conclusions are drawn from the results obtained: 1) The altitudinal distribution patterns of lake macroinvertebrates are the consequence of both the selective influence of the environment and the more stochastic nature of dispersal. 2) Environmental factors covarying with altitude are not equally relevant for all macroinvertebrate groups. 3) Mountain lakes are biogeographic islands. 4) Similarity between communities is slightly higher, and stochasticity slightly lower, at mid altitudes. 5) The stochastic influence of environmental dynamics also contributes to explain species richness patterns. 6) Large river basins do not play a relevant role in the similarity of communities, which is more dependent on the altitudinal location of lakes. 7) An altitudinal ecological threshold in community assemblages occurs at ca. 2550 m a.s.l., for all groups responding to environmental changes across altitude, but independently of their dispersal strategy. 8) The altitudinal threshold, because of its environmental nature, is expected to shift upwards under current climate warming. 9) Global changes will affect macroinvertebrate communities of mountain lakes through different components, including climate warming, habitat loss and fragmentation, and invasive species, which may also show mutual interactions., “Lake macroinvertebrates and the altitudinal gradient in the Pyrenees [Los macroinvertebrados lacustres y el gradiente altitudinal en los Pirineos]” es una tesis sobre las comunidades de macroinvertebrados acuáticos que habitan la zona litoral de los lagos de montaña de los Pirineos, y sobre el efecto de la altitud en la composición y riqueza de especies de estas comunidades. La investigación se efectúa analizando la importancia relativa de los componentes ambientales y espaciales del gradiente altitudinal sobre las comunidades de macroinvertebrados. Para ello, se comparan diferentes grupos de macroinvertebrados, de distinta idiosincrasia ecológica, incluyendo diferencias en cuanto a capacidad de dispersión. La resolución taxonómica con la que se analizan los datos es elevada, lo cual permite comparaciones entre grupos a nivel de especie, útiles para contrastar teorías ecológicas de uso actual. Las conclusiones de la tesis son las siguientes: 1) Los patrones de distribución altitudinal de los macroinvertebrados lacustres son consecuencia tanto de la influencia selectiva del ambiente, como de la dispersión, un proceso de naturaleza más estocástica. 2) Los distintos factores ambientales que covarían con la altitud no son igualmente relevantes para todos los grupos de macroinvertebrados. 3) Los lagos de montaña son islas biogeográficas. 4) La similaridad entre las comunidades es ligeramente mayor, y la estocasticidad en el ensamblaje de las mismas ligeramente menor, en altitudes intermedias. 5) La influencia de la dinámica estocástica del ambiente también contribuye a explicar los patrones de riqueza de especies. 6) Las cuencas de los ríos principales no juegan un papel relevante en la similaridad de las comunidades, que es más dependiente de la altitud de los lagos. 7) Existe un umbral ecológico para las comunidades de macro-invertebrados, situado a una altitud aproximada de 2550 m, que afecta a todos los grupos que responden a los cambios ambientales asociados a la altitud, pero con independencia de su estrategia de dispersión. 8) El umbral altitudinal, debido a su naturaleza ambiental, posiblemente se desplazará hacia arriba en altitud con el cambio climático actual. 9) El cambio global afectará a las comunidades de macroinvertebrados de los lagos de montaña a través de varios de sus componentes, incluyendo cambio climático, pérdida y fragmentación de hábitat, y especies invasoras, los cuales pueden mostrar también efectos de interacción mutua.

We used a nonintrusive field experiment carried out at six sites - Wales (UK), Denmark (DK), the Netherlands (NL), Hungary (HU), Sardinia (Italy - IT), and Catalonia (Spain - SP) - along a climatic and latitudinal gradient to examine the response of plant species richness and primary productivity to warming and drought in shrubland ecosystems. The warming treatment raised the plot daily temperature by ca. 1 degrees C, while the drought treatment led to a reduction in soil moisture at the peak of the growing season that ranged from 26% at the SP site to 82% in the NL site. During the 7 years the experiment lasted (1999-2005), we used the pin-point method to measure the species composition of plant communities and plant biomass, litterfall, and shoot growth of the dominant plant species at each site. A significantly lower increase in the number of species pin-pointed per transect was found in the drought plots at the SP site, where the plant community was still in a process of recovering from a forest fire in 1994. No changes in species richness were found at the other sites, which were at a more mature and stable state of succession and, thus less liable to recruitment of new species. The relationship between annual biomass accumulation and temperature of the growing season was positive at the coldest site and negative at the warmest site. The warming treatment tended to increase the aboveground net primary productivity (ANPP) at the northern sites. The relationship between annual biomass accumulation and soil moisture during the growing season was not significant at the wettest sites, but was positive at the driest sites. The drought treatment tended to reduce the ANPP in the NL, HU, IT, and SP sites. The responses to warming were very strongly related to the Gaussen aridity index (stronger responses the lower the aridity), whereas the responses to drought were not. Changes in the annual aboveground biomass accumulation, litterfall, and, thus, the ANPP, mirrored the interannual variation in climate conditions: the most outstanding change was a decrease in biomass accumulation and an increase in litterfall at most sites during the abnormally hot year of 2003. Species richness also tended to decrease in 2003 at all sites except the cold and wet UK site. Species-specific responses to warming were found in shoot growth: at the SP site, Globularia alypum was not affected, while the other dominant species, Erica multiflora, grew 30% more; at the UK site, Calluna vulgaris tended to grow more in the warming plots, while Empetrum nigrum tended to grow less. Drought treatment decreased plant growth in several studied species, although there were some species such as Pinus halepensis at the SP site or C. vulgaris at the UK site that were not affected. The magnitude of responses to warming and drought thus depended greatly on the differences between sites, years, and species and these multiple plant responses may be expected to have consequences at ecosystem and community level. Decreases in biodiversity and the increase in E. multiflora growth at the SP site as a response to warming challenge the assumption that sensitivity to warming may be less well developed at more southerly latitudes; likewise, the fact that one of the studied shrublands presented negative ANPP as a response to the 2003 heat wave also challenges the hypothesis that future climate warming will lead to an enhancement of plant growth and carbon sequestration in temperate ecosystems. Extreme events may thus change the general trend of increased productivity in response to warming n the colder sites.

El control de les emissions de gasos amb efecte hivernacle com el diòxid de carboni és un dels principals objectius del protocol de Kyoto. L'important és entendre que és un proble-ma greu i que cadascú pot ajudar a solucionar-lo.

Cada vez que ocurre un determinado acontecimiento meteorológico digno de un titular en los medios de comunicación, sea una tormenta devastadora, un tiempo anómalamente cálido o frío, una grave sequía, etc., surge la misma cuestión: ¿es debido al cambio climático?