Search results for "climate change"
showing 10 items of 1151 documents
Signals and memory in tree-ring width and density data
2015
It has been suggested that maximum latewood density (MXD) should be used instead of tree-ring width (TRW) data to reconstruct post-volcanic cooling effects. A thorough assessment of high frequency signals and potentially differing memory effects in long MXD and TRW chronologies, in response to large volcanic eruptions, is still missing, however. We here present a compilation of MXD and TRW chronologies from 11 sites in the Northern Hemisphere, covering the past 750+ years, and containing significant June–August temperature signals. Basic assessment of the data using Superposed Epoch Analysis reveals a temporally extended response in TRW, by 2–3 years, to large volcanic eruptions, though pos…
Growth impacts in a changing ocean: insights from two coral reef fishes in an extreme environment
2020
AbstractDetermining the life history consequences for fishes living in extreme and variable environments will be vital in predicting the likely impacts of ongoing climate change on reef fish demography. Here, we compare size-at-age and maximum body size of two common reef fish species (Lutjanus ehrenbergiiandPomacanthus maculosus) between the environmentally extreme Arabian/Persian Gulf (‘Arabian Gulf’) and adjacent comparably benign Oman Sea. Additionally, we use otolith increment width profiles to investigate the influence of temperature, salinity and productivity on the individual growth rates. Individuals of both species showed smaller size-at-age and lower maximum size in the Arabian G…
Pattern Classification from Multi-beam Acoustic Data Acquired in Kongsfjorden
2021
Climate change is causing a structural change in Arctic ecosystems, decreasing the effectiveness that the polar regions have in cooling water masses, with inevitable repercussions on the climate and with an impact on marine biodiversity. The Svalbard islands under study are an area greatly influenced by Atlantic waters. This area is undergoing changes that are modifying the composition and distribution of the species present. The aim of this work is to provide a method for the classification of acoustic patterns acquired in the Kongsfjorden, Svalbard, Arctic Circle using multibeam technology. Therefore the general objective is the implementation of a methodology useful for identifying the a…
A Methodology for Comparing the Surface Urban Heat Island in Selected Urban Agglomerations Around the World from Sentinel-3 SLSTR Data
2020
[EN] Retrieval of land surface temperature (LST) from satellite data allows to estimate the surface urban heat island (SUHI) as the difference between the LST obtained in the urban area and the LST of its surroundings. However, this definition depends on the selection of the urban and surroundings references, which translates into greater difficulty in comparing SUHI values in different urban agglomerations across the world. In order to avoid this problem, a methodology is proposed that allows reliable quantification of the SUHI. The urban reference is obtained from the European Space Agency Climate Change Initiative Land Cover and three surroundings references are considered; that is, the …
Experimental deformation of deuterated ice in 3D and 2D: identification of grain-scale processes
2015
Major polar ice sheets and ice caps experience cycles of variable flow during different glacial periods and as a response to past warming. The rate and localisation of deformation inside an ice body controls the evolution of ice microstructure and crystallographic fabric. This is critical for interpreting proxy signals for climate change, with deformation overprinting and disrupting stratigraphy deep under ice caps due to the nature of the flow. The final crystallographic fabric in polar ice sheets provides a record of deformation history, which in turn controls the flow properties of ice during further deformation and affects geophysical sensing of ice sheets. For example, identification o…
Globālo klimata pārmaiņu novēršanas politikas izvērtējums
2020
Bakalaura darba temats ir “Globālo klimata pārmaiņu novēršanas politikas izvērtējums”. Globālo klimata pārmaiņu jautājums pēdējo gadu laikā ir atzīts par vienu no steidzamāk risināmajām pasaules problēmām. Darba teorētisko ietvaru veido ieviešanas teorijas un dažādu ieviešanas aspektu teorijas, kā arī teorija par klimata pārmaiņu politiku. Darba empīriskajā daļā, izmantojot teorētiskajā daļā izvirzītos kritērijus, tiek analizēti septiņi Latvijas Republikas Nacionālie ziņojumi ANO Vispārējās konvencijas par klimata pārmaiņām ietvaros. Darba mērķis ir izvērtēt konvencijas saistību īstenošanas laikā veiktos klimata politikas pasākumus un to atbilstību konvencijas mērķim. Atslēgvārdi : globālās…
Infection success of Echinoparyphium aconiatum (Trematoda) in its snail host under high temperature: role of host resistance
2014
Background Extreme weather events such as summer heat waves become more frequent owing to global climate change and are predicted to alter disease dynamics. This is because high temperatures can reduce host immune function. Predicting the impact of climate change on host-parasite interactions is, however, difficult as temperature may also affect parasite infective stages and other host characteristics determining the outcome of interaction. Methods Two experiments were conducted to investigate these phenomena in a Lymnaea stagnalis–Echinoparyphium aconiatum (Trematoda) interaction. In the first experiment, the effects of exposure of snails to experimental heat waves [maintenance at 25°C vs.…
Water-use efficiency and transpiration across European forests during the Anthropocene
2015
Considering the combined effects of CO2 fertilization and climate change drivers on plant physiology leads to a modest increase in simulated European forest transpiration in spite of the effects of CO2-induced stomatal closure. The Earth’s carbon and hydrologic cycles are intimately coupled by gas exchange through plant stomata1,2,3. However, uncertainties in the magnitude4,5,6 and consequences7,8 of the physiological responses9,10 of plants to elevated CO2 in natural environments hinders modelling of terrestrial water cycling and carbon storage11. Here we use annually resolved long-term δ13C tree-ring measurements across a European forest network to reconstruct the physiologically driven r…
MODELING PUBLIC POLICIES ANALYSIS OF LOGISTICS COLLABORATION IN THE PERFORMANCE OF THE AGRICULTURAL SECTOR OF THE POTATO IN COLOMBIA.
2020
The agricultural sector is considered fundamental for the supply of food needs of humanity, given the population growth. According to the Food and Agriculture Organization (FAO), the world population is estimated to be 9 billion people by the year 2050 and where the conditions of climate change can decrease crop yield up to 25%. This triggers greater vulnerability to the neediest population, being the rural sector the one hosting the poorest people. The rural area of Colombia represents 94% of extend the national territory, where 24% of the population lives a scenario of multiple problems that affect the country, such as the armed conflict of more than five decades, the presence of illicit …