Das Projekt "GOSAC: globale Speicherung anthropogenen Kohlenstoffs in den Ozeanen" wird vom Umweltbundesamt gefördert und von Universität Bern, Physikalisches Institut, Abteilung für Klima- und Umweltphysik durchgeführt. This study has three primary objectives: (1) to better quantify past, present, and future C02 uptake by the ocean, which is limited by relatively slow natural processes; (2) to evaluate global aspects of the proposal which offers to artificially accelerate ocean storage of C02 by diverting C02 emissions from fossil-fuel fired power plants directly into the abyss, thereby short-circuiting the natural process; and (3) to assess if predictions stemming from the first two objectives are reasonable, by paying close attention to model validation. Here, seven independantly developed 3-D ocean models from Europe jointly seek European Community support to participate in the Ocean Carbon-Cycle Model Intercomparison Project (OCMIP), an IGBP/GAIM initiative begun in 1995 to compare and validate ocean carbon-cycle models of the global ocean (Objective 1). Support is further sought to use these same models to assess one potential means to help mitigate increasing concentrations of atmospheric C02: deep-ocean C02 disposal (Objective 2). Model validation (Objective 3) is necessary to determine if any envelope of model predictions is likely to bracket real ocean behavior. The ocean is by far the largest reactive reservoir of carbon on earth. Most anthropogenic C02 will one day be stored there, despite relatively slow oceanic uptake which cannot keep pace with excess C02 emissions to the atmosphere. Ocean models provide the best means to assess past and present oceanic C02 uptake; they provide the only means to predict future changes. Comparison and validation of global ocean models is crucial to improving the large uncertainties associated with our understanding of the ocean's role in the global carbon cycle. Well validated ocean models offer our only tool to assess how ocean uptake will change due to future changes in ocean chemistry, biology, and circulation. This effort will assess how changes in ocean carbonate chemistry will effectively reduce oceanic uptake, and how differences in biology and circulation between some of the models may affect results. Ocean models have shown that certain strategies to artificially enhance ocean C02 uptake, such as iron fertilization, would be inefficient at sequestering additional C02; conversely, direct injection of excess C02 appears promising, but only one 3-D model has begun to assess its effectiveness. Prime Contractor: Centre National de la Recherche Scientifique, FU 0005 - Institut Pierre-Simon Laplace; Guyancourt/France.
Das Projekt "TIMECHS: Zeitlicher Verlauf und Mechanismen holozaener Klimaaenderungen in NW-Europa auf der Grundlage von stabilen Isotopen, Pollen und Makrofossilien aus Binnenseeumfeldern" wird vom Umweltbundesamt gefördert und von Universität Bern, Physikalisches Institut, Abteilung für Klima- und Umweltphysik durchgeführt. The project combines the palynological and faunal-assemblage approach with detailed geochemical investigations of calcareous lake sediments and ostracod shell contained therein, to establish a well-dated high-resolution Holocene climate record for western-most Europe. The cores are from a small deep lake, An Loch Mor, Inis O;rr (Inisheer), off the west coast of Ireland (OS grid ref. L 990 020; 9 Grad 30.2'W, 53 Grad 03.4'N). Objectives: (i) To reconstruct, at a fine temporal scale, the paleoclimatic record for the Holocene in a high resolution core from An Loch Mor, Inis Orr. The emphasis will be on establishing high-resolution records to identify periods of rapid climate change (precipitations, temperature, Atlantic storminess, etc.), and on quantifying rates of change. (ii) To reconstruct the role of human activity in bringing about change in both the lake and its catchment. Apart from the intrinsic interest in the reconstructing the timing and factors that have resulted in the present-day treeless karstic landscape, this information is critical to differentiate between chamges brougth about by climate as against those of anthropogenic origin. (iii) To evaluate the role of oceanic thermal inertia in controlling the amplitude and rate of climate fluctuations in the Holocene. This will be achieved by comparing our new high-resolution record with other well-dated records from similar latitudes in western and central Europe. (iv) To test whether climate change events recorded in cores from terrestrial situations in western Europe are synchronous with the atmosphere-driven events recorded in the Holocene parts of the Greenland ice cores, the changing temperature regimes in the North Atlantic and also patterns in North Atlantic Deep Water formation. Prime Contractor: National University of Ireland, Galway, Department of Botany Paleoenvironmental Research Unit; Galway.
Das Projekt "ADVANCE-10K: Analyse der dendrochronologischen Variabilitaet und entsprechender natuericher Kllimata in Eurasien waehrend der vergangenen 10000 Jahre" wird vom Umweltbundesamt gefördert und von Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft durchgeführt. Objective: To reconstruct a range of climate variables in different regions of northern Eurasia to enhance our knowledge of natural climate variability on a range of timescales within the last 10,000 years and advance our understanding of the mechanisms and forcings that have generated this variability. General Information: This project is focused in the area of dendroclimatology. The absolute dating control and seasonal growth of long tree-ring chronologies will be used to reconstruct a range of climate variables in different regions. The project encompasses extensive development of new densitometric chronologies in northern Siberia, part of ongoing work funded largely by The Swiss National Science Foundation. In addition, the major collections of European historical and sub-fossil oak ring-width data, principally from Great Britain, Sweden, Holland, Denmark, Germany and Poland, are being centralised, quality-controlled and entered into a common European tree-ring data base. Some modern chronology development is being undertaken to update these data and provide modern analogues for comparison with recent climate data. The project will reconstruct changes in temperature and precipitation-related variables over a range of temporal and spatial scales determined by the length, location and climate sensitivity of the available tree-ring data. This work will generate detailed individual maps of summer temperatures over several centuries across northern Siberia. These data will be interpreted in terms of large-scale atmospheric circulation patterns over western Europe and northern Eurasia and within the context of the large-scale general circulation of the Northern Hemisphere. Tree-growth and derived climate variability will be compared with (less well resolved) independent evidence of climate change in, and outside of, Europe, and with proxies of potential climate forcings such as volcanic, solar and Milankovitch changes throughout the Holocene. Evidence for the influence of ocean dynamics on European climates will be explored by comparing the statistical characteristics of the reconstructions with those of climate data produced by appropriate fully-coupled Ocean-Atmosphere General Circulation Models. Continuous regional-average timeseries will be produced spanning several millennia in specific regions of Sweden, Finland and Central Europe. These will allow an exploration of the evidence for contemporaneous, widespread and abrupt tree-growth changes that may indicate the effects of major environmental disruption potentially due to volcanic or cometary activity.
Das Projekt "CHILL-10000: Klimageschichte ausgehend von Untersuchungsergebnissen oekologisch empfindlicher arktischer und Alpenseenfuer die vergangenen 10000 Jahre, ein Ansatz mit mehreren beobachtbaren Groessen" wird vom Umweltbundesamt gefördert und von Universität Bern, Departement Biologie, Institut für Pflanzenwissenschaften durchgeführt. The general lack of long-term observational climate data results in uncertainties in the understanding of global change and in the ability to predict future changes. Because of the similarities in the distribution of solar radiation and Earth boundary conditions, Holocene palaeoclimates, in particular, can offer insights into the dynamics of climate change as well as providing a means to test the validity of different circulation models (GCMs). The overall goal of this study is to improve knowledge of Holocene climate evolution and variability by producing high-resolution, multi-proxy, and quantitative climate reconstructions across Europe. A particular emphasis will be paid to the spatial and temporal variation of Holocene climates and the relevance of these patterns to the validation and improvement of GCM simulations. The reconstructions will be achieved through the analysis of the extensive and unique proxy data available from the sedimentary deposits of remote high-altitude alpine and sub-arctic European lakes, largerly unaffected by human impact. The approach is highly focused, innovative, methodologically harmonized, and has an explicit multi-proxy nature. The project will improve, expand and apply existing quantitative inference models (transfer functions), based on regional quality-controlled modern organism-climate calibration data-sets, to reconstruct past climates from biological sedimentary sources such as chironomids, cladocerans, diatoms, chrysophyceans, and pollen. The most rigorous numerical techniques available, such as weighted averaging calibration and regression techniques (WA), WA partial least squares regression (WA-PLS), and modern analoque techniques (MAT) will be used in the reconstruction along with sample-spezific errors of prediction. The climate reconstructions derived from the biological data will be complemented by various geochemical and sedimentological analyses, and the overall methodology will be validated by statistical comparison with instrumentally measured climate data. Considerable effort will be paid to sediment sequence quality control, chronology, analytical quality control, and taxonomic consistency and harmonization throughout the work. The final result will be numerical, reliable, statistically-verifiable, precisely-dated, and spatially-weighted reconstructions of European climate within the last 10,000 years.