A Late Pleistocene sea level stack Climate of the Past DOI 10.5194/cp-12-1079-2016 26 April 2016 This study presents an average of seven Late Pleistocene sea level records, which improves the signal-to-noise ratio for estimates of sea level change during glacial cycles of the past 800 000 years. Read more
Revolutions in energy input and material cycling in Earth history and human history Earth System Dynamics DOI 10.5194/esd-7-353-2016 22 April 2016 We identify six past revolutions in energy input and material cycling in Earth and human history. We find that human energy use has now reached a magnitude comparable to the biosphere, and conclude that a prospective sustainability revolution will require scaling up new solar energy technologies and the development of much more efficient material recycling systems. Our work was inspired by recognising the connections between Earth system science and industrial ecology at the “LOOPS” workshop. Read more
Differential climate impacts for policy-relevant limits to global warming: the case of 1.5 ∘C and 2 ∘C Earth System Dynamics DOI 10.5194/esd-7-327-2016 21 April 2016 We present for the first time a comprehensive assessment of key climate impacts for the policy relevant warming levels of 1.5 °C and 2 °C above pre-industrial levels. We report substantial impact differences in intensity and frequency of extreme weather events, regional water availability and agricultural yields, sea-level rise and risk of coral reef loss. The increase in climate impacts is particularly pronounced in tropical and sub-tropical regions. Read more
Effects of wood chip amendments on the revegetation performance of plant species on eroded marly terrains in a Mediterranean mountainous climate (Southern Alps, France) Solid Earth DOI 10.5194/se-7-599-2016 15 April 2016 This paper presents the results of two experiments of revegetation techniques in context of water erosion and mountainous Mediterranean climate. We studied the interest of a wood chip amendment, applied on soil surface (mulch), and its interaction with plant development. The use of different plant species and the monitoring on three growing seasons (with climatic variations) allow us to specify the interest of wood chip mulch to improve revegetation especially in erosion and drought conditions. Read more
The link between marine sediment records and changes in Holocene Saharan landscape: simulating the dust cycle Climate of the Past DOI 10.5194/cp-12-1009-2016 15 April 2016 We demonstrate for the first time the direct link between dust accumulation in marine sediment cores and Saharan land surface by simulating the mid-Holocene and pre-industrial dust cycle as a function of Saharan land surface cover and atmosphere-ocean conditions using the coupled atmosphere-aerosol model ECHAM6-HAM2.1. Mid-Holocene surface characteristics, including vegetation cover and lake surface area, are derived from proxy data and simulations. Read more
Combined fluvial and pluvial urban flood hazard analysis: concept development and application to Can Tho city, Mekong Delta, Vietnam Natural Hazards and Earth System Sciences DOI 10.5194/nhess-16-941-2016 13 April 2016 Many urban areas experience both fluvial and pluvial floods, thus this study aims to analyse fluvial and pluvial flood hazards as well as combined pluvial and fluvial flood hazards. This combined fluvial-pluvial flood hazard analysis is performed in a tropical environment for Can Tho city in the Mekong Delta. The final results are probabilistic hazard maps, showing the maximum inundation caused by floods of different magnitudes along with an uncertainty estimation. Read more
Non-deforestation fire vs. fossil fuel combustion: the source of CO2 emissions affects the global carbon cycle and climate responses Biogeosciences DOI 10.5194/bg-13-2137-2016 13 April 2016 We simulated both fire pulses and stable fire regimes and found the resulting climatic impacts to be irreconcilable with equivalent amounts of CO2 emissions produced by fossil fuel combustion. Consequently, side-by-side comparisons of fire and fossil fuel CO2 emissions—implicitly implying that they have similar effects—should be avoided. Our study calls for the explicit representation of fire in climate models in order to improve our understanding of its impacts in the Earth system. Read more
Early warning signals of tipping points in periodically forced systems Earth System Dynamics DOI 10.5194/esd-7-313-2016 13 April 2016 We find early warnings of abrupt changes in complex dynamical systems such as the climate where the usual early warning indicators do not work. In particular, these are systems that are periodically forced, for example by the annual cycle of solar insolation. We show these indicators are good theoretically in a general setting then apply them to a specific system, that of the Arctic sea ice, which has been conjectured to be close to such a tipping point. We do not find evidence of it. Read more
Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2015 Atmospheric Chemistry and Physics DOI 10.5194/acp-16-4605-2016 13 April 2016 We examine changes in SO2 and NO2 over the world’s most polluted regions during the first decade of Aura OMI observations. Over the eastern US, both NO2 and SO2 levels decreased by 40% and 80%, respectively. OMI confirmed large reductions in SO2 over eastern Europe’s largest coal power plants. The North China Plain has the world’s most severe SO2 pollution, but a decreasing trend been observed since 2011, with a 50% reduction in 2012-2014. India’s SO2 and NO2 levels are growing at a fast pace. Read more
Statistical analysis of magnetotail fast flows and related magnetic disturbances Annales Geophysicae DOI 10.5194/angeo-34-399-2016 12 April 2016 This study presents an investigation on the occurrence of fast flows in the magnetotail using the complete available data set of the THEMIS spacecraft for the years 2007 to 2015. First, basic statistical findings concerning velocity distributions, occurrence rates, group structures and key features of 16 000 events are presented using Superposed Epoch and Minimum Variance Analysis techniques. Read more
Kinetic isotope effects of 13CH3D + OH and 13CH3D + OH from 278 to 313 K Atmospheric Chemistry and Physics DOI 10.5194/acp-16-4439-2016 11 April 2016 We present experimental kinetic isotope effects (KIE) for the OH oxidation of CH3D and 13CH3D and their temperature dependence. Our determination of the 13CH3D+OH KIE is novel and we find no “clumped” isotope effect within the experimental uncertainty. Read more
A multiproxy approach to understanding the “enhanced” flux of organic matter through the oxygen-deficient waters of the Arabian Sea Biogeosciences DOI 10.5194/bg-13-2077-2016 8 April 2016 Drifting sediment traps were deployed in the oxygen-deficient waters of the Arabian Sea, where the sinking flux is less attenuated than in more oxic waters. Six mechanisms that might explain this “enhanced flux” were evaluated using literature and data. In the upper 500m, evidence was found supporting an oxygen effect and/or changes in the efficiency of the microbial loop, including the addition of chemoautotrophic carbon to the sinking flux. Read more
Ideas and perspectives: Holocene thermokarst sediments of the Yedoma permafrost region do not increase the northern peatland carbon pool Biogeosciences DOI 10.5194/bg-13-2003-2016 6 April 2016 We investigate the properties of soils and sediments in a particular and ancient Siberian permafrost landscape. We critically examine statements from a recent study that specific permafrost landforms affected by thawed permafrost (alases) in this region contain very large quantities of peat that previous studies had failed to include because of data set biases. We conclude that there is no evidence to suggest biases in existing data sets or that alas deposits increase the northern peatland pool. Read more
Solar modulation of flood frequency in central Europe during spring and summer on interannual to multi-centennial timescales Climate of the Past DOI 10.5194/cp-12-799-2016 1 April 2016 Integrating discharge data of the River Ammer back to 1926 and a 5500-year flood layer record from an annually laminated sediment core of the downstream Ammersee allowed investigating changes in the frequency of major floods in Central Europe on interannual to multi-centennial timescales. Significant correlations between flood frequency variations in both archives and changes in the activity of the Sun suggest a solar influence on the frequency of these hydrometeorological extremes. Read more
Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality Atmospheric Chemistry and Physics DOI 10.5194/acp-16-4191-2016 31 March 2016 Various forms of solar radiation management (SRM) have been proposed to counteract man-made climate change. However, all these countermeasures could have unintended side-effects. We add a novel perspective to this discussion by showing how atmospheric ozone changes under solar geoengineering could affect UV exposure and air pollution. This would have implications for human health and ecology. Atmospheric composition changes are therefore important to consider in the evaluation of any SRM scheme. Read more
Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 ∘C global warming could be dangerous Atmospheric Chemistry and Physics DOI 10.5194/acp-16-3761-2016 22 March 2016 We use climate simulations, paleoclimate data and modern observations to infer that continued high fossil fuel emissions will yield cooling of Southern Ocean and North Atlantic surfaces, slowdown and shutdown of SMOC & AMOC, increasingly powerful storms and nonlinear sea level rise reaching several meters in 50-150 years, effects missed in IPCC reports because of omission of ice sheet melt and an insensitivity of most climate models, likely due to excessive ocean mixing. Read more
Coevolution of volcanic catchments in Japan Hydrology and Earth System Sciences DOI 10.5194/hess-20-1133-2016 16 March 2016 We derived indices of landscape properties as well as hydrological response and examined their relation with catchment age and climate. We found significant correlation between drainage density and baseflow index with age, but not with climate. We compared our data with data from volcanic catchments in Oregon and could confirm that baseflow index decreases with time, but also discovered that drainage density seems to stabilize after 2M years, after an initial increase due to landscape incision. Read more
Maximum wind radius estimated by the 50 kt radius: improvement of storm surge forecasting over the western North Pacific Natural Hazards and Earth System Sciences DOI 10.5194/nhess-16-705-2016 11 March 2016 We proposed an Rmax estimation method based on the radius of the 50 knot wind (R50). The data obtained during the passage of strong typhoons by a meteorological station network in the Japanese archipelago enabled us to derive the following simple formula, Rmax = 0.23 R50. The proposed method is expected to increase the reliability of storm surge prediction and contribute to disaster risk management, particularly in the western North Pacific. Read more
Imprints of climate forcings in global gridded temperature data Earth System Dynamics DOI 10.5194/esd-7-231-2016 11 March 2016 Using regression analysis, near-surface temperatures from several gridded data sets were investigated for the presence of components attributable to external climate forcings and to major internal climate variability modes, over the 1901-2010 period. The spatial patterns of local temperature response and their combination in globally averaged temperature were shown and discussed, with special focus on highlighting the inter-dataset contrasts. Read more
Phase, composition, and growth mechanism for secondary organic aerosol from the ozonolysis of α-cedrene Atmospheric Chemistry and Physics DOI 10.5194/acp-16-3245-2016 11 March 2016 A significant fraction of airborne particles, which have significant impacts on human health, visibility, and climate, are formed from the oxidation of gaseous precursors to generate low-volatility products. We show here that a sesquiterpene, α-cedrene, efficiently forms high-viscosity semisolid particles with complex composition via mechanisms that involve the highly reactive Criegee intermediate and that high molecular weight products play an important role in new particle formation. Read more