Relating climate sensitivity indices to projection uncertainty Earth System Dynamics DOI 10.5194/esd-11-721-2020 18 August 2020 Here, we assess the degree to which the idealized responses to transient forcing increase and step change forcing increase relate to warming under future scenarios. We find a possible explanation for the poor performance of transient metrics (relative to equilibrium response) as a metric of high-emission future warming in terms of their sensitivity to non-equilibrated initial conditions, and propose alternative metrics which better describe warming under high mitigation scenarios. Read more
Incremental improvements of 2030 targets insufficient to achieve the Paris Agreement goals Earth System Dynamics DOI 10.5194/esd-11-697-2020 13 August 2020 Current global mitigation ambition in the National Determined Contributions (NDCs) up to 2030 is insufficient to achieve the 1.5 °C long-term temperature limit. As governments are preparing new and updated NDCs for 2020, we address the question of what level of collective ambition is pivotal regarding the Paris Agreement goals. We provide estimates for global mean temperature increase by 2100 for different incremental NDC update scenarios and illustrate climate impacts under those scenarios. Read more
Remote sensing of methane leakage from natural gas and petroleum systems revisited Atmospheric Chemistry and Physics DOI 10.5194/acp-20-9169-2020 13 August 2020 The switch from the use of coal to natural gas or oil for energy generation potentially reduces the impact on global warming due to lower CO 2 emissions with the same energy content. However, this climate benefit is offset by fugitive methane emissions during the production and distribution process. We quantify emission and leakage rates relative to production for several large production regions based on satellite observations to evaluate the climate footprint of the gas and oil industry. Read more
Survival of the Qaidam mega-lake system under mid-Pliocene climates and itsrestoration under future climates Hydrology and Earth System Sciences DOI 10.5194/hess-24-3835-2020 11 August 2020 During the Pliocene, the Qaidam Basin on the Tibetan Plateau contained a mega-lake system. During the Pleistocene, it disappeared almost completely. Today, hyperarid climates prevail in the low-altitude parts of the basin. This study reveals that today’s mean water balance of the Qaidam Basin is nearly zero and is positive during warmer, less dry years. The results explain how the mega-lake system could survive for a long time in the past and could eventually be restored in the future. Read more
The recent state and variability of the carbonate system of the CanadianArctic Archipelago and adjacent basins in the context of ocean acidification Biogeosciences DOI 10.5194/bg-17-3923-2020 11 August 2020 Ocean acidification is the process by which the oceans are changing due to carbon dioxide emissions from human activities. Studying this process in the Arctic Ocean is essential as this ocean and its ecosystems are more vulnerable to the effects of acidification. Water chemistry measurements made in recent years show that waters in and around the Canadian Arctic Archipelago are considerably affected by this process and show dynamic conditions that might have an impact on local marine organisms. Read more
Impact of environmental changes and land management practices on wheatproduction in India Earth System Dynamics DOI 10.5194/esd-11-641-2020 6 August 2020 Spring wheat, a staple for millions of people in India and the world, is vulnerable to changing environmental and management factors. Using a new spring wheat model, we find that over the 1980–2016 period elevated CO 2 levels, irrigation, and nitrogen fertilizers led to an increase of 30 %, 12 %, and 15 % in countrywide production, respectively. In contrast, rising temperatures have reduced production by 18 %. These effects vary across the country, thereby affecting production at regional scales. Read more
Multidecadal trend analysis of in situ aerosol radiative properties around the world Atmospheric Chemistry and Physics DOI 10.5194/acp-20-8867-2020 6 August 2020 Long-term trends of aerosol radiative properties (52 stations) prove that aerosol load has significantly decreased over the last 20 years. Scattering trends are negative in Europe (EU) and North America (NA), not ss in Asia, and show a mix of positive and negative trends at polar stations. Absorption has mainly negative trends. The single scattering albedo has positive trends in Asia and eastern EU and negative in western EU and NA, leading to a global positive median trend of 0.02 % per year. Read more
Reviewing global estimates of surface reactive nitrogen concentration anddeposition using satellite retrievals Atmospheric Chemistry and Physics DOI 10.5194/acp-20-8641-2020 4 August 2020 Excessive atmospheric reactive nitrogen (N r ) deposition can cause a series of negative effects. Thus, it is necessary to accurately estimate N r deposition to evaluate its impact on the ecosystems and environment. Scientists attempted to estimate surface N r concentration and deposition using satellite retrievals. We give a thorough review of recent advances in estimating surface N r concentration and deposition using satellite retrievals of NO 2 and NH 3 and summarize the existing challenges. Read more
Invited perspectives: The volcanoes of Naples: how can the highest volcanic risk in the world be effectively mitigated? Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-2037-2020 4 August 2020 This paper starts by showing the present low performance of eruption forecasting and then addresses the problem of effectively mitigating the highest volcanic risk in the world, represented by the Naples area (southern Italy). The problem is considered in a highly multidisciplinary way, taking into account the main economic, sociological and urban planning issues. Our study gives precise guidelines to assessing and managing volcanic risk in any densely urbanised area. Read more
Results of the third Marine Ice Sheet Model Intercomparison Project (MISMIP+) The Cryosphere DOI 10.5194/tc-14-2283-2020 30 July 2020 We present the results of the third Marine Ice Sheet Intercomparison Project (MISMIP+). MISMIP+ is one in a series of exercises that test numerical models of ice sheet flow in simple situations. This particular exercise concentrates on the response of ice sheet models to the thinning of their floating ice shelves, which is of interest because numerical models are currently used to model the response to contemporary and near-future thinning in Antarctic ice shelves. Read more
Spatial database and website for reservoir-triggered seismicity in Brazil Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-2001-2020 30 July 2020 One of the biggest challenges in studying reservoir-triggered seismicity (RTS) is to identify factors that can trigger seismicity. A spatial database and a web viewer were created, gathering the data pertinent to the RTS study. Results were obtained in processing these data; for example, the occurrence of RTS increases with the height of the dam, the minimum limiting volume value is 1 × 10 −4 km 3 for occurrence of RTS, and for geology no correlations were found, among other results. Read more
Coastal impacts of Storm Gloria (January 2020) over the north-western Mediterranean Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-1955-2020 28 July 2020 Storm Gloria hit the Mediterranean Spanish coastlines between 20 and 23 January 2020, causing severe damages such as flooding of the Ebro River delta. We evaluate its coastal impacts with a numerical simulation of the wind waves and the accumulated ocean water along the coastline (storm surge). The storm surge that reached values up to 1 m was mainly driven by the wind that also generated wind waves up to 8 m in height. We also determine the extent of the Ebro Delta flooded by marine water. Read more
Mātauranga Māori in geomorphology: existing frameworks, case studies, and recommendations for incorporating Indigenous knowledge in Earth science Earth Surface Dynamics DOI 10.5194/esurf-8-595-2020 28 July 2020 This review highlights potential contributions that Indigenous knowledge can make to geomorphic research. We evaluate several frameworks and models for including Indigenous knowledge in geomorphic research and discuss how they can be adapted for use with Indigenous communities across the world. We propose that weaving Indigenous knowledge with geomorphic science has the potential to create new solutions and understandings that neither body of knowledge could produce in isolation. Read more
Smoke of extreme Australian bushfires observed in the stratosphere over Punta Arenas, Chile, in January 2020: optical thickness, lidar ratios, and depolarization ratios at 355 and 532 nm Atmospheric Chemistry and Physics DOI 10.5194/acp-20-8003-2020 23 July 2020 Unique lidar observations of a strong perturbation in stratospheric aerosol conditions in the Southern Hemisphere caused by the extreme Australian bushfires in 2019–2020 are presented. One of the main goals of this article is to provide the CALIPSO and Aeolus spaceborne lidar science teams with basic input parameters (lidar ratios, depolarization ratios) for a trustworthy documentation of this record-breaking event. Read more
Why does a conceptual hydrological model fail to correctly predict discharge changes in response to climate change? Hydrology and Earth System Sciences DOI 10.5194/hess-24-3493-2020 23 July 2020 We investigate why a conceptual hydrological model failed to correctly predict observed discharge changes in response to increasing precipitation and air temperature in 156 Austrian catchments. Simulations indicate that poor model performance is related to two problems, namely a model structure that neglects changes in vegetation dynamics and inhomogeneities in precipitation data caused by changes in stations density with time. Other hypotheses did not improve simulated discharge changes. Read more
On giant shoulders: how a seamount affects the microbial communitycomposition of seawater and sponges Biogeosciences DOI 10.5194/bg-17-3471-2020 21 July 2020 Seamounts are globally abundant submarine structures that offer great potential to study the impacts and interactions of environmental gradients at a single geographic location. In an exemplary way, we describe potential mechanisms by which a seamount can affect the structure of pelagic and benthic (sponge-)associated microbial communities. We conclude that the geology, physical oceanography, biogeochemistry, and microbiology of seamounts are even more closely linked than currently appreciated. Read more
N2O changes from the Last Glacial Maximum to the preindustrial – Part 2: terrestrial N2O emissions and carbon–nitrogen cycle interactions Biogeosciences DOI 10.5194/bg-17-3511-2020 21 July 2020 Results of the first globally resolved simulations of terrestrial carbon and nitrogen (N) cycling and N 2 O emissions over the past 21 000 years are compared with reconstructed N 2 O emissions. Modelled and reconstructed emissions increased strongly during past abrupt warming events. This evidence appears consistent with a dynamic response of biological N fixation to increasing N demand by ecosystems, thereby reducing N limitation of plant productivity and supporting a land sink for atmospheric CO 2 . Read more
The MOSAiC ice floe: sediment-laden survivor from the Siberian shelf The Cryosphere DOI 10.5194/tc-14-2173-2020 16 July 2020 In October 2019 the research vessel Polarstern was moored to an ice floe in order to travel with it on the 1-year-long MOSAiC journey through the Arctic. Here we provide historical context of the floe’s evolution and initial state for upcoming studies. We show that the ice encountered on site was exceptionally thin and was formed on the shallow Siberian shelf. The analyses presented provide the initial state for the analysis and interpretation of upcoming biogeochemical and ecological studies. Read more
The enigmatic curvature of Central Iberia and its puzzling kinematics Solid Earth DOI 10.5194/se-11-1247-2020 16 July 2020 Pangea was assembled during Devonian to early Permian times and resulted in a large-scale and winding orogeny that today transects Europe, northwestern Africa, and eastern North America. This orogen is characterized by an S shape corrugated geometry in Iberia. This paper presents the advances and milestones in our understanding of the geometry and kinematics of the Central Iberian curve from the last decade with particular attention paid to structural and paleomagnetic studies. Read more
Landfast sea ice material properties derived from ice bridge simulations using the Maxwell elasto-brittle rheology The Cryosphere DOI 10.5194/tc-14-2137-2020 14 July 2020 We study the formation of ice arches between two islands using a model that resolves crack initiation and propagation. This model uses a damage parameter to parameterize the presence or absence of cracks in the ice. We find that the damage parameter allows for cracks to propagate in the ice but in a different orientation than predicted by theory. The results call for improvement in how stress relaxation associated with this damage is parameterized. Read more