Effects of Earth system feedbacks on the potential mitigation of large-scale tropical forest restoration Biogeosciences DOI 10.5194/bg-18-2627-2021 17 June 2021 Estimates of large-scale tree planting and forest restoration as a carbon sequestration tool typically miss a crucial aspect: the Earth system response to the increased land carbon sink from new vegetation. We assess the impact of tropical forest restoration using an Earth system model under a scenario that limits warming to 2 °C. Almost two-thirds of the carbon impact of forest restoration is offset by negative carbon cycle feedbacks, suggesting a more modest benefit than in previous studies. Read more
Revision of the World Meteorological Organization Global Atmosphere Watch (WMO/GAW) CO2 calibration scale Atmospheric Measurement Techniques DOI 10.5194/amt-14-3015-2021 16 June 2021 We have recently revised the carbon dioxide calibration scale used by numerous laboratories that measure atmospheric CO2. The revision follows from an improved understanding of the manometric method used to determine the absolute amount of CO2 in an atmospheric air sample. The new scale is 0.18 μmol mol−1 (ppm) greater than the previous scale at 400 ppm CO2. While this difference is small in relative terms (0.045 %), it is significant in terms of atmospheric monitoring. WMO/GAW) CO2 calibration scale">Read more
Observing the timescales of aerosol–cloud interactions in snapshot satellite images Atmospheric Chemistry and Physics DOI 10.5194/acp-21-6093-2021 15 June 2021 Cloud responses to aerosol are time-sensitive, but this development is rarely observed. This study uses isolated aerosol perturbations from ships to measure this development and shows that macrophysical (width, cloud fraction, detectability) and microphysical (droplet number) properties of ship tracks vary strongly with time since emission, background cloud and meteorological state. This temporal development should be considered when constraining aerosol–cloud interactions with observations. Read more
On the attribution of industrial-era glacier mass loss to anthropogenic climate change The Cryosphere DOI 10.5194/tc-15-1889-2021 14 June 2021 The worldwide retreat of mountain glaciers and consequent loss of ice mass is one of the most obvious signs of a changing climate and has significant implications for the hydrology and natural hazards in mountain landscapes. Consistent with our understanding of the human role in temperature change, we demonstrate that the central estimate of the size of the human-caused mass loss is essentially 100 % of the observed loss. This assessment resolves some important inconsistencies in the literature. Read more
Development of smart boulders to monitor mass movements via the Internet of Things: a pilot study in Nepal Earth Surface Dynamics DOI 10.5194/esurf-9-295-2021 11 June 2021 We use long-range smart sensors connected to a network based on the Internet of Things to explore the possibility of detecting hazardous boulder movements in real time. Prior to the 2019 monsoon season we inserted the devices in 23 boulders spread over debris flow channels and a landslide in northeastern Nepal. The data obtained in this pilot study show the potential of this technology to be used in remote hazard-prone areas in future early warning systems. Read more
Robust increase of Indian monsoon rainfall and its variability under future warming in CMIP6 models Earth System Dynamics DOI 10.5194/esd-12-367-2021 10 June 2021 All state-of-the-art global climate models that contributed to the latest Coupled Model Intercomparison Project (CMIP6) show a robust increase in Indian summer monsoon rainfall that is even stronger than in the previous intercomparison (CMIP5). Furthermore, they show an increase in the year-to-year variability of this seasonal rainfall that crucially influences the livelihood of more than 1 billion people in India. Read more
Uncertainties in the Emissions Database for Global Atmospheric Research (EDGAR) emission inventory of greenhouse gases Atmospheric Chemistry and Physics DOI 10.5194/acp-21-5655-2021 10 June 2021 We conducted an extensive analysis of the structural uncertainty of the Emissions Database for Global Atmospheric Research (EDGAR) emission inventory of greenhouse gases, which adds a much needed reliability dimension to the accuracy of the emission estimates. The study undertakes in-depth analyses of the implication of aggregating emissions from different sources and/or countries on the accuracy. Results are presented for all emissions sectors according to IPCC definitions. EDGAR) emission inventory of greenhouse gases">Read more
Snapshots of mean ocean temperature over the last 700 000 years using noble gases in the EPICA Dome C ice core Climate of the Past DOI 10.5194/cp-17-843-2021 9 June 2021 Using the temperature-dependent solubility of noble gases in ocean water, we reconstruct global mean ocean temperature (MOT) over the last 700 kyr using noble gas ratios in air enclosed in polar ice cores. Our record shows that glacial MOT was about 3 °C cooler compared to the Holocene. Interglacials before 450 kyr ago were characterized by about 1.5 °C lower MOT than the Holocene. In addition, some interglacials show transient maxima in ocean temperature related to changes in ocean circulation. EPICA Dome C ice core">Read more
Pervasive diffusion of climate signals recorded in ice-vein ionic impurities The Cryosphere DOI 10.5194/tc-15-1787-2021 8 June 2021 Current theory predicts climate signals in the vein chemistry of ice cores to migrate, hampering their dating. I show that the Gibbs–Thomson effect, which has been overlooked, causes fast diffusion that prevents signals from surviving into deep ice. Hence the deep climatic peaks in Antarctic and Greenlandic ice must be due to impurities in the ice matrix (outside veins) and safe from migration. These findings reset our understanding of postdepositional changes of ice-core climate signals. Read more
FES2014 global ocean tide atlas: design and performance Ocean Science DOI 10.5194/os-17-615-2021 7 June 2021 Since the mid-1990s, a series of FES (finite element solution) global ocean tidal atlases has been produced with the primary objective to provide altimetry missions with a tidal de-aliasing correction. We describe the underlying hydrodynamic/data assimilation design and accuracy assessments for the FES2014 release. The FES2014 atlas shows overall improved performance and has consequently been integrated in satellite altimetry and gravimetric data processing and adopted in ITRF standards. Read more
