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Atmospheric H2 observations from the NOAA Cooperative Global Air Sampling Network

Hydrogen (H2) is a gas in trace amounts in the Earth’s atmosphere with indirect impacts on climate and air quality. Renewed interest in H2 as a low- or zero-carbon source of energy may lead to increased production, uses, and supply chain emissions. NOAA measurements of weekly air samples collected between 2009 and 2021 at over 50 sites in mostly remote locations are now available, and they complement other datasets to study the H2 global budget.

NOAA Cooperative Global Air Sampling Network">Read more

Absence of causality between seismic activity and global warming

It was recently suggested that global warming can be explained by the non-anthropogenic factor of seismic activity. If that is the case, it would have profound implications. We have assessed the validity of the claim by using a statistical technique that evaluates the existence of causal connections between variables, finding no evidence for any causal relationship between seismic activity and global warming.

Tipping point detection and early warnings in climate, ecological, and human systems

Tipping points are abrupt, rapid, and sometimes irreversible changes, and numerous approaches have been proposed to detect them in advance. Such approaches have been termed early warning signals and represent a set of methods for identifying changes in the underlying behaviour of a system across time or space that might indicate an approaching tipping point. Here, we review the literature to explore where, how, and which early warnings have been used in real-world case studies so far.

Sourcing and long-range transport of particulate organic matter in river bedload: Río Bermejo, Argentina

The transport of plant debris in rivers is an important part of the global carbon cycle and influences atmospheric carbon levels through time. We sampled plant debris at the bed of a lowland river and determined the sources as it is transported hundreds of kilometers. Plant debris can persist at the riverbed, but mechanical breakdown reduces its amount, and it is only a small fraction compared to the suspended load. This plant debris and transport patterns need further investigation globally.

ESD Ideas: Exoplanet, origins of life and biosphere researchers offer a perspective fundamental to ensuring humanity’s future

Scientists exploring the histories of planets and life are uniquely positioned to communicate a perspective that is fundamental to our survival: humanity is wholly embedded in Earth and its biosphere. There is no escaping our planet and its history. Only policies that build on this perspective will contribute to a flourishing future for humanity. We offer a few brief glimpses of this cosmic perspective and call on our colleagues to acknowledge the powerful stories emanating from their work.

ESD Ideas: Exoplanet, origins of life and biosphere researchers offer a perspective fundamental to ensuring humanity’s future">Read more

Using historical temperature to constrain the climate sensitivity, the transient climate response, and aerosol-induced cooling

Using errors in climate model simulations this paper derives correction factors for the impacts of greenhouse gases and particles that bring these simulated temperature fields into agreement with an observational reconstruction of the Earth’s temperature. On average across eight models, a reduction by about one-half of the particle-induced cooling would be required, causing only 0.24 K of cooling since 1850–1899. The greenhouse gas warming simulated by several highly sensitive models would also reduce.

Continuous synchronization of the Greenland ice-core and U–Th timescales using probabilistic inversion

The first continuously measured transfer functions that quantify the age difference between the Greenland ice-core chronology 2005 (GICC05) and the U–Th timescale are presented. The transfer functions were generated using a novel probabilistic algorithm for the synchronization of proxy signals. The results greatly improve the accuracy and precision of previous synchronization estimates and reveal that the annual-layer counting error of GICC05 is less systematic than previously assumed.

Observation-inferred resilience loss of the Amazon rainforest possibly due to internal climate variability

We investigate whether the Amazon rainforest has lost substantial resilience since 1990. This assertion is based on trends in the observational record of vegetation density. We calculate the same metrics in a large number of climate model simulations and find that several models behave indistinguishably from the observations, suggesting that the observed trend could be caused by internal variability and that the cause of the ongoing rapid loss of Amazon rainforest is not mainly global warming.

Can corporate supply chain sustainability standards contribute to soil protection?

SOIL
DOI 10.5194/soil-10-505-2024
2 August 2024

We explore business efforts to ensure soil quality in their supply chains through the application of supplier sustainability standards. Through a content analysis of existing sustainability standards and companies’ sustainability reports, we found that soil sustainability is an important priority for food retailers. However, the standards currently applied tend to have a limited impact on soil protection due to a lack of specific criteria and thresholds.

Hydro-pedotransfer functions: a roadmap for future development

Pedotransfer functions (PTFs) are used to predict parameters of models describing the hydraulic properties of soils. The appropriateness of these predictions critically relies on the nature of the datasets for training the PTFs and the physical comprehensiveness of the models. This roadmap paper is addressed to PTF developers and users and critically reflects the utility and future of PTFs. To this end, we present a manifesto aiming at a paradigm shift in PTF research.

Linking geomorphological processes and wildlife microhabitat selection: nesting birds select refuges generated by permafrost degradation in the Arctic

In the Arctic tundra, climate change is transforming the landscape, and this may impact wildlife. We focus on three nesting bird species and the islets they select as refuges from their main predator, the Arctic fox. A geomorphological process, ice-wedge polygon degradation, was found to play a key role in creating these refuges. This process is likely to affect predator–prey dynamics in the Arctic tundra, highlighting the connections between nature’s physical and ecological systems.

Brief communication: Storm Daniel flood impact in Greece in 2023: mapping crop and livestock exposure from synthetic-aperture radar (SAR)

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-24-2375-2024
22 July 2024

About 820 km2 of agricultural land was inundated in central Greece due to Storm Daniel. A detailed analysis revealed that the crop most affected by the flooding was cotton; the inundated area of more than 282 km2 comprised ~ 30 % of the total area planted with cotton in central Greece. In terms of livestock, we estimate that more than 14 000 ornithoids and 21 500 sheep and goats were affected. Consequences for agriculture and animal husbandry in Greece are expected to be severe.

SAR)">Read more

The risk of synoptic-scale Arctic cyclones to shipping

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-24-2115-2024
19 July 2024

The risk posed to ships by Arctic cyclones has seldom been quantified due to the lack of publicly available historical Arctic ship track data. This study investigates historical Arctic ship tracks, cyclone tracks, and shipping incident reports to determine the number of shipping incidents caused by the passage of Arctic cyclones. Results suggest that Arctic cyclones have not been hazardous to ships and that ships are resilient to the rough sea conditions caused by Arctic cyclones.

Isotopomer labeling and oxygen dependence of hybrid nitrous oxide production

Nitrous oxide, a potent greenhouse gas, accumulates in regions of the ocean that are low in dissolved oxygen. We used a novel combination of chemical tracers to determine how nitrous oxide is produced in one of these regions, the eastern tropical North Pacific Ocean. Our experiments showed that the two most important sources of nitrous oxide under low-oxygen conditions are denitrification, an anaerobic process, and a novel “hybrid” process performed by ammonia-oxidizing archaea.

Coupled ice–ocean interactions during future retreat of West Antarctic ice streams in the Amundsen Sea sector

A new ice–ocean model simulates future ice sheet evolution in the Amundsen Sea sector of Antarctica. Substantial ice retreat is simulated in all scenarios, with some retreat still occurring even with no future ocean melting. The future of small “pinning points” (islands of ice that contact the seabed) is an important control on this retreat. Ocean melting is crucial in causing these features to go afloat, providing the link by which climate change may affect this sector’s sea level contribution.

Quantum data assimilation: a new approach to solving data assimilation on quantum annealers

Data assimilation is a crucial component in the Earth science field, enabling the integration of observation data with numerical models. In the context of numerical weather prediction (NWP), data assimilation is particularly vital for improving initial conditions and subsequent predictions. However, the computational demands imposed by conventional approaches, which employ iterative processes to minimize cost functions, pose notable challenges in computational time. The emergence of quantum computing provides promising opportunities to address these computation challenges by harnessing the inherent parallelism and optimization capabilities of quantum annealing machines.

Elevation-dependent warming: observations, models, and energetic mechanisms

Observational data and numerical models suggest that, under climate change, elevated land surfaces warm faster than non-elevated ones. Proposed drivers of this “elevation-dependent warming” (EDW) include surface albedo and water vapour feedbacks, the temperature dependence of longwave emission, and aerosols. Yet the relative importance of each proposed mechanism both regionally and at large scales is unclear, highlighting an incomplete physical understanding of EDW.

A downward-counterfactual analysis of flash floods in Germany

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-24-2147-2024
8 July 2024

To identify flash flood potential in Germany, we shifted the most extreme rainfall events from the last 22 years systematically across Germany and simulated the consequent runoff reaction. Our results show that almost all areas in Germany have not seen the worst-case scenario of flood peaks within the last 22 years. With a slight spatial change of historical rainfall events, flood peaks of a factor of 2 or more would be achieved for most areas. The results can aid disaster risk management.

The impacts of elevated CO2 on forest growth, mortality, and recovery in the Amazon rainforest

Elevated CO2 concentration (eCO2) is critical for shaping the future path of forest carbon uptake, while uncertainties remain about concurrent carbon loss. Here, we found that eCO2 might amplify competition-induced carbon loss, while the extent of drought-induced carbon loss hinges on the balance between heightened biomass density and water-saving benefits. This is the first time that such carbon loss responses to ongoing climate change have been quantified separately over the Amazon rainforest.

Evaluation of forecasts by a global data-driven weather model with and without probabilistic post-processing at Norwegian stations

During the last 2 years, tremendous progress has been made in global data-driven weather models trained on reanalysis data. In this study, the Pangu-Weather model is compared to several numerical weather prediction models with and without probabilistic post-processing for temperature and wind speed forecasting. The results confirm that global data-driven models are promising for operational weather forecasting and that post-processing can improve these forecasts considerably.

Opinion: Optimizing climate models with process knowledge, resolution, and artificial intelligence

Climate models are crucial for predicting climate change in detail. This paper proposes a balanced approach to improving their accuracy by combining traditional process-based methods with modern artificial intelligence (AI) techniques while maximizing the resolution to allow for ensemble simulations. The authors propose using AI to learn from both observational and simulated data while incorporating existing physical knowledge to reduce data demands and improve climate prediction reliability.

600 years of wine must quality and April to August temperatures in western Europe 1420–2019

This bottle of Riesling from the traditional Bassermann Jordan winery in Deidesheim (Germany) is a relic of the premium wine harvested in 1811. It was named “Comet Wine” after the bright comet that year. The study shows that wine quality can be used to infer summer weather conditions over the past 600 years. After rainy summers with cold winds, wines turned sour, while long periods of high pressure led to excellent qualities. Since 1990, only good wines have been produced due to rapid warming.

Impact of Hurricane Irma on coral reef sediment redistribution at Looe Key Reef, Florida, USA

Global understanding of storm-driven sediment transport along coral reefs and its impact on species and habitats is limited. Measurement of seafloor elevation and volume change due to a category 4 hurricane showed rapid burial of coral reef habitats and migration of large seafloor features due to the storm. Post-storm erosion rates were 2 orders of magnitude greater than historical rates, indicating areas of seafloor instability that could be less suitable for restoration of benthic species.

A perspective on the next generation of Earth system model scenarios: towards representative emission pathways (REPs)

The scientific community is considering new scenarios to succeed RCPs and SSPs for the next generation of Earth system model runs to project future climate change. To contribute to that effort, we reflect on relevant policy and scientific research questions and suggest categories for representative emission pathways. These categories are tailored to the Paris Agreement long-term temperature goal, high-risk outcomes in the absence of further climate policy and worlds “that could have been”.

REPs)">Read more

Opinion: Strengthening research in the Global South – atmospheric science opportunities in South America and Africa

To tackle the current pressing atmospheric science issues, as well as those in the future, a robust scientific community is necessary in all regions across the globe. Unfortunately, this does not yet exist. There are many geographical areas that are still underrepresented in the atmospheric science community, many of which are in the Global South. There are also larger gaps in the understanding of atmospheric composition, processes, and impacts in these regions. In this opinion, we focus on two geographical areas in the Global South to discuss some common challenges and constraints, with a focus on our strengths in atmospheric science research. It is these strengths, we believe, that highlight the critical role of Global South researchers in the future of atmospheric science research.

Applying global warming levels of emergence to highlight the increasing population exposure to temperature and precipitation extremes

Using a special suite of climate simulations, we determine if and when climate change is detectable and translate this to the global warming prevalent in the corresponding year. Our results show that, at 1.5°C warming, >85 % of the global population (>95 % at 2.0° warming) is already exposed to nighttime temperatures altered by climate change beyond natural variability. Furthermore, even incremental changes in global warming levels result in increased human exposure to emerged climate signals.

Synergistic approach of frozen hydrometeor retrievals: considerations on radiative transfer and model uncertainties in a simulated framework

In cloudy situations, infrared and microwave observations are complementary, with infrared being sensitive to cloud tops and microwave sensitive to precipitation. However, infrared satellite observations are underused. This study aims to quantify if the inconsistencies in the modelling of clouds prevent the use of cloudy infrared observations in the process of weather forecasting. It shows that the synergistic use of infrared and microwave observations is beneficial, despite inconsistencies.

On the importance of middle-atmosphere observations on ionospheric dynamics using WACCM-X and SAMI3

This study shows how middle-atmospheric data (starting at 40 km) affect day-to-day ionospheric variability. We do this by using lower atmospheric measurements that include and exclude the middle atmosphere in a coupled ionosphere–thermosphere model. Comparing the two simulations reveals differences in two thermosphere–ionosphere coupling mechanisms. Additionally, comparison against observations showed that including the middle-atmospheric data improved the resulting ionosphere.

WACCM-X and SAMI3">Read more

The effect of temperature on photosystem II efficiency across plant functional types and climate

A first-of-its-kind global-scale model of temperature resilience and tolerance of photosystem II maximum quantum yield informs how plants maintain their efficiency of converting light energy to chemical energy for photosynthesis under temperature changes. Our finding explores this variation across plant functional types and habitat climatology, highlighting diverse temperature response strategies and a method to improve global-scale photosynthesis modeling under climate change.

Geomorphic risk maps for river migration using probabilistic modeling – a framework

In this paper, we propose a framework for generating risk maps that provide the probabilities of erosion due to river migration. This framework uses concepts from probability theory to learn the river migration model’s parameter values from satellite data while taking into account parameter uncertainty. Our analysis shows that such geomorphic risk estimation is more reliable than models that do not explicitly consider various sources of variability and uncertainty.

Opinion: A research roadmap for exploring atmospheric methane removal via iron salt aerosol

Rapid reduction in atmospheric methane is needed to slow the rate of global warming. Reducing anthropogenic methane emissions is a top priority. However, atmospheric methane is also impacted by rising natural emissions and changing sinks. Studies of possible atmospheric methane removal approaches, such as iron salt aerosols to increase the chlorine radical sink, benefit from a roadmapped approach to understand if there may be viable and socially acceptable ways to decrease future risk.

Does high-latitude ionospheric electrodynamics exhibit hemispheric mirror symmetry?

In studies of the Earth’s ionosphere, a hot topic is how to estimate ionospheric conductivity. This is hard to do for a variety of reasons that mostly amount to a lack of measurements. In this study we use satellite measurements to estimate electromagnetic work and ionospheric conductances in both hemispheres. We identify where our model estimates are inconsistent with laws of physics, which partially solves a previous problem with unrealistic predictions of ionospheric conductances.

Extensive coverage of ultrathin tropical tropopause layer cirrus clouds revealed by balloon-borne lidar observations

Upper tropical clouds have a strong impact on Earth’s climate but are challenging to observe. We report the first long-duration observations of tropical clouds from lidars flying on board stratospheric balloons. Comparisons with spaceborne observations reveal the enhanced sensitivity of balloon-borne lidar to optically thin cirrus. These clouds, which have a significant coverage and lie in the uppermost troposphere, are linked with the dehydration of air masses on their way to the stratosphere.

A major midlatitude hurricane in the Little Ice Age

A Little Ice Age (LIA) hurricane was characterized using key storm intensity metrics from historical naval records. Its unusual intensity was driven by a higher temperature gradient between continental and coastal atmospheric circulation that drove intense midlatitude extratropical transition. Quantitative attributes embedded in historical records allow multidisciplinary research to extend our understanding of climate processes through the historical period.

Does a convection-permitting regional climate model bring new perspectives on the projection of Mediterranean floods?

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-24-1163-2024
20 May 2024

High-resolution convection-permitting climate models (CPMs) are now available to better simulate rainstorm events leading to flash floods. In this study, two hydrological models are compared to simulate floods in a Mediterranean basin, showing a better ability of the CPM to reproduce flood peaks compared to coarser-resolution climate models. Future projections are also different, with a projected increase for the most severe floods and a potential decrease for the most frequent events.

A network approach for multiscale catchment classification using traits

We present a new method based on network science for unsupervised classification of large datasets and apply it to classify 9067 US catchments and 274 biophysical traits at multiple scales. We find that our trait-based approach produces catchment classes with distinct streamflow behavior and that spatial patterns emerge amongst pristine and human-impacted catchments. This method can be widely used beyond hydrology to identify patterns, reduce trait redundancy, and select representative sites.

Unraveling biogeographical patterns and environmental drivers of soil fungal diversity at the French national scale

SOIL
DOI 10.5194/soil-10-251-2024
15 May 2024

The fungal kingdom has been diversifying for more than 800 million years by colonizing a large number of habitats on Earth. Based on a unique dataset (18S rDNA meta-barcoding), we described the spatial distribution of fungal diversity at the scale of France and the environmental drivers by tackling biogeographical patterns. We also explored the fungal network interactions across land uses and climate types.

NEWTS1.0: Numerical model of coastal Erosion by Waves and Transgressive Scarps

Models of rocky coastal erosion help us understand the controls on coastal morphology and evolution. In this paper, we present a simplified model of coastline erosion driven by either uniform erosion where coastline erosion is constant or wave-driven erosion where coastline erosion is a function of the wave power. This model can be used to evaluate how coastline changes reflect climate, sea-level history, material properties, and the relative influence of different erosional processes.

The perfect storm? Co-occurring climate extremes in East Africa

Climate change affects the interaction, dependence, and joint occurrence of climate extremes. Here we investigate the joint occurrence of pairs of river floods, droughts, heatwaves, crop failures, wildfires, and tropical cyclones in East Africa under past and future climate conditions. Our results show that, across all future warming scenarios, the frequency and spatial extent of these co-occurring extremes will increase in this region, particularly in areas close to the Nile and Congo rivers.

Resemblance of the global depth distribution of internal-tide generation and cold-water coral occurrences

Cold-water corals (CWCs) and tidal waves in the interior of the ocean have been connected in case studies. We demonstrate this connection globally using hydrodynamic simulations and a CWC database. Internal-tide generation shows a similar depth pattern with slope steepness and latitude as CWCs. Our results suggest that internal-tide generation can be a useful predictor of CWC habitat and that current CWC habitats might change following climate-change-related shoaling of internal-tide generation.

Evaluating the impact of climate communication activities by scientists: what is known and necessary?

Climate scientists are urged to communicate climate science; there is very little evidence about what types of communication work well for which audiences. We have performed a systematic literature review to analyze what is known about the efficacy of climate communication by scientists. While we have found more than 60 articles in the last 10 years about climate communication activities by scientists, only 7 of these included some form of evaluation of the impact of the activity.

Dependency of the impacts of geoengineering on the stratospheric sulfur injection strategy – Part 2: How changes in the hydrological cycle depend on the injection rate and model used

This study is the second in a two-part series in which we explore the dependency of the impacts of stratospheric sulfur injections on both the model employed and the strategy of injection utilized. The study uncovers uncertainties associated with these techniques to cool climate, highlighting how the simulated climate impacts are dependent on both the selected model and the magnitude of the injections. We also show that estimating precipitation impacts of aerosol injection is a complex task.

The six rights of how and when to test for soil C saturation

SOIL
DOI 10.5194/soil-10-275-2024
29 April 2024

Soil C saturation has been tested in several recent studies and led to a debate about its existence. We argue that, to test C saturation, one should pay attention to six fundamental principles: the right measures, the right units, the right dispersive energy and application, the right soil type, the right clay type, and the right saturation level. Once we take care of those six rights across studies, we find support for a maximum of C stabilized by minerals and thus soil C saturation.

Interpretability of negative latent heat fluxes from eddy covariance measurements in dry conditions

Porous materials are known to reversibly trap water from the air, even at low humidity. However, this behavior is poorly understood for soils. In this analysis, we test whether eddy covariance is able to measure the so-called adsorption of atmospheric water vapor by soils. We find that this flux occurs frequently during dry nights in a Mediterranean ecosystem, while EC detects downwardly directed vapor fluxes. These results can help to map moisture uptake globally.

Carbon budget concept and its deviation through the pulse response lens

The carbon budget approach is based on a close linear relationship between the global temperature and cumulative emissions. This article reinterprets the carbon budget approach through the lens of the temperature response to an emission pulse in the role of a Green’s function, or as a generalization of TCRE. It shows that inspecting the simple model’s pulse response allows for a prediction of deviations for any possible emission scenario and derivation of a nonlinear carbon budget equation.

Quantitative imaging of carbon dioxide plumes using a ground-based shortwave infrared spectral camera

Imaging carbon dioxide (CO2) plumes of anthropogenic sources from planes and satellites has proven valuable for detecting emitters and monitoring climate mitigation efforts. We present the first images of CO2 plumes taken with a ground-based spectral camera, observing a coal-fired power plant as a validation target. We develop a technique to find the source emission strength with an hourly resolution, which reasonably agrees with the expected emissions under favorable conditions.

HydroFATE (v1): a high-resolution contaminant fate model for the global river system

Treated and untreated wastewaters are sources of contaminants of emerging concern. HydroFATE, a new global model, estimates their concentrations in surface waters, identifying streams that are most at risk and guiding monitoring/mitigation efforts to safeguard aquatic ecosystems and human health. Model predictions were validated against field measurements of the antibiotic sulfamethoxazole, with predicted concentrations exceeding ecological thresholds in more than 400 000 km of rivers worldwide.

Rates of palaeoecological change can inform ecosystem restoration

Rate-of-change records based on compositional data are ambiguous as they may rise irrespective of the underlying trajectory of ecosystems. We emphasize the importance of characterizing both the direction and the rate of palaeoecological changes in terms of key features of ecosystems rather than solely on community composition. Past accelerations of community transformation may document the potential of ecosystems to rapidly recover important ecological attributes and functions.

Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates

This study uses airborne radar data and satellite imagery to map mountainous topography hidden beneath the Greenland Ice Sheet. We find that the landscape records the former extent and configuration of ice masses that were restricted to areas of high topography. Computer models of ice flow indicate that valley glaciers eroded this landscape millions of years ago when local air temperatures were at least 4 °C higher than today and Greenland’s ice volume was < 10 % of that of the modern ice sheet.

Minimizing the effects of Pb loss in detrital and igneous U–Pb zircon geochronology by CA-LA-ICP-MS

Chemical abrasion (CA) is a technique that reduces or eliminates the effects of Pb loss in zircon U–Pb geochronology. However, CA has yet to be applied to large-n detrital zircon (DZ) analyses. We show that CA does not negatively impact or systematically bias U–Pb dates, improves the resolution of age populations defined by 206Pb/238U dates, and increases the percentage of concordant analyses in age populations defined by 207Pb/206Pb dates.

ICP-MS">Read more