Minimising soil organic carbon erosion by wind is critical for land degradation neutrality

The Land Degradation-Neutrality (LDN) framework of the United Nations Convention to Combat Desertification (UNCCD) is underpinned by three complementary interactive indicators (metrics: vegetation cover, net primary productivity; NPP and soil organic carbon; SOC) as proxies for change in land-based natural capital. The LDN framework assumes that SOC changes slowly primarily by decomposition and respiration of CO2 to the atmosphere. However, there is growing evidence that soil erosion by wind, water and tillage also reduces SOC stocks rapidly after land use and cover change. Here we modify a physically-based sediment transport model to estimate wind erosion and better represent the vegetation cover (using land surface aerodynamic roughness; that is the plant canopy coverage, stone cover, soil aggregates, etc. that protects the soil surface from wind erosion) and quantify the contribution of wind erosion to global SOC erosion (2001-2016). We use the wind erosion model to identify global dryland regions where SOC erosion by wind may be a significant problem for achieving LDN. Selected sites in global drylands show SOC erosion by wind accelerating over time. Without targeting and reducing SOC erosion, management practices in these regions will fail to sequester SOC and reduce land degradation. We describe the interrelated nature of the LDN indicators, the importance of including SOC erosion by wind erosion and how by explicitly accounting for wind erosion processes, we can better represent the physical effects of changing land cover on land degradation. Our results for Earth’s drylands show that modelling SOC stock reduction by wind erosion is better than using land cover and SOC independently. Furthermore, emphasising the role of wind erosion in UNCCD and Intergovernmental Panel on Climate Change (IPCC) reporting will better support LDN and climate change mitigation and adaptation globall

A tribute to Michael R. Raupach for contributions to aeolian fluid dynamics

Since the pioneering work of Bagnold in the 1940s, aeolian research has grown to become an integral part of earth-system science. Many individuals have contributed to this development, and Dr. Michael R. Raupach (1950–2015) has played a pivotal role. Raupach worked intensively on wind erosion problems for about a decade (1985–1995), during which time he applied his deep knowledge of turbulence to aeolian research problems and made profound contributions with far-reaching impact. The beauty of Raupach’s work lies in his clear conceptual thinking and his ability to reduce complex problems to their bare essentials. The results of his work are fundamentally important and have many practical applications. In this review we reflect on Raupach’s contribution to a number of important aspects of aeolian research, summarise developments since his inspirational work and place Raupach’s efforts in the context of aeolian science. We also demonstrate how Raupach’s work provided a foundation for new developments in aeolian research. In this tribute, we concentrate on five areas of research: (1) drag partition theory; (2) saltation roughness length; (3) saltation bombardment; (4) threshold friction velocity and (5) the carbon cycl

Discourse or dialogue? Habermas, the Bakhtin Circle, and the question of concrete utterances

This is the author's accepted manuscript. The final publication is available at Springer via the link below.This article argues that the Bakhtin Circle presents a more realistic theory of concrete dialogue than the theory of discourse elaborated by Habermas. The Bakhtin Circle places speech within the “concrete whole utterance” and by this phrase they mean that the study of everyday language should be analyzed through the mediations of historical social systems such as capitalism. These mediations are also characterized by a determinate set of contradictions—the capital-labor contradiction in capitalism, for example—that are reproduced in unique ways in more concrete forms of life (the state, education, religion, culture, and so on). Utterances always dialectically refract these processes and as such are internal concrete moments, or concrete social forms, of them. Moreover, new and unrepeatable dialogic events arise in these concrete social forms in order to overcome and understand the constant dialectical flux of social life. But this theory of dialogue is different from that expounded by Habermas, who tends to explore speech acts by reproducing a dualism between repeatable and universal “abstract” discursive processes (commonly known as the ideal speech situation) and empirical uses of discourse. These critical points against Habermas are developed by focusing on six main areas: sentences and utterances; the lifeworld and background language; active versus passive understandings of language; validity claims; obligation and relevance in language; and dialectical universalism

Indicators and Benchmarks for Wind Erosion Monitoring, Assessment and Management

Wind erosion and blowing dust threaten food security, human health and ecosystem services across global drylands. Monitoring wind erosion is needed to inform management, with explicit monitoring objectives being critical for interpreting and translating monitoring information into management actions. Monitoring objectives should establish quantitative guidelines for determining the relationship of wind erosion indicators to management benchmarks that reflect tolerable erosion and dust production levels considering impacts to, for example, ecosystem processes, species, agricultural production systems and human well-being. Here we: 1) critically review indicators of wind erosion and blowing dust that are currently available to practitioners; and 2) describe approaches for establishing benchmarks to support wind erosion assessments and management. We find that while numerous indicators are available for monitoring wind erosion, only a subset have been used routinely and most monitoring efforts have focused on air quality impacts of dust. Indicators need to be related to the causal soil and vegetation controls in eroding areas to directly inform management. There is great potential to use regional standardized soil and vegetation monitoring datasets, remote sensing and models to provide new information on wind erosion across landscapes. We identify best practices for establishing benchmarks for these indicators based on experimental studies, mechanistic and empirical models, and distributions of indicator values obtained from monitoring data at historic or existing reference sites. The approaches to establishing benchmarks described here have enduring utility as monitoring technologies change and enable managers to evaluate co-benefits and potential trade-offs among ecosystem services as affected by wind erosion management

Challenges, solutions and research priorities for sustainable rangelands

Australia’s rangeland communities, industries, and environment are under increasing pressures from anthropogenic activities and global changes more broadly. We conducted a horizon scan to identify and prioritise key challenges facing Australian rangelands and their communities, and outline possible avenues to address these challenges, with a particular focus on research priorities. We surveyed participants of the Australian Rangeland Society 20th Biennial Conference, held in Canberra in September 2019, before the conference and in interactive workshops during the conference, in order to identify key challenges, potential solutions, and research priorities. The feedback was broadly grouped into six themes associated with supporting local communities, managing natural capital, climate variability and change, traditional knowledge, governance, and research and development. Each theme had several sub-themes and potential solutions to ensure positive, long-term outcomes for the rangelands. The survey responses made it clear that supporting ‘resilient and sustainable rangelands that provide cultural, societal, environmental and economic outcomes simultaneously’ is of great value to stakeholders. The synthesis of survey responses combined with expert knowledge highlighted that sustaining local communities in the long term will require that the inherent social, cultural and natural capital of rangelands are managed sustainably, particularly in light of current and projected variability in climate. Establishment of guidelines and approaches to address these challenges will benefit from: (i) an increased recognition of the value and contributions of traditional knowledge and practices; (ii) development of better governance that is guided by and benefits local stakeholders; and (iii) more funding to conduct and implement strong research and development activities, with research focused on addressing critical knowledge gaps as identified by the local stakeholders. This requires strong governance with legislation and policies that work for the rangelands. We provide a framework that indicates the key knowledge gaps and how innovations may be implemented and scaled out, up and deep to achieve the resilience of Australia’s rangelands. The same principles could be adapted to address challenges in rangelands on other continents, with similar beneficial outcomes

Indicators and benchmarks for wind erosion monitoring, assessment and management

Wind erosion and blowing dust threaten food security, human health and ecosystem services across global drylands. Monitoring wind erosion is needed to inform management, with explicit monitoring objectives being critical for interpreting and translating monitoring information into management actions. Monitoring objectives should establish quantitative guidelines for determining the relationship of wind erosion indicators to management benchmarks that reflect tolerable erosion and dust production levels considering impacts to, for example, ecosystem processes, species, agricultural production systems and human well-being. Here we: 1) critically review indicators of wind erosion and blowing dust that are currently available to practitioners; and 2) describe approaches for establishing benchmarks to support wind erosion assessments and management. We find that while numerous indicators are available for monitoring wind erosion, only a subset have been used routinely and most monitoring efforts have focused on air quality impacts of dust. Indicators need to be related to the causal soil and vegetation controls in eroding areas to directly inform management. There is great potential to use regional standardized soil and vegetation monitoring datasets, remote sensing and models to provide new information on wind erosion across landscapes. We identify best practices for establishing benchmarks for these indicators based on experimental studies, mechanistic and empirical models, and distributions of indicator values obtained from monitoring data at historic or existing reference sites. The approaches to establishing benchmarks described here have enduring utility as monitoring technologies change and enable managers to evaluate co-benefits and potential trade-offs among ecosystem services as affected by wind erosion management

Elucidating hidden and enduring weaknesses in dust emission modelling

Large-scale classical dust cycle models, developed more than two decades ago, assume for simplicity that the Earth’s land surface is devoid of vegetation, reduce dust emission estimates using a vegetation cover complement, and calibrate estimates to observed atmospheric dust optical depth (DOD). Consequently, these models are expected to be valid for use with dust-climate projections in Earth System Models. We reveal little spatial relation between DOD frequency and satellite observed dust emission from point sources (DPS) and a difference of up to two orders of magnitude. We compared DPS data to an exemplar traditional dust emission model (TEM) and the albedo-based dust emission model (AEM) which represents aerodynamic roughness over space and time. Both models over-estimated dust emission probability but showed strong spatial relations to DPS, suitable for calibration. Relative to the AEM calibrated to the DPS, the TEM over-estimated large dust emission over vast vegetated areas and produced considerable false change in dust emission. It is difficult to avoid the conclusion that calibrating dust cycle models to DOD has hidden for more than two decades, these TEM modelling weaknesses. The AEM overcomes these weaknesses without using masks or vegetation cover data. Considerable potential therefore exists for ESMs driven by prognostic albedo, to reveal new insights of aerosol effects on, and responses to, contemporary and environmental change projections

Satellites reveal Earth's seasonally shifting dust emission sources

Establishing mineral dust impacts on Earth's systems requires numerical models of the dust cycle. Differences between dust optical depth (DOD) measurements and modelling the cycle of dust emission, atmospheric transport, and deposition of dust indicate large model uncertainty due partially to unrealistic model assumptions about dust emission frequency. Calibrating dust cycle models to DOD measurements typically in North Africa, are routinely used to reduce dust model magnitude. This calibration forces modelled dust emissions to match atmospheric DOD but may hide the correct magnitude and frequency of dust emission events at source, compensating biases in other modelled processes of the dust cycle. Therefore, it is essential to improve physically based dust emission modules. Here we use a global collation of satellite observations from previous studies of dust emission point source (DPS) dichotomous frequency data. We show that these DPS data have little-to-no relation with MODIS DOD frequency. We calibrate the albedo-based dust emission model using the frequency distribution of those DPS data. The global dust emission uncertainty constrained by DPS data (±3.8 kg m−2 y−1) provides a benchmark for dust emission model development. Our calibrated model results reveal much less global dust emission (29.1 ± 14.9 Tg y−1) than previous estimates, and show seasonally shifting dust emission predominance within and between hemispheres, as opposed to a persistent North African dust emission primacy widely interpreted from DOD measurements. Earth's largest dust emissions, proceed seasonally from East Asian deserts in boreal spring, to Middle Eastern and North African deserts in boreal summer and then Australian shrublands in boreal autumn-winter. This new analysis of dust emissions, from global sources of varying geochemical properties, have far-reaching implications for current and future dust-climate effects. For more reliable coupled representation of dust-climate projections, our findings suggest the need to re-evaluate dust cycle modelling and benefit from the albedo-based parameterisation

EndoVAscular treatment and ThRombolysis for Ischemic Stroke Patients (EVA-TRISP) registry: basis and methodology of a pan-European prospective ischaemic stroke revascularisation treatment registry.

PURPOSE The Thrombolysis in Ischemic Stroke Patients (TRISP) collaboration was a concerted effort initiated in 2010 with the purpose to address relevant research questions about the effectiveness and safety of intravenous thrombolysis (IVT). The collaboration also aims to prospectively collect data on patients undergoing endovascular treatment (EVT) and hence the name of the collaboration was changed from TRISP to EVA-TRISP. The methodology of the former TRISP registry for patients treated with IVT has already been published. This paper focuses on describing the EVT part of the registry. PARTICIPANTS All centres committed to collecting predefined variables on consecutive patients prospectively. We aim for accuracy and completeness of the data and to adapt local databases to investigate novel research questions. Herein, we introduce the methodology of a recently constructed academic investigator-initiated open collaboration EVT registry built as an extension of an existing IVT registry in patients with acute ischaemic stroke (AIS). FINDINGS TO DATE Currently, the EVA-TRISP network includes 20 stroke centres with considerable expertise in EVT and maintenance of high-quality hospital-based registries. Following several successful randomised controlled trials (RCTs), many important clinical questions remain unanswered in the (EVT) field and some of them will unlikely be investigated in future RCTs. Prospective registries with high-quality data on EVT-treated patients may help answering some of these unanswered issues, especially on safety and efficacy of EVT in specific patient subgroups. FUTURE PLANS This collaborative effort aims at addressing clinically important questions on safety and efficacy of EVT in conditions not covered by RCTs. The TRISP registry generated substantial novel data supporting stroke physicians in their daily decision making considering IVT candidate patients. While providing observational data on EVT in daily clinical practice, our future findings may likewise be hypothesis generating for future research as well as for quality improvement (on EVT). The collaboration welcomes participation of further centres willing to fulfill the commitment and the outlined requirements

Common variation in PHACTR1 is associated with susceptibility to cervical artery dissection

Cervical artery dissection (CeAD), a mural hematoma in a carotid or vertebral artery, is a major cause of ischemic stroke in young adults although relatively uncommon in the general population (incidence of 2.6/100,000 per year). Minor cervical traumas, infection, migraine and hypertension are putative risk factors, and inverse associations with obesity and hypercholesterolemia are described. No confirmed genetic susceptibility factors have been identified using candidate gene approaches. We performed genome-wide association studies (GWAS) in 1,393 CeAD cases and 14,416 controls. The rs9349379[G] allele (PHACTR1) was associated with lower CeAD risk (odds ratio (OR) = 0.75, 95% confidence interval (CI) = 0.69-0.82; P = 4.46 × 10(-10)), with confirmation in independent follow-up samples (659 CeAD cases and 2,648 controls; P = 3.91 × 10(-3); combined P = 1.00 × 10(-11)). The rs9349379[G] allele was previously shown to be associated with lower risk of migraine and increased risk of myocardial infarction. Deciphering the mechanisms underlying this pleiotropy might provide important information on the biological underpinnings of these disabling conditions