Deglacial landform assemblage records fast ice-flow and retreat, Inner Hebrides, Scotland

High-resolution bathymetric data have been central to recent advances in the understanding of past dynamics of the former British–Irish Ice Sheet (BIIS). As approximately two-thirds of the former BIIS was probably marine-based during the Last Glacial Maximum (LGM) (c. 29–23 ka), geomorphic observations of the seabed are required increasingly to understand the extent, pattern and timing of past glaciation. Until recently, glacial reconstructions for the Inner Hebrides, offshore of western Scotland, have been based primarily on terrestrial observations. Previous workers have proposed generalized reconstructions in which the Inner Hebrides are located within a significant former ice-sheet flow pathway that drained the western Scottish sector of the BIIS, feeding the Barra Fan during the LGM and earlier glaciations (Fig. 1). Results from numerical ice-sheet modelling suggest that former ice-flow velocities within the region were on the order of hundreds to thousands of metres per year, but yield further insight by demonstrating how dynamic binge/purge cycles may have affected ice-sheet mass balance over time (Hubbard et al. 2009). Following the LGM, ice-sheet retreat through the area is estimated to have been in the order of 20 m per year (Clark et al. 2012). Here we present swath-bathymetric data from the Inner Hebrides that provide in situ constraints on ice-sheet flow and subsequent retreat dynamics from within this important sector of the BIIS

Rapid ice sheet retreat triggered by ice stream debuttressing: Evidence from the North Sea

Using high-resolution bathymetric and shallow seismic data from the North Sea, we have mapped hitherto unknown glacial landforms that connect and resolve longstanding gaps in the Quaternary geological history of the basin. We use these data combined with published information and dates from sediment cores to reconstruct the extent of the Fennoscandian and British Ice Sheets (FIS and BIS) in the North Sea during the last phases of the last glacial stage. It is concluded that the BIS occupied a much larger part of the North Sea than previously suggested and that North Sea ice underwent a dramatic disintegration ~18,500 yr ago. This was triggered by grounding-line retreat of the Norwegian Channel Ice Stream, which debuttressed adjacent ice masses, and led to an unzipping of the BIS and FIS accompanied by drainage of a large ice-dammed lake. Our reconstruction of events provides an opportunity to improve understanding and modeling of the disintegration of marine-based ice sheets, and the complex interplay between ocean circulation and the cryosphere

The geomorphology of Svínafellsjökull and Virkisjökull-Falljökull glacier forelands, southeast Iceland

A detailed, 1:10,500-scale, surficial geology and glacial geomorphology map of Svínafellsjökull and Virkisjökull-Falljökull glacier forelands in southeast Iceland depicts the landsystem imprint of Holocene glacier fluctuations, volcanogenic outburst floods and recent (post-1990) climate-induced rapid ice-front retreat. The map is based on field survey data in combination with 2012 airborne LiDAR data, 2009–2012 terrestrial LiDAR data and 2007 colour aerial photography. The base digital elevation model (DEM) is compiled from an ice-cap wide airborne LiDAR dataset. The mapped glacial landforms are dominated by sequences of recessional moraines laid down in the mid-Holocene, the Little Ice Age, and the last ∼100 years; the state of landform preservation generally decreasing with age. Interspersed with glaciofluvial sedimentation associated with typical ice-marginal retreat sequences is key geomorphological evidence of high-magnitude volcanogenic outburst floods (jökulhlaups) associated with the eruptions of Öraefajökull in 1362 and 1727 CE. Ice-front retreat has accelerated since c.2005 leaving a rapidly evolving buried-ice landscape in front of Virkisjökull-Falljökull – including an ice-cored esker, a large ice-floored (supraglacial) lake, and numerous actively forming kettle holes and ice caverns. This map could act as a ‘reference frame’ for geomorphologists studying the temporal evolution of glacial landform-sediment assemblages undergoing rapid change

Increased North Atlantic dust deposition linked to Holocene Icelandic glacier fluctuations

Mineral dust concentrations are coupled to climate over glacial-interglacial cycles with increased dust deposition occurring during major cold phases over the last ~100 ka. Holocene records suggest considerable spatial and temporal variability in the magnitude, frequency and timing of dust peaks that reflects regional or local drivers of dust emissions and transport. Here, we present stratigraphical, geochemical and isotopic evidence for dust deposition from two high-resolution peat sequences 200 km apart in northern Scotland spanning the last c. 8200 years. εNd isotope data suggest the dominant minerogenic dust source switches between a low latitude (likely Saharan) and a high latitude, Icelandic source. Marked peaks in increased minerogenic dust deposition at: c. 5.4–5.1, 4.0–3.9, 2.8–2.6, 1.0 and 0.3 ka BP occur against a backdrop of low dust deposition during the mid-Holocene (c. 5.0–4.0 ka BP) and increased background levels of dust during the neoglacial period (<4.0 ka BP). These dust peaks coincide with periods of glacial advance in Iceland and heightened storminess in the North Atlantic. Isotope data for additional dust peaks at c. 1.0 and 0.7 ka BP and the last ~50 years suggest these reflect increased dust from the Sahara associated with aridity and land-use change in North Africa during the Late-Holocene, and modern anthropogenic sources. This work highlights the complexity of Holocene records of dust deposition in the North Atlantic and emphasises the role of dynamic sub-Polar glaciers and their meltwater systems as a significant dust source.Output Status: Forthcoming/Available Onlin

Training of Trainers on Enhancing Forecasting Capacities and Crop Capability Prediction Model and Tools

The negative impact of hydro-meteorological hazards on the agricultural sector often leads to food insecurity. It is, therefore, incumbent upon policymakers to formulate appropriate strategies aimed at minimizing the effects of hydro-meteorological hazards on communities and economies. Hence, there is a need for timely and tailored climaterelated knowledge, information and products that support decision-making to reduce climate-related losses and enhance benefits. A series of studies have been commissioned by the ACPC-UNECA and its regional partners, such as CCAFS, under the WISER program to demonstrate the SEB of CIS in the agricultural sector. One such effort was conducting a study on Enhancing Forecasting Capacities and Developing Crop Capability Prediction Models in Malawi, Mozambique and Zimbabwe, where CIS-based DST has been developed. This DST is a critical tool to guide policymakers and communities in making science-informed decisions for optimum productivity through improved efficiencies in agricultural production systems and contributing to minimizing impacts of hydro-meteorological hazards. To operationalize this tool, however, there is a need to conduct a concerted capacity development across the SADC sub-region and beyond

Training of Trainers Workshop on Enhancing Forecasting Capacities and Crop Capability Prediction Models and Tools - 2023

The detrimental impact of hydro-meteorological risks on agriculture frequently leads to food insecurity, particularly in Sub-Saharan Africa (SSA). Hence, the agriculture communities require climate-informed decision support tools that guide adaptation measures against climate change in the agriculture sector. The climate-informed crop capability prediction tool is one of these tools to benefit user community in making tactical and strategic decisions on inputs needed for agriculture and food security sectors as early as the crop-growing season. In this regard, regional partners1 commissioned a series of studies to develop a crop capacity prediction tool in order to maximize agricultural productivity in the Southern Africa Development Community (SADC) region while limiting the consequences of hydrometeorological risks on the food system. This tool can assist policymakers and user communities in making decisions on the most up-to-date crop capability based on projected seasonal climate data. However, for this tool to be operationalized and bring maximum impacts, roving training of trainers (ToT) workshops are required for agricultural yield prediction users, seasonal climate forecast (SCF) providers, researchers, and academics. The first of such ToT workshops was held in Harare, Zimbabwe, and the second one in Maputo, Mozambique, from 2–5 May 2023. Around 30 professionals who came from the Universidade Eduardo Mondlane (UEM), the Ministry of Agriculture (MADER), Mozambique National Institute of Meteorology (INAM) and other relevant departments attended this session. This ToT workshop covered a wide range of topics, including providing a conceptual framework for the Climate Agriculture Modelling and Decision Tool (CAMDT) - Decision Support System for Agrotechnology Transfer (DSSAT) platform; the importance of seasonal climate forecast (SCF); a hands-on exercise in data management (quality control and missing values, as well as a specific template/format); data acquisition; model descriptions (assumptions and uncertainties); and model analysis (simulation and validation). Participants' feedback indicated that the model and its outputs were successfully transferred, resulting in proficiency with the tool for future applications. They also thought the training was extremely relevant and valuable to the user communities. Despite the availability of a user manual, participants preferred a simpler programme-assisted method so that individuals with less computer knowledge could run the model for immediate use and application. It was emphasized that complete implementation of the SFC-driven crop capability prediction model and its timely deployment will result in large savings considering the vital role agriculture plays in the area. Participants recommended that the model be improved by including local circumstances and cultivars. However, for this capacity-building programme to be successful and have a lasting impact, it needs the full support of pertinent national and regional organizations, projects, and governments in the area. More resources are also required to guarantee that developers continued to engage in model improvement and skill transfer within SADC and beyond

Harnessing climate informed digital crop intelligence technologies is key to building the resilience of food systems against climate change in the SADC region

Climate-informed crop intelligence technologies are vital for building the resilience of food systems against the impacts of extremes in climate variation and climate change. As a result, agricultural policymakers, practitioners, and planners have used them to make tactical and strategic decisions, including estimating agricultural inputs needed months before the crop-growing season, selecting potential management practices, estimating crop performance and yields under various seasonal climate forecast scenarios, and providing anticipatory options against climate change. They may also be used in crop insurance evaluation schemes since they track real-time crop growth and estimate yield loss. Such tools are especially important in the SADC region, where severe weather and climate shocks have become more frequent and stronger in recent years, with catastrophic effects on livelihoods, food security, agriculture, human habitations, and ecosystems. As a result, the regional partners developed a user-friendly crop capability prediction tool and then conducted a series of capacity-building training in the SADC region. This capacity-building activity, however, requires the full cooperation of relevant national and regional organizations, initiatives, and governments in the region to be sustainable and have a long-term impact