Impacts of large-scale Sahara solar farms on global climate and vegetation cover

Large‐scale photovoltaic solar farms envisioned over the Sahara Desert can meet the world's energy demand while increasing regional rainfall and vegetation cover. However, adverse remote effects resulting from atmospheric teleconnections could offset such regional benefits. We use state‐of‐the‐art Earth system model simulations to evaluate the global impacts of Sahara solar farms. Our results indicate a redistribution of precipitation causing Amazon droughts and forest degradation, and global surface temperature rise and sea‐ice loss, particularly over the Arctic due to increased polarward heat transport, and northward expansion of deciduous forests in the Northern Hemisphere. We also identify reduced El Niño‐Southern Oscillation and Atlantic Niño variability and enhanced tropical cyclone activity. Comparison to proxy inferences for a wetter and greener Sahara ∼6,000 years ago appear to substantiate these results. Understanding these responses within the Earth system provides insights into the site selection concerning any massive deployment of solar energy in the world's deserts

Advancing global & regional reanalyses

This report outlines the structure of and summarizes the recommendations made at the 5th International Conference on Reanalysis (ICR5), attended by 259 participants from 37 countries, in Rome (Italy), on 13-17 November 2017. It first summarizes the conference structure. Then, the key recommendations of ICR5 are given for the five main conference topics: production; observations (data rescue and preparation); data assimilation methods; quality assurance of reanalysis; and applications in science, services, and policymaking. Lastly, five high-level recommendations are proposed to managing agencies on how best to advance the field of reanalyses, which serves tens of thousands of users, via enhanced research, development, and operations

The tropical Atlantic observing system

The tropical Atlantic is home to multiple coupled climate variations covering a wide range of timescales and impacting societally relevant phenomena such as continental rainfall, Atlantic hurricane activity, oceanic biological productivity, and atmospheric circulation in the equatorial Pacific. The tropical Atlantic also connects the southern and northern branches of the Atlantic meridional overturning circulation and receives freshwater input from some of the world’s largest rivers. To address these diverse, unique, and interconnected research challenges, a rich network of ocean observations has developed, building on the backbone of the Prediction and Research Moored Array in the Tropical Atlantic (PIRATA). This network has evolved naturally over time and out of necessity in order to address the most important outstanding scientific questions and to improve predictions of tropical Atlantic severe weather and global climate variability and change. The tropical Atlantic observing system is motivated by goals to understand and better predict phenomena such as tropical Atlantic interannual to decadal variability and climate change; multidecadal variability and its links to the meridional overturning circulation; air-sea fluxes of CO2 and their implications for the fate of anthropogenic CO2; the Amazon River plume and its interactions with biogeochemistry, vertical mixing, and hurricanes; the highly productive eastern boundary and equatorial upwelling systems; and oceanic oxygen minimum zones, their impacts on biogeochemical cycles and marine ecosystems, and their feedbacks to climate. Past success of the tropical Atlantic observing system is the result of an international commitment to sustained observations and scientific cooperation, a willingness to evolve with changing research and monitoring needs, and a desire to share data openly with the scientific community and operational centers. The observing system must continue to evolve in order to meet an expanding set of research priorities and operational challenges. This paper discusses the tropical Atlantic observing system, including emerging scientific questions that demand sustained ocean observations, the potential for further integration of the observing system, and the requirements for sustaining and enhancing the tropical Atlantic observing system

Mid-Pliocene West African Monsoon Rainfall as simulated in the PlioMIP2 ensemble

International audienceAbstract. The mid-Pliocene warm period (mPWP; ∼3.2 million years ago) is seen as the most recent time period characterized by a warm climate state, with similar to modern geography and ∼400 ppmv atmospheric CO2 concentration, and is therefore often considered an interesting analogue for near-future climate projections. Paleoenvironmental reconstructions indicate higher surface temperatures, decreasing tropical deserts, and a more humid climate in West Africa characterized by a strengthened West African Monsoon (WAM). Using model results from the second phase of the Pliocene Modelling Intercomparison Project (PlioMIP2) ensemble, we analyse changes of the WAM rainfall during the mPWP by comparing them with the control simulations for the pre-industrial period. The ensemble shows a robust increase in the summer rainfall over West Africa and the Sahara region, with an average increase of 2.5 mm/d, contrasted by a rainfall decrease over the equatorial Atlantic. An anomalous warming of the Sahara and deepening of the Saharan Heat Low, seen in >90 % of the models, leads to a strengthening of the WAM and an increased monsoonal flow into the continent. A similar warming of the Sahara is seen in future projections using both phase 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5). Though previous studies of future projections indicate a west–east drying–wetting contrast over the Sahel, PlioMIP2 simulations indicate a uniform rainfall increase in that region in warm climates characterized by increasing greenhouse gas forcing. We note that this effect will further depend on the long-term response of the vegetation to the CO2 forcing

Understanding West African Monsoon Variability : Insights from Paleoclimate Modelling of Past Warm Climates

The Sahel, a water-vulnerable region in West Africa, relies heavily on rainfed agriculture. The region experienced pronounced droughts during the 20th Century, emphasising the socio-economic importance of understanding the drivers of the rainfall variability. However, future rainfall projections remain uncertain due to the complex nature of the West African Monsoon (WAM), which is influenced by internal climate variability, external forcing, and feedback processes. Limited observational records in West Africa and the need for longer time series further complicate the understanding of these drivers.  This thesis uses paleoclimate modelling to investigate internal and external drivers of monsoon variability in West Africa across four distinct periods. Our study confirms that atmosphere-only model simulations can capture the observed multidecadal rainfall variability in the 20th Century, even though reanalyses struggle to reproduce the correct timing. Analysis of a last millennium simulation using the Earth System Model EC-Earth3 identified two drivers of multidecadal rainfall variability, accounting for 90% of the total co-variability between the West African rainfall and Atlantic sea surface temperatures (SSTs). This finding strengthens our understanding of SST-WAM relationships observed during the 20th Century. An ensemble of climate model simulations (PlioMIP2) shows that high CO2 levels and a different paleogeography during the mid-Pliocene Warm Period led to increased rainfall and a strengthened WAM. Our study emphasised vegetation's crucial role in enhancing the monsoon in past climates.  However, simulations forced with prescribed vegetation only capture a one-directional forcing. A mid-Holocene simulation using an Earth System Model with dynamic vegetation revealed that vegetation feedbacks strengthen the WAM response to external orbital forcing but are insufficient to shift the monsoon northward or increase vegetation cover over the Sahara. These results reveal a dry bias and under-representation of simulated vegetation compared to proxy records, highlighting the importance of model development and the need for additional feedback processes in driving an enhanced, northward WAM and extending vegetation to the Sahara.  Overall, this thesis advances our understanding of the drivers of West African monsoon variability and provides valuable insights for improving future rainfall projections in this vulnerable region

Understanding West African Monsoon Variability : Insights from Paleoclimate Modelling of Past Warm Climates

The Sahel, a water-vulnerable region in West Africa, relies heavily on rainfed agriculture. The region experienced pronounced droughts during the 20th Century, emphasising the socio-economic importance of understanding the drivers of the rainfall variability. However, future rainfall projections remain uncertain due to the complex nature of the West African Monsoon (WAM), which is influenced by internal climate variability, external forcing, and feedback processes. Limited observational records in West Africa and the need for longer time series further complicate the understanding of these drivers.  This thesis uses paleoclimate modelling to investigate internal and external drivers of monsoon variability in West Africa across four distinct periods. Our study confirms that atmosphere-only model simulations can capture the observed multidecadal rainfall variability in the 20th Century, even though reanalyses struggle to reproduce the correct timing. Analysis of a last millennium simulation using the Earth System Model EC-Earth3 identified two drivers of multidecadal rainfall variability, accounting for 90% of the total co-variability between the West African rainfall and Atlantic sea surface temperatures (SSTs). This finding strengthens our understanding of SST-WAM relationships observed during the 20th Century. An ensemble of climate model simulations (PlioMIP2) shows that high CO2 levels and a different paleogeography during the mid-Pliocene Warm Period led to increased rainfall and a strengthened WAM. Our study emphasised vegetation's crucial role in enhancing the monsoon in past climates.  However, simulations forced with prescribed vegetation only capture a one-directional forcing. A mid-Holocene simulation using an Earth System Model with dynamic vegetation revealed that vegetation feedbacks strengthen the WAM response to external orbital forcing but are insufficient to shift the monsoon northward or increase vegetation cover over the Sahara. These results reveal a dry bias and under-representation of simulated vegetation compared to proxy records, highlighting the importance of model development and the need for additional feedback processes in driving an enhanced, northward WAM and extending vegetation to the Sahara.  Overall, this thesis advances our understanding of the drivers of West African monsoon variability and provides valuable insights for improving future rainfall projections in this vulnerable region

Children's voice and participation in social welfare investigations

There is a principal consent both in the convention on the rights of the child, the Swedish social service act and in “Barns behov i centrum” (BBiC, similar to the British “Looking after children”, LAC) that children should participate and have an impact on matters that affect them in relation to their age and maturity. This thesis focus on how children’s voices are recorded in social welfare files and how their participation in the investigation is constructed. I have read the interviews and the social reports of ten children, conducted by social workers in a municipality in the outskirts of Stockholm. The children’s voices in the files are a secondary voice, they are the social worker’s interpretation of the interviews with the children. I have used thematic analysis in order to answer my research questions. The result shows that all children had been able to talk to the social worker and nearly all of them were informed about why there was an investigation. The children’s stories were valued as true by the social workers and they were referred as information givers. Most of them were only interviewed orally, without support from child adaptive methods. They had very limited impact on how the investigation were conducted, how their information would be used and on the choice of intervention

“…It’s not only about giving children a voice”- social workers accounts of child participation in social investigations

There is a consensus in Sweden that children are right-bearers and shall participate in matters that affect them among legislators, the government’s instructions by Barns Behov I Centrum (BBIC) (Child’s needs in focus) and among social workers. Despite this, previous research shows that children’s participation in social investigations is limited. The aim of this study is to analyse and interpret how social worker’s describe and understand children’s participation in their daily work at a social welfare unit. It is their perception of child participation that is studied. The data consists of interviews with nine social workers investigating children of 0-12 years of age at three social welfare units in municipalities’ in the outskirts of Stockholm. The theoretical perspective of this study is childhood sociology. The social workers in this study regard children as competent enough to receive information as well as capable contributors to the investigations. Participation was viewed as a cornerstone in their work with children. Children were described as capable of communicating information and their perspective on their situation through speech, behaviour or play indicating that all children can contribute despite age. But oral communication dominates and has a higher value, showing that age and maturity has an impact on children’s participation. Restrictions by guardians, time-restraint and heavy workloads also limited children’s participation during the investigation.

Swedish wool’s possibility for application in fine-knitted clothing : a comparison between merino wool, jämtland’s wool and finull’s wool

Produktionen av textila fibrer ökar varje år och domineras idag av bomull och polyester. Denna industri innebär en stor miljöpåverkan, inte bara genom användandet av kemikalier tidigt i värdekedjan utan även utsläpp vid transport av råvaror och textila produkter över långa sträckor. Ett alternativ till denna globala värdekedja, och ett steg mot en mer förnyelsebar textilindustri, är att i större utsträckning utnyttja de lokalt producerade råvaror som i dagsläget förbises. Idag slängs ca 54% av den ull som årligen produceras i Sverige. Flera projekt för att använda mer av den svenska ullen, bland annat Swedish Wool Initiative, har genomförts. Detta har resulterat i att ett par olika företag har börjat sälja plagg av svensk ull, men då grövre stickade plagg. Här finns en kunskapslucka kring hur tunna garn och sedermera tyg som kan tillverkas och hur deras egenskaper skiljer sig från garn och tyg av importerad merinoull. Detta arbete jämför därför svensk jämtlandsull och finull med importerad merinoull genom karakterisering av fibrer, garn och tyg. Testerna visar att fibrerna av jämtlandsull har större diameter och kortare längd än de andra sorterna, men det färdiga garnet visade ingen signifikant skillnad i styrka utan alla tre hade en styrka kring 3-4 cN/tex. Garnet av finull kunde inte användas till stickning då det var för ojämnt och hade för stor variation i styrka. Av jämtlands- och merinogarnen producerades stickade tyger med en kvadratmetervikt kring 270 g/m2. Arbetet visade således att den svenska finullen inte lämpar sig för produktion av finstickade plagg. Dock har jämtlandsullen potential att användas i något grövre plagg än det väldigt tunna tyget som var arbetets målbild. Detta då garnet av jämtlandsull hade väldigt lika egenskaper som det av merinoull.The production of textile fibres increases each year and is today dominated by cotton and polyester. This industry causes a large environmental impact, not only through the use of chemicals early in the values chain but also emissions from transports of raw materials and textile products over long distances. An alternative to this global value chain, and a step towards a more renewable textile industry, is to a greater extent use locally produces raw materials that currently are overlooked. Today, about 54% of the wool produced in Sweden is thrown away. Several projects aimed to increase the use of the wool have been done, for example Swedish Wool Initiative. This resulted in a couple of companies starting to sell garments made of Swedish wool, but only coarser knitted garments. Here a knowledge gap exists around how thin yarns and subsequently fabrics that can be produced and how their characteristics differ from the ones of yarn and fabric made of imported Merino wool. Therefore, this study compares wool from the Swedish Jämtlands sheep and Finulls sheep with imported merino wool through characterization of fibres, yarn, and fabric. The tests showed that the fibres from the Jämtlands sheep have a larger diameter and shorter length than the other fibres, but the final yarn didn’t show any significant difference in strength. All three yarns had a strength around 3-4 cN/tex. The yarn made from the wool from the Finull sheep was not possible to knit because of irregularities and variation in strength. The yarn made from Merino and Jämtlands wool was knitted into fabrics with a square metre weight of about 270 g/ 2 m . Thus, the work shows that wool from the Finull sheep isn’t suited for production of fine knitted clothing. The Jämtlands wool on the other hand, has potential to be used in slightly coarser garments than the very thin ones that was the aim of this work. This is thought possible because of the similar characteristics between the yarn made from Merino wool and the one made from Jämtlands wool

Swedish wool’s possibility for application in fine-knitted clothing : a comparison between merino wool, jämtland’s wool and finull’s wool

Produktionen av textila fibrer ökar varje år och domineras idag av bomull och polyester. Denna industri innebär en stor miljöpåverkan, inte bara genom användandet av kemikalier tidigt i värdekedjan utan även utsläpp vid transport av råvaror och textila produkter över långa sträckor. Ett alternativ till denna globala värdekedja, och ett steg mot en mer förnyelsebar textilindustri, är att i större utsträckning utnyttja de lokalt producerade råvaror som i dagsläget förbises. Idag slängs ca 54% av den ull som årligen produceras i Sverige. Flera projekt för att använda mer av den svenska ullen, bland annat Swedish Wool Initiative, har genomförts. Detta har resulterat i att ett par olika företag har börjat sälja plagg av svensk ull, men då grövre stickade plagg. Här finns en kunskapslucka kring hur tunna garn och sedermera tyg som kan tillverkas och hur deras egenskaper skiljer sig från garn och tyg av importerad merinoull. Detta arbete jämför därför svensk jämtlandsull och finull med importerad merinoull genom karakterisering av fibrer, garn och tyg. Testerna visar att fibrerna av jämtlandsull har större diameter och kortare längd än de andra sorterna, men det färdiga garnet visade ingen signifikant skillnad i styrka utan alla tre hade en styrka kring 3-4 cN/tex. Garnet av finull kunde inte användas till stickning då det var för ojämnt och hade för stor variation i styrka. Av jämtlands- och merinogarnen producerades stickade tyger med en kvadratmetervikt kring 270 g/m2. Arbetet visade således att den svenska finullen inte lämpar sig för produktion av finstickade plagg. Dock har jämtlandsullen potential att användas i något grövre plagg än det väldigt tunna tyget som var arbetets målbild. Detta då garnet av jämtlandsull hade väldigt lika egenskaper som det av merinoull.The production of textile fibres increases each year and is today dominated by cotton and polyester. This industry causes a large environmental impact, not only through the use of chemicals early in the values chain but also emissions from transports of raw materials and textile products over long distances. An alternative to this global value chain, and a step towards a more renewable textile industry, is to a greater extent use locally produces raw materials that currently are overlooked. Today, about 54% of the wool produced in Sweden is thrown away. Several projects aimed to increase the use of the wool have been done, for example Swedish Wool Initiative. This resulted in a couple of companies starting to sell garments made of Swedish wool, but only coarser knitted garments. Here a knowledge gap exists around how thin yarns and subsequently fabrics that can be produced and how their characteristics differ from the ones of yarn and fabric made of imported Merino wool. Therefore, this study compares wool from the Swedish Jämtlands sheep and Finulls sheep with imported merino wool through characterization of fibres, yarn, and fabric. The tests showed that the fibres from the Jämtlands sheep have a larger diameter and shorter length than the other fibres, but the final yarn didn’t show any significant difference in strength. All three yarns had a strength around 3-4 cN/tex. The yarn made from the wool from the Finull sheep was not possible to knit because of irregularities and variation in strength. The yarn made from Merino and Jämtlands wool was knitted into fabrics with a square metre weight of about 270 g/ 2 m . Thus, the work shows that wool from the Finull sheep isn’t suited for production of fine knitted clothing. The Jämtlands wool on the other hand, has potential to be used in slightly coarser garments than the very thin ones that was the aim of this work. This is thought possible because of the similar characteristics between the yarn made from Merino wool and the one made from Jämtlands wool