Limits to climate action - Narratives of bioenergy with carbon capture and storage

In recent years, bio-energy with carbon capture and storage (BECCS) has been awarded a key role in climate mitigation scenarios explored by integrated assessment models and referenced in reports by the Intergovernmental Panel on Climate Change. Because a majority of scenarios limiting global warming to 2 °C or 1,5 °C include vast deployment of BECCS, a critical discussion has emerged among experts about the moral implications of thus introducing an unproven technology into the policy realm.In this paper, we analyse this discussion as it has played out between 2013 and 2019, with a focus on how expert narratives are constructed in the mass media about the possibilities for decarbonisation within the current political-economic order. We find there are almost no narratives that support massive deployment of BECCS, and that all narratives presuppose limits to decarbonisation imposed by the current political-economic system. The perception of such limits lead some to argue, through deterministic and apolitical narratives, for the necessity of negative emissions technologies, while others argue instead that “degrowth” is the only solution. Thus, there is a distinct lack of positive narratives about how capitalism can bring about decarbonisation.     

Breadfruit Fermentation in Pohnpei,Micronesia: Site Formation,Archaeological Visibility,and Interpretive Strategies

Fermentation is a common method of processing and preserving breadfruit throughout the Pacific Islands. While these pits are often reported in the archaeological record, they can pose some interpretive challenges. This paper presents an analysis of probable archaeological breadfruit (Artocarpus altilis (Parkinson) Fosberg) fermentation pits on Temwen Island, Pohnpei, Micronesia. Using the existing ethnographic record as a guide, I present archaeological and paleoethnobotanical criteria for identifying fermentation features. Architectural and stratigraphic analyses from four excavated pits match ethnographic expectations. Phytolith analysis shows some concurrence in terms of taxonomic data, but is more useful for indicating disturbance specific to building activities. Based on the distribution and size of pits present in the survey area, I suggest that breadfruit fermentation took place as primarily a household level (rather than community level) activity during the late prehistoric and early historic period in Pohnpei.     

The Neolithic refrigerator on a Friday night: How many people are coming to dinner and just what should I do with the slimy veggies in the back of the fridge?

Abstract

The prehistoric development of food storage represents a major evolutionary transition, one potentially more important than the initial domestication of plants. Researchers, however, have yet to really deal with some of the critical practical questions related to the materiality of food storage and decision-making. Drawing upon experimental research this paper seeks to identify and model some of the critical interconnections between anticipated food loss due to spoilage, storage decision-making and the need for people to store food for multiple years. Building on this foundation, and echoing ethnographic, ethnoarchaeological and archaeological research, this study argues that the concept of storage and surplus is underdeveloped and that in many cases the storage practices of prehistoric sedentary people do not reflect a food surplus so much as normal storage. Turning to a case study of changing Near Eastern Neolithic grain storage practices, this research argues that from the Natufian through Neolithic periods people increasingly relied upon cultivated domesticated plants and food storage. This required people to expand their use of pre-existing technology, such as plaster for lining storage features, to store sufficient amounts of food to overcome seasonal shortages, potential crop failures and minimise food spoilage due to a range of biological agents. Tracking shifts through time, the results of this study suggest that it is only with increased scale of food storage in the later stages of the Neolithic that we may see a materialization of a food surplus.     

Surface controls on the characteristics of natural CO2 seeps: implications for engineered CO2 stores

CO₂ injected into rock formations for deep geological storage must not leak to surface, since this would be economically and environmentally unfavourable, and could present a human health hazard. In Italy natural CO₂ degassing to the surface via seeps is widespread, providing an insight into the various styles of subsurface ‘plumbing’ as well as surface expression of CO₂ fluids. Here we investigate surface controls on the distribution of CO₂ seep characteristics (type, flux and temperature) using a large geographical and historical data set. When the locations of documented seeps are compared to a synthetic statistically random data set, we find that the nature of the CO₂ seeps is most strongly governed by the flow properties of the outcropping rocks, and local topography. Where low‐permeability rocks outcrop, numerous dry seeps occur and have a range of fluxes. Aqueous fluid flow will be limited in these low‐permeability rocks, and so relative permeability effects may enable preferential CO₂ flow. CO₂ vents typically occur along faults in rocks that are located above the water table or are low permeability. Diffuse seeps develop where CO₂ (laterally supplied by these faults) emerges from the vadose zone and where CO₂ degassing from groundwater follows a different flow path due to flow differences for water and CO₂ gas. Bubbling water seeps (characterized by water bubbling with CO₂) arise where CO₂ supply enters the phreatic zone or an aquifer. CO₂‐rich springs often emerge where valleys erode into CO₂ aquifers, and these are typically high flux seeps. Seep type is known to influence human health risk at CO₂ seeps in Italy, as well as the topography surrounding the seep which affects the rate of gas dispersion by wind. Identifying the physical controls on potential seep locations and seep type above engineered CO₂ storage operations is therefore crucial to targeted site monitoring strategy and risk assessment. The surface geology and topography above a CO₂ store must therefore be characterized in order to design the most effective monitoring strategy.     

Food for all: An agent-based model to explore the emergence and implications of cooperation for food storage

Abstract

A consistent access to food is paramount for humans at individual and group level. Besides providing the basic nutritional needs, access to food defines social structures and has stimulated innovation in food procurement, processing and storage. We focus on the social aspects of food storage, namely the role of cooperation for the emergence and maintenance of common stocks. Cooperative food stocks are examined here as a type of common-pool resource, where appropriators must cooperate to avoid shortage (i.e. the tragedy of commons). ‘Food for all’ is an agent-based model in which agents face the social dilemma of whether or not to store in a cooperative stock, adapting their strategies through a simple reinforcement learning mechanism. The model provides insights on the evolution of cooperation in terms of storage efficiency and considering the presence of social norms that regulate reciprocity. For cooperative food storage to emerge and be maintained, a significant dependency on the stored food and some degree of external pressure are needed. In fact, cooperative food storage emerges as the best performing strategy when facing environmental stress. Likewise, an intermediate control over reciprocity favours cooperation for food storage, suggesting that concepts of closed reciprocity are precursors to cooperative stocks, while excess control over reciprocity is detrimental for such institution.     

Droughts as random events in the Maya lowlands

Because the values of most of the parameters controlling the occurrence and severity of a drought in a given location are unknown, and no periodicity has been observed, droughts can be considered random events. Running a random number generator within the limits of the annual rainfall variability relevant to the Maya lowlands, and defining a “Lean Year”, it is observed that strings of lean years occur quite frequently. Defining “Severe Drought”, “Disaster”, and “Catastrophe” based on the length of these strings, it is observed that a severe drought occurs on average every 32 years, a disaster occurs on average every 130 years, and a catastrophe on average every 500 years. These values fit the measured variability of the Yucatan climate, as observed in lake core sediments and in the post conquest written records. It also fits the average occurrence of “megadroughts” in the US Great Plains.The fit between the random occurrence model and the actual, “measured” occurrence of droughts supports the notion that for all practical purposes, droughts had been random events in the Maya region and could not be predicted. The lack of evident periodicity could be one of the reasons why means for long-term storage of food products were not developed there. It may also have affected the relationship between the priesthood and the general populace in that region.Since the method described here can be applied to any climatic region once the rainfall variability and the sensitivity of the local agriculture are known or can be estimated, if similar results are found they may probably have affected other regions with other ancient cultures in a similar way.     

Are rocks still water‐wet in the presence of dense CO2 or H2S?

The various modes of acid gas storage in aquifers, namely structural, residual, and local capillary trapping, are effective only if the rock remains water‐wet. This paper reports an evaluation, by means of the captive‐bubble method, of the water‐wet character in presence of dense acid gases (CO₂, H₂S) of typical rock‐forming minerals such as mica, quartz, calcite, and of a carbonate‐rich rock sampled from the caprock of a CO₂ storage reservoir in the South‐West of France. The method, which is improved from that previously implemented with similar systems by Chiquet et al. (Geofluids 2007; 7 : 112), allows the advancing and receding contact angles, as well as the adhesion behavior of the acid gas on the mineral substrate, to be evaluated over a large range of temperatures (up to 140°C), pressures (up to 150 bar), and brine salinities (up to NaCl saturation) representative of various geological storage conditions. The water‐receding (or gas‐advancing) angle that controls structural and local capillary trapping is observed to be not significantly altered in the presence of dense CO₂ or H₂S. In contrast, some alteration of the water‐advancing (or gas‐receding) angle involved in residual trapping is observed, along with acid gas adhesion, particularly on mica. A spectacular wettability reversal is even observed with mica and liquid H₂S. These results complement other recent observations on similar systems and present analogies with the wetting behavior of crude oil/brine/mineral systems, which has been thoroughly studied over the past decades. An insight is given into the interfacial forces that govern wettability in acid gas‐bearing aquifers, and the consequences for acid gas geological storage are discussed along with open questions for future work.     

墓葬出土堆塑瓶(罐)类明器功用研究

本文以汉代至明代墓葬出土堆塑瓶(罐)类明器为研究对象,它们在制作技术与基本功用上的一致性是能够进行研究的基础。堆塑瓶(罐)类明器在墓葬中的基本功用为储存物品随葬,在此基础上逐渐显现出引魂升天、保佑后人、镇墓护魂等多元功用,并体现出与当时社会的丧葬习俗、民间信仰紧密结合的趋势。     

试析河南汉墓出土陶仓楼的分期及区域特征

本文在陶仓楼类型划分基础上,认为河南汉墓出土的陶仓楼至西汉晚期在豫中地区首先出现,为二层带腰檐建筑.西汉末至东汉早期此型陶仓楼向高层发展,区域由豫中扩展到豫北地区.东汉早期豫西、豫西南地区出现二层无腰檐陶仓楼.这时期河南陶仓楼数量和式样增多,分布范围广泛.东汉中期为陶仓楼繁荣期,豫北地区出现带附楼的院落式陶仓楼.东汉晚期各区域陶仓楼走向衰落.     

Natural flood management: small-scale progress and larger-scale challenges

ABSTRACT

Management of fluvial flood risk in the UK is undergoing a paradigm shift, with a change in emphasis from solely working with structural defences to considering catchment-based measures which attenuate flood runoff. Natural Flood Management (NFM) is promoted as a method that can reduce flood risk through the alteration, restoration or use of landscape features. Here we highlight the potential to manage runoff locally in the rural landscape using NFM by targeting flow pathways and utilising floodplains and riparian zones. Using two case study examples from the UK, we show that by accumulating dispersed small-scale storage in small catchment areas (<10 km²) can assist in attenuating flood runoff. However, there is currently a lack of evidence of measure effectiveness at larger catchment scales and for managing extreme flood events. Nevertheless, there is a strong evidence base to suggest many of these measures deliver a range of different ecosystem services if installed in the correct location in the landscape.