Earthen heritage constitutes 10% of sites on the World Heritage List and many of these sites are experiencing extensive deterioration caused by environmental forces, such as wind and rain. This study used a well-established test wall to investigate the impact of environmental conditions on the deterioration of earthen heritage at the remote and under-studied site of Suoyang Ancient City, Gansu Province, China, which is exhibiting widespread deterioration. Test walls have previously been used in earthen heritage research as they allow controlled experiments to be undertaken on complex, realistic structures without risking damage or loss of value to the historic material. This study used portable wind and rain erosion simulation devices to investigate experimentally (i) the comparative effect of wind, sediment-laden wind and wind-driven rain in causing deterioration to earthen heritage and (ii) how the incipient deterioration features produced by wind, sediment-laden wind and wind-driven rain on the test wall relate to the deterioration features recorded on the historic city walls. The test wall was subjected to low, medium and high intensities of clean wind, sediment-laden wind and wind-driven rain. The extent of deterioration produced was measured using repeat, high resolution laser scans before and after each test run. The deterioration features caused by each environmental force were notably different with clean wind removing the loose surface material, sedimentladen wind causing pitting and wind-driven rain causing incipient gullying. These incipient features compare well with more developed features seen on the historic walls. Wind-driven rain caused the greatest amount of deterioration while clean wind caused the least. However, as the frequency and duration of wind events at Suoyang is much greater than those of rain events, wind is likely to play an important role in the deterioration of earthen heritage over annual timescales. These findings show that conservation strategies at rammed earth sites like Suoyang need to address the impact of multiple environmental forces, such as clean wind, sediment laden wind and wind-driven rain.

ABSTRACT:This study was motivated by an interest in understanding the potential effects of climate change and glacier retreat on late summer water temperatures in alpine areas. Fieldwork was carried out between July and September 2007 at Place Lake, located below Place Glacier in the southern Coast Mountains of British Columbia. Place Lake has an area of 72 000 m 2 , a single inlet and outlet channel, and an approximate residence time of 4 days. Warming between the inlet and outlet of the lake ranged up to 3 C and averaged 1.8 C, which exceeds the amount of warming that occurred over the 1 km reach of Place Creek between the lake outlet and tree line. Over a 23-day period, net radiation totalled about 210 MJÁm , with sensible heat flux adding another 56 MJ m -2 . The latent heat flux consumed about 8% of the surface heat input. The dominant heat sink was the net horizontal advection associated with lake inflow and outflow. Early in the study period, temperatures between the surface and 6-m depth were dominantly at or above 4 C and were generally neutral to thermally stable, whereas temperatures decreased with depth below 6 m and exhibited irregular sub-diurnal variations. The maximum outflow temperature of almost 7 C occurred in this period. We hypothesize that turbidity currents associated with cold, sediment-laden glacier discharge formed an underflow and influenced temperatures in the deeper portion of the lake but did not mix with the upper layers. Later in the study period, the lake was dominantly well mixed with some near-surface stability associated with nocturnal cooling. Further research is required to examine the combined effects of sediment concentrations and thermal processes on mixing in small proglacial lakes to make projections of the consequences of glacier retreat on alpine lake and stream temperatures.

Stream surface albedo was measured at a location downstream of Place Glacier, Canada, in a steep bouldery channel. Portions of the water surface were visibly aerated as a result of the cascading flow even at lower discharges; at high flows, the stream was near-continuous whitewater. Albedo generally increased with discharge, from around 0.1 at the lower flows to 0.4 at the highest flows. This increase is consistent with the known effect of aeration on the reflectance of water. This discharge dependence of albedo needs to be accounted for in physically based models for predicting stream temperature to avoid biased predictions of net radiation. For steep proglacial streams that experience decreasing late-summer flows as a result of ongoing and future glacier recession, the associated decrease in albedo could promote higher stream temperatures, in addition to the effects of reduced flow depth and velocity.

Research focusing on climate change and cultural heritage informs heritage management and policy. Fatorić and Seekamp assessed this field up to 2015, highlighting the need for periodic reassessment of the field given the observed growth and research that documents how cultural heritage contributes to climate change mitigation and adaptation. Five years on, this systematic review reflects on the state of the art by evaluating 165 publications (2016-2020) about cultural heritage and climate change. We find the field continues to grow, and remains rich in disciplinary and methodological diversity, but predominantly represents research in and about Europe. The number of publications about integrating cultural heritage into adaptation and mitigation are increasing but remain relatively few compared to those about physical impacts on individual buildings or sites. The impact of climate change on intangible heritage has rarely been the sole focus of recent research. Although researchers are increasingly situating their research in a wider context of opportunities and barriers, vague timescales, and unspecific references to changes in the natural environment are additional limitations. This review also identified a lack of international collaboration, highlighting the urgent need for global cooperation and knowledge exchange on climate change and cultural heritage.

The variable climatic and environmental conditions associated with dryland regions can cause rapid erosion to both natural and man‐made earthen structures. Whilst there is a long history of research into the evolution of erosional landforms such as yardangs, little research has investigated how dryland processes influence the erosion of built structures. Earthen heritage sites located in arid and semi‐arid environments experience rapid deterioration caused by exposure to environmental drivers such as wind and rain. Understanding how these environmental drivers interact with each other and cause deterioration to earthen material is vital for successful conservation strategies. To address this need, we present the Vegetation and Sediment TrAnsport model for Heritage Deterioration (ViSTA‐HD) that simulates the risk of polishing, pitting and slurry on earthen heritage in a spatially specific manner. A technical description of the model is provided, and sensitivity and validation tests are reported. The model is then used to simulate the risk of deterioration occurring over centennial timescales at a Suoyang Ancient City, located in semi‐arid northwest China. The modelled risk of deterioration is in good agreement with deterioration patterns found at Suoyang, with the risk of polishing predominantly occurring around the wall edges, areas at risk of pitting echoing the dune formation and the risk of slurry occurring in drape‐like patterns down the wall face. Consequently, ViSTA‐HD is a powerful and versatile model that can be used to help inform our understandings of long‐term interactions between dryland processes and deteriorative impact on earthen structures. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd

Earthen heritage is one of the oldest and universal forms of heritage but its conservation poses many challenges. Establishing international collaborations could provide an efficient, sustainable mechanism to increase knowledge exchange, aiding the development of earthen heritage conservation strategies around the world. However, perceived differences in how Eastern and Western countries value earthen heritage and develop conservation strategies can pose challenges for establishing collaborations. To understand these perceived differences and whether they hinder collaborations, this paper compares British and Chinese heritage conservation policy and practice and then reports the results from an innovative workshop examining the approaches of 13 Chinese and 13 UK based heritage experts and researchers towards earthen heritage conservation. Workshop participants undertook bilingual discussions and completed a co-created questionnaire available in English and Mandarin. Both groups identified historic value as the most important value and maintenance of authenticity and integrity, need for scientific research and site scale conservation as vital considerations for conservation strategies. This study found that to understand the potential for collaboration, individual perspectives need consideration as well as policies and practices. This innovative bilingual, discussion-based approach has potential to aid collaborations for diverse international issues from wildlife conservation to cross-boundary pollution and climate change.

Uncertainties over future climatic conditions pose significant challenges when selecting appropriate conservation strategies for heritage sites. Choosing effective strategies is especially important for earthen heritage sites located in dryland regions, as many are experiencing rapid environmentally-driven deterioration. We use a newly developed cellular automaton model (ViSTA-HD), to evaluate the environmental deterioration risk, over a 100-year period, under a range of potential climate and conservation scenarios. Results show increased wind velocities could substantially increase the overall deterioration risk, implying the need for wind-reducing conservation strategies. In contrast, predicted increases in rainfall are not likely to increase the overall deterioration risk, despite greater risk of rain-driven deterioration features. Of the four conservation strategies tested in our model, deterioration risk under all climatic scenarios was best reduced by increasing the coverage of natural, randomly-distributed vegetation to 80%. We suggest this approach could be an appropriate long-term conservation strategy for other earthen sites in dryland regions.

Purpose This paper questions the common perception within heritage science that the environment is seen primarily as a risk factor that can change or impact heritage. The purpose of this paper is to reconceptualise the relationship between heritage and the environment within an Earth System Science framework, enabling a more sustainable approach for understanding and conserving heritage sites to be implemented. Design/methodology/approach To explore the relationship between heritage and the environment, this paper considers how perceptions of the environment within heritage science have been shaped in response to the conservation challenges facing movable heritage. Furthermore, as heritage encompasses a wide array of immovable buildings and sites whose relationships with the environment are complex and nuanced, this paper premises that the environment cannot be considered separately from heritage as it is intrinsically related by: providing components of heritage; modifying heritage; being modified by heritage; adding to heritage value; and acting as a co-creator of heritage. Findings This paper proposes that heritage science should learn from, and work within, the well-established Earth System Science framework. This enables interactions and feedbacks between heritage and components of the environment to be explored across a range of scales. Practical implications This systems-based approach allows heritage science to consider the environment more holistically and sustainably within its research and practice and better equips it to conserve movable and immovable heritage in the Anthropocene. Originality/value This paper provides a novel approach for viewing the relationship between heritage and the environment by using a well-established framework from other highly interdisciplinary fields.