The current issue and full text archive of this journal is available on Emerald Insight at: www.emeraldinsight.com/1756-8692.htm IJCCSM 11,1 Scenario-based hazard analysis of extreme high-temperatures experienced between 1959 and 2 2014 in Hulunbuir, China Received 2 May 2017 Chunlan Li, Jun Wang, Min Liu, Desalegn Yayeh Ayal, Qian Gong, Revised 15 August 2017 26 November 2017 Richa Hu, Shan Yin and Yuhai Bao 17 January 2018 (Author affiliations can be found at the end of the article) Accepted 8 February 2018 Abstract Purpose – Extreme high temperatures are a significant feature of global climate change and have become more frequent and intense in recent years. These pose a significant threat to both human health and economic activity, and thus are receiving increasing research attention. Understanding the hazards posed by extreme high temperatures are important for selecting intervention measures targeted at reducing socioeconomic and environmental damage. Design/methodology/approach – In this study, detrended fluctuation analysis is used to identify extreme high-temperature events, based on homogenized daily minimum and maximum temperatures from nine meteorological stations in a major grassland region, Hulunbuir, China, over the past 56 years. Findings – Compared with the commonly used functions, Weibull distribution has been selected to simulate extreme high-temperature scenarios. It has been found that there was an increasing trend of extreme high temperature, and in addition, the probability of its indices increased significantly, with regional differences. The extreme high temperatures in four return periods exhibited an extreme low hazard in the central region of Hulunbuir, and increased from the center to the periphery. With the increased length of the return period, the area of high hazard and extreme high hazard increased. Topography and anomalous atmospheric circulation patterns may be the main factors influencing the occurrence of extreme high temperatures. Originality/value – These results may contribute to a better insight in the hazard of extreme high temperatures, and facilitate the development of appropriate adaptation and mitigation strategies to cope with the adverse effects. Keywords Hazard, Detrended fluctuation analysis (DFA), Extreme high temperature, Hulunbuir, Weibull Paper type Research paper © Chunlan Li, Jun Wang, Min Liu, Desalegn Yayeh Ayal, Qian Gong, Richa Hu, Shan Yin and Yuhai Bao. Published by Emerald Publishing Limited. This article is published under the Creative Commons Attribution (CC BY 4.0) licence. Anyone may reproduce, distribute, translate and create derivative works of this article (for both commercial and non-commercial purposes), subject to full International Journal of Climate Change Strategies and attribution to the original publication and authors. The full terms of this licence may be seen at http:// Management creativecommons.org/licences/by/4.0/legalcode Vol. 11 No. 1, 2019 pp. 2-17 This study was jointly supported by the National Natural Science Foundation of China (grants no. Emerald Publishing Limited 41671095, 51761135024, 61631011 and 71373084) and the National Key Research and Development 1756-8692 DOI 10.1108/IJCCSM-05-2017-0098 Program of China (grant no. 2017YFE0100700). 1. Introduction Extreme high The environmental and socioeconomic impacts of climate change are of fundamental temperatures importance for future planning and management, and these are likely to result specifically from increasing climate variability, especially in terms of the frequency and/or intensity of extreme weather events (Easterling et al., 2000; Xu et al., 2006). Temperature and precipitation are perhaps the most widely used indicators to describe climate and weather, and small variations in mean temperature can also be associated with large changes in the frequency, intensity and magnitude of extreme events (Katz and Brown, 1992; Feng et al., 3 2013). For many impact applications and decision support systems, the evidence of extreme events is much more important than the mean climate state (Kunkel et al., 1999). Thus, there is a consensus within the climate change community that the frequency or intensity of extreme climate events will have more serious impacts on ecosystems, agriculture and human society (e.g. through floods, droughts, hurricanes, storms, extreme heat and cold) than changes in the mean values (New et al.,2006). In arid and semiarid areas, the spatial and temporal distribution of water resources is directly impacted by temperature conditions (Zhang et al.,2009), and these areas are much more vulnerable to climate change. Thus, exploring the changing characteristics of extreme temperature events in arid and semiarid areas is a prerequisite for assessing the impact of climate change on the regional ecological environment and agricultural development. As noted by the Intergovernmental Panel on Climate Change (IPCC) (IPCC, 2012), the vulnerability of an area to extreme weather events depends not only on the number of people affected but also on the area’s response capacity to extreme weather. These factors are related to the latitude, altitude, habitat suitability, climate zone, topography, other natural conditions, the level of economic development, traffic accessibility, irrigation, water conservation facilities and other socioeconomic conditions (Chong et al., 2015). Northeastern China is sensitive to climatic warming and has experienced dramatic changes in the past several decades (Piao et al., 2006); for example, the annual temperature has increased by more than 1°C over the past 20 years (Sha et al.,2002). Hulunbuir is a city within the territory of Inner Mongolia, which is one of the world’s four major natural grassland regions and is sensitive to global warming. Detailed climatic knowledge of this region is currently lacking and climate data are too sporadic and incomplete for informed decision-making. Previous studies of the region have mainly addressed the issues of vegetation protection and desertification, and the studies of extreme temperature events are sparse. Few studies of climate change in Inner Mongolia have mainly focused on the temporal and spatial variations of low temperature in winter and high temperature in summer (Chen et al., 2012a), and precipitation change (You et al., 2010; Su et al.,2010). Alternatively, they have selected simple indicators to analyze extreme events (Bai et al., 2009, 2014; Yan et al.,2014; Guo et al., 2015; Song et al., 2015; Jiang et al.,2016) that have mainly concerned the entire province, and ignored regional differences. Inner Mongolia is particularly vulnerable to temperature extremes as it is a wide provincial region in China, and is strongly influenced by the East Asian monsoon (Song, 2005), which may undermine development efforts and lead to incoherent responses to climate change. Extreme low temperature is prone to occur in Inner Mongolia and has been paid much attention to by researchers, from both long-term and short-term perspectives. For example, An (2015) analyzed the circulation characteristics of abnormal low temperature types during 1961- 2012, Chen et al. (2012b) analyzed the characteristics and causes of extreme low temperature in Inner Mongolia in the winter of 2009 and 2010 and Yang et al. (2011) investigated the effects of extreme low temperature. However, the analysis of extreme high temperature in a normally cold area is important as there is a focus on adaptation and mitigation strategies for extreme IJCCSM events. Moreover, for extreme high temperatures, there is no effective measure available to 11,1 prevent or minimize the impacts. Detailed information relating, for example, to variations in the frequency of extreme high temperatures and their effects on human activities is lacking in most conventional studies using hazard-scenario analysis. Thus, it is necessary to systematically address the occurrence of extreme temperature events in hazard-scenario analysis of Hulunbuir. The objectives of this study of Hulunbuir are: 4 to identify extreme high-temperature events during the past 56 years; to model the hazard of extreme high temperatures and then to produce a hazard- scenario design for further analysis; and to consider the possible impact factors of extreme high temperatures. 2. Material and methods 2.1 Study area Hulunbuir is located in between 47005’-53°200N and 115°310-126°04’E. It is governed as a prefecture-level city in northeastern Inner Mongolia of the People’sRepublicof China. The region is occupied by the grassland, the Hulun and Buir Lakes (the latter partially in Mongolia) and the Khingan mountain range (Figure 1). It is bordered by Russia to the north and west, Mongolia to the south and west, Heilongjiang Province to the east and Hinggan League to the south. The topography becomes gradually flatter from east to west, with decreasing elevation. The city of Hulunbuir has a humid continental climate (Köppen Dwb) bordering on subarctic (Köppen Dwc), although the northern part of the city is subarctic. Winters are long, very dry and severe, due to the semi-permanent Siberian High; whereas summers are short, very warm and rather wet, due to the influence of the East Asian monsoon. The weather tends to be sunny throughout the year with at least a 55 per cent probability of sunshine in all the months and an annual total greater than 2,700 h. Approximately, 70 per cent of the annual rainfall occurs during the three summer months. The annual mean air temperature and precipitation are approximately