Adaptation to climate change in the Mekong River Basin: introduction to the special issue

Climatic Change (2018) 149:1–11 https://doi.org/10.1007/s10584-018-2242-y EDITORIAL Adaptation to climate change in the Mekong River Basin: introduction to the special issue Jaap Evers 1 & Assela Pathirana 1 Received: 13 February 2018 / Accepted: 15 June 2018 / Published online: 3 July 2018 # Springer Nature B.V. 2018 1 Introduction Adaptation, the adjustment in natural or human systems to a new or changing environment (Smit et al. 2000; Watson and Albritton 2001), has come to the forefront of discussions on climate change. Over the past decade, the number of scientific publications on adaptation to climate change has quadrupled (see Fig. 1). Human adaptation to climate change is about changing and adjusting behaviors at the present and also developing strategies to deal with the impacts of expected climate change in the near and far future. The majority of the world’s governments have ratified or signed the Paris Climate Agreement which, in addition to aiming to keep global warming below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels, established a global goal of Benhancing adaptive capacity, strengthening resilience and reducing vulnerability to climate change^ (Article 7). Yet, investment in adaptation is to date insufficient; the annual costs of adaptation for developing countries have been estimated as between US$140 billion and US$300 billion by 2030, an order of magnitude greater than current financing (UNEP 2016). Greater communication, cooperation, and coordination of both policy and scientific work that crosses both disciplinary and geographical boundaries are needed to help reduce or clarify uncertainties in future climate projections and inform adaptation decisions. This special issue attempts to improve the knowledge related to climate change adaptation in the Mekong River Basin and contribute to the broader literature on climate change adaptation (Fig. 2). The focus on the Mekong River Basin is critical: past research on climate change adaptation in the basin is limited, key areas in the basin have been identified as vulnerable to climate change (e.g., the Vietnamese Mekong Delta, the Cambodian Tonle Sap lake), and the basin is developing rapidly. * Jaap Evers 1 IHE Delft - Institute for Water Education, Delft, The Netherlands 7472 Climatic Change (2018) 149:1–11 7328 2 2337 4 45 3 2 36 1 620 739 1724 676 105 0 0 0 1998-2002 0 6 0 1993-1997 303 544 29 0 0 0 178 198 16 0 0 0 18 18 6 1988-1992 2429 CC and Migaon CC and Adaptaon CC and Migaon and Adaptaon CC and Migaon and Mekong CC and Adaptaon and Mekong CC and Migaon and Adaptaon and Mekong 2003-2007 2008-2012 2013-2017 Based on Google Scholar search "allintle: climate change migaon adaptaon", "allintle: climate change migaon ", "allintle: climate change adaptaon", similar search phrases were used including "Mekong", searches where done for the respecve me periods. Note: the search results unavoidably do contain tles of papers wich are not relevant for the topic under discussion. Fig. 1 Number of search results in Google Scholar with climate change and mitigation and/or adaptation with/ without Mekong in title, 1988–2017 This special issue will contribute to developing sustainable climate change adaptation strategies at basin, national, regional, and local scales. The papers in this issue focus on four interrelated themes: (1) impacts of climate change and human interferences on water, nutrient, and sediment flows (Shrestha et al. 2018); (2) climate change adaptation in urban centers (Radhakrishnan et al. 2018; Pathirana, Radhakrishnan, Ashley, Nguyen, and Zevenbergen 2018; Pathirana, Radhakrishnan, Nguyen, and Zevenbergen 2018); (3) climate change adaptation in rural areas (Gong et al. 2018; Gustafson et al. 2018); and (4) transboundary river management (Ngo et al. 2018). In the following section, we discuss the impacts of climate change on water resources in the Mekong River Basin. Next, we continue to further discuss the relation between climate change impacts and other developments in the basin and the interrelations. Finally, we present the lessons learned from the various contributions to this special issue and provide some overall conclusions. 2 The Mekong River Basin water resources and climate change The Mekong is a transboundary river with its watershed spanning over PR China, Myanmar, Thailand, Lao PDR, Cambodia, and Vietnam (Fig. 2). The portion of the Climatic Change (2018) 149:1–11 3 Fig. 2 Forecasted mean annual maximum daily temperature change (left; source: TTK and SASRC 2008) and forecasted mean annual precipitation change (right; source: MRC 2010) watershed in the latter four countries is also referred to as the Lower Mekong River Basin.1 The water resources of the Mekong River Basin are less well understood and less developed compared to the other large river basins of the world (e.g., Danube, Nile, and Amazon). Several emerging issues affect water security in the Mekong River Basin and its inhabitants’ ability to adapt to climate change. First, by 2060, the total population in the basin is projected to reach approximately 83 million, an increase of approximately 20% (MRC 2016). Though much of the population will live in urban environments,2 a large fraction of the population is expected to remain strongly dependent on the water resources of the Mekong River Basin for irrigated agriculture and fisheries. Second, there are plans for expansion of irrigation schemes and many hydropower projects (MRC 2016). Hydropower development, in tributaries and the main stem, results in unequal distribution of costs and benefits (Merme et al. 2013). Third, urbanization and economic 1 Cambodia, Lao, Thailand, and Vietnam are council members of the Mekong River Commission. Myanmar and China are dialogue partners. 2 The MRC (2016) expects that by 2060, between 50 and 70% of the people in Thailand, Vietnam, and Lao PDR, and 35% in Cambodia are living in cities. 4 Climatic Change (2018) 149:1–11 development are causing declining water quality and increasing irrigation demand. Reduced water and sediment flows contribute to coastal erosion, soil subsidence, and saltwater intrusion in the Vietnamese Mekong Delta (MRC 2016). In addition, the Mekong River Basin is also undergoing rapid socioeconomic change. A growing population and increasing wealth creates greater demand for water, energy, and food and drives land cover change. The challenges of managing and allocating water resources are exacerbated by the continuous development of dams in the Mekong River Basin. Water resources management and broader societal challenges might be amplified by the interaction of climate change and human interventions in the river basin and its local subsystems (e.g., hydropower dams, urban centers, irrigation systems). Given these challenges, the projected impacts of climate cha (...truncated)