So far, planning documents directly related to climate change adaptation are very rare. The earliest was that in 1990 Jim Titus of the U.S. Environmental Protection Agency published an innovative article in the Journal of the American Planning Association (Journal of the American Planning Association) on climate change adaptation strategies. He advocated adopting long-term projects. Take forward-looking steps, set priorities, and conduct strategic evaluations (Titus, 1990a). Therefore, the research on adaptive planning to adapt to climate change is still in the development stage. It is closely related to a new field of planning research—natural disaster mitigation. This research includes planning theory, land use, and infrastructure. The core areas of the system recognize the importance of climate change adaptation.
-The meaning of adaptation. In the climate change literature, the term adaptation is defined in the context of vulnerability, sensitivity, and adaptive capacity. Fussel and Klein (Fussel and Klein, 2006; Fussel, 2007) believe that the comprehensive concept of vulnerability should include two factors: external aspects related to the system exposed to the influence of climate; and system sensitivity and adaptability Relevant internal aspects. Vulnerability refers to the degree to which a system is susceptible or unable to cope with the adverse effects of climate change. Such effects include variability and extreme conditions. Vulnerability is a function that reflects the nature and scale of climate change and the speed of climate change faced by the system, as well as its sensitivity and adaptability (IPCC, 2007b: 883). Therefore, “adaptation” is defined as an adjustment made by the system, nature, or humans to respond to the existing or possible impacts of climate change (such as sea level rise) to ensure that they face the observed or predicted climate. When changing and related extreme situations, reduce its vulnerability or increase resilience (IPCC, 2007b: 869).
——The main content of adaptation. Adaptation to climate change mainly includes temperature changes, sea level rise, rainfall changes and extreme events. ① Temperature changes. According to carbon emissions, the world will warm at a rate of 0.2°C every 10 years (North America will be higher than the average warming rate) (IPCC, 2007c: 12). ②The sea level rises. According to carbon emissions, by the end of the 21st century, excluding the dynamic changes in the form of rapid ice drifting in the future, the sea level will rise from 0.18m to 0.59m (IPCC, 2007c; 13). ③ Changes in rainfall. The average value of the median rainfall is likely to increase in high latitudes and decrease in most subtropical regions (IPCC, 2007: 16); snow cover may decrease (IPCC, 2007: 15). ④ Extreme events (Figure 1). “The frequency of extreme heat, heat waves and heavy precipitation is likely to continue to increase” (IPCC, 2007c: 15). Planning needs to understand the precipitation types and coastal characteristics of the planned area on the basis of regional-scale climate change models, including land and residential types, topography, water resources, weather types and related variables. Based on these data, the regional model is connected to the global climate change model to determine more regional-based climate change impacts and prepare corresponding plans.
-Planning and analysis of adaptation to extension. Adaptive planning to deal with climate change needs to rely on an emerging interdisciplinary field that connects human beings with nature and their interrelationships. When the mitigation of natural disasters makes planners dependent on the research of geoscientists and other scientists, a new discipline including landscape ecology and land use ecology is emerging. This is an area where planners can show their talents (Alberti, 2008; Feddema et al. al., 2005; Liu et al., 2007; Turner et al., 2007). This new research field integrates science and policy, absorbs complexity research and system analysis methods, and clarifies vulnerabilities and adaptability.
-Types of adaptive planning. Adaptive planning can be carried out at multiple levels. Many cities have now incorporated climate change adaptation measures into their planning. They are an important part of sustainable development in a broad sense. At the community planning level, an integrated, strategic, participatory and flexible risk response plan needs to be prepared; at the overall planning level, it needs to include physical, biological, social science, climate change models, climate impact and vulnerability assessment, etc. For a comprehensive plan in many aspects, at least the content of the preparation should include coastline, watershed, land use and infrastructure planning, energy planning, etc.; at the regional planning level, the coastline master plan is the most important plan to deal with extreme conditions in the coastal zone (Blanco andAlberti, 2008). For example, the City of Seattle has adopted LEED standards in its public building construction and commercial district density award regulations. King County in Washington State takes into account both climate change mitigation and climate change adaptation measures in its county climate planning (King County, 2007; Swope, 2007). New York City’s new plan PlaNYC2030 (2007) is an early model of comprehensive and strategic planning. It integrates climate change mitigation and adaptation strategies, and emphasizes energy, sea level rise and water resources (Rosenzweig & Solecki, 2001) .
——Adaptive planning strategy. In the planning process, choose a planning strategy in response to various climate changes. For example, for sea level rise, there are three types of strategies. They are: ① Protective strategies. Through the construction of hardware facilities (for example, coastal levee) or the use of software measures (shore maintenance) to protect the land from marine encroachment, continue to play the current use. ②Adjustable strategy. With this, people can continue to occupy the land, but need to make some corresponding adjustments, such as lifting the building above the pillars. ③ Avoid or abandon strategy. That is, no attempt is made to protect the land from the effects of sea level rise (Bijlsma et al., 1996).
——Adaptability planning assessment. Adaptive planning requires planning evaluation, such as cost-benefit analysis, cost-benefit analysis, or multi-criteria evaluation methods. A recent report by the Organization for Economic Cooperation and Development (OECD) (Hallegatte, Henriet et al., 2008) proposed a conceptual framework for evaluating costs and benefits on a city scale.
-Research on the adaptability of mega-urban areas. The World Wide Fund for Nature (WWF) published in November 2009 “Huge Pressure on Mega-Cities: Ranking of Climate Vulnerability of Major Coastal Cities in Asia” (Figure 2) (Mega-Stress for Mega-Cities: A Climate Vulnerability Ranking of Major Coastal Cities in Asia) pointed out that many cities are extremely vulnerable to the threat of storms and floods, a large number of people and property are at critical juncture, and the level of socio-economic sensitivity is worrying. Among the countries and regions in the world, Asia can be said to be the most vulnerable region to climate change. Climate change and climate variability have and will continue to affect all areas of national security, economic security, human health, food production, infrastructure, water supply, and ecosystems. The report covers 11 central cities in Asia that are located in coastal areas or river deltas. Dhaka has the highest vulnerability ranking (9 points out of a 10 total vulnerability score), and others facing extremely high risks. The cities are Manila and Jakarta (8 points each), Kolkata and Phnom Penh (7 points each), Ho Chi Minh City and Shanghai (6 points each), Bangkok (5 points), Kuala Lumpur, Hong Kong and Singapore (4 points each). The report pointed out that Shanghai and Hong Kong have better adaptation strategies in the face of climate threats, while cities such as Dhaka, Manila and Jakarta are very vulnerable under the influence of sea level rise and extreme weather.