Evaluation of Climate Change Adaptation in the Energy Sector in China via a Composite Index

Climate change will affect the energy sector and the energy sector must take measures to adapt to future climate conditions. Before taking measures, it is necessary to understand the current adaptation of energy sector to climate change. Therefore, this paper is to assess the adaptation of energy sector in China to climate change in 2000-2017 through a comprehensive index. In order to establish a comprehensive index, three sub-indexes are determined first, and the climate change adaptation index (CCAI) is finally obtained through standardization treatment, weight determination and index summary. The results of CCAI show the energy sector in China put forward a reactive adaptation scheme in 2000-2010, which has a high system vulnerability. After 2010, there was an anticipatory adaptation scenario in which vulnerability was average. Although a short leap of planned adaptation was achieved in 2011 and 2013, which greatly reduced the vulnerability of the system, the state is not stable. As a whole, the energy sector in China has made some progress from the reactive adaptation scenario wherein the vulnerability was high to an anticipatory adaptation scenario wherein the vulnerability was average, indicating that the foundations for this sector to build a planned adaptation are currently being laid.


Introduction
Climate change is a major global problem that the international community is generally concerned about. Human beings are experiencing global warming, frequent extreme climate events, increasing disaster intensity and other climate change issues. Climate change is becoming a slow-onset disaster, which has a serious impact on human society, and its potential loss puts forward the requirements of adaptation to climate change to all countries in the world. The issue of global climate change is not only an environmental issue, but also an energy issue. Optimizing energy structure, improving energy efficiency, developing and applying low-carbon technology, changing ideas and enhancing awareness of low-carbon consumption are considered to be important ways to deal with climate change globally. The World Energy Council reports that sea-level rise, extreme weather, drought and flood caused by climate change can wreak havoc on the global energy system. At the same time, energy facilities such as power plants and distribution networks are likely to be affected by accelerated global warming. Christoph Frei, the secretary-general of the World Energy Council, added: "climate change is bound to affect the energy sector. We need a strong and transparent policy framework to unlock the long-term investments we desperately need for the future." So there is no doubt that the energy sector should take adaptive measures to deal with climate change and avoid serious problems, such as protecting power plants from the threat of water shortages and building power grid restoration systems. The energy sector is a key factor in climate change, as it not only generates GHG, but is also affected by climate change and has to adapt to future climate conditions. However, according to the current research on the energy sector in China in the context of climate change, it is generally divided into two categories. One is the study of energy law under climate change. For example, in 2011, Chen Jue focused on the relationship between energy development and climate change, and discussed the necessity and significance of providing legal protection for China to deal with climate change in energy legislation. Focusing on the Renewable Energy Law, Ke Jian (2015) analyzed and reviewed China's renewable energy legislation, and put forward many concrete policies and suggestions. In 2016, Wang Juan studied the development and law of renewable energy in the context of climate change. In the course of exploring the relevant systems of China's energy law, Liu Congcong (2017) found that optimizing the energy law system from the aspects of energy legal system, energy planning system and ecological compensation system can enable China to obtain certain advantages in the field of international climate negotiations In 2018, Zhai Ruiyan expounded the legal countermeasures or suggestions to deal with climate change from the point of view of energy law. The second is to assess the climate risks of energy in China. For example, Ding Ding(et al.2015) preliminarily analyzed the climate risk and its characteristics of the energy sector, tried to put forward the framework of climate risk assessment and management system of energy sector, and put forward corresponding suggestions on how to assess and manage the climate risk of energy sector and industry. Based on the influence factors of renewable energy development, Wang Bing (2016) discussed the vulnerability of climate change, quota system and social cognitive risk in its natural risk, and put forward relevant policy suggestions for climate risk aversion of renewable energy in China in the future. Yang Lizhi (et al.2016) studied the marine environment response in the context of climate change and its possible impact and potential risks on the safety of offshore energy channels to provide decision-making reference for addressing climate change and ensuring the safety of energy channels in China.
At present, China has become the largest energy producer and consumer in the world. All aspects of energy production and utilization are potentially affected by climate change, and even face severe climate challenges. Therefore, while carrying out climate risk assessment and formulating corresponding risk management strategies in the energy sector, China should also understand the current climate change adaptation of the energy sector in China. As far as the existing studies are concerned, there is almost no study on climate change adaptation in the energy sector. The energy sector is one of the sectors most vulnerable to climate change, and its role is far-reaching, which means that the energy sector must take measures to adapt to future climate conditions. Therefore, this paper uses a comprehensive index to evaluate the current adaptation of China's energy sector to climate change, which is not only the first time to directly reflect the adaptability of China's energy sector to climate change through quantitative comprehensive indicators, but also helps decision makers to look at the reality of the energy sector in a more comprehensive perspective, which is conducive to the decision-making in the future. This paper can initially meet the demand for tools, which provide more certainty for assessing the progress of the energy sector in adapting to climate change.

Methodology
In order to be able to evaluate the progress of the energy sector in adapting to climate change based on the comprehensive index, this paper is based on the following research steps: conceptual definition, indicator selection, indicator standardization, weighting of indicators, and aggregation of indicators, and finally a comprehensive indicator.

Definition of the conceptual
Adaptation is the adjustment of natural or human systems to actual or anticipated climate stimuli and their effects, thereby mitigating harm or taking advantage of beneficial opportunities (IPCC 2007). Generally speaking, adaptation can be divided into reactive adaptation and active adaptation. Reactive adaptation refers to the measures taken to deal with climate change after natural events, while the active adaptation includes expected adaptation and planned adaptation, which refers to the adaptation that occurs before the climate impact is observed and requires conscious and planned intervention to reduce its vulnerability (Beermann 2011;Busch 2011). In addition, according to IPCC (2001IPCC ( , 2007IPCC ( , 2014, vulnerability refers to the tendency of human systems to be adversely affected. According to the IPCC, the concept of vulnerability includes sensitivity or susceptibility to damage, or lack of capacity to respond and adapt to climate impacts. Therefore, vulnerability is understood as the opposite relationship with adaptive ability, that is, the greater the adaptive ability, the smaller the vulnerability of the system.

Indicator selection
According to the availability and correlation of the index, this paper selects five variables (three kinds of sub-indicators) as the object of analysis. The first category is reactive adaptation index, in which thermal energy is used instead of hydraulic energy for evaluation. The second category is the anticipatory adaptation index, measured by the gap between the total power production and the total power consumption. The third category is the planned adaptation index, in which three variables should be taken into account, including climate assistance funds for the energy sector in the area of adaptation, energy law in the context of climate change, and percentage of total installed renewable energy power generation. Based on the previously referenced criteria, Table 1 lists the selected indicators. For the index of "energy law in the context of climate change", this paper combs the relevant legal documents and divides them into different levels (see Table 2). Through the above method, the related index data of five variables under different adaptation types are obtained, and the original index data are summarized in Table 3. Table 1. Index selection based on adaptation type.  There is no specialized law on renewable energy.

2
There are specialized laws on renewable energy, but there are no corresponding administrative regulations. (but corresponding government rules, local regulations, 3 There are specialized laws on renewable energy, and there are corresponding administrative regulations, etc.

Indicator standardization
Because the variables are expressed in different units of measurement, in order to convert them into an index, according to the relationship between the indicators and adaptation to climate change, the deviation standardization method is used to convert them to obtain standardized indicators.
Then, if the relationship is positive, the formula used is However, when the relationship is negative, the equation used is where Xi is the parameter value of indicator for a given period, m is the minimum value of the variable for a given period, and M is the maximum value. Standardized by formulas (1) and (2), the values of each variable fluctuate between 0 and 1.

Weighting of indicators
After standardizing the data, the weight of each variable is determined according to the entropy method, and the following index weights are obtained: Reactive adaptation (W1)=7.01%, Anticipatory adaptation(W2)=10.6%, Planned adaptation(W3)=82.39%.(Among them, the proportion of climate assistance funds to the energy sector in the field of adaptation is 52.32%, the proportion of the legal level of energy to adapt to climate change is 16.08%, and the proportion of the total installed capacity of renewable energy is 13.99%.)

Aggregation of indicators
When each kind of data is standardized, the data of each variable are obtained. There are three variables under the planning adaptation index. If we want to get the planning adaptation index, we must summarize the data. Therefore, according to the proportion of the three variables in the planned adaptation, the planned adaptation index was obtained by weighted summary of X3'、X4'、X5'.

Climate change adaptation index (CCAI)
In order to obtain a comprehensive index for each year, the indices of each variable are multiplied by their respective weights, then the indicators are summarized and the climate change adaptation index (CCAI) is finally calculated. The index calculation formula would be the following: Where Wi represents the weight of various indicators, TOA represents a different type of adaptation index.
According to the research and collation of Professor Pineda (2019), we obtained the relationship between the comprehensive index of adaptation to climate change and the type of adaptation to climate change and the state of the system (see Table 4). Table 4. General system conditions as a function of the value of CCAI.

CCAI Range
System status Type of adaptation CCAI≤0.33 High vulnerability Reactive adaptation 0.33<CCAI≤0.66 Intermediate vulnerability Anticipatory adaptation CCAI≤1 Low vulnerability Planned adaptation The study of adaptability in China begins with the understanding of vulnerability, so the study of adaptability to China's energy sector cannot be separated from vulnerability. Table 4 shows the relationship between the indicator results and the adaptation type and the system state, where the index value is low when the vulnerability is high, and the index value is high when the vulnerability is low. Therefore, we can say that we pursue planned adaptation, because in this type of adaptation, not only the value of CCAI is higher, but also the value of vulnerability is lower.

Results
In order to understand the results, a classification index for each adaptation is first given: a reactivity adaptation index, an anticipatory adaptation index, and a planned adaptation index. And then the comprehensive index is analyzed.

Reactive adaptation index
This index (Thermal Generation /Total Generation) can be used to evaluate the substitution of thermal energy for hydraulic energy. When this index is increased, the hydraulic energy used for power generation is reduced. By producing thermal energy, more carbon dioxide is emitted, but the system vulnerability can be prevented from increasing. The relationship between this indicator and adaptation to climate change is therefore positive when the data are standardized (Abraham 2019). So the formula defined in equation (1)  In 2007, China's hydro-power development was booming, showing a vigorous scene, especially the successful closure of Xiluodu Hydro-power Station on the Jinsha River, indicates that China's hydro-power development has started a new journey. By the end of 2007, the total installed capacity of hydropower in China reached 145 million kilowatts, accounting for about 20.3% of the total capacity, an increase of 11.49% over the same period last year, which is consistent with the decline of thermal power generation in 2007-2008 shown in Fig. 1. In 2008, the natural disaster in China was very serious. In the south of China, 20 provinces (autonomous regions and municipalities directly under the central government) were affected by the severe cold rain, snow and freezing disaster, causing serious damage to water conservancy facilities. The earthquake disaster in Wenchuan, Sichuan Province, has resulted in the damage of a large number of reservoirs and hydro-power stations in 8 provinces (municipalities directly under the Central Government). This is also consistent with the increased reactivity adaptation behavior after 2008. In December 2009, the world climate conference was held in Copenhagen. Representatives from 192 countries discussed the global emission reduction agreement from 2012 to 2020. Since then, countries have begun to gradually control greenhouse gas emissions, including China. After 2011, the thermal power generation started to decline significantly, so the reactive adaptation index of energy sector in China gradually decreased, indicating that energy sector is also in the process of adapting to climate change.

Anticipatory adaptation index
When standardizing the data, the gap between the total power production and the total power consumption has a positive relationship with adaptation to climate change, so the formula defined in equation (1) was used.  From the raw data, the amount of electricity generated during this period is in excess of the demand, which is a good trend for the anticipatory adaptation. Moreover, by comparing the time of completion of the hydro-power station in Table 5 and the year of growth in the anticipatory adaptation index in Fig. 2, it was found that the time of the two was substantially consistent. It is indicated that the construction of the hydro-power station is in a certain degree beneficial to the anticipatory adaptation. Conversely, the good trends in the anticipatory adaptation are mainly due to construction of power plants, hydro-power stations and expansion of installed capacity of reservoirs and dams by predicting the impact of climate change.

Planned adaptation index
Planned adaptation consists of three variables: climate assistance funds for the energy sector in the field of adaptation, energy law in the context of climate change, and the percentage of total renewable energy power generation installations.
First, the data on climate aid funding for the energy sector in the adaptation area are mainly derived from OECD statistics on climate-related financing for development. By analyzing the proportion of energy sector in China in the funds used to adapt to climate change, we can measure the planned adaptation behavior of energy sector.
Secondly, the energy law in the context of climate change is measured according to the degree of perfection of renewable energy laws. At present, there are three levels. Until 2005, there were few specialized laws on renewable energy, even if there were regulations and policies for individual industries and regions. The adoption of the "Renewable Energy Law" in 2005 marks the existence of specialized laws on renewable energy in China, but there are no corresponding administrative regulations (corresponding government regulations, local regulations, etc). In 2013, the State Council issued "Some opinions of the State Council on promoting the healthy Development of Photovoltaic Industry", and so China has corresponding administrative regulations. Appendix 1 lists the relevant legal documents and hierarchical divisions.
Finally, the percentage of renewable energy power generation installed is increasing year by year from the original data. Among them, for China, the largest installed capacity is hydro-power. China has 678 million kilowatts of hydro-power resources and 5.92 trillion kilowatt hours of annual electricity generation, ranking first in the world and has a bright development prospect. The famous hydro-power stations in China include Three Gorges Hydro-power Station, Gezhouba Hydro-power Station and Xiaolangdi Hydro-power Station. Among them, the Three Gorges Hydro-power Station is the largest hydro-power station in the world, with an installed capacity of 22.5 million kilowatts.
When the data are standardized, the three indices show a positive relationship to adaptation to climate change, so the formula defined in equation (1) is also used. The standardized data are weighted summarized (see 2.5) and the planned adaptation index is obtained (Fig. 3). It is clear from Fig. 3 that there has been a small ladder jump in the planned adaptation index after 2005, mainly due to the adoption of the "Renewable Energy Law" in China. After 2010, the planned adaptation index increased significantly, which is the result of the comprehensive effect of three kinds of data. However, from the perspective of weight and raw data, climate assistance funds to the energy sector in the field of adaptation have played a relatively large role, as evidenced by the sharp drop in the 2015.

Aggregate adaptation to climate change index
Based on the formula defined in equation (3), the sum of the reactive, anticipatory, and planned adaptation indices results in the CCAI for the energy sector of China in the 2000-2017 period.