Abstract
Purpose
Studies addressing rural residents’ understanding of global warming and their willingness to pay higher prices to mitigate it are very limited. The purpose of this study is to examine the general understanding and attitudes of rural residents in China regarding global warming and their willingness to pay higher prices to mitigate it.
Design/methodology/approach
This study surveyed 1,185 rural residents in three counties of coastal, middle and western China. Multivariate regression analysis was conducted to reveal the relationships between the willingness to pay higher prices to mitigate global warming and influencing factors.
Findings
The majority of respondents had heard of global warming; however, their knowledge of the phenomenon and its causes was very limited. Most respondents admitted the likelihood of risks from global warming. Although most respondents thought they had an obligation to mitigate global warming, only a small percentage of them were willing to pay higher prices to address the problem; the unwillingness of respondents to pay higher prices to mitigate global warming may have been associated with their low income and perceived inability to handle the cost, externalisation of responsibility and causes and lack of knowledge of how to affect it.
Originality/value
This study examines the general understanding and attitudes of rural residents in China regarding global warming and their willingness to pay higher prices to mitigate it. The research is conducive to climate change communications and the implementation of climate policies in China’s rural areas.
Keywords
Citation
Chang, G. (2018), "Rural residents’ understanding and willingness to pay higher prices for mitigation against global warming in China", International Journal of Climate Change Strategies and Management, Vol. 10 No. 5, pp. 711-728. https://doi.org/10.1108/IJCCSM-01-2017-0002
Publisher
:Emerald Publishing Limited
Copyright © 2018, Genying Chang.
License
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 & non-commercial purposes), subject to full attribution to the original publication and authors. The full terms of this licence may be seen at http://creativecommons.org/licences/by/4.0/legalcode
1. Introduction
The Intergovernmental Panel on Climate Change (2014) reported that since the 1950s, we have witnessed an unprecedented warming of the atmosphere and ocean, diminishing of snow and ice and a rise in sea level. It is extremely likely that global warming from 1951 to 2010 was the result of anthropogenic causes, especially the increase in greenhouse gas concentrations induced by human activity. Global warming may have severe, pervasive and irreversible effects on people, species and ecosystems with greater potential risks for disadvantaged people and communities. Mitigation measures can reduce the risks of global warming, and the way in which the public understands global warming is very important for its mitigation. The public’s understanding of global warming may affect their attitudes towards climate policies and the effectiveness of those policies, and the public’s low-carbon-consumption behaviour and lifestyle could result in less emission of greenhouse gases (Bostrom et al., 1994; Weber, 2010; Tobler et al., 2012).
Studies on the public’s understanding of global warming have mainly been conducted in developed countries, especially in the USA (Brechin, 2003; Capstick et al., 2015), and more attention should be paid to rural residents’ understanding of global warming in developing countries. Rural residents in developing countries are more exposed to the risks of global warming than urban residents because their livelihoods, such as farming and the availability of drinking water, are closely linked to the climate (IPCC, 2014). As far as China is concerned, although more studies are needed before allowing a clear assessment of the impact of anthropogenic climate change on China’s water resources and agriculture (Piao et al., 2010), global warming is likely to be harmful to rainfed farms in China, and the damage of global warming to those farms will grow over time (Wang et al., 2009). The damage of global warming to rainfed farms, their greater dependence on weather and their relatively disadvantaged socio-economic situations can make rural residents more vulnerable to global warming than urban residents. In addition, personal experience of a natural hazard has a substantial impact on risk perception (Wachinger et al., 2013), and it is likely that personal experience with local temperature changes may influence global warming beliefs and even behavioural responses (Weber, 2010; Spence et al., 2011; Shao, 2015). Specific experiences with local temperature changes, vulnerability to global warming and backward socio-economic situations may be responsible for rural residents’ particular understanding of and mitigation responses to global warming.
China is the most populous country in the world; its economy is the second largest. Because of its rapid economic development, China’s emission of greenhouse gases has been on the rise in the past decades. Its efforts to control and even reduce the emission of greenhouse gases can be very important for the mitigation of climate change. However, knowledge of the public’s understanding of global warming in China is relatively limited. Several international surveys have shown that the Chinese are more concerned about global warming and are more willing to pay to address it in comparison with Americans (Brechin and Bhandari, 2011; Jamelske et al., 2015). Those studies, as well as some domestic studies (Li, 2013; Yu et al., 2013; Duan et al., 2014; Yang et al., 2014), have included both urban and rural Chinese; however, they have generally included a higher percentage of urban respondents than urban Chinese in the total population. Nearly half of the Chinese population lives in rural areas; however, there are few studies that specifically address how rural Chinese understand global warming. This paper analyses rural residents’ understanding of global warming and willingness to pay higher prices to mitigate it. The respondents were from three counties in coastal Shandong Province, middle Shanxi Province and western Gansu Province. There may be regional differences in farmers’ perceptions of global warming. The physical, socio-economic contexts in eastern, middle and western China vary greatly. There are many geographical factors that might lead to regional differences, and it is beyond the scope of this study to reveal such factors. Thus, the possible differences in the understanding of global warming among the counties are ignored.
2. The factors that influence willingness to pay to mitigate climate change
To promote the public’s involvement in the mitigation of global warming, it is necessary to understand the factors that influence the public’s mitigation behaviours and their willingness to pay to support climate policies. Among the socio-demographic variables, it is consistently found in US studies that political affiliation has significant influence on the public’s support for climate polices (Dietz et al., 2007; McCright, 2009). The findings on the relationships between other socio-demographic variables, including income, race, age and education and support for climate policies, have been inconsistent (Dietz et al., 2007; McCright, 2009; Tobler et al., 2012).
In the literature on pro-environmental behaviour, it is widely argued that pro-environmental behaviours are value-based (Schultz and Zelezny, 1998), and a mega-analysis showed that certain clusters of values, in particular, self-transcendent and/or altruistic values, are strongly predictive of positive engagement with climate change (Corner et al., 2014). Perceived scientific agreement on anthropogenic global warming has been linked to support for climate policy and societal action (Ding et al., 2011; Marquart-Pyatt et al., 2011; McCright et al., 2013), whereas scepticism has been found to negatively influence people’s willingness to engage in climate change mitigation (Tobler et al., 2012). A correct understanding of the causes of global warming (O’Connor et al., 1999; McCright, 2009; Bord et al., 2000), concern (McCright, 2009; Spence et al., 2011) and perceived risks (Zahran et al., 2006; Dietz et al., 2007; O’Connor et al., 1999; Bord et al., 2000; Spence et al., 2011) was found to have a significant correlation with the public’s support for climate policies and their mitigation behaviours. Other factors that influence respondents’ willingness to pay for climate change include trust in information providers (Vainio and Paloniemi, 2013), confidence in policy (Yang et al., 2014), their level of mass media exposure (Akter and Bennett, 2011), perceived costs and perceived climate benefit (Tobler et al., 2012), perceived personal efficacy in climate change mitigation (Spence et al., 2011) and affect and imagery (Leiserowitz, 2006).
In this study, the factors that influence farmers’ willingness to pay higher prices to mitigate climate change were surveyed from two complementary perspectives. One perspective was that some respondents who were not willing to pay higher prices to mitigate global warming were asked to explain the reasons for their unwillingness. The other was that a quantitative analysis was made to test whether farmers’ willingness to pay higher prices was associated with the demographic variables of sex, age and education, perceived impact of local temperature rise on wheat and maize, perceived risks, knowledge of global warming, perceived ability to mitigate global warming and perceived obligation to mitigate global warming. According to the value-belief-norm theory, perceived ability to reduce threat and the sense of obligation to take pro-environmental actions are causally associated with pro-environmental actions (Stern et al., 1999). Two factors could explain private-sphere behaviour, environmental citizenship and policy support (Stern, 2000). It is hypothesised that perceived ability and obligation to mitigate global warming are associated with willingness to pay higher prices to mitigate global warming.
3. Methods
3.1 Three case counties
The three case counties are Shanxian in coastal Shandong Province, Wenxi County in middle Shanxi Province and Anding District in western Gansu Province. These three counties lie near the dividing line between North and South China, within similar latitudes (Figure 1). As the altitude increases, the average annual temperatures decrease, and the average annual precipitation decreases from eastern Shanxian to middle Wenxi and further to western Anding. The altitude in Shanxian varies between 40 and 59 m, and that in Wenxi varies between 450 and 1,500 m, whereas the altitude in Anding increases from 1,671 to 2,577 m. The average annual temperature in Shanxian between 2006 and 2015 was 15.0°C, 1.8°C higher than that in Wenxi and 6.8°C higher than that in Anding. The average annual precipitation in Shanxian, Wenxi and Anding between 2006 and 2015 was 670, 510 and 454 mm, respectively. The average temperature has increased over the past 50 years in all three counties. The annual increase in temperature varies between 0.02°C and 0.05°C (Figure 2). Rainfed agriculture is dominant in the three counties, which are subject to drought and other extreme weather. Wheat and maize are planted in all three counties. The population of rural residents in Shanxian, Wenxi and Anding in 2015 was 611,000, 219,000 and 234,000, respectively.
3.2 Respondents and procedure
A total of 1,185 questionnaires were received in the three case counties: 531 in Shanxian, 340 in Wenxi and 314 in Anding. The samples in each county were not fully proportional to the rural population, and more samples in Shanxian should have been received. In each county, several towns and townships were randomly selected as case areas. The potential respondents in each town or township were selected randomly, and their number was proportional to their residents. The potential respondents were no less than 20 years old. The enumerators were graduate and undergraduate students, and they conducted face-to-face surveys. They explained the survey’s purpose to potential respondents and then asked them to accept the survey. The enumerators read the items on the questionnaire to respondents and recorded their responses. After completing the structured questions, some respondents were further interviewed on issues such as the concrete benefits and costs of local temperature increases and the reasons for their unwillingness to accept higher prices to mitigate global warming. It took approximately 30-40 min to complete each survey. The respondents received a towel as incentive for their participation, and the response rate was approximately 60 per cent. Because of the face-to-face nature of the survey, missing data were very limited.
Some of the female respondents said they knew nothing and refused to take the survey. Thus, male respondents were somewhat overrepresented (Table I). Other demographic features of the respondents in the three counties were similar to those of the whole population that resides in those counties most of the year.
3.3 Questions and items
The three-page questionnaire included the following questions and items: demographic variables sex, age and education level (Table I); perceived impacts of local temperature change on wheat and maize; whether respondents had heard of global warming and from where; understanding of the phenomenon of global warming and its causes; perceived risks of global warming; perceived individual and family ability to mitigate global warming; perceived obligation to mitigate global warming; and willingness to pay higher prices to mitigate global warming. Understanding of the phenomenon of global warming and its causes are open-ended questions, while the others are structured questions (Table II).
Fossil fuels and their related products are the main source of greenhouse gas emissions in China (Chmutina et al., 2012). China has used economic instruments of taxation and flexible pricing systems to restrict the use of fossil fuels (Xu et al., 2010). For example, consumption taxes on petrol increased from 0.2 to 1.0 CNY per litre in 2009, to 1.4 CNY per litre in 2014 and further to 1.52 CNY per litre in 2015; and consumption taxes on diesel increased from 0.1 to 0.8 CNY per litre in 2009, to 1.1 CNY per litre in 2014 and further to 1.2 CNY per litre in 2015. In 2012, electricity tariffs were introduced for household electricity consumption, and an extra tariff must be paid for excessive electricity consumption. Increases in taxes and the introduction of electricity tariff systems could lead to increase in the prices of fossil energy and its related products. Thus, it was surveyed in this study whether farmers are willing to pay higher prices for fossil fuel energy and related products to mitigate global warming. In the previous studies, willingness to pay to reduce emissions of greenhouse gases has been an important aspect of understanding the public’s mitigation behaviours (Dietz et al., 2007; Brechin and Bhandari, 2011; Duan et al., 2014; Yang et al., 2014).
3.4 Analysis method
The features of how respondents understood global warming and their willingness to pay higher prices to mitigate it were reported by percentages. Cronbach’s alpha coefficients were calculated to evaluate the internal consistency of the latent variables (Table II). A linear ordinary least squares regression analysis was conducted to reveal the relationships between the willingness to pay higher prices to mitigate global warming and the underlying variables. When a variable has several measuring items, the mean value of all the items was calculated:
The software PASW Statistics 18.0 was used to calculate percentages and Cronbach’s alphas and to perform regression analysis. Figure 1 was made by the software ArcGIS 10.2, and Figure 2 was made by Microsoft Office Excel 2007.
4. Perceived impact of local temperature rise on agriculture
The three counties selected for this case study exhibit a monsoon climate with much more precipitation in July, August and September than in other months. Drought is common during the wheat-growing season between March and July. Of all respondents, 41.1 per cent said that the rise in local temperature had a minor negative impact on wheat, and 13.5 per cent recognised a significant negative impact (Table III). Only 20.0 per cent of respondents thought that the rise in local temperature had a positive impact on wheat. The respondents explained that the higher temperature led to a greater degree of drought and more severe cases of wheat diseases. During the growing season for maize, there is relatively more precipitation, and drought caused by higher temperature occurs less frequently. Of respondents, 43.2 per cent said that the rise in local temperature had a negative impact on maize, 11.4 per cent points less than for wheat. Of respondents, 28.9 per cent recognised a positive impact on maize, approximately 9 per cent points more than for wheat. The respondents who observed a rise in local temperature as a positive for wheat and maize said that the temperature increase is associated with a longer growth season and a higher yield of wheat and maize.
5. Understanding of global warming
5.1 Awareness and understanding of the phenomenon of global warming
Of all respondents, 73.2 per cent had heard of global warming. The respondents had learned about global warming mainly through television programmes (72.3 per cent), followed by the internet (20.5 per cent), other people (15.8 per cent), newspapers (9.9 per cent) and radio (4.1 per cent).
Although the majority of respondents declared they had heard of global warming, most of them did not have a clear understanding of what global warming is. Approximately 73 per cent of all respondents said that they did not know what global warming was (Table IV).
Of all respondents, 58 per cent who revealed their understanding of the phenomenon of global warming viewed global warming as a rise in temperature, which was followed by air pollution (12.6 per cent), environmental pollution (7.0 per cent), emission of carbon dioxide (6.3 per cent), ice melting (4.4 per cent) and deforestation (4.1 per cent).
5.2 Perceived causes of global warming
Most respondents (78.3 per cent) said that they did not know the causes of global warming (Table V). Among respondents who offered answers to the causes of global warming, only 5.8 per cent regarded it as a natural process, whereas the remaining majority of survey respondents attributed global warming to anthropogenic causes. Four types of anthropogenic causes were cited by respondents: pollution, including air pollution (21.8 per cent), industrial pollution (8.2 per cent) and environmental pollution (16.0 per cent); emissions of gases, including emission of carbon dioxide (16.3 per cent), hot gases (3.9 per cent) and waste gases (6.6 per cent); deforestation (9.7 per cent) and ecological degeneration (7.0 per cent); other causes that may be linked to the emission of gases and heat included too many cars (8.6 per cent), too many industrial plants (8.2 per cent), too many people (7.0 per cent) and consumption of fossil fuel (3.5 per cent).
5.3 Perceived risks of global warming
The Cronbach’s α for the five items of risk perception is 0.823, indicating that the risk perceptions of respondents are internally consistent. More than half of respondents thought it was likely that global warming would cause unpredictable risks and risks for individuals, their families, the whole of society and future generations (Table VI). Approximately two-thirds of those who perceived the likelihood of risks from global warming thought it was mildly likely that global warming would cause various risks, whereas the remaining one-third said it was very likely. Approximately 10 per cent of all respondents could not judge the likelihood of the risks from global warming for individuals and their families, whereas approximately 20 per cent could not judge the likelihood of the unpredicted risks and risks from global warming for society and future generations. Less than 5 per cent of respondents thought it was absolutely unlikely that global warming would cause various risks.
6. Mitigating global warming
6.1 Responsibility attribution
Of respondents, 31.2 per cent thought that the central government should be mainly responsible for the mitigation of global warming, and 14.7 per cent thought it was the responsibility of the local government to mitigate global warming. In total, 45.9 per cent of respondents thought that the government should take on the main responsibility of addressing global warming, which was followed by industrial firms (21.6 per cent), nongovernmental organisations (11.3 per cent) and international organisations (5.5 per cent). Only 8.7 per cent of respondents thought that individuals and their families should take the lead in addressing global warming, whereas 7.0 per cent did not have any idea of who should be responsible for mitigating global warming.
6.2 Perceived ability to mitigate global warming
Most respondents thought they or their families would be unable to mitigate global warming. Less than 3 per cent of all respondents thought that they or their families had a strong ability to mitigate global warming, and approximately one-quarter of them showed a little ability (Table VII). The respondents with declared ability thought that they and their families could help to mitigate global warming by reducing car and electricity use, not directly using straw as fuel, planting trees and not polluting the environment. The reasons listed by respondents who showed inability included lack of money, powerlessness, elderliness, lack of knowledge of how to do it and inability of human beings to control the natural process of global warming.
6.3 Perceived obligation to mitigate global warming
Most respondents thought they and their families had an obligation to mitigate global warming. Approximately 20 per cent of all respondents thought that they and their families had a full obligation to mitigate global warming, whereas approximately half of respondents recognised a slight obligation (Table VIII). The respondents who admitted obligation to mitigate global warming thought that everyone had an obligation to do the same. Approximately 30 per cent of all respondents did not think they and their families had an obligation to mitigate global warming due to powerlessness, uncontrollability of global warming and lack of knowledge of how to act to mitigate global warming.
6.4 Willingness to pay higher prices to mitigate global warming
The majority of respondents did not agree to increases in the prices of gasoline and diesel oil, coal, electricity, chemical fertiliser and agricultural plastic film to mitigate global warming (Table IX). Of respondents, 65.0, 66.8, 78.5, 79.4 and 74.2 per cent refused to increase the prices of gasoline and diesel oil, coal, electricity, chemical fertiliser and agricultural plastic film, respectively.
6.5 The factors that influence willingness to pay higher prices to mitigate global warming
Of all respondents, 147 were interviewed concerning the reasons for their unwillingness to pay higher prices to mitigate global warming. A total of 62.6 per cent of them said that their incomes were too low and higher prices would become a heavy burden for them, and 38.1 per cent said that farming benefits are low and higher prices would make farming no longer profitable (some respondents said both), whereas only 12.9 per cent of the interviewed respondents reported other reasons. In comparison to electricity (13.6 per cent), chemical fertiliser (12.5 per cent) and agricultural plastic film (14.1 per cent), relatively more respondents supported the increase in prices of gasoline and diesel oil (22.8 per cent) and coal (20.8 per cent). Some respondents who were willing to accept higher prices on gasoline and diesel oil said that their consumption of gasoline and diesel oil was very limited, and thus, higher prices would not have an obvious impact on them.
The regression analysis involved 1,159 samples. The F-value was 17.00, significant at the 1 per cent level, which means that the whole linear equation was significant (Table X). The adjusted R2 was 11.0 per cent, showing that all of the independent variables could explain 11.0 per cent of the variance in the willingness to pay higher prices to mitigate global warming. Both non-standardised and standardised coefficients of independent variables were reported. According to the non-standardised coefficients, perceived ability and obligation to mitigate global warming were significantly and positively correlated with willingness. The standardised coefficient of perceived ability to mitigate global warming was 0.16, 0.05 larger than that of perceived obligation to mitigate global warming, meaning that the former played a somewhat more important role in influencing the willingness to pay higher prices to mitigate global warming than the latter. The non-standardised coefficient of the variable county was also positive and significant, showing that respondents in Anding were more willing to pay higher prices to mitigate global warming than those in Wenxi, and that respondents in Wenxi were more willing to pay than those in Shanxian. Perceived impact of local temperature change on wheat and maize was negatively and significantly correlated with willingness, and it seems that the farmers who encountered a relatively significant negative impact of global warming were not inclined to be more willing to pay higher prices to mitigate global warming than those who encountered a minor negative impact and who had experienced a significant impact. Sex, age, education level, perceived risks of global warming and knowledge of global warming had no significant correlation with willingness.
7. Discussion
The rise in local temperature may have brought both benefits and costs to rainfed agricultural production in the three northern Chinese counties of this case study. The main cost is related to prolonged drought, whereas the main benefit is associated with a longer growing season and a higher yield. Benefits and costs varied by region, and it seems that they also varied by households. The impacts of the rise in local temperature in the past decades on agriculture, as well as on health and household fuel consumption in winter, may have led to concern on the part of Chinese rural residents about global warming. More than 70 per cent of the rural respondents in this study paid attention to television programmes related to climate change and had heard of global warming.
Although most of the rural respondents had heard of global warming, their knowledge about it is very limited. Only approximately one in five respondents had a clear mental picture of global warming. Among those who shared their understanding of global warming, more than 60 per cent observed global warming as a temperature rise and emissions of carbon dioxide, whereas approximately 20 per cent regarded global warming as pollution. Many residents in Western countries tend to misunderstand global warming as ozone depletion (Kempton, 1991; Read et al., 1994; Kempton, 1997; Dunlap, 1998; Nisbet and Myers, 2007; Reynolds et al., 2010). In comparison, very few respondents in this study linked global warming to ozone depletion, which may be because rural residents in China are not familiar with ozone depletion. The overwhelming majority of respondents attributed global warming to anthropogenic causes, linking it mainly to emissions of gases from industrial plants and vehicles, pollution and reduction in vegetation. Some respondents associated global warming directly with emissions of carbon dioxide. Industry in the rural areas of the three case counties is underdeveloped, and the number of various vehicles is also limited. This means that, to a great degree, respondents were disassociated from the causes of global warming.
Most respondents recognised the negative impact of the rise in local temperature on wheat and maize, and they further admitted that global warming is likely to cause unpredicted risks and risks for individuals, their families, the whole society and future generations. This may support the argument that experience with local weather may influence global warming beliefs (Howe et al., 2013). In addition, these results are in line with the findings in Western countries, where many respondents think that the risks of global warming outweigh its benefits (Leiserowitz, 2005; Lorenzoni and Pidgeon, 2006).
The majority of respondents in this study were unwilling to accept higher prices to mitigate global warming. This seems contrary to some of the previous studies, according to which most of the Chinese are willing to pay to address climate change (Brechin and Bhandari, 2011; Li, 2013). One possible reason for this inconsistency is that respondents in the previous studies have been disproportionately urban (Brechin and Bhandari, 2011; Li, 2013; Yu et al., 2013; Duan et al., 2014; Yang et al., 2014). Another reason may be that respondents of this study cannot represent the whole of rural China, and it is possible that the percentage of all of rural China that are willing to pay to address global warming is higher than that in this study. However, the most important reason for this inconsistency may result from the different questions and the choice of wording with regard to willingness to pay. Two surveys are cited here for comparison. In the nationwide survey conducted by the China Climate Change Communication Centre in 2012, the question was whether the respondent would be willing to pay more for environmentally friendly products. Environmentally friendly products include a wide range of products that may not be necessities, and the price increase of these products may not have a direct impact on respondents and their families. In contrast, the products that are used in this study are necessities for most (if not all) respondents, and price increases would have a direct impact on respondents and their families. Household agricultural production costs would be increased, as well as transportation costs and the costs of energy consumption. Just as most Americans do not support policies of carbon taxes or a gas tax (Dietz et al., 2007), most of the rural residents in China are unwilling to accept higher prices on the goods that are necessary for agricultural production and daily life. The other survey is an international one conducted in 2009 by the Pew Global Attitudes Project, and the wording was “please tell me whether you agree or disagree with the following statement: people should be willing to pay higher prices to address global climate change” (Brechin and Bhandari, 2011, p. 874). In this wording, it is not clear which products are involved, and respondents may not link higher prices with their own lives. Similarly, many respondents may disconnect “people” from themselves. When respondents are not aware of the direct impact of higher prices on their own lives, they may support higher prices. It seems that more careful surveys are needed to reveal the willingness of both urban and rural Chinese to pay to address global warming.
The respondents attributed their unwillingness to pay higher prices to mitigate global warming mainly to low income; that is, higher prices may make agricultural production with low benefits unprofitable and function as a burden on their lives. Overwhelmingly, respondents attributed the main responsibility of addressing global warming to government, industry, international organisations and non-governmental organisations, as has the public in developed countries (Leiserowitz, 2006; Whitmarsh, 2009). The externalisation of responsibility and causes can also be a reason for their unwillingness to pay. The regression analysis further revealed that the perceived ability was positively correlated with willingness to pay higher prices to mitigate global warming. Most respondents believed that they were unable to mitigate global warming, and their perceived inability may lead to unwillingness to pay higher prices to mitigate it.
Most respondents declared an obligation to mitigate global warming, and the perceived obligation was positively correlated with willingness to pay to mitigate global warming. However, it seems that perceived obligation did not lead to general acceptance of higher prices to mitigate global warming. Furthermore, previous studies have shown that perceived risks could result in the public’s support for climate policies or low-carbon behaviour (Dietz et al., 2007; Bord et al., 2000; Spence et al., 2011; Zahran et al., 2006). However, the regression analysis in this study showed that perceived risks did not have an obvious influence on willingness to pay higher prices. Moreover, most respondents in this study admitted that it is likely that global warming will cause various risks. This does not match low acceptance of higher prices. The question is why their perceived obligation and perceived risks do not translate into a willingness to pay higher prices. Previous studies in natural hazards and climate change can help explain this paradox (Lorenzoni et al., 2007; Whitmarsh, 2008; Whitmarsh et al., 2011; Wachinger et al., 2013). There may be barriers that hamper personal accountability for the purported risks of global warming, which typically translate into a willingness to pay higher prices. Low income and perceived inability may act as main obstacles for rural Chinese in mitigating global warming. Other factors may include the externalisation of responsibility and blame, as well as a lack of knowledge of the causes of global warming and how to act to mitigate it.
It is difficult to explain why the perceived impact of the rise in local temperature was negatively correlated with a willingness to pay higher prices. One potential reason may be that the farmers who encountered a relatively large negative impact from global warming are poor and thus are unable to pay higher prices. In contrast, farmers who encountered a minor negative impact from global warming are more capable of paying higher prices to mitigate climate change. More studies are needed to explain this negative relationship. The respondents’ knowledge of global warming in this study was very limited. This correlates with low acceptance of higher prices, and this may be the reason for the insignificant relationship between knowledge of global warming and willingness to pay higher prices. The demographic variables of sex, age and education had no obvious correlation with willingness to pay, and any meaningful connection may be sample-specific.
China’s rural residents are less to blame for the causes of global warming, and they are inclined to externalise the responsibility for the mitigation of global warming. However, it is still important to obtain their perceptions of global warming and willingness to participate in mitigation actions. First, most of the public in Western countries is inclined to favour mitigation behaviours that could be easily undertaken and that do not levy unusual hardships (Bord et al., 1998; Tobler et al., 2012). This may also be the case for rural Chinese. A better understanding of global warming may promote mitigating behaviour in rural Chinese in daily life, including recycling, reuse and energy saving methods. Second, although inconvenient, some types of mitigation behaviour will not bring any obvious economic burden to farmers. A typical example is the use of methane gas. The Government of China has made great efforts to expand the development of the methane gas industry over the past decades, and a better understanding of global warming may be conducive to helping to expand it further. This would involve its more efficient use and the reduction in the burning of crop straw, which until now has been quite common in rural China. Third, a better understanding of global warming may promote the adoption of mitigation behaviours among richer farmers, who would be able to bear the higher economic weight of more energy-efficient household appliances and vehicles. Finally, the income of rural Chinese will increase continuously with further economic development, and more and more rural Chinese will live in towns and cities as a result of urbanisation. Their contribution to global warming may increase, and therefore, it is becoming more and more pertinent to learn how they understand global warning and their potential mitigation behaviour.
The samples from the three case counties may not represent all the residents in rural China, and efforts should be made in the future to obtain nationally representative samples. Further, there are differences in the willingness of farmers to pay higher prices to mitigate global warming, and additional studies are needed to reveal the reasons behind such differences. Possible regional differences in the public’s understanding of global warming should also be addressed in the future. In addition, the perception of local temperature changes should be surveyed, and its possible relationship with global warming beliefs should be analysed (Shao, 2015). Still, research methods are important, and the results from qualitative and quantitative research (open-ended questions and checklist questions) may differ (Henry, 2000; Whitmarsh, 2009; Akerlof et al., 2010). More accurate and abundant information may be obtained if open-ended questions are used by surveying risk perception, the impacts of increases in local temperature and the ability to mitigate global warming. Moreover, family income information and other possible explanatory variables should be included within surveys, and integrated models should be developed to explain willingness to pay. Finally, various avenues of greenhouse gas emission and mitigation behaviour and projects in rural China, such as the use of renewable energy and reforestation, should be surveyed in the future.
One policy suggestion is that climate change communications in China should be improved and strengthened. The rural residents in China have learned about global warming mainly through television programmes, especially China Central Television. Television programmes have introduced general knowledge about the phenomena, causes and impacts of global warming by using academic terms that may challenge a broader audience, usually without clear geographical linkages and personal relevance to the audience. Most rural Chinese are unfamiliar with and uninterested in some frequently reported concepts such as rising sea levels, melting ice and species extinction. Such information may lead them to feel to some degree that global warming is something irrelevant to them. The concept of emissions of greenhouse gases is too abstract for them to understand, and they hardly link straw burning and their consumption of fossil fuels to global warming. It may be possible that rural Chinese need more locally and personally relevant information on global warming. They need concrete information on local climate change and its possible impact on them, on the relationships between their agricultural production, behaviour and lifestyles and global warming and on how to act to mitigate global warming (Leal-Filho, 2009). Armed with locally and personally relevant information and knowledge, they are more likely to respond to global warming. The other policy suggestion is that climate policies should take their possible influence on residents into account. Measures that will not bring obvious economic costs to individuals and families should be preferentially adopted. Additionally, governments at various levels should provide financial support for rural Chinese to mitigate global warming, such as subsidies for the recycling of agricultural plastic film, more energy-efficient vehicles and the use of renewable energy.
8. Conclusion
The main purpose of this study is to examine the general understanding and attitudes of rural residents in China regarding global warming and their willingness to pay higher prices to mitigate it. The respondents were 1,185 rural residents in three counties of coastal, middle and western China. The majority of the rural respondents in this study had heard of global warming, but at the same time, they had very limited knowledge about it. Most respondents recognised both the negative impact of the rise in local temperature on agriculture and the various risks that are caused by global warming. The majority of them were unwilling to accept higher prices to mitigate global warming, although they felt an obligation to do so. Their unwillingness could be attributed to low income, the externalisation of responsibility and causes, a perceived inability to mitigate global warming and a lack of knowledge of how to affect it. Rural Chinese need more locally and personally relevant information on global warming, and climate policies should consider their possible influence on local residents.
Figures
Demographic features of the respondents (%)
| Demographic variables | (%) |
|---|---|
| Sex | |
| Male (0) | 53.8 |
| Female (1) | 46.2 |
| Age (years) | |
| 20-29 (1) | 16.3 |
| 30-39 (2) | 18.4 |
| 40-49 (3) | 28.0 |
| 50-59 (4) | 17.9 |
| 60 and over (5) | 19.4 |
| Education level | |
| Illiteracy (1) | 12.5 |
| Primary school (2) | 23.2 |
| Senior middle school (3) | 49.4 |
| Junior middle school (4) | 11.2 |
| College and university (5) | 3.7 |
(1): Coding
Variables and items
| Variables | Wordings and items | Categories and coding | Cronbach’s α |
|---|---|---|---|
| County | Shanxian (1), Wenxi (2), Anding (3) | ||
| Perceived impact of local temperature change on wheat and maize | Do you think how local temperature change impacted wheat and corn, respectively? (two items) | Significant positive impact (1), minor positive impact (2), unsure or no impact (3), minor negative impact (4) and Significant negative impact (5) | 0.673 |
| Awareness of global warming | Have you ever heard of global warming? | Yes, no | |
| Channels of knowing global warming | Through which channels did you know global warming? a | Television programmes, the internet, other people, newspapers, radio | |
| Understanding of the phenomenon of global warming | How do you understand the phenomenon of global warming? a | Open-ended | |
| Knowledge of global warming | Please explain causes of global warming a | Open-ended; when a respondent said he/she did not know causes of global warming, it was coded 0, otherwise it was coded 1 | |
| Perceived risks of global warming | Do you think how likely would global warming cause the following risks: risks for you, risks for your family, risks for the whole of society, unpredicted risks, risks for future generations? (five items) | Very likely (5), mildly likely (4), do not know or unsure (3), mildly unlikely (2), absolutely unlikely (1) | 0.823 |
| Perceived ability to mitigate global warming | Do you think you or your family is able to mitigate global warming? (two items) | Strong ability (4), a little ability (3), basically unable (2), fully unable (1) | 0.856 |
| Perceived obligation to mitigate global warming | Do you think you or your family has obligation to mitigate global warming? (two items) | Full obligation (4), a little obligation (3), basically no obligation (2), absolutely no obligation (1) | 0.890 |
| Willingness to pay higher prices to mitigate global warming | To mitigate global warming, do you agree to increase the prices of the following goods? gasoline and diesel oil; coal; electricity; chemical fertilizer; agricultural plastic film. (five items) | Strongly agree (5), mildly agree (4), unsure (3), mildly disagree (2), strongly disagree (1) | 0.890 |
Several responses are possible
Impact of local temperature changes on agriculture (%)
| Crops | Significant positive impact | Minor positive impact | Uncertain or no impact | Minor negative impact | Significant negative impact |
|---|---|---|---|---|---|
| Wheat | 6.0 | 14.0 | 25.4 | 41.1 | 13.5 |
| Maize | 4.8 | 24.1 | 27.8 | 32.7 | 10.5 |
| Cronbach’s α | 0.673 |
Understanding of the phenomenon of global warming
| Understandings of global warming | No. | (%) |
|---|---|---|
| The respondents who answered the question of the phenomenon of global warming | 270 | 22.8 |
| Various understandings (the total number is 270) | ||
| Pollution | ||
| Air pollution | 34 | 12.6 |
| Industrial pollution | 6 | 2.2 |
| Environmental pollution | 19 | 7.0 |
| Temperature rise | 157 | 58.1 |
| Emission of carbon dioxide | 17 | 6.3 |
| Other understandings | ||
| Ice melting | 12 | 4.4 |
| Sea level rise | 4 | 1.5 |
| Abnormal local temperature | 7 | 2.6 |
| Environmental degeneration | 6 | 2.2 |
| Deforestation | 11 | 4.1 |
| Ozone depletion | 10 | 3.7 |
Causes of global warming
| Causes of global warming | No. | (%) |
|---|---|---|
| The respondents who explained causes of global warming | 257 | 21.7 |
| Various causes (the total number is 257) | ||
| Anthropogenic causes | ||
| General anthropogenic causes (no details) | 25 | 9.7 |
| Pollution | ||
| Air pollution | 56 | 21.8 |
| Industrial pollution | 21 | 8.2 |
| Environmental pollution | 41 | 16.0 |
| Gas emission-related causes | ||
| Emission of carbon dioxide | 42 | 16.3 |
| Emission of hot gases | 10 | 3.9 |
| Emission of waste gases | 17 | 6.6 |
| Ecological causes | ||
| Ecological degeneration | 18 | 7.0 |
| Deforestation | 25 | 9.7 |
| Others | ||
| Too many cars | 22 | 8.6 |
| Too many plants | 21 | 8.2 |
| Too many people | 18 | 7.0 |
| Consumption of fossil fuel | 9 | 3.5 |
| Ozone depletion | 13 | 5.1 |
| Natural phenomena | 15 | 5.8 |
Perceived risks of global warming (%)
| Risks | Very likely | Mildly likely | Do not know or unsure | Mildly unlikely | Absolutely unlikely |
|---|---|---|---|---|---|
| Individual | 17.7 | 43.5 | 10.5 | 23.8 | 4.6 |
| Family | 13.9 | 43.9 | 10.8 | 27.2 | 4.2 |
| Society | 19.2 | 36.6 | 19.5 | 20.8 | 3.9 |
| Unpredicted risks | 17.4 | 39.7 | 23.7 | 14.5 | 4.7 |
| Future generations | 20.8 | 38.5 | 19.6 | 16.2 | 4.9 |
Perceived ability to mitigate global warming (%)
| Members | Strong ability | Some ability | Basically unable | Fully unable |
|---|---|---|---|---|
| I personally | 2.3 | 25.9 | 44.5 | 27.3 |
| My family | 2.7 | 27.2 | 44.0 | 26.1 |
Perceived obligation to mitigate global warming (%)
| Members | Full obligation | Little obligation | Basically, no obligation | Absolutely no obligation |
|---|---|---|---|---|
| I personally | 21.7 | 48.9 | 18.8 | 10.7 |
| My family | 20.6 | 49.7 | 18.2 | 11.4 |
Willingness to pay higher prices to mitigate global warming (%)
| Products | Strongly agree | Mildly agree | Unsure | Mildly disagree | Strongly disagree |
|---|---|---|---|---|---|
| Gasoline and diesel oil | 7.3 | 15.5 | 12.2 | 40.3 | 24.7 |
| Coal | 5.7 | 15.1 | 12.4 | 39.9 | 26.9 |
| Electricity | 3.0 | 10.6 | 7.9 | 41.6 | 36.9 |
| Chemical fertiliser | 3.0 | 9.5 | 8.1 | 40.5 | 38.9 |
| Agricultural plastic film | 4.1 | 10.1 | 11.6 | 42.1 | 32.1 |
Regression analysis of explaining factors of willingness to pay higher prices to mitigate global warming
| Independent variables | Non-standardised coefficient | Standardised coefficient |
|---|---|---|
| Constant | 1.30*** | |
| Sex | 0.07 | 0.04 |
| Age | 0.01 | 0.02 |
| Education level | −0.03 | −0.04 |
| Perceived impact of local temperature change on wheat and maize | −0.11*** | −0.11 |
| Perceived risks of global warming | 0.02 | 0.02 |
| Knowledge of global warming | −0.09 | −0.04 |
| Perceived ability to mitigate global warming | 0.20*** | 0.16 |
| Perceived obligation to mitigate global warming | 0.12** | 0.11 |
| County | 0.24*** | 0.21 |
N = 1,159, Adjusted R2 = 11.0%; F(9,1150) = 17.00***;
p < 0.01,
p < 0.05
References
Akerlof, K., DeBono, R., Berry, P., Leiserowitz, A., Roser-Renouf, C., Clarke, K., Rogaeva, A., Nisbet, M.C., Weathers, M.R. and Maibach, E.W. (2010), “Public perceptions of climate change as a human health risk: surveys of the United States, Canada and Malta”, International Journal of Environmental Research and Public Health, Vol. 7 No. 6, pp. 2559-2606.
Akter, S. and Bennett, J. (2011), “Household perceptions of climate change and preferences for mitigation action: the case of the carbon pollution reduction scheme in Australia”, Climatic Change, Vol. 109 Nos 3/4, pp. 417-436.
Bord, R.J., Fisher, A. and O’Connor, R.E. (1998), “Public perceptions of global warming: United States and international perspectives”, Climate Research, Vol. 11 No. 1, pp. 75-84.
Bord, R.J., O’Connor, R.E. and Fisher, A. (2000), “In what sense does the public need to understand global climate change?”, Public Understanding of Science, Vol. 9 No. 3, pp. 205-218.
Bostrom, A., Morgan, M.G., Fischhoff, B. and Read, D. (1994), “What do people know about global climate change? 1. Mental models”, Risk Analysis, Vol. 14 No. 6, pp. 959-970.
Brechin, S.R. (2003), “Comparative public opinion and knowledge on global climatic change and the Kyoto protocol: the US versus the world?”, International Journal of Sociology and Social Policy, Vol. 23 No. 10, pp. 106-134.
Brechin, S.R. and Bhandari, M. (2011), “Perceptions of climate change worldwide”, Wiley Interdisciplinary Reviews: Climate Change, Vol. 2 No. 6, pp. 871-885.
Capstick, S., Whitmarsh, L., Poortinga, W., Pidgeon, N. and Upham, P. (2015), “International trends in public perceptions of climate change over the past quarter century”, WIREs: Climate Change, Vol. 6 No. 1, pp. 35-61.
Chmutina, K., Zhu, J. and Riffat, S. (2012), “An analysis of climate change policy-making and implementation in China”, International Journal of Climate Change Strategies and Management, Vol. 4 No. 2, pp. 138-151.
Corner, A., Markowitz, E. and Pidgeon, N. (2014), “Public engagement with climate change: the role of human values”, Wiley Interdisciplinary Reviews: Climate Change, Vol. 5 No. 3, pp. 411-422.
Dietz, T., Dan, A. and Shwom, R. (2007), “Support for climate change policy: social psychological and social structural influences”, Rural Sociology, Vol. 72 No. 2, pp. 185-214.
Ding, D., Maibach, E.W., Zhao, X.Q., Roser-Renouf, C. and Leiserowitz, A. (2011), “Support for climate policy and societal action are linked to perceptions about scientific agreement”, Nature Climate Change, Vol. 1 No. 9, pp. 462-466.
Duan, H.X., Lv, Y.L. and Li, Y. (2014), “Chinese public’s willingness to pay for CO2 emissions reductions: a case study from four provinces/cities”, Advances in Climate Change Research, Vol. 5 No. 2, pp. 100-110.
Dunlap, R.E. (1998), “Lay perceptions of global risk: public views of global warming in cross national context”, International Sociology, Vol. 13 No. 4, pp. 473-498.
Henry, A.D. (2000), “Public perceptions of global warming”, Human Ecology Review, Vol. 7 No. 1, pp. 25-30.
Howe, P.D., Markowitz, E.M., Lee, T.M., Ko, C.Y. and Leiserowitz, A. (2013), “Global perceptions of local temperature change”, Nature Climate Change, Vol. 3 No. 4, pp. 352-356.
Intergovernmental Panel on Climate Change (IPCC) (2014), Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, IPCC, Geneva.
Jamelske, E., Boulter, J., Jang, W., Barrett, J., Miller, L. and Han, W.L. (2015), “Examining differences in public opinion on climate change between college students in China and the USA”, Journal of Environmental Studies and Sciences, Vol. 5 No. 2, pp. 87-98.
Kempton, W. (1991), “Lay perspectives on global climate change”, Global Environmental Change, Vol. 1 No. 3, pp. 183-208.
Kempton, W. (1997), “How the public views climate change”, Environment, Vol. 39 No. 9, pp. 12-21.
Leal-Filho, W. (2009), “Communicating climate change: challenges ahead and action needed”, International Journal of Climate Change Strategies and Management, Vol. 1 No. 1, pp. 6-8.
Leiserowitz, A.A. (2005), “American risk perceptions: is climate change dangerous?”, Risk Analysis, Vol. 25 No. 6, pp. 1433-1442.
Leiserowitz, A.A. (2006), “Climate change risk perception and policy preferences: the role of affect, imagery, and values”, Climatic Change, Vol. 77 Nos 1/2, pp. 45-72.
Li, Y.J. (2013), “Differences in perceptions of climate change of rural and urban residents in China”, Dong Yue Tribune, Vol. 34 No. 10, pp. 39-47.
Lorenzoni, I. and Pidgeon, N.F. (2006), “Public views on climate change: European and USA. Perspectives”, Climatic Change, Vol. 77 Nos 1/2, pp. 73-95.
Lorenzoni, I., Nicholson-Cole, S. and Whitmarsh, L. (2007), “Barriers perceived to engaging with climate change among the UK public and their policy implications”, Global Environmental Change, Vol. 17 Nos 3/4, pp. 445-459.
McCright, A.M. (2009), “The social bases of climate change knowledge, concern, and policy support in the US”, General Public. Hofstra Law Review, Vol. 37 No. 4, pp. 1017-1046.
McCright, A.M., Dunlap, R.E. and Xiao, C.Y. (2013), “Perceived scientific agreement and support for government action on climate change in the USA”, Climatic Change, Vol. 119 No. 2, pp. 511-518.
Marquart-Pyatt, S.T., Shwom, R.L., Dietz, T., Dunlap, R.E., Kaplowitz, S.A., McCright, A.M. and Zahran, S. (2011), “Understanding public opinion on climate change: a call for research”, Environment, Vol. 53 No. 4, pp. 38-42.
Nisbet, M.C. and Myers, T. (2007), “The polls trends: twenty years of public opinion about global warming”, Public Opinion Quarterly, Vol. 71 No. 3, pp. 444-470.
O’Connor, R.E., Bord, R.J. and Fisher, A. (1999), “Risk perceptions, general environmental beliefs, and willingness to address climate change”, Risk Analysis, Vol. 19 No. 3, pp. 461-471.
Piao, S.L., Ciais, P., Huang, Y., Shen, Z.H., Peng, S.S., Li, J.S., Zhou, L.P., Liu, H.Y., Ma, Y.C., Ding, Y.H., Friedlingstein, P., Liu, C.Z., Tan, K., Yu, Y.Q., Zhang, T.Y. and Fang, J.Y. (2010), “The impacts of climate change on water resources and agriculture in China”, Nature, Vol. 467 No. 7311, pp. 43-51.
Read, D., Bostrom, A., Morgan, M.G., Fischhoff, B. and Smuts, T. (1994), “What do people know about global climate change? 2. Survey studies of educated laypeople”, Risk Analysis, Vol. 14 No. 6, pp. 971-982.
Reynolds, T.W., Bostrom, A., Read, D. and Morgan, M.G. (2010), “Now what do people know about global climate change? Survey studies of educated laypeople”, Risk Analysis, Vol. 30 No. 10, pp. 1520-1538.
Schultz, P.W. and Zelezny, L. (1998), “Values and proenvironmental behavior: a five-country survey”, Journal of Cross-Cultural Psychology, Vol. 29 No. 4, pp. 540-558.
Shao, W.Y. (2015), “Are actual weather and perceived weather the same? Understanding perceptions of local weather and their effects on risk perceptions of global warming”, Journal of Risk Research, Vol. 19 No. 6, pp. 1-21.
Spence, A., Poortinga, W., Butler, C. and Pidgeon, N.F. (2011), “Perceptions of climate change and willingness to save energy related to flood experience”, Nature Climate Change, Vol. 1 No. 1, pp. 46-49.
Stern, P.C. (2000), “Toward a coherent theory of environmentally significant behavior”, Journal of Social Issues, Vol. 56 No. 3, pp. 407-424.
Stern, P.C., Dietz, T., Abel, T., Guagnano, G.A. and Kalof, L. (1999), “A value-belief-norm theory of support for social movements: the case of environmentalism”, Human Ecology Review, Vol. 6 No. 2, pp. 81-97.
Tobler, C., Visschers, V.H.M. and Siegrist, M. (2012), “Addressing climate change: determinants of consumers’ willingness to act and to support policy measures”, Journal of Environmental Psychology, Vol. 32 No. 3, pp. 197-207.
Vainio, A. and Paloniemi, R. (2013), “Does belief matter in climate change action?”, Public Understanding of Science, Vol. 22 No. 4, pp. 382-395.
Wachinger, G., Renn, O., Begg, C. and Kuhlicke, C. (2013), “The risk perception paradox-implications for governance and communication of natural hazards”, Risk Analysis, Vol. 33 No. 6, pp. 1049-1065.
Wang, J.X., Mendelsohn, R., Dinar, A., Huang, J., Rozelle, S. and Zhang, L.J. (2009), “The impact of climate change on China’s agriculture”, Agricultural Economics, Vol. 40 No. 3, pp. 323-337.
Weber, E.U. (2010), “What shapes perceptions of climate change?”, Wiley Interdisciplinary Reviews: Climate Change, Vol. 1 No. 3, pp. 332-342.
Whitmarsh, L. (2008), “Are flood victims more concerned about climate change than other people? The role of direct experience in risk perception and behavioural response”, Journal of Risk Research, Vol. 11 No. 3, pp. 351-374.
Whitmarsh, L. (2009), “What’s in a name? Commonalities and differences in public understanding of ‘climate change’ and ‘global warming’”, Public Understanding of Science, Vol. 18 No. 4, pp. 401-420.
Whitmarsh, L., Seyfang, G. and O’Neill, S. (2011), “Public engagement with carbon and climate change: to what extent is the public ‘carbon capable’?”, Global Environmental Change, Vol. 21 No. 1, pp. 56-65.
Xu, B., Sun, Q., Wennersten, R. and Brandt, N. (2010), “An analysis of Chinese policy instruments for climate change mitigation”, International Journal of Climate Change Strategies and Management, Vol. 2 No. 4, pp. 380-392.
Yang, J., Zou, L.P., Lin, T.S., Wu, Y. and Wang, H.K. (2014), “Public willingness to pay for CO2 mitigation and the determinants under climate change: a case study of Suzhou, China”, Journal of Environmental Management, Vol. 146 No. 1, pp. 1-8.
Yu, H., Wang, B., Zhang, Y.J., Wang, S.Y. and Wei, Y.M. (2013), “Public perception of climate change in China: results from the questionnaire survey”, Natural Hazards, Vol. 69 No. 1, pp. 459-472.
Zahran, S., Brody, S.D., Grover, H. and Vedlitz, A. (2006), “Climate change vulnerability and policy support”, Society and Natural Resources, Vol. 19 No. 9, pp. 771-789.
Acknowledgements
This research project was supported by Grant No. 2016YFC0501701 from the Major State Basic Research Development Program of China and by Grant No. lzujbky-2017-ct05 from the Fundamental Research Funds for the Central Universities. The author is grateful to two anonymous reviewers who provided constructive suggestions for the improvement of an earlier version of this paper.