*4.2. Spatial Spillover Effects of Tourism Development on Urban Carbon Emission Intensity and Green Economic Efficiency*

The spatial spillover effect can be decomposed into the direct effect, indirect effect and total effect. Among them, the direct effect includes the direct effect of tourism development on the explained variables and the feedback effect caused by tourism development affecting the explained variables in adjacent areas. The indirect effect represents the spatial spillover effect of tourism development, including the influence of tourism development in neighboring areas on the explained variables in the region and the influence of tourism development in neighboring areas on their own explained variables, which in turn has an impact on the explained variables in the region. The total effect, on the other hand, is the sum of the direct and indirect effects, reflecting the average effect of tourism development on the explanatory variables.

As seen from Table 4, the total effect coefficient (lnTC) of the impact of tourism development on urban green economic efficiency is significantly positive, indicating that the development of tourism is conducive to enhancing urban green economic efficiency. On the one hand, tourism is a resource-dependent industry, and good ecological and

environmental conditions are the basis of its development, so tourism investment involves financial support for the ecological and environmental restoration of tourism destinations. On the other hand, tourism development produces change in the industrial structure of destinations, forcing enterprises to conduct energy restructuring, and especially has a crowding-out effect on industries, but due to market demand, tourism development can have a significant impact on the service sector. However, tourism development can optimize the service and manufacturing industries due to market demand and technology spillover, reduce their pollution emissions, and thus improve the efficiency of the destination's green economy. The direct effect of tourism development is not significant. Tourism itself has low pollution emissions, and tourism development does not act directly on green economic efficiency but indirectly enhances urban green economic efficiency by forcing local industrial structure optimization and other forms through high correlation with other industries. For example, for every 1% increase in the tourism development level, the green economic efficiency of neighboring areas is indirectly enhanced by 0.442%, i.e., the promotion effect of tourism development on urban green economic efficiency is mainly manifested as an indirect effect, i.e., spillover effect [60]. Therefore, hypothesis H1 is verified.

**Table 4.** Benchmark regression results on the impact of tourism development on urban carbon emissions and green economic efficiency.


Note: \*\*\*\*, \*\*, and \* represent significance levels of 1%, 5%, and 10%, respectively.

As seen from Table 4, the total effect coefficient of the impact of tourism development on the intensity of urban carbon emissions is significantly negative, indicating that tourism development can mitigate urban carbon emissions and achieve urban emission reduction. On the one hand, because tourism itself is a low-consumption and low-carbon industry, its development is based on the ecological environment. On the other hand, the tourism development model is constantly updated, and green development has been a basic requirement, especially the development of the digital economy in recent years, which provides the basis for the creation of a digital tourism model and, to a large extent, relieves the pressure of urban carbon emission reduction. As tourism development affects the green economic efficiency of cities, the urban carbon reduction effect of tourism development also shows a significant spillover effect, with each 1% increase in the tourism development level indirectly reducing the carbon emission intensity of neighboring areas by 1.336%. The development of tourism is one of the main paths for carbon reduction in cities [32]. Therefore, hypothesis H3 is verified.

From the control variables, the effect of industrial structure on green economic efficiency mainly works as a direct effect, and the effect on carbon emission intensity mainly works as an indirect effect. Tourism development leads to an increase in factor costs, which makes the maximum use of energy structure through reasonable resource allocation and reduces the redundancy of resource inputs and pollution emissions such as carbon dioxide. The results of the effect of economic level on green economy efficiency are not significant, indicating that economic development and green economy development are not equivalent. Meanwhile, the effect of the economic level on carbon emission intensity shows a significant positive direction, which integrally indicates that most of China's cities are still trying to eliminate the severe development model, and are still sacrificing resources and the environment for the improvement of the economic level, which does not correspond to the development of the green economy. To a certain extent, the enhancement of the city's reputation and the brand effect, in addition to the management experience provided by foreign investment, improved production processes, technological innovation and improvement of the business environment caused by the growth of tourism development promote the city's carbon emission reduction and green economy development [6]. The direct and indirect effects of technological innovation on the efficiency of the green economy are significantly positive, and innovation has been an important variable that has helped green economic development to reach a turning point. Under the stimulation of the policy of cultural tourism integration, "tourism +" continues to push out new ideas and become richer in industries, but "tourism + technology" still has serious deficiencies that inhibit economic growth and green development, but the development of the technology level is not enough to significantly reduce carbon emission intensity in most cities at present [63]. The spillover effect of environmental regulation variables is significant [64]; environmental regulation is necessary due to pollution externalities; in the short term, it is inhibitory to economic development, and the direct effect is not obvious. Tourism development causes the agglomeration of the tourism industry, which not only promotes the improvement of the carbon emission efficiency of tourism but also promotes the expansion of the service industry and the development of manufacturing services by forcing the optimization of industrial structure, bringing the "innovation compensation" effect and ultimately achieving a Porter "win-win" [64]. Through the interaction and correlation with foreign investment and environmental regulations, tourism development drives technological innovation and industrial structure optimization, reduces the intensity of urban carbon emissions, and enhances the efficiency of the green economy.
