*4.1. Calculation of Tourism's Carbon Emission Efficiency (TCEE)*

Under the condition that tourism's carbon emissions are taken as an undesirable output, according to Formula (1), the Super-SBM model was used to calculate the tourism carbon emission efficiency (TCEE) of nine provinces in the Yellow River Basin from 2010 to 2019. The results are shown in Table 3. Tourism's carbon efficiency in the Yellow River Basin has been fluctuating, rising slightly in 2010 compared to 2019. The average TCEE was 0.9782, in the medium level of efficiency, with the frontier still having room for improvement. Obviously, there is a big waste and diseconomy in tourism resources, and tourism's carbon efficiency has great development potential.


**Table 3.** Tourism's carbon emission efficiency (TCEE) in the nine provinces in the Yellow River Basin.

From the perspective of spatial distribution, there were six provinces whose average TCEE exceeded 1 and whose TCEE was effective, which were, respectively, Ningxia, Inner Mongolia, Sichuan, Qinghai, Henan, and Shanxi. Among them, Ningxia ranked first in tourism's carbon emission efficiency (1.1518). The last three provinces, Gansu, Shaanxi, and Shandong, had relatively low efficiency of tourism's carbon emissions. Among them, the efficiency of Shandong was at the bottom of the Yellow River Basin (0.6908). The difference of TCEE between Shandong and Ningxia was 0.461, and the latter was 1.67 times of the former, indicating that there is a large inter-provincial difference in TCEE in the Yellow River Basin.

From the perspective of time distribution, the inter-annual change rates of TCEE in the Yellow River Basin from 2010 to 2019 were higher in Henan, Gansu, and Qinghai, while the inter-annual change rates were lower in Ningxia, Sichuan, and Shandong. In 2019, the TCEE of all provinces was effective, except for Shandong. Compared to 2010, the TCEE increased significantly in Qinghai, Gansu, Shaanxi, Shanxi, and Henan provinces, and it decreased significantly in Ningxia and Shandong provinces. It can be seen that the TCEE in the Yellow River Basin also had a large time difference.

From the perspective of the weight of each resource index of TCEE (Table 4), the weight of the output index was higher than that of the input, indicating that input factors need to be strengthened in order to achieve a higher efficiency of tourism carbon.

**Table 4.** Weight of tourism's carbon emission efficiency (TCEE) evaluation index of the nine provinces in the Yellow River Basin.


In terms of input index, energy input had the highest weight (0.1136), while resource input had the lowest weight (0.0792). Among them, total energy consumption (0.0289) had the highest weight. It can be seen that this index plays a significant role in TCEE. It is especially significant for the provinces with sparse population and abundant energy

resources, such as Qinghai, Gansu, and Inner Mongolia, and the provinces with developed economy and large energy consumption, such as Henan and Shandong. The weight of the index of fixed asset investment of travel agencies (0.0156) was low, which shows that the existing capital investment of travel agencies cannot provide enough development space for tourism and needs to be strengthened, especially for Shanxi, Gansu, and Ningxia.

In terms of output index, the weight of desirable output (0.2879) was significantly higher than that of the undesirable output (0.1356), among which the weight of total number of visits (0.0431) was the highest, which is more significant for Qinghai, Sichuan, Inner Mongolia, Shanxi, and Henan. While the effect of total number of visits on Shandong is not obvious, the number of visitors plays a more important role in TCEE. The income of travel agencies (0.0162) had a low weight, and the contribution rate in Sichuan, Gansu, Inner Mongolia, and Shandong provinces was low, which is more dependent on the income of star hotels and scenic spots.
