This study aims to prove the environmental kuznet curve (EKC) hypothesis in Indonesia and the effect of GDP per capita, income inequality, and population on CO2 emissions. This research uses a descriptive quantitative method. The data used is the time series from 1990-2021. The data analysis method used is the error correction model (ECM) to see the effect of the independent variables on the dependent variable in the short term and long term. The results of this study indicate that the EKC hypothesis is not proven in Indonesia either in the short term or in the long term. GDP per capita has a significant positive effect on CO2 emissions both in the short term and long term. Income inequality has no significant positive effect on CO2 emissions in the short term and no significant negative effect in the long term. The population has no significant negative effect on CO2 emissions in the short term and has a significant positive effect in the long term.

The most significant reduction in environmental quality is thought to have occurred in low-income countries, while low environmental degradation occurred in those high-income countries. Using the cluster purposive sampling technique, countries from 5 continents were examined to see if they had complete data and represented three categories. Seventy-eight countries were found to meet these requirements and were then used as research samples from 2015 to 2019. The Data Panel Regression technique was used to analyses the data. This study is expected to be able to produce policies in the form of a sustainable environmental management model that continues to support economic growth. This study proved that the Environmental Kuznets Curve (EKC) phenomenon applies from 2015 to 2019 in high-income countries, and population growth rates have a significant negative impact on Carbon Dioxide (CO2) emissions. This means that the more prosperous a country, the less the environmental degradation, while in low-income countries, carbon emissions increase when economic growth increases. In developing countries, as the population increases, environmental degradation increases, while in low-income countries the amount of carbon emissions is affected by economic growth and population. Some compensate and subsidies low-income countries which are able to care for their environment.

The capability of innovation is an important factor for the economic performance of tourism companies, (Martínez-Román et al. 2015). This study aims to examine the influence of innovation capabilities on product innovation and process innovation and then these results influence marketing performance. The design of the research is explanatory research with a quantitative approach. The population of this research is 168 starred hotels in southern Sumatra, the data used are primary data. Processing data used a structural equation model. The conclusion of this study shows that the capability of innovation influences product innovation and process innovation, which in turn influences marketing performance.