Carbon emissions trading is essential for reducing carbon emissions, and its role in regional carbon unlocking needs further clarification. This study uses the difference-in-differences (DID) model and synthetic control model (SCM) to evaluate the carbon unlocking effect of China’s six pilot carbon trading provinces. This study found that (1) carbon lock-in effects in China are mainly influenced by technology lock-in and fixed input lock-in; (2) each province’s overall carbon lock-in level presents a decreasing trend yearly, and the regional distribution presents characteristics of “low in the east and high in the west”; (3) carbon emissions trading pilot policies effectively promote the carbon unlocking effect in pilot regions overall, with Guangdong having the most significant unlocking effect. Conversely, Beijing, Hubei, Chongqing, and Shanghai also had different degrees of carbon unlocking. Finally, (4) an assessment of impact mechanisms indicates that technology and institutions have a significant mediating role in effectively promoting carbon unlocking under the carbon trading policy. Conversely, social behavior has an inverse effect, and fixed assets are not affected by the policy. This study demonstrates the carbon unlocking effect of carbon emissions trading and provides a quantitative reference for implementing carbon emissions trading policies and determining carbon unlocking paths.

The impact of international tourism on emerging markets has been overwhelmingly beneficial. Despite the obvious benefits of tourism, it comes at a high price for the environment in the form of pollution. Brazil's annual tourist influx has the potential to boost economic development and damage the country's ecosystems. The objective of this investigation is to analyze, using time series data ranging from 1990 to 2019, the effects of tourism and economic growth (GDP) on carbon dioxide (CO₂) emissions in Brazil. The stationarity of the data was examined by employing unit root tests, and an autoregressive distributed lag (ARDL) technique was used to investigate the link between the factors, taking both the long- and the short-run into consideration. This research shows that there are long-term and short-term ties between Brazil's tourism industry, GDP, and CO₂ emissions. Yet, both tourism and economic expansion have had serious negative effects on Brazil's ecology. These results indicate that in order to maintain environmental quality in Brazil, policymakers need to pursue more eco-friendly economic expansion as well as environmentally conscious tourist regulations.