The aim and novelty of this study consist of estimating the nexus between CO₂ (carbon dioxide) emissions, energy use, economic growth, and financial development for ten Central and Eastern European countries (CEEC) over the 2000–2017 period, starting from Environmental Kuznets Curve (EKC) theory. The Fully Modified Ordinary Least Squares (FMOLS) method was used for testing the cointegration relationship. Granger causality estimation based on the Vector Error Correction Model (VECM) and Pairwise Granger causality test were applied to identify the causality relationships between the variables and to identify the direction of causality. The implementation of the tests led to significant conclusions. In the long run, the levels of CO₂ emissions and energy use do not have any influence on economic growth. Furthermore, there is a bidirectional causality among economic growth in terms of GDP and financial development variables. Thus, increasing financial development will generate more CO₂ emissions and more energy use, and increasing economic growth will lead to rising financial development. In the short run, increasing financial development will generate more CO₂ emissions and will lead to increased energy use and economic growth. Also, a bidirectional causality is being revealed between financial development and CO₂ emissions. This indicates that financial development may help to reduce CO₂ emissions.

One of the European Union’s (EU) objectives regarding climate change is a 40% reduction in greenhouse gas emissions by 2030, ensuring that member states focus on sustainable development. The aim of this study was the comparison of a three-dimensional relationship between green taxation, environmental performance and economic growth for the time period between 1995 and 2017 in Romania and Sweden. The novelty consists of simultaneously using the double dividend theory and environmental Kuznets curve theory for Romania. The autoregressive distributed lag (ARDL) method was used for testing the cointegration relationship. The Granger causality estimation based on the ARDL-error correction model was applied to identify the causality relationship between the variables and the pairwise Granger causality test to detect the direction of causality. The implementation of the tests led to the conclusion that environmental taxes will have a significant influence on the reduction of greenhouse gas emissions in the long run in both Romania and Sweden, while in the short run, no such influence will be noticed. Also, in Romania, in the long term, there was a bidirectional causality relationship between economic growth and greenhouse gas emissions, while in Sweden, the causality relationship was from economic growth to greenhouse gas emissions.

To mitigate the negative effects of climate change on the environment, the Member States of the European Union implement fiscal measures and commit budgetary expenditures to ensure sustainable economic development. Romania, in line with the Union’s objectives, resorted to the application of a system of environmental taxes and provided in the budgetary policy government expenditures for environmental protection. The aim of the research is to highlight the effects of these measures on the environment by analysing the short-run and long-run causal relationships between greenhouse gas emissions, green taxes and government expenditures on environmental protection. Autoregressive Distributed Lag (ARDL) method and Granger causality tests were used to demonstrate the existence of these relationships and the intensity with which they manifest. Following the analysis, we identified a significant long-run influence of government spending on environmental protection on greenhouse gas emissions but also numerous short-run and long-run causal relationships between greenhouse gas emissions and green taxes, applied in Romania. The results of the research consider the impact of public expenses for environment protection, a variable not yet applied for Romania, on greenhouse gas emissions’ decrease, in correlation with environmental taxes per source of origin.