The study looked at how economic development affects the environment in 120 countries from 1990 to 2016. They used a method called the Fixed Effect Model to see how economic growth influences environmental degradation. Contrary to the idea that more money leads to greener practices (known as the Environmental Kuznets Curve), the researchers didn't find that trend in their data. They discovered that factors like GDP growth, spending on research, energy use, and oil revenue strongly impact CO2 emissions. Interestingly, foreign investments didn't seem to have a big effect on environmental quality.