Carbon Dioxide is released whenever ocean, venting volcanoes, & natural wildfires. With that in mind, the amount of CO2 has been steadily increasing along with the temperature.
In addition, human has been a major help in increasing CO2 with the action of burning gasoline in our cars, fuel in our planes, & coal in our factories.
With the massive amount of CO2 in the atmosphere more than ever before, it's no surprise that it'll have an effect on our temperature & environment, effectively helping climate change increase even faster.
Greenhouse gas is a certain gas, caused by humans, that blocks heat from escaping, essentially, it’s an alternative name for carbon dioxide, in which we've already discussed.
The "Normal" Greenhouse effect would be that 30% of Solar Energy would return to the atmosphere before hitting the Earth (indicated by the yellow arrows). 50% of Solar Energy would be absorbed by the Earth, & 20% is absorbed radiation trapped inside of Earth (Indicated by the red arrows).
Some of the possible effects of the greenhouse effect would be Earth having warmer temperatures, which can make some places more drier than before, melt glaciers & other ice, & the sea level will rise heavily.