The gas known for causing greenhouse effects is carbon dioxide (CO2). Carbon dioxide is a significant greenhouse gas that contributes to global warming by trapping heat in the Earth's atmosphere. It is produced naturally through processes like respiration and volcanic eruptions, but human activities, particularly the burning of fossil fuels and deforestation, have significantly increased its concentration. This rise in CO2 levels is a major factor in climate change, prompting global discussions on the need for reducing emissions and finding sustainable energy alternatives to mitigate environmental impact.