The primary way greenhouse gases enter the atmosphere is through human activities such as burning fossil fuels, deforestation, and industrial processes. When fossil fuels like coal, oil, and natural gas are burned for energy, they release significant amounts of carbon dioxide (CO₂) and other greenhouse gases into the atmosphere. Deforestation contributes to greenhouse gas emissions as trees that absorb CO₂ are removed. These activities lead to an enhanced greenhouse effect, contributing to global warming and climate change, highlighting the need for sustainable practices and policies aimed at reducing emissions and protecting natural carbon sinks.