Which gas is primarily responsible for increased greenhouse effect in recent decades?

Carbon dioxide is primarily responsible for the increased greenhouse effect in recent decades due to its significant increase in atmospheric concentration stemming from human activities. The burning of fossil fuels, deforestation, and land-use changes have led to a marked rise in carbon dioxide levels since the Industrial Revolution. This gas is particularly effective at absorbing infrared radiation, which contributes to the greenhouse effect by trapping heat in the atmosphere and causing global temperatures to rise.

While other greenhouse gases like methane and nitrous oxide also impact climate change, carbon dioxide is the most abundant and long-lived in the atmosphere, which amplifies its effect over time. The substantial enhancements in carbon dioxide levels directly correlate with global warming trends observed in the past century, highlighting its critical role in the ongoing climate crisis. Ozone, although a greenhouse gas, primarily exists in the stratosphere and is not a major factor in the recent trends associated with human-induced climate change.