Which major factor contributes most to the warming observed in recent decades?

The significant warming observed in recent decades is primarily attributed to heightened greenhouse gas levels due to human activity. This conclusion is supported by extensive scientific research demonstrating that the burning of fossil fuels, deforestation, and industrial processes have led to an increase in carbon dioxide and other greenhouse gases in the atmosphere. These gases trap heat from the Earth's surface, leading to a rise in global temperatures—a phenomenon known as the greenhouse effect.

As human activities accelerated in the 20th century, the concentrations of greenhouse gases reached unprecedented levels, correlating closely with the increase in average global temperatures. The Intergovernmental Panel on Climate Change (IPCC) has presented robust data indicating that human-driven emissions are the leading cause of climate change observed over recent decades.

While natural climate cycles, such as El Niño or volcanic activity, can influence short-term climate variations, they do not account for the long-term warming trend noted since the mid-20th century. Similarly, increased solar activities and changes in land use, while they can have localized effects on climate, do not explain the overarching trend of increasing temperatures as effectively as human-induced greenhouse gas emissions do. This understanding is fundamental in addressing climate change and its impacts on the environment.