AGW

Anthropogenic global warming (AGW) refers to the long-term increase in Earth's average surface temperature caused primarily by human activities. While natural climate fluctuations occur, the current warming trend is distinguished by rapidly rising greenhouse gas concentrations and other anthropogenic forcings since the Industrial Revolution. AGW is assessed through temperature records, ice and ocean data, and climate models that separate human effects from natural variability.

The main human drivers are emissions of greenhouse gases from burning fossil fuels (coal, oil, and gas) and cement production, along with land-use changes such as deforestation. Greenhouse gases trap infrared radiation, raising the planet’s energy balance. Other forcings, including aerosols from pollution and changes in albedo due to snow and ice loss, also influence the net effect.

Evidence shows warming across land, oceans, and the atmosphere, with the ocean absorbing most excess heat. Glaciers and Arctic sea ice decline, sea levels rise, and weather extremes such as heat waves and heavy rainfall become more frequent. Climate models that include human-caused forcings reproduce observed trends better than those that exclude them. Global surface temperatures have risen about 1.1–1.2°C above late 19th-century levels.

Projections depend on future emissions. Without substantial mitigation, warming could exceed 2°C by the end of the century. Meeting ambitious targets would require rapid decarbonization, a transition to low-carbon energy, and adaptation to climate impacts, along with policies such as carbon pricing and emission reductions across sectors.

The scientific consensus is that human activities are the dominant cause of recent warming. Major scientific organizations and assessment reports, including the IPCC, state that anthropogenic emissions are responsible for most of the observed increase since the mid-20th century.