Final answer:
Atmospheric carbon dioxide is a significant driver of climate change, largely due to human activities such as burning fossil fuels. CO₂ levels have risen from about 280 ppm before the Industrial Revolution to over 400 ppm today, contributing to global warming.
Step-by-step explanation:
The atmospheric concentration of carbon dioxide (CO₂) has emerged as a primary driver of climate change, especially since the onset of the Industrial Revolution. Carbon dioxide is a critical greenhouse gas that traps heat in our planet's atmosphere. Human activities, such as the burning of fossil fuels (coal, oil, and natural gas), deforestation, and various industrial processes, are the main sources of the increased CO₂ emissions that have accelerated the greenhouse effect. This has been accompanied by a rise in global temperatures, and a host of related climate effects.
Scientists have employed indirect evidence from ice cores, tree rings, and other sources to understand past climate and CO₂ levels. These studies have shown that atmospheric CO₂ concentrations were stable at around 280 parts per million (ppm) before the Industrial Revolution but have since risen to over 400 ppm in recent years, a level not seen in hundreds of thousands of years.