Which of the following is a natural process affecting climate?

Tectonic processes are indeed a natural process that affects the climate over geological timeframes. These processes include the movement of the Earth's plates, which can lead to the formation of mountains, earthquakes, and volcanic activity. For instance, volcanic eruptions can release large amounts of ash and gases into the atmosphere, which can temporarily affect global temperatures and weather patterns.

In contrast, human industrial emissions, ocean pollution, and deforestation are all anthropogenic activities, meaning they are caused by human actions and significantly contribute to climate change and environmental degradation. While important in the context of understanding climate change, they do not fall under the category of natural processes. Thus, tectonic processes are the only option that directly links to natural geological and atmospheric shifts that can influence climate over long periods.