Climate change is a complex and ongoing process that has been occurring for millions of years. However, when people refer to "climate change" in the context of its current global significance, they are typically referring to the rapid changes in Earth's climate that have been observed over the past few centuries, particularly since the Industrial Revolution.
The Industrial Revolution, which began in the mid-18th century, marked a significant turning point in human history. It brought about widespread industrialization, the burning of fossil fuels (coal, oil, and gas), and large-scale emissions of greenhouse gases (such as carbon dioxide) into the atmosphere. These activities have contributed to an increase in the concentration of greenhouse gases, trapping more heat in the Earth's atmosphere and leading to a rise in global temperatures. This period marked the beginning of anthropogenic (human-caused) climate change.
Since the late 19th century, there has been a clear upward trend in global average temperatures, as well as other observed changes in climate patterns, such as shifts in precipitation, rising sea levels, and more frequent extreme weather events. These changes are largely attributed to human activities and are commonly referred to as modern climate change.
It's important to note that while climate change has been accelerated by human activities in recent centuries, natural factors and variations have always influenced the Earth's climate. These include volcanic eruptions, variations in solar radiation, and natural cycles like El Niño and La Niña. However, the current pace and magnitude of climate change are primarily driven by human-induced factors.