What are the natural causes of climate change?

Climate change can occur due to several natural processes. One of these processes is known as the Milankovitch cycle. These cycles involve natural variations in the Earth’s orbit and tilt, affecting the amount of solar radiation the Earth receives. During some phases of these cycles, the Earth gets less solar radiation, resulting in cooler periods. The Earth receives more radiation in other phases, leading to warmer periods or global warming. There are three main types of Milankovitch cycles:

• Eccentricity: Over approximately 100,000 years, the shape of the Earth’s orbit changes from more circular to more elliptical. When the orbit is more circular, the Earth tends to be warmer (interglacial periods), while when it is more elliptical, it tends to be cooler (glacial periods).
• Axial Tilt: The Earth is tilted at about 23° from a vertical position, causing seasonal changes. However, over about 40,000 years, the angle of tilt varies. When the tilt increases, the seasonal contrast becomes more pronounced, leading to warmer summers and colder winters. When the tilt decreases, the seasonal differences are less extreme.
• Precession: As the Earth rotates, it wobbles slightly on its axis, similar to a slowing spinning top. This wobble changes the direction the axis points over a cycle of about 24,000 years, affecting the intensity of seasons.

Other natural factors influencing climate change include:

• Solar Variation: The Sun’s radiation output fluctuates over time. Lower solar activity is associated with glacial periods, while higher activity leads to interglacial periods.
• Volcanism: Major volcanic eruptions can release vast amounts of ash and dust into the atmosphere. This material can block sunlight, temporarily cooling the Earth’s surface.
• Surface Impacts: Large impacts from cosmic bodies like asteroids or comets can throw significant dust into the atmosphere. This can block sunlight and cause cooling periods. A famous example is the impact event around 65 million years ago, which drastically altered the climate and contributed to the extinction of the dinosaurs.

These natural processes have significantly shaped the Earth’s climate throughout its history.