Final answer:
The Milankovitch cycles are long-term changes in the Earth's orbit that impact climate by altering solar radiation received. These include variations in eccentricity, obliquity, and precession, contributing to climatic shifts like ice ages. Geological records support their influence on Earth's historical climate changes.
Step-by-step explanation:
The Milankovitch cycles are cyclic changes in the Earth's orbit that have a profound impact on its climate over long periods. These cycles alter the amount of solar radiation the Earth receives and include variations in the Earth’s axial tilt (obliquity), the shape of its orbit around the sun (eccentricity), and the wobble in its axis (precession). The shape of Earth's orbit changes from more circular to more elliptical with a cycle of approximately 100,000 years, known as eccentricity, which influences the distance of the Earth from the sun. Eccentricity has longer cycles of around 400,000 and 2.4 million years. Similarly, obliquity, which affects the angle at which sunlight strikes the Earth, has a cycle of about 41,000 years with a longer cycle of 1.2 million years. Precession, which changes the timing of the seasons, has a cycle of roughly 26,000 years.
On time scales of tens of thousands to hundreds of thousands of years, the Earth's orbital patterns, including the Milankovitch cycles, are the most significant natural factors affecting the climate. These cycles can either amplify or reduce the effects of climate change depending on their phases and interactions. For example, periods of higher eccentricity, where Earth's orbit becomes more elliptical, lead to greater variance in the distance to the sun and can result in more extreme seasons, potentially leading to ice ages or warmer intervals.
The relevance of the Milankovich cycles to climate is supported by geological records such as deep-sea sediments which show variations that align with these cycles, offering explanations for past climatic events, such as ice ages. They are important when considering the natural drivers of climate change that occur over long timeframes and how they have historically influenced Earth’s temperature and climate systems.