The Milankovitch theory, named after the Serbian scientist Milutin Milankovitch, attempts to explain the long-term variations in Earth's climate and its relationship to astronomical factors. The theory proposes that changes in Earth's orbit and axial tilt, known as orbital forcing, play a significant role in shaping the climate patterns over tens of thousands to millions of years.
Milankovitch developed his theory in the early 20th century based on observations and calculations. He analyzed the changes in Earth's orbit, which include eccentricity (variations in the shape of Earth's orbit around the Sun), obliquity (changes in the tilt of Earth's axis), and precession (the wobbling of Earth's axis).
According to the Milankovitch theory, these orbital parameters cause variations in the amount and distribution of solar radiation reaching the Earth's surface. The changes in solar radiation affect the intensity and geographical distribution of seasons and can impact the long-term climate patterns.
Eccentricity, with a period of about 100,000 years, influences the amount of solar radiation received by Earth, as the shape of the orbit changes from more circular to more elliptical. Obliquity, with a period of about 41,000 years, affects the tilt of Earth's axis, which in turn alters the intensity of seasons in different hemispheres. Precession, with a period of about 26,000 years, causes the orientation of Earth's axis to change slowly over time.
These variations in orbital parameters can lead to changes in the amount and distribution of solar energy received by Earth, influencing climate patterns. For example, periods of higher eccentricity can result in stronger seasonal contrasts, while changes in obliquity can impact the severity of ice ages.
The Milankovitch theory provides a framework to understand the long-term climate changes observed in geological records, such as ice core samples and sediment layers. However, it's important to note that the Milankovitch cycles alone do not explain all aspects of climate variability and must be considered alongside other factors, including greenhouse gas concentrations, oceanic circulation, and feedback mechanisms within the climate system.
In summary, the Milankovitch theory is a widely accepted explanation for long-term climate variations based on changes in Earth's orbit and axial tilt, providing insights into the factors influencing Earth's climate over geological timescales.