Milutin's Milankovich wave theory is a key model explaining natural climate change on a geological scale through cyclical changes in Earth's orbital parameters: eccentricity, axial tilt, and precession. These factors influence the distribution of solar radiation (insolation), causing alternating periods of glaciation and warming. In the context of contemporary climate change, supposedly largely driven by human activity, the question arises whether Milankovich's theory better explains climate change than other mechanisms, such as anthropogenic greenhouse gas emissions, volcanism, or changes in solar activity.
The Milankovich theory is based on three orbital parameters. Orbital eccentricity, which varies in cycles of 100,000 and 400,000 years, causes differences in insolation between perihelion and aphelion. The Earth's axial tilt (obliquity), which varies between 22.1° and 24.5° approximately every 41,000 years, influences seasonal contrasts, particularly at high latitudes. Axial precession, with a cycle of approximately 26,000 years, changes the orientation of the seasons relative to the orbit, modifying the radiation distribution. These changes, called Milankovich cycles, lead to fluctuations in insolation, particularly in the Northern Hemisphere (e.g., 65°N), which historically favored glaciation or warming. Geological evidence, such as analysis of ice cores and ocean sediments, confirms a strong correlation between the Milankovich cycles and the Pleistocene ice ages, which occurred approximately every 100,000 years. For example, changes in atmospheric CO₂ concentrations in the past have been coupled to these cycles, amplifying climate effects through natural feedback mechanisms such as glacial melting.
Compared to other natural mechanisms of climate change, Milankovich's theory is more effective in explaining long-term climate cycles. Volcanic activity, although it can cause short-term cooling (e.g., by emitting reflective aerosols), operates on timescales of decades rather than thousands of years and does not exhibit cyclicality comparable to orbits. Variations in solar activity, such as sunspot cycles (approximately 11 years), have a limited impact on climate on geological timescales, and their effects are too weak to explain major glaciations. Milankovich's theory better explains the regularity and amplitude of past climate change because it is based on predictable, mathematically computable orbital changes, which are reflected in paleoclimate data.
The Milankowicz wave theory is exceptionally effective in explaining natural, long-term climate changes, such as the Pleistocene glacial cycles, thanks to its precise description of the influence of orbital parameters on insolation. Compared to other natural mechanisms, such as volcanism or changes in solar activity, it offers a more coherent and empirically supported explanation of cyclical climate changes on geological scales. The Milankowicz theory remains an indispensable tool for studying Earth's past climate.
