Climate cycles

1914 Climate cycles

The book of science

Tom Sharp

Milutin Milanković atmospheric_sciences Climate cycles

Climate cycles

The Earth’s position relative to the Sun changes in a complex rhythm, influenced by gravity of the Moon, the Sun, Jupiter, and Saturn. Milutin Milanković studied how Earth’s orbital eccentricity, its obliquity, and its axial precession influenced climate. The earth orbits in an imperfect circle that becomes more elliptical and then more circular every 100,000 years. It spins on a tilted axis that describes a loop every 26,000 years. The angle between the equatorial and orbital planes varies by 2.4 degrees every 41,000 years. Milutin Milanković showed that the combination of these cycles governed variations of sunlight on Earth, explained the ice ages, and could be used to predict future long-term climate changes.

Models

Milanković made mathematical models to predict the climate on Earth— any where and any time. He modeled temperatures of the earth’s atmosphere at high altitudes. He modeled the climates of the Moon and other planets— Mars, Venus, and Mercury. His worked echoed what Newton had done for celestial mechanics and helped the transformation of descriptive sciences into exact ones.

Changes

The climate changes without human intervention. For a scientist, the causes, for a poet, the effects are difficult to attribute, but the beauty is in the relation— how the perfection of the machine is rediscovered in its obliquity, how the icicle catches the bright light of morning.

Milutin Milanković developed a generalized mathematical theory of insolation, describing how much solar radiation each area on a planet receives over time.

The best climate models today would take into account several factors in addition to insolation—the rate at which energy is lost to space, oceanic processes, plate tectonics, volcanic eruptions, and the accumulation of greenhouse gases from human activities.

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