1914: Climate cycles - The book of science

Climate cycles
Models
Changes
Commentary

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.