Scientists have finally put to bed a long-standing question over the role of Earth's orbit in driving global ice age cycles.
© Cardiff University
In a new study published today in the journal
Science, the team from Cardiff University has been able to pinpoint exactly
how the tilting and wobbling of the Earth as it orbits around the Sun has influenced the melting of ice sheets in the Northern Hemisphere over the past 2 million years or so.Scientists have long been aware that the
waxing and waning of massive Northern Hemisphere ice sheets results from changes in the geometry of Earth's orbit around the Sun.There are two aspects of the Earth's geometry that can influence the melting of ice sheets: obliquity and precession.
Obliquity is the angle of the Earth's tilt as it travels around the Sun and is the reason why we have different seasons.
Precession is how the Earth wobbles as it rotates, much like a slightly off-centre spinning top. The angle of this wobble means that sometimes the Northern Hemisphere is closest to the Sun and other times the Southern Hemisphere is closest, meaning that roughly every 10,000 years one hemisphere will have warmer summers compared to the other, before it switches.
