In the context of climate change, when Earth's orbit becomes more eccentric (our path over the next 200k years) seasonal changes increase in magnitude.
[1] https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_sh...
In the context of climate change, when Earth's orbit becomes more eccentric (our path over the next 200k years) seasonal changes increase in magnitude.
[1] https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_sh...
Isn't that only so on one of the hemispheres? Right now, earth is slightly further away from the sun when its summer on the northern hemisphere which means that our summers are some 5-7 days longer than our winters and our seasons are actually less intense here.
In a circular orbit, the seasonal variation is driven solely by the axial tilt and relative hemispherical insolation bought about by earth’s own shadow, and angle of the sun to terrain.
With a variable distance from the sun, the seasons become erratic, as these two variables precess out of sync - you end up with winters in one hemisphere where the earth is close to the sun, making for mild winter and scorching summer in the other hemisphere. Equally you end up with the earth far from the sun, and bitter winters and cool summers. Finally, you have the precessions 180 degrees out of sync, and you end up with almost no seasonal variation.
So - it makes the overall swings far more extreme, but in some phases can result in milder seasons.
The last interglacial (the Eemian [1]) lasted 15k years and was warmer than what we experience today; sea level at peak was probably 6 to 9 m (20 to 30 feet) higher than today; Scandinavia was an island. Then the glaciation returned for 100k years with mile-thick ice sheets covering huge parts of Europe and North America, until the current interglacial got going almost 12,000 years ago. [2]
"The axial tilt varies between 22.1° and 24.5°, over a cycle of about 41,000 years. The current tilt is 23.44°, roughly halfway between its extreme values. The tilt last reached its maximum in 8,700 BCE. It is now in the decreasing phase of its cycle, and will reach its minimum around the year 11,800 CE. ... decreasing tilt may encourage the onset of an ice age ..." [3]
[1] https://en.wikipedia.org/wiki/Eemian
[2] https://en.wikipedia.org/wiki/Last_glacial_period
[3] https://en.wikipedia.org/wiki/Milankovitch_cycles#Axial_tilt...
How do you determine the exact position in a cycle of 400000 years?