Earth's recession

[Jim_Baur]

This is an easy one for some of you, but not for me.

How is the Earth’s recession involved in climate changes? (If it is involved)

 

[Farsight001]

Can you elaborate? what kind of recession are you talking about?

 

[Alberti_Devoveo]

This is an easy one for some of you, but not for me.

How is the Earth’s recession involved in climate changes? (If it is involved)

I think you mean precession, not recession.

I do not know much about the colloquial climate change (i.e., global warming before we noticed the decline), but I do not see how precession could play a role in it: the earth’s precession has been pretty much constant over the lifetime of the planet, compared to climate change which varies regularly.

 

[Jim_Baur]

If my sixth grade geography class was correct, we have documented global change or warming since the Ice Ages ended.

I thought the word was recession. The concept that I was trying to understand was the “earth is like a top, it goes back and forth.”

Recession or procession–concept: the wobble of the earth over about 46,000 years.

SORRY and THANKS!!!

 

[lynnvinc]

If my sixth grade geography class was correct, we have documented global change or warming since the Ice Ages ended.

I thought the word was recession. The concept that I was trying to understand was the “earth is like a top, it goes back and forth.”

Recession or procession–concept: the wobble of the earth over about 46,000 years.

SORRY and THANKS!!!

I’m not a climate scientist, but I think it goes like this: When the earth is closer to the sun due to the orbital configuration and precession (see en.wikipedia.org/wiki/Climate_change#Orbital_variations & en.wikipedia.org/wiki/Milankovitch_cycles ) this can cause some increased warming. The increased warming then causes more ice and snow to melt, revealing darker surfaces which absorb more heat, causing more warming, causing more melting. It also causes release of greenhouse gases from melting permafrost and ocean hydrates (ice cages with methane trapped inside). This positive feedback then causes more warming, which causes more ice/snow to melt and GHGs to be released, causing more warming and so on. Some refer to this as the methane shotgun, with some other factor of initial warming pulling the trigger.

The reverse has also happened in the distant past: “snowball earth” – see en.wikipedia.org/wiki/Snowball_Earth

Some climate scientists say we will never again go into an ice age or snowball earth because (1) the sun is emitting more irradiance than in the past (on its way to self-destruction in some billions of years), and (2) our very rapid (in geological time) human-caused warming of today, with much of the warming still in the pipes, has pretty much pushed us past the possibility of a serious global cooling. They say we are pretty much headed toward climate hysteresis (a great warming) or even runaway warming if we continue on our business as usual path.

It seems these Milankovitch cycles (we have been in a Milankovitch cooling cycle for 6000 years and that will continue for 1000s of years) may not be able to counteract this great and rapid warming trend. And with the lifetime of CO2 in the atmosphere being up to 100,000 years, the warming Milankovitch part of the cycle may piggy back on the warming from these other factors.