[IzzieC (OP)]

Donald asks:

"If the earth/ moon system axis was 0 degrees tilt, and we had monthly complete solar and lunar eclipses, what would the Earth's climate be? Particularly at the poles, and how far would glaciers extend. Would the jet stream change?"

Can you help?

[alancalverd]

No tilt = no seasons. The long-term average temperature and precipitation at any point probably wouldn't change much but the ocean currents and jet streams would have very different and non-seasonal patterns.

[evan_au]

we had monthly complete solar and lunar eclipses

Monthly eclipses of Sun & Moon won't affect Earth's climate noticeably.
- An eclipse of the Sun by the Moon only has a period of totality of a few minutes at any given spot on the Earth, drops temperatures by a couple of degrees and will pass over a different part of the Earth each time
- An eclipse of the Moon by the Earth lasts much longer (because the Earth is bigger than the Moon, and blocks more Sunlight). But it has even less impact on Earth's climate, because the Moon doesn't heat the Earth very much.

The really big and important impact on Earth's climate is from those eclipses where the Earth passes between you and the Sun. This lasts for many hours, and drops temperatures by quite a few degrees; it happens pretty often compared to Lunar eclipses. We call it "Night".

[Colin2B]

Please do not post Spam or you will be banned

[Janus]

Donald asks:

"If the earth/ moon system axis was 0 degrees tilt, and we had monthly complete solar and lunar eclipses, what would the Earth's climate be? Particularly at the poles, and how far would glaciers extend. Would the jet stream change?"

Can you help?

Just to clear up any possible misunderstanding: The axial tilt of the Earth and the orbital inclination of the Moon with respect to the ecliptic are two separate and unrelated things.   The Earth's equator is tilted some 23 degrees to the ecliptic, while the moon's orbit is only tilted by 5 degrees to it. 

[evan_au]

If the earth... axis was 0 degrees tilt... what would the Earth's climate be?

Tropical regions would not experience much change in sunlight from what they receive now. But seasonal affects like the monsoon would not occur.
It is very had to guess the impact of changed ocean currents and air currents.

what would the Earth's climate be at the poles?

At the poles, the sun would seem to skirt around the horizon, all year long - much as it does at the equinoxes today.
The poles would be below 0C all year round, so they would both remain a frozen wasteland.
Today's summer melt would not occur in the arctic, so the thickness of the ice cover would increase steadily. Whales could not enter the arctic ocean.

how far would glaciers extend

This is hard to tell.
However, we know that ice is far more reflective than rock and greenery or sea, so once an area is ice-covered, it is likely to remain ice-covered, and this ice/snow-covered area will tend to extend unless something breaks it up.
So we can guess that the extent of snow cover will exceed today's summer snow cover - and possibly reach (or even exceed) today's extent of winter snow cover.

Once the now pack gets thick enough, it will turn to ice, and become a glacier.

Due to the moon's orbit, changes in Earth's axial tilt are limited to a fairly narrow range - and nowhere near 0 degrees as this thread discusses.
Even so, it is thought that axial tilt has a major impact on glacial periods (but there are other drivers too).
See: https://en.wikipedia.org/wiki/Ice_age#Variations_in_Earth's_orbit_(Milankovitch_cycles)

[CliffordK]

One still might have minimal seasons with a zero tilt as Earth has an elliptical orbit around the sun.  However, the seasonal shifts would be minimal, unless the orbit was also made more elliptical.

As far as climate, It could well be similar to an average of the spring and fall equinoxes. 

[RjMaan]

Yes, the statement is correct. If the earth does not revolve in its axis then there would be do fluctuation of day and night and all seasons. Everything is moving in a mechanized way.