Groundwater.
I'll bet you, most people don't think very much about groundwater.
Well, that's because it's out of sight.
And they say out of sight out of mind.
But groundwater is really important.
We get groundwater while we get it from the ground, we dig a hole and in the bottom of the hole, water comes out of the walls of the hole and it fills up and then we take the water out, that's groundwater.
Groundwater is always moving.
A lot of people don't realize it, but there are vast underground rivers.
When I say underground, it's not like there's a space underground.
The water is moving through the ground and it's flowing very, very slowly.
But it's real.
The groundwater gets replaced by rain and snow as the snow melts, some of it goes down into the soil.
So this is kind of a cycle.
The water goes into the ground and then it flows away, the water goes into the ground and then it flows away.
But man started digging holes, we call them wells and he dug the well to take the water out, more water fills in.
But soon man was taking out a lot of water.
In fact, over the last 30 years, man has taken out so much water from the ground that it's changing the earth's wobble, the earth spins, but it doesn't stand straight up and down as it goes around the sun.
It's got a sort of a tilt.
And by taking the water out of the ground, we've changed the tilt of the earth.
That's amazing.
This is like a enormously massive planetary body and we've changed how it spins.
I mean, we couldn't do that with nuclear bombs.
This is just shocking if you think that the CO2 levels are going up and that's a danger.
Well, taking water out of the ground is also a danger.
We're changing how the earth spins around the sun and those kind of changes are much, much more difficult to reverse.
We better think about what we're doing.