<p><pre><code> > This tilt causes different parts of the Earth to be
> nearer or further away from the Sun at different parts
> of the orbit. It is this change of distance that causes
> our seasons.
</code></pre>
This is nonsense - it's not how close - the variation is negligible. What's different is the projected surface area. That causes a change in the total radiation influx per unit area. When tilted towards the Sun you get more radiation per unit area than when "tilted away."
I'm sure the rest of it is reasonably accurate, but after a while I found myself thinking about other things, so I didn't check everything thoroughly.