Green-Leaf Theory

I once fell into a conversation with a young lad who told me that he had an interesting theory about the seasons. He said that he new why the seasons changed; it was all to do with the number of green leaves on the trees. The lad lived in the UK and so he observed the changing leaf-colours and made an interesting correlation between the number and colour of leaves on deciduous trees and how this varied from season to season. This observation and correlation would have been more difficult to make had he lived in an equatorial region. He then went on to advance his theory: when the leaves are green, there is active removal of carbon dioxide from the atmosphere as a result of photosynthesis; however, when there are no leaves on the trees, there is no photosynthesis. This means that the amount of carbon dioxide in the atmosphere increases and prevents the sun’s heat getting to us. This is why it is cold in the winter and warm in the summer. Interesting theory I thought.