What would happen if there was no such thing as the mesosphere?

Well, isn't that an interesting thought! The mesosphere plays an important role in our atmosphere, helping protect us from meteoroids and allowing for the beautiful phenomenon of noctilucent clouds. Without it, our atmosphere would be quite different, but nature has a way of finding balance, so I'm sure something else would step in to fill the gap. Just like in painting, every element has its place and purpose.