The mesosphere — part of Earth’s upper atmosphere — is shrinking. ☁️ The mesosphere is a layer in the Earth’s atmosphere that starts about 30 miles above Earth’s surface, and extends to heights of around 50 miles above our heads. ‘Meso’ means middle, since the mesosphere is in the middle of our atmosphere. Even in the middle, the air is really thin, so you wouldn’t be able to breathe up there! This cooling in the mesosphere is an expected effect of human-driven climate change. In the troposphere