A rise in water vapor in the mesosphere has led to the formation of high-altitude clouds that are visible at night. What is causing this change in the mesosphere?
The mesosphere is the layer of the Earth's atmosphere that lies between the stratosphere and the thermosphere, located at an altitude of about 50 to 85 kilometers (31 to 53 miles). This layer is very cold, and the low temperatures cause water vapor to freeze into tiny ice crystals, forming noctilucent clouds (also known as polar mesospheric clouds) when conditions are just right.
The recent increase in noctilucent clouds could be caused by climate change, as rising greenhouse gas emissions lead to an overall warming of the Earth's atmosphere. This warming creates a more stable atmosphere, reducing the turbulence that typically occurs around the mesosphere, and reducing the overall water content of the upper atmosphere. However, other factors such as changes in solar activity and the level of cosmic rays reaching the atmosphere can also affect the formation of noctilucent clouds.