A team of environmental scientists, atmospheric chemists and space physicists analyzed data from NASA’s Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) mission launched in 2001. Collecting insights on atmospheric infrared radiation, or heat, just over a year after launch. It is these nearly two decades of insights that researchers have used to assess how building CO2 levels have affected the atmosphere over time.
According to the dual research they published Journal of Geophysical Research: Atmosphere, Researchers have found that Earth’s upper atmosphere is actually contracting – something scientists have suspected for some time, but it’s hard to confirm. In the lower atmosphere, CO2 absorbs and re-emits heat in all directions, creating a warming effect. But in the upper atmosphere, CO2 is allowed to escape into space, causing gradual cooling. This cooling effect not only causes the stratosphere to contract but also the mesosphere and thermosphere (together known as the MLT).
The MLT has shrunk by 1,333 meters in just under 20 years. The researchers estimate that about 342 of them were a direct result of CO2 cooling. MLT cooling is negatively correlated with atmospheric drag; Atmospheric drag decreases as the MLT cools. Essential to the ability of given atmospheric tugs and satellites to deorbit, continued carbon buildup could impact future (or even current long-term) missions. This includes the increasingly necessary task of removing space debris.
The team believes that CO2-related MLT cooling could affect the broader space industry sooner than we think. “As long as carbon dioxide increases at roughly the same rate, we can expect these rates of temperature change to remain roughly constant,” they wrote. “It seems likely that ongoing changes in the space climate will become important issues in space law, space policy and the business of underwriting insurance for space endeavors.”