Human-caused global warming has dozens of effects on Earth. If the living conditions on the surface are obviously very different from three centuries ago, this month of October is the proof, the changes are also measured at the limits of the atmosphere.
Indeed, the overconcentration of carbon dioxide in the very high atmosphere (between 90 and 500 kilometers high) has a direct impact. By capturing heat from the Sun, CO2 densifies and cools the rest of the atmosphere. This has the effect of better drawing the boundary between atmosphere and space. This lowering of the level of the atmosphere causes de facto less drag for satellites orbiting just above.
A real boon for scientists and space companies who can extend the life of their satellites thanks to global warming. But according to the results of a study conducted by the British Antarctic Survey, this change has far less pleasant consequences.
Satellites, but also ever-increasing debris
As Ingrid Cnossen, lead author of the study, explains, the drop in density in the upper atmosphere has an impact on the drag caused by satellites, but also for debris in orbit around the Earth. While the latter are becoming the poison of our space, they could be even more harmful than expected.
The researcher explains that with a lower density of the atmosphere, the satellites fall less quickly, but this is also the case for debris. The latter therefore remain in orbit for months longer than expected. Published in the journal Geophysical Research Letters, the study estimates that the situation should not improve in the next 50 years.
For the researcher, her work should guide the authorities in the fight against space pollution. Today the standards in terms of deorbiting space waste are not respected everywhere and the number of debris present in low orbit is increasing every day.
Kessler syndrome: the end is already written?
To combat this, ESA has launched several solutions, now at the prototype stage, to “capture” space debris and bring it back into the atmosphere. Many scientists are warning about the situation in orbit which could spiral out of control in a short time.
While companies like SpaceX or Amazon have received FCC and FAA approval to launch constellations of thousands of satellites into low orbit, many are talking about a risk of “Kessler syndrome”. In this scenario, currently fictitious, human activity in orbit would be so intense and uncontrolled that it would have “locked” the Earth in on itself. In this dystopian world, space travel is impossible, a barrier of debris and satellites blocks the way to explorers.
To avoid this, Cnossen asks the major nations to take the issue of space debris seriously from now on. According to her, the sooner we act against this space pollution, the more likely we are to maintain a clean and usable orbit.