The earth has lost around one per cent its atmosphere due to climate change, according to scientific research in a new study.
The depth of the stratosphere has diminished by about one per cent, or 1,300 feet, since 1980 according to an analysis of NASA data by Petr Pisoft, an atmospheric physicist at Charles University in Prague. Above the stratosphere, the mesosphere and lower thermosphere contracted by almost 4,400 feet between 2002 and 2019. 1,120 feet of it was due to cooling caused by the extra CO2, he calculates.
This contraction means the upper atmosphere is becoming less dense and scientists are worried about the effect this change could have on orbiting satellites, the ozone layer, and Earth’s weather.
While the Earth’s surface is warming, most of the atmosphere above is becoming dramatically colder. This had been predicted by climate modellers and only recently confirmed by satellite sensors.
The earth’s atmosphere has a number of layers. The troposphere is where our weather happens. It is a dense blanket of air five to nine miles thick and contains 80 per cent of the mass of the atmosphere but only a small fraction of its volume. Above it are wide open spaces of progressively less dense air. The stratosphere, which ends around 30 miles up, is followed by the mesosphere, which extends to 50 miles, and then the thermosphere, which reaches more than 400 miles up.
These higher zones are buffeted by high winds and huge tides of rising and descending air that occasionally invade our troposphere. And the concern is that this already dynamic environment could change again as it is infiltrated by CO2 and other human-made climate change chemicals that mess with the temperature, density, and chemistry of the air aloft.
Increases in the amount of CO2 are now “manifest throughout the entire perceptible atmosphere,” says Martin Mlynczak, an atmospheric physicist at the NASA Langley Research Center in Hampton, Virginia. They are “driving dramatic changes that scientists are just now beginning to grasp.” Those changes far above our heads could feed back to change our world below.”
For satellite operators, it means payloads should stay operational for longer before falling back to Earth. But the problem is the other objects that share these altitudes. The growing amount of space junk—bits of equipment of various sorts left behind in orbit—are also sticking around longer, increasing the risk of collisions with currently operational satellites.
More than 5,000 active and defunct satellites, including the International Space Station, are in orbit at these altitudes, accompanied by more than 30,000 known items of debris more than 4 inches in diameter. The risks of collision, says Cnossen, will grow ever greater as the cooling and contraction gathers pace.