Scientists warn that incessant carbon is compressing Earth’s upper atmosphere

(ORDO NEWS) — Rising levels of carbon dioxide in the Earth‘s atmosphere could exacerbate efforts to clean up our increasingly cluttered shell of orbital space debris.

Greenhouse gas has contributed significantly to the shrinking of the upper atmosphere, according to two new studies. This reduction has been envisioned for decades; now, for the first time, it has actually been observed.

Some of the shrinkage observed is normal and will return to normal; but the contribution of CO2, scientists say, is probably constant.

This means that failed satellites and other elements of old technology in low Earth orbit are likely to stay in place longer due to reduced atmospheric drag. , cluttering the region and creating problems for new satellites and space observations.

“One of the implications of this is that the satellites will last longer, which is great because people want their satellites to stay up and running,” explains geospace scientist Martin. Mlynchak of NASA‘s Langley Research Center.

“However, the debris will also stay on the surface for longer and likely increase the likelihood that satellites and other valuable space objects will have to adjust their path to avoid collisions.”

Descriptions of the earth’s atmosphere usually place layers at certain heights, but the truth is that the volume of gases surrounding our world is not static. It expands and contracts in response to various influences, the largest of which is probably the Sun.

The sun is also not static. It goes through cycles of activity, from high to low and back again, approximately every 11 years. We are currently in the middle of the 25th such cycle since the beginning of the countdown that began around December 2019.

The previous cycle, number 24, was unusually subdued even at the peak of solar activity, and this is what allowed Mlynchak and his colleagues to take action. atmospheric compression measurements.

Their focus was on two layers collectively known as the MLT: the mesosphere, which begins at about 60 kilometers (37 miles); and the lower thermosphere, which begins at an altitude of about 90 kilometers.

Scientists warn that incessant carbon is compressing Earths upper atmosphere 2
Layers of the Earth’s atmosphere

Data from NASA’s TIMED satellite, an observatory that collects data on the upper atmosphere, has provided them with pressure and temperature information for the MLT for almost 20 years. period from 2002 to 2021.

In some of the lower atmosphere, CO2 creates a heating effect by absorbing and re-emitting infrared radiation in all directions, effectively capturing some of it.

However, in the much thinner MLT, some of the infrared radiation emitted by CO2 escapes into space, effectively carrying heat away and cooling the upper atmosphere. The higher the CO2 content, the cooler the atmosphere.

We already knew that this cooling causes the stratosphere to contract. Now we can see that it does the same with the mesosphere and the thermosphere above it.

Using TIMED data, Mlinczak and his team found that the MLT has shrunk by about 1,333 meters (4,373 feet). Approximately 342 meters of them are the result of radiative cooling caused by CO2.

“It was very interesting to see if we could actually observe this cooling and contraction of the atmosphere,” says Mlynchak.

“Finally, we presented these observations in this article. We are the first to show such atmospheric compression on a global scale.”

Considering that the thermosphere expands to several hundred kilometers, that 342 meters may not seem like much.

However, a paper published in September by physicist Ingrid Knossen of the British Antarctic Survey in the UK showed that a cooling of the thermosphere could result in a 33 percent reduction in atmospheric drag by 2070.

Atmospheric drag is what helps satellites and rocket stages de-orbit after completing their mission. Knossen found that this reduction in drag could increase the lifespan of extinct space debris by 30% by 2070.

As more and more satellites are launched into low Earth orbit, this problem will become more and more serious. , without any real mitigation measures – either to reduce the number of satellites or the amount of CO2.

“There is a cooling and contraction at every altitude, which we attribute in part to the increase in carbon dioxide,” says Mlinczak.

“As long as the amount of carbon dioxide is increasing at about the same rate, we can expect these rates of temperature change to also remain roughly constant, about half a degree Kelvin [cooling] per decade.”


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