The data from the National Aeronautics and Space Administration (NASA) in the US have shown that parts of the upper atmosphere are gradually contracting due to greenhouse gas emissions.

The combined data of three satellites produced a long-term record that reveals the mesosphere (the layer which is 30 to 50 miles above the surface) is cooling and contracting gradually.

The observations over a 30-year period have indicated the summer mesosphere over Earth’s poles is cooling four to five degrees Fahrenheit and been contracting every 10 years by nearly 500 to 650 feet.

Scientists have confirmed these numbers would remain unchanged if human-made greenhouse gas emissions are not cut down.

The mesosphere is much thinner than the atmosphere that we live in. Simply put, heat generated from the earth easily escapes to the mesosphere as molecules are lesser in number.

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The toxic carbon dioxide, meanwhile, also emits heat and it escapes to space sooner than a molecule can absorb the gas. As more heat is lost to space, the upper atmosphere cools leading to contractions in the upper atmosphere.

While earlier studies did observe this cooling, none have used a data record of this length or shown the upper atmosphere contracting. The researchers say these new results will help them model the upper atmosphere’s complicated changes.

According to a published article in the Journal of Atmospheric and Solar-Terrestrial Physics, a team led by Scott Bailey, an atmospheric scientist at Virginia Tech in Blacksburg, analyzed how the temperature and pressure had changed over 29 years.

Covering the summer skies of the North and South Poles, they analyzed a stretch 30 to 60 miles above the surface and found the mesosphere cooled as carbon dioxide increased in effect proving the mesosphere was contracting.

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First Published:Jul 2, 2021 6:19 PM IST