Concentration of carbon dioxide on the rise in upper layers of Earth’s atmosphere

The SABER instrument, aboard the TIMED satellite (NASA), has measured an increase of between five and twelve percent per decade in the concentration of CO2 in the top atmospheric layers

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16/09/2015

The increase in the concentration of carbon dioxide (CO2) in the atmosphere, which causes its lower layer (the troposphere) to warm up – driving what is globally known as climate change – also affects the higher layers of the atmosphere. Measures carried out by the SABER instrument, aboard the TIMED satellite (NASA), have revealed an increase in the amount of carbon dioxide contained in the top layers of the atmosphere between 2002 and 2014 from 5% to 12%, which is more than the increase recorded in the lower layers.

"CO2 has a long average lifespan: every new molecule that is produced will remain in the atmosphere for more than a century,” says Manuel López Puertas, researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) involved in the study and co-director of the SABER instrument, “and carbon dioxide from the lower layers of the atmosphere seeps into the higher layers over a span of five to seven years, so that any increase in the lower layers will also impact the higher atmosphere.”   

SAME GAS, DIFFERENT EFFECTS

The SABER data show an increase in the concentration of COof 5% per decade up to an altitude of eighty kilometers (stratosphere and mesosphere), a measure similar to that obtained in the troposphere, and an increase of up to 12% at altitudes of approximately one hundred and ten kilometers (lower thermosphere).

In the troposphere, the layer that encompasses the first twelve kilometers of the atmosphere and where climatic phenomena occur, carbon dioxide behaves like a greenhouse gas and its increase produces an increase in temperature. In the intermediate and higher layers, however, the situation is reversed and CO2 has a cooling effect.

"Over the last decade, considerable decreases in temperature - between three and four degrees - had been registered in the higher layers of the atmosphere, which could be attributed to an increase in the concentration of CO2, but the relationship had not been firmly established. The measures carried out by the SABER instrument in the course of the last thirteen years confirm an unequivocal increase in the amount of carbon dioxide in the higher atmosphere not related to natural causes such as the eleven year solar cycle,” says López Puertas (IAA-CSIC).

The increase of carbon dioxide in these atmospheric layers produces a drop in temperatures which triggers a contraction. Thus, the higher layers of the atmosphere become less dense, which could prolong the average lifespan of artificial satellites on low orbits, since the friction will decrease. On the other hand, the contraction could have adverse effects on the already unstable balance of spatial detritus.

"The results confirm once more the interconnected nature of the Earth’s atmosphere. The CO2 emissions are producing a change in the temperature of the different layers and in the energetic balance of the atmosphere which may alter its structure,” López Puertas (IAA-CSIC) concludes.

 
Referencia:

J. Yue et al. "Increasing carbon dioxide concentration in the upper atmosphere observed by SABER". Geophysical Research Letters. DOI: 10.1002/2015GL064696

Contacto:

Instituto de Astrofísica de Andalucía (IAA-CSIC)
Unidad de Divulgación y Comunicación
Silbia López de Lacalle - sll[arroba]iaa.es - 958230532
http://www.iaa.es
http://www-divulgacion.iaa.es


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