CO2 emissions reduce stratosphere, study finds

The ozone layer is not the only one affected by greenhouse gas emissions produced by humans. A new study reveals that these also have an impact on the stratosphere, the layer of our atmosphere which contains ozone, reducing its thickness by several meters each year.

Since the 1980s, a period when humans spread greenhouse gases (GHGs) in large quantities, the thickness of the stratosphere has contracted by 400 meters. According to the researchers, it will thin about an additional kilometer by 2080 if emissions are not significantly reduced. From a technological point of view, these changes may affect the operation of satellites, GPS navigation systems and radio communications.

Studies showing the impact of humans on the planet, there are many, but this is the first to focus on a particular layer of the atmosphere other than ozone. In April, researchers showed that the climate crisis caused the Earth’s axis to shift, with the massive melting of glaciers redistributing mass across the globe.

” It’s shocking “

The stratosphere extends from about 20 km to 60 km above the Earth’s surface. Below is the troposphere, where carbon dioxide warms and expands the air. This brings up the lower limit of the stratosphere. In addition, when CO2 enters the stratosphere, it cools the air, causing it to contract.

According to Juan Añel, from the University of Vigo, Ourense in Spain and member of the research team, the shrinking of the stratosphere is a strong signal of the climate emergency and of the global influence exerted by now humanity. ” It’s shocking “, did he declare. ” This proves that we disturb the atmosphere up to 60 kilometers “.

The different layers of the Earth’s atmosphere. The figures shown are approximate and may vary greatly depending on the time of year or the position relative to the Earth. © Eros

With the increase in carbon dioxide emissions, scientists already knew that the troposphere was gaining altitude, and had even hypothesized that the stratosphere was shrinking. But this new study is the first to demonstrate it. It reveals that it has contracted around the globe since at least the 1980s, when satellite data was first collected.

A decrease directly linked to the increase in CO2 levels

The ozone layer, which absorbs UV rays from the sun, is found in the stratosphere, and researchers believed that ozone losses over the past several decades may be responsible for this shrinkage, with less ozone meaning less warming in the stratosphere.

But the new research shows that it is the increase in CO2 that is causing the constant contraction of the stratosphere, not the ozone levels, which started to rise after the CFC ban by the Protocol. de Montréal in 1989. The study reached these conclusions using the small set of satellite observations made since the 1980s, in combination with several climate models, which take into account the complex chemical interactions that occur in the atmosphere. . Details were published in the journal Environmental Research Letters.

This could affect the trajectories of the satellites, their orbital lifespan and their recovery. […], the propagation of radio waves and, ultimately, the overall performance of the Global Positioning System and other space-based navigation systems The researchers said.

This study finds the first observational evidence for the contraction of the stratosphere and shows that the cause is actually our greenhouse gas emissions rather than ozone Says Professor Paul Williams of the University of Reading in the UK, who was not involved in the new research. ” Some scientists have started to call the upper atmosphere the ‘ignorosphere’ because it is so little studied. […] This new article will strengthen the case for better observations of this remote but critically important part of the atmosphere. “.

It is remarkable that we are still discovering new aspects of climate change after decades of research Says Williams, whose own research has shown that the climate crisis could triple the number of severe turbulence suffered by airliners. ” It makes me wonder what other changes our emissions are inflicting on the atmosphere that we haven’t discovered yet. “.

Furthermore, the researchers here demonstrate that the contraction of the stratosphere is not only a response to cooling, as pressure changes in both the tropopause and the stratopause contribute to it. In addition, its short duration of appearance (less than 15 years) makes it a new and independent indicator of climate change induced by greenhouse gases.

The domination of human activities on the planet has led scientists to recommend the declaration of a new geological epoch: the Anthropocene. Suggested Anthropocene markers include radioactive elements dispersed by nuclear weapons tests in the 1950s and domestic chicken bones, especially due to the boom in poultry production after World War II. Indeed, geologists therefore expect fossilized chicken bones to be found in the same geological layers, all over Earth. A direct marker of the Anthropocene.

Environmental Research Letters

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