Quantum effect of CO2 plays a key role in global warming

Physicists have just discovered the phenomenon that explains the greenhouse effect of CO2, the cause of global warming. It is a quantum phenomenon.

Could this help in the fight against global warming? In any case, a veil has been lifted on the functioning of the CO2 greenhouse effect. Explanations from Mathilde Fontez, editor-in-chief of the magazine Epsiloon.

franceinfo: Physicists from Harvard University have just discovered that a quantum phenomenon explains the greenhouse effect of CO2, which is the cause of global warming. What is it?

Mathilde Fontez : Yes, a quantum phenomenon, which occurs at the scale of the atoms of the carbon dioxide molecule. Until then, it had never been completely described. As surprising as it may seem, we did not understand, from a physical point of view, why CO2 warms the atmosphere so much, even if we had no doubt about the reality of warming.

Three physicists from Harvard University have just solved the whole enigma: in The Planetary Science Journal, they dissect the mechanics at play, they talk about their pleasure in seeing all the pieces of the puzzle come together to form a single equation, which describes the effect of CO2 on the climate.

So what is it, how does this effect work?

This is called Fermi resonance, it is an effect that had already been described – but never fully applied to CO2: we could describe it as molecular friction, the movements of the CO2 atoms couple, and exchange their energy in passing. Thus the molecule absorbs more infrared radiation, and therefore heat.

Without this effect, CO2 absorbs heat around 20 terahertz. With this effect, it absorbs lower and higher frequencies, which doubles its capacity. This explains why each time our CO2 emissions double in the atmosphere, the temperature increases by about 3°C. This is a specificity of CO2: no other greenhouse gas reacts this way, neither water vapor nor methane.

Will this discovery help to clarify climate models?

No, this will not have any impact on the forecasts. The models are based on observations, measurements, and already take into account this double absorption of CO2. Nevertheless, this demonstrates to those who still doubt the existence of global warming (by pointing out the opacity and complexity of the models) that the phenomenon is well understood.

“This shows that we understand basic phenomena and can explain them from fundamental principles.”explain the researchers. And then it is the first description of a quantum phenomenon on a planetary scale: a tiny effect in the intimacy of molecules, a friction between atoms, which impacts the entire Earth.