The heat emitted by our planet finds its escape routes and disperses in space, but if the global average temperature rises too much, the mechanism could be interrupted and the Earth will turn into an oven.

Venus

If the global average temperature of our planet reaches 26-27 ° C, the Earth system will no longer be able to disperse heat into space and our planet will turn into … Venus

Think of the Earth as the oven you have in the kitchen: the more it heats up, the greater the heat emitted all around, and for the Earth the “all around” is the Space. In the middle of the last century, scientists detected a phenomenon in accordance with the laws of physics: a direct and linear relationship between the surface temperature of our planet and the heat dispersed in space.

But there was a problem, not easy to solve: that is, the fact that the Earth is an incredibly disordered system, with many complex elements forming the surface and the atmosphere. All elements that interact with each other and that should deeply influence that process and make it much more complex.

Earth

this phenomenon instead, surprisingly, is linear, and curiously, scientists have always found it rather difficult to explain why it is so and what influence it can have on understanding climate changes.

Green building. MIT earth science department

Recently, researchers from the Department of Earth Sciences at MIT have developed a model that seems to be able to explain the issue and, above all, predict its evolution, that is when and if it will be interrupted.

The model is the one in which we live. The Earth emits heat into space both from the surface and from the atmosphere. When both systems heat up, for example as a result of the increase in carbon dioxide (CO2), there is an increase in water vapor, which traps heat into the atmosphere. For what we know about the physics and nature of gases, water vapor should cancel or reduce the emission of heat into space. But so, in fact, it does not happen.

The working group has developed a model of the “Earth system” and how it emits heat in the form of infrared radiation in space, in practice, the representation of a vertical column of air similar to the Earth’s atmosphere. By varying the temperature of the system it was possible to see what happens with the dispersed heat.

The team, coordinated by Daniel Koll, has discovered that there is a temperature band that maintains the linear dispersion relationship, which stops only above 340 K (about 27 ° C) – while now the global average temperature on the surface is of 285 K (about 14 ° C).

Swollen river

This way of proceeding has shown that not all the infrared radiation is dispersed in the same way. Some irradiation intervals are effectively blocked by water vapor, as expected, and yet the heat has been shown to behave in the system, as a river would flood in the presence of a barrier: the water simply flows out into the free zones, at higher speed, and the total amount of water is not appreciably reduced. Similarly, in the temperature range in which we are, the heat is dispersed in space because it finds its free zones, without being affected much by the water vapor.

But this does not work for every temperature range. The linear relationship undergoes a profound alteration when the average global temperature rises. At that point the water vapor actually acts as a sponge to the heat, preventing the infrared radiation from leaving the atmosphere and dispersing in the space in a vicious circle that produces a further increase in temperature.

At the moment we are still far below that threshold and that “global warming” alone does not seem sufficient to cause such a rise. But there could be other events, as has happened in the past, capable of pushing the Earth system closer if not beyond that limit, and in that case the planet would be destined to become like Venus.

             All the images are licensed CC0-CreativeCommons or in the public domain:

                                        Featured image  

Venus

                                                                                     Green building

 Swollen river

                                                                                                        Earth

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Responses

  1. SugarFix

    > “this phenomenon instead, surprisingly, is linear,”
    It is? Are you sure that it is just not the influence of a Western scientific tradition who are trained to see linearity in everything. It’s often the case that the outcome is perceived to be linear however it is only a fascia and underlying elements are constrained by that fascia popping out and triggering what is viewed as out of context. Thanks for the piece though I learned quite a bit.

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  2. Workin2005

    Very well written @ferra. The earth has been through many extremes long before humans were around. Major warming, major cooling (ice age), major warming…etc. The only thing we know for certain is, the climate has always, and will always change. That said, I find articles like this fascinating. Thanks for the insightful post. I look forward to more.

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