Environment: Climate Change:



On Climate Change


by Dr. Manuel Alfonseca

Escuela Politécnica Superior, Universidad Autónoma de Madrid

Francisco Tomás y Valiente

Madrid, Spain


Resultado de imagen de mecacho, qué calor hace Guille

Milankovitch Cycles: By Incredio - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=6930545

https://stryptor.herokuapp.com/mafalda/09-056 © Quino


From a comic strip by the Argentinian cartoonist Quino:


Mafalda, her little brother Guille, and their friend Felipe, are sitting on a doorstep during a very hot day.

Felipe: Bother! It’s really hot!

Guille: It’s the fault of the government, right?

Mafalda: No, it's the fault of the summer.

Turning toward Felipe, she adds:

Mafalda: He’s a small boy, he still can’t put the blame right.


Heard on a radio station's news broadcast in June 2017, during a very hot week:


Announcer: The cause of the heat we are experiencing is the climate change.


Like Guille, this announcer (or the person who wrote what she said) can’t put the blame right.


Nobody doubts that climate change is a fact. In recent decades there have been some evident changes in the global climate: the average temperature of the planet is rising; the glaciers are receding; the polar ice is melting; the distribution and intensity of extreme weather events (storms and hurricanes) is changing. What we must discover is the cause of these phenomena.


Regarding this, there are two main theories:

1.     The current situation is the result of a combination of natural cycles in the evolution of the climate of our planet. Among these cycles, the following can be mentioned:

·        Milankovitch cycles, consequence of periodic alterations in the orbit of the Earth that modify the amount of solar radiation it receives. These changes, which affect the eccentricity of the orbit, its obliquity and its precession, take place over periods of thousands of years, but the combination of several cycles with different periods can give rise to perceptible changes in much shorter periods.


Milankovitch Cycles: By Incredio - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=6930545




·        Solar cycles, which affect the amount of energy that the sun emits, and therefore the amount we receive. The best known is the 11-year cycle of sunspots, of very short duration, but there are other overlapping cycles. A curious fact: the almost total disappearance of sunspots between 1650 and 1700 happened at the same time as the peak in an epoch of abnormal cold, which is called the little ice age.


2.     The current situation is a consequence of human activity. Among these causes, the following can be highlighted:


·        The concentration of CO2 in the atmosphere, which has gone up from 290 to 370 parts per million between 1850 and 2000. It is well-known that carbon dioxide is one of the gases that can cause a greenhouse effect, by absorbing and accumulating in the atmosphere part of the solar energy that in its absence would be ejected into outer space. A spectacular example of this effect is the planet Venus, whose atmosphere, composed mainly of nitrogen and carbon dioxide, has a surface pressure 90 times greater than that of the Earth, and a temperature of about 470C, higher than that of Mercury and able to melt lead. (See my science fiction novel Descent into the hell of Venus, which can be downloaded free from my website).


Par toony — common Image: Carbon History and Flux-2.png, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2965461




·        The continuous and growing consumption of energy. In another paper I pointed out that this increase has turned, from exponential, to approximately linear. In other words, we are already in the linear part of the logistic curve, as is also the case with the world population. The UN forecasts indicate that the increase in population will probably reach a maximum between 2050 and 2100. We can expect, therefore, that the increase in energy consumption will also slow down around the same dates.


If the first theory were the only one right, the consequence would be that the current climate change would be almost impossible to prevent. It is obvious that, just now, we cannot change the solar cycles, or the cycles in the Earth movement. Perhaps, in the far future, a tremendously advanced civilization, such as those in futuristic novels, would be able to do something, but for the time being this is just science fiction.


At most, what we could do, is to find ways to palliate the changes. For instance, we could build dams to counter the ascent of the sea level, as the Dutch have been doing for centuries. Or we could devise novel ways to confront other possible future problems. After all, that’s what technology is about: using artificial means to confront natural dangers. When man dominated fire, for instance, it was used as a protection from cold, as a defense against predators, and to cook. Yes, it was also used as a deadly weapon against other people, but such is human nature!


On the other hand, if the second theory were the right one, there are many things we could do. We can, for instance, reduce the amount of CO2 we send to the atmosphere. We can find ways to extract that gas from the air, and perhaps use it to generate different materials (even petroleum). We can replace the fossil fuels we are currently using by renewable sources of energy, such as solar, wind, the tides, the waves, geothermal, and so forth.


We could finally find ways to generate energy by means of nuclear fusion. In all these cases, technology would help us to solve the problem. Or we could just reduce the amount of energy we are using. It is undeniable that we are wasting and squandering lots of it; that we could live with much less.


What is the most likely cause of the climate change? In my opinion, a combination of both theories. In any case, we must use our technology to solve the problems. And if our action could be one of the causes of the phenomenon, we should do something about it. We have the very recent example of the hole in the ozone layer, which was considered a consequence of the massive use of chlorofluorocarbons (CFCs) in industrial and domestic applications. Their almost total ban since 1989 (in the Montreal Protocol) has managed to put at least a partial brake on the deterioration of the ozone layer.


A different question is whether the use of renewable energies will serve to stop the possible effects of human influence on climate change. The answer to this question is yes and no. If the consumption of fossil fuels stops, the amount of CO2 that we are sending to the atmosphere will decrease. But renewable energies, by themselves, would also cause an increase in the global temperature of the planet. It has been calculated that, if all the energy consumed now in the United States came from wind power installations, the temperature on the surface would increase by 0.24C. Similar considerations apply to all the other forms of renewable sources of energy. One cannot get something for nothing.




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