From a comic strip
by 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.
Listened in a radio
station news in June 2017, on 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:
- 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.
- 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.
- 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).
- The continuous and growing consumption
of energy. In another
post in this blog 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.
CO2 concentration in the atmosphere |
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.
One cannot get something for nothing.
The same post in Spanish
Thematic Thread on Politics and Economy: Previous Next
Extended version published in Journal of Global Issues & Solutions
Manuel Alfonseca
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