Solar energy and thermal pollution

A previous post in this blog stated that if 100% of the energy used by man came from solar energy, the Earth would warm up, and although air pollution and the greenhouse effect would decrease, there would still be thermal pollution. Can we give figures? By how much would the Earth's temperature rise in that case?

According to various sources ([1] and [2]), world power consumption by humans is currently about 18.5 Terawatts (18.5 trillion watts). To find the energy consumed during a given period of time, we should just multiply this figure by the given time. For example, the total energy expenditure during a non-leap year, expressed in Terawatt-hours, will be found by multiplying 18.5 by 365 and by 24 (the number of hours in a year), which is equal to about 162,000 Terawatts-hour.

Is solar energy clean?

For decades we have been sold the idea that when we fully harness solar energy, all our problems of getting cheap and abundant energy, air pollution, and global warming will be solved.

For decades I have been warning that this optimistic approach is not true. If we were able to completely replace energy from fossil fuels (coal, oil and natural gas) by solar energy, some of our problems will not go away, they will just take longer to become unsustainable, especially the problem of global warming.

Why do I think this? Because the Earth receives a certain amount of solar energy. A part is used by plants to carry out the chlorophyll function, which transforms inorganic matter into organic matter, thus making life possible for all animals, including us, humans. Another part heats the oceans and the continents, allowing the Earth to maintain an almost constant temperature, despite the heat losses it suffers every day from the side opposite the sun. Finally, another part of the solar energy is reflected or diverted, in the atmosphere or on the surface, and is lost in outer space.

Jules Verne’s scientific predictions for 2889

Jules Verne

In a science fiction story published in English in the United States in 1889, entitled In the Twenty-Ninth Century and subtitled One Day of an American Journalist in 2889, Jules Verne made several scientific predictions that, according to him, would take almost a millennium to be put into practice. Let us look at a few of the most interesting:

•         The average lifetime of the human population will have increased from 37 in 1889, to 68 in 2889. According to the UN, the average longevity in the world exceeded 68 years in the five-year period from 2005 to 2010, almost nine centuries before Verne’s forecast. Here, as elsewhere, he underestimated.

•         The land and sea voyages of the nineteenth century will have been replaced in the XXIX by air travel, or intercontinental underwater pneumatic tubes. At present, little more than a century after Verne’s story, although air travel has achieved great primacy, land and sea travel continue to exist, and for distances less than a thousand kilometers make a successful competition to air travel. Intercontinental pneumatic tubes, on the other hand, are still science fiction, although there some recent steps in this direction.