What is reflected in a cup of coffee? Column in ComputerreOnline #16
Humanity, whose main source of energy is non‑renewable resources, is already in a transitional state because of this.
the thermonuclear energy of previous generations of stars (nuclear energy from the decay of heavy elements; part of the Earth’s internal heat);
the energy of mass and momentum distribution during Earth’s formation (heat released by planetary gravitational differentiation) and during the formation of the Earth–Moon system (tidal energy).
Nuclear energy contributes to processes occurring on Earth’s surface (there is even a natural nuclear reactor that operated in the geological past), but only one type directly uses this energy: ours. This is one of our unique features, though probably not the most important one.
Which energy source provides the most to modern humanity? Fossil fuel. Want to hear about its significance? “Oil is the blood of the economy”; “the gas pipeline is Russia’s main weapon”; “the real cause of wars in recent decades is the reshaping of the energy‑carrier market and oil price fluctuations”: you have heard all of that.
What is the main difference between using the energy of modern versus fossil photosynthesis? In the peat‑coal period, relatives of modern horsetails, clubmosses, and ferns grew in the swamps. The same processes that occur today were taking place then. Today, dead plant parts fall to the bottom of organic‑rich water bodies. At the sediment layer, where free oxygen is absent, the dead biomass undergoes transformation. Peat formation is a relatively rapid process. Coal forms over a longer time…
For us now two aspects of the distinction between modern and fossil photosynthesis are important. First, the consumption of modern photosynthesis products is limited by its intensity; the consumption of fossil fuels depends on the efficiency of their extraction and combustion. Second, the products of modern photosynthesis are a renewable resource. Fossil fuel is non‑renewable.
Roughly, on one square centimetre of the planet’s external surface perpendicular to solar rays, just under two calories per minute fall. The atmosphere filters some and scatters some; plants convert about one thousandth of the incident solar energy into chemical‑bond energy. Thus, the potential productivity of photosynthesis on the planet is a finite quantity with an upper limit. Naturally, the actual biospheric production falls far short of that limit: large parts of the land lack water, and large parts of the ocean lack essential mineral nutrients.
Consumers of modern photosynthesis products cannot convert more energy than is fixed—of course, when expressed over a given time period. Trees in a forest grow in summer, and firewood heats a stove in winter, yet the annual consumption is limited by the production. Yes, you can burn more wood than the forest regrows, but over a century the limitation remains.
Humanity bypassed this limitation thanks to fossils! Combustible fossils are better and more convenient than wood—point one. Fossil fuel is concentrated in specific locations—point two. Dig a mine and extract layer after layer of lignite—a fuel that does not depend on whether forests roar above it or desert sand drifts over it.
And here it turns out that lignite is a non‑renewable resource. Is that significant? Very much so. A stream flowing from mountain glaciers will run as long as snow falls in the mountains in winter and rain in summer. Of course, that will eventually cease (the Earth is now roughly halfway through its lifespan), but it is too early to worry. A stream draining a very large reservoir is doomed to dry up when the reservoir empties.
Species that exist thanks to the “stream” of modern photosynthesis could, in principle, persist in that state indefinitely. Conditions will change, adaptations will be required, but one can hope that such organisms will be able to maintain a relatively stable way of life far into the future.
Humanity, whose main energy sources are non‑renewable, is already in a transitional state because of this. One can debate the timeframe within which our energy sources will change radically; such a change is inevitable. At present we (by a very rough estimate) burn in a year as much fossil fuel as was formed over a million years.
By the way, aren’t nuclear energy sources also non‑renewable? Yes. But they are not easy to exhaust. Some isotopes are extremely rare, with very limited availability, while others are relatively common, and their reserves are said to last a very long time.
Returning to the cup of coffee. It seems there is a solution. Heat the morning coffee over a fire instead of a gas stove (or perhaps an electric stove powered by either a nuclear plant or wind turbines)—and will our great‑grandchildren be able to enjoy the same aroma? Unfortunately not. The production of coffee and sugar, the very substances we consume, required a greater “expenditure” of fossil fuel energy than the energy of modern plant photosynthesis.
Fields for coffee and sugar beet plantations were ploughed using fossil‑fuel energy. Fertilizers, produced with fossil‑fuel energy, were applied to the soil. Water for irrigation was delivered using fossil‑fuel energy. Fossil‑fuel energy was also needed to produce plant protection agents and to apply them. Harvesting was carried out with fossil‑fuel energy. Processing as well. Can you guess what energy was used to roast the beans and to refine the sugar? And how did the coffee and sugar get from the place where they were grown and processed to you? Heating the coffee during preparation is a drop in the ocean of energy expenditures required to obtain it. By the way, this coffee is heated in buildings constructed with fossil‑fuel energy. Maintaining the necessary thermal regime, delivering water, removing waste, lighting—all of this is largely accomplished thanks to the same source of energy.
Buildings are buildings, and back to coffee with sugar. What source of energy will our bodies extract from it? The one stored as a result of photosynthesis on the plantation or field. And where did the fossil‑fuel energy go? It was spent (very inefficiently, by the way) on sustaining that primary process. Imagine a child who can walk only while holding an adult’s hand. The child’s own muscles perform the movement, but the condition for this is the adult’s movement, a far more energy‑intensive process. Are you surprised that I compare the natural (and ancient) process of photosynthesis to a small child? The point is not photosynthesis per se, but its implementation in our fragile and unstable agro‑ecosystems: turn away for a moment, and everything will go wrong…
Energy subsidies are external energy inputs that support the primary process and increase its efficiency. The simplest type of subsidy is the energy of a human’s muscles working the field (or, for example, the muscles of a leaf‑cutter ant tending its fungal garden). Diesel fuel for a tractor or combine provides a far more powerful energy flow. I have no reliable estimates of the ratio between the primary (photosynthesis) and auxiliary (subsidy) flows, but there are grounds to doubt that they are not severely disproportionate. In the 1970s in the United States the “auxiliary” flow was ten times stronger than the “primary” (producing 1 kcal of food required 10 kcal of subsidies); today the disproportion has intensified markedly.
Therefore, if today we abandon energy from non‑renewable sources, tomorrow we will not only lose our morning coffee—we will endanger the survival of a substantial part of humanity due to a sharp reduction in available food. Yet the day after tomorrow (figuratively speaking), harsh reality will force us to give up those sources. What should we do?
I will not have time to substantiate the answer in this column, but I will declare an important thought for myself. There is no way back. The belief that the lifestyle of our ancestors will save modern humanity withstands no criticism. Only one path lies before us. Forward. In terms of energy production this means mastering renewable or practically inexhaustible energy sources of sufficient power—whether solar, thermonuclear, I do not know.
Is the discussion of the unique features of our species finished? It has only just begun.