Table of contents:
- Will a vegan diet reduce our environmental burden?
- Why do plants need large herbivores?
- Why can't wild large animals replace livestock today?
- Vegetables or meat: who will win?
Each of us has heard: do not eat meat, so you will weaken global warming. To paraphrase the classics: "Greta Thunberg didn't eat meat either." And in general, plant food from one hectare can feed much more people than meat or milk from the same hectare.
Refusal from meat-eating seems to be correct from all sides, concern for nature. What does science think about this? Alas, the merciless numbers paint a slightly different picture. Refusal to keep livestock can lead to a decrease in soil fertility. Plant biomass will follow. And trendy vegan products often require more hectares than livestock. How does this happen and how will Thunberg's possible victory over cattle turn out?
Will a vegan diet reduce our environmental burden?
It is generally accepted that plant food requires fewer hectares to feed one person. And not only hectares: cattle farms consume a lot of water and produce a lot of greenhouse gases.
Let's start with hectares. Livestock, of course, requires a lot more of them than crop production - especially one that is based on grazing, and not on stall fattening. On average, 0.37 hectares of pasture are required per kilogram of beef per year - the same amount as growing a ton or two of grain. Carbon dioxide in the production of a kilogram of such meat is emitted 1.05 tons. A resident of America eats 120 kilograms of meat a year, poorer Slovenia - 88 kilograms, and even in Russia - 75 kilograms, that is, in total, the numbers are very large.
Meat and milk provide only 18% of calories and 37% of protein consumed by mankind, but at the same time they occupy 83% of all agricultural land and provide 58% of all CO2 emissions generated by agriculture. It turns out that if we graze less livestock, then people will take less of all new hectares from nature?
But, alas, not everything is so simple. The first thing to understand is that there is no food shortage on Earth, as well as agricultural land. Food production is constantly growing faster than the population, while the area of land use is increasing at a moderate rate.
The reason why people in Brazil and other developing countries are expanding farmland by cutting down the jungle is not because they lack food - especially since, due to deep social stratification, no matter how you raise food production, the local poor will still not consume normal food. the amount of protein, but the fact that there is a powerful agricultural export. In these places, meat is like oil or gas in Russia: one of the few local products that are competitive on the world market.
If the consumption of meat in the world stops, Brazil or Indonesia will not cut down less jungle: they will simply expand their already huge biofuel plantations. But for a second, let's forget that we live in the real world, and suppose that none of this exists and the rejection of meat will force the already not very rich Brazilians to simply lose their jobs and die out or emigrate. Can avoiding animal food then reduce the burden on the environment?
This is where the second point comes into play. If we are talking about animal food, then in reality it can be obtained from one hectare no less than plant food suitable for humans. Yes, you heard right.
If from a hectare of sea surface it is really possible to catch with an average of two kilograms of fish per year, then from a hectare of a lake - already 200 kilograms per year, and from a hectare of a fish-breeding plant 40 years ago they were able to "extract" 1,5-2,0 thousand tons (up to 20 thousand centners) per hectare.This is hundreds of times more than you can grow wheat in the field, and no less than the yield of the best existing greenhouses. Today, aquaculture (which includes fish factories) supplies more seafood than wildlife.
The cultivation of molluscs has a similar efficiency: 98.5 centners per hectare per year for green mussels is also much more than wheat can be obtained from a unit of area.
An important point: a person eats up fish faster than most types of plant foods. So, one hectare of aquaculture can feed many more people than one hectare of arable land.
Why fish factories are so much more productive than land-based cattle breeding is easy to understand. Fish, crustaceans and molluscs are cold-blooded, that is, they spend 5-10 times less energy, because they do not need to constantly warm themselves up. They do not need to capture the highly deconcentrated and unstable energy of the sun's rays, as plants do.
Algae and other feed are supplied ready-made. Moreover, obtaining algae by the same aquaculture is much more efficient than land-based crop production: the former spend much less energy on transporting nutrients and protecting against fluctuations in the brightness of the sun.
The other is harder to understand. Why, with such a huge efficiency of "aquatic" livestock farming, the fighters against the terrible and terrible global warming are not promoting it, but a vegan diet that takes more space from the environment?
We don't know for sure, but the working hypothesis is this: Vegans do not want to eat animals for ideological - or ethical - reasons, thus seeking to perceive themselves as more moral individuals. The fact that such morality can lead to alienation from nature of large areas than with the use of aquaculture - apparently, they simply do not know. At least from their side there is no and never was any mention of this fact.
However, there is some rationality behind the position of vegans: meat production creates more greenhouse gas emissions than growing plant foods. Even fish - and in aquaculture too - require decent CO2 emissions: from 2.2 to 2.5 kilograms of carbon dioxide per kilo. This is less than chicken (4.1 kilograms of CO2), and about the same as popular fruits and berries. True, fish satisfies hunger faster: vegans can eat 3, 5-4, 0 kilograms of the mentioned fruits and berries a day. It is clear that when trying to eat the same amount of fish, the average person will not succeed, that is, on a fish-eating diet, he will emit less CO2.
So, the intermediate result: with the reasonable cultivation of animal food - and not insects, but the most common fish and seafood - you can take away from nature as much or even less land than if you are a vegan. Moreover, if you choose the right types of fish to eat, your CO2 emissions will be similar to those who eat only plants.
In the meantime, let us recall one more moment carefully avoided in the "green" rhetoric. As we already wrote, in the 20th century, thanks to anthropogenic CO2 emissions, the biomass of terrestrial plants is 31% higher than in the pre-industrial era, and the highest in 54 thousand years. Moreover: according to scientists' calculations, the higher CO2 emissions in the 21st century, the more biomass on Earth will be by the end of the century. In the scenario of maximum emissions (RCP 8.5) in 2075-2099 it will be 50% more than in 1850-1999. In the scenario of moderate emissions (RCP 4.5) - by 31%.
In other words, the smaller the carbon footprint you leave behind, the lower the biomass of our planet will be. Think for yourself, decide for yourself. Opponents of warming, of course, have already decided everything, and, to be honest, no one among them has heard that the bioproductivity of the planet with anthropogenic CO2 emissions is growing.
If we were on their point of view, we now recommended to massively switch to "low-carbon" tuna and avoid high-carbon tilapia.But first, a little warning: as we will show below, the rejection of cattle meat would lead our planet to very serious problems, or rather, to an environmental disaster.
Why do plants need large herbivores?
All living things on Earth in terms of dry carbon (excluding water) contain 550 billion tons of carbon. Of these, plants account for 450 billion tons, 98% of which are terrestrial. That is, 80% of the entire biomass of the planet is precisely these green citizens. Another 77 billion tons are bacteria and archaea. There are only two billion tons of animals left, and half of them are arthropods (mainly insects). About one ten-thousandth remains per person.
The numbers speak directly: the king of nature here is not a man, but terrestrial plants, and trees dominate in their biomass. It seems that 1/220 animals cannot influence the flora, but this is a mistake. Despite their insignificant mass, it is animals that have a decisive influence on the productivity of plants.
Why? Well, green creatures are quite selfish. If the plants are not touched, they slowly return nutrients from their bodies to the soil. Falling leaves (not in all species), moreover, decompose slowly, and even make up only a very small part of the mass of plants.
After its death, the plant (and, recall, among them trees dominate in biomass) often does not completely decompose. The trunk is so well protected during life that the mushrooms normally manage to “consume” the easiest part of it to assimilate - but not all of it. This is especially true for the return of phosphorus from plant tissue back to the soil. And not in every environment, mushrooms have enough time to decompose trees.
The undecomposed residues turn into peat, coal, gas or oil - but all this happens very deeply, that is, it will not return to the plant world in the foreseeable future. One could put up with the loss of carbon, but phosphorus is already a real tragedy. You can't get it out of the air like CO2.
The "pipe" through which phosphorus enters the biosphere has a constant cross-section. It is washed out of rocks by erosion, but the amount of such rocks and the rate of their erosion is a value that may not change for millions of years. If trees bury phosphorus with their dead trunks, the soil will become so poor in them that the growth of the same plants will seriously slow down.
Large herbivores intensively consume leaves, shoots and much more, excreting nitrogen, phosphorus and potassium with manure and urine. They return phosphorus and nitrogen to the soil faster than other mechanisms, for example, decomposition of fallen leaves.
We didn't say the word "large" for nothing. It is creatures larger than one hundred kilograms (where they exist) that absorb the bulk of plant food, and it is impossible to replace them with smaller animals. Therefore, the importance of large herbivores for ecosystems cannot be overestimated. According to estimates from the latest scientific works on the topic, their extermination in a particular biocenosis leads to a decrease in the flux of phosphorus entering the soil by 98% at once.
Our species about fifty thousand years ago set up a major experiment - killed all large herbivores on one of the continents, in Australia. Before that, it was green, wet and abundant in swamps.
Now is the time to take stock: today there is an ecological disaster. Local soils are extremely poor in phosphorus, which is why wild "photosynthesizing" there grow much slower than in other parts of the world, and agricultural crops without phosphorus fertilizers show lower yields than on other continents.
Often, attempts are made to explain the phosphorus deficiency in Australian soils by the small amount of the corresponding minerals on the continent. But, as researchers from other similar regions of the world have repeatedly noted, the jungles of the Amazon and Congo also have almost no access to such minerals, but there is nothing wrong with phosphorus. The reason is that until recently there were many large herbivores.
As a result, among Australian plants in terms of biomass, eucalyptus trees dominate, which before the arrival of man were there a rather rare species. They not only use phosphorus more carefully (due to poor growth), but also have an unusual mechanism for returning this element to the soil: fire.
Eucalyptus is an arson plant. Its wood is saturated with highly combustible oils and flashes as if doused with gasoline. The seeds are in fire-resistant capsules and the roots survive the fire effectively so that they can sprout immediately. In addition, they intensively pump water out of the soil: this allows them to get more phosphorus, which is scarce in Australia, and at the same time make the environment around them drier and suitable for fire.
It is because of the adaptation of eucalyptus to dominance with the help of fires, even a small branch of such a tree can flare up in a way that ordinary plants are not able to.
Periodic self-immolations not only allowed the once rare eucalyptus there to capture 75% of the Australian forests. The phenomenon has another side: dead tree trunks do not have time to go "to the depth" undecomposed, phosphorus continuously returns to the soil with ash.
If, in line with the wishes of vegans, the whole world abandons meat and milk, more than a billion existing cattle will leave the arena. And along with them, phosphorus will begin to leave the soil, leaving them less and less fertile.
Why can't wild large animals replace livestock today?
Okay, everything is clear: without large herbivores, the land quickly turns into an unproductive quasi-desert, where it is difficult for anything to grow. But what have vegans got to do with it? After all, they say that pastures with livestock will be replaced by wild herbivores, whose waste products will successfully replace livestock manure.
Unfortunately, in real life this does not work and most likely will not work. And to a large extent - due to the efforts of environmentalists and green people.
There are more than half a million camels in Australia, but locals are not happy with the acceleration of the phosphorus cycle due to the ships of the desert. Animals in huge numbers are shot from helicopters, leaving their carcasses to rot in uninhabited places of the country / © Wikimedia Commons
As an example, you can take the same Australia. In the last decades, relatively large herbivores have appeared in the wild, inner part of it. Camels, pigs and horses brought by people, and then feral, eat plants, with manure quickly returning phosphorus to the biological cycle.
However, despite this, all such species of animals are actively exterminated by the Australians. They are shot from helicopters, and in relation to pigs, it has come to savage methods: they are fed the food additive E250 (sodium nitrite), which naturally causes them to die - the pigs have problems with the feeling of satiety, and they eat a lethal dose of this food additive.
What is the matter, why do the locals so dislike the growing vegetation following the return of herbivores? It's all about the common ideas of our time, and more specifically, about caring for the environment. The environment, where there are many large herbivores, begins to drift away from the species composition that has fixed on it during the absence of such animals.
For example, eucalyptus trees and other common plants in Australia today - and rare there 50,000 years ago - will no longer receive such strong benefits from more efficient use of phosphorus. But on the same eucalyptus and other "native inhabitants" koalas and many other species - the emblems of Australia - rely in their diet.
Of course, koalas as a species have existed for a very long time. Judging by the fact that they lived there before the arrival of man fifty thousand years ago, it is not at all necessary for them to survive that 75% of the continent's forests were eucalyptus trees. But go explain it to the local greens. From their point of view, nature must somehow freeze in the state in which it is in our time.And it does not matter at all that this "natural environment", in fact, could not have arisen without the destruction of the mass of local species by the aborigines 40-50 thousand years ago.
But do not think that people behave so strangely only in Australia. Take North America: not so long ago, tens of millions of bison lived there, which were then exterminated. (By the way, camels were there too, but died out 13 thousand years ago, soon after the massive arrival of people).
Today they are kept in several parks such as Yellowstone, but the vast majority of these animals live on private ranches, where they are raised for meat. They do not need winter cowsheds, their wool is enough, they dig out forage from under the snow better than ordinary cows, and their meat is richer in protein and contains less fat.
Why not release them on the prairie? The fact is that a person is not used to treating anyone on an equal footing and giving large wild animals freedom of movement. In Yellowstone Park, bison make more attacks on tourists than bears, and sometimes it comes to death.
Live the bison outside the park, where people most expect to see a wild animal, there could be more victims. At least 60 million bison that lived in North America before European colonization will never be bred there again.
Yes, scientists have put forward the Buffalo Commons project to repopulate at least part of the Midwest with bison. But he was "stabbed" by the locals, who do not smile at all to enclose their vast farms with unusual hedges. The bison jumps to a height of 1.8 meters and accelerates to 64 kilometers per hour, and also breaks through barbed wire and even an "electric shepherd" without fatal damage to itself.
The only reliable obstacle in his path is a fence made of a steel bar several meters high, and the bars from it must go into the concrete to a depth of 1.8 meters, otherwise the bison will bend them with multiple strikes from a run. It is expensive to decorate many kilometers of your own fields with such exoticism, and living next to the bison without it means losing the feeling of complete security of your property and life. It's doubtful that Buffalo Commons will ever come true.
There is no chance for a truly massive - in the number of the Stone Age - return of bison to the wild nature of Europe. The modern balance of species in local forests can exist only because the bison has been destroyed there. Previously, he ate the undergrowth to a state close to an English park.
Today, many underbrush trees, fighting with their neighbors for light, eventually die, while under the bison, almost everyone who avoided eating them grew up. The presence of such animals in the forest contributed to the success of those species that have a lot of tannin in the bark (it makes the plant taste bitter, scaring away the herbivore).
If bison are massively resettled in the forests, the species composition in them will greatly change in favor of plants, which once prevailed here, but in recent centuries have greatly receded into the background. However, for modern European ecologists and greens, the preservation of the species diversity that exists today is imperative number one. And they, in general, do not care that today's species diversity of forests is deeply unnatural and developed only due to the fact that the ancestors of today's Europeans killed bison.
A similar picture is in the forest-steppe. Before the extermination by the Eurasians, the Tur (the ancestor of domestic cows) lived here, and not in the forests, where he retreated later. Under him, among the herbaceous plants of the forest-steppes, it was precisely those species that were best tolerated by gnawing by rounds dominated - and today they are in secondary roles. The restoration of wild populations of large herbivores will lead to such serious changes in the species balance of forests, forest-steppe and steppes that, against its background, other processes that threaten the ecological stability of these regions will simply fade away.
Of course, we can say that the idea “stop life as it is, and freeze forever in this form” is false. That there was no "eternal" ecological balance even before man.That the restructuring of ecosystems is a normal part of evolution, but an attempt to stop these restructuring, on the contrary, is abnormal and limits nature. But all this has no meaning for the bulk of environmental activists.
They were brought up on the idea that the current species balance should be maintained as long as possible, regardless of the degree of its “naturalness”.
All this means that in case of refusal to breed cattle, wild analogues will not come to replace it. The land will be "empty and formless" - that is, it will be of limited bioproductive, like those areas of Australia where camels and other large herbivores are most effectively destroyed.
Vegetables or meat: who will win?
Although animal food from aquaculture does not require more land than plant food, and although herbivores, which include cattle, are useful in maintaining normal phosphorus levels, this does not change anything, because the masses simply do not know about it.
Therefore, with a high probability, we will see an increasingly widespread vegan movement - under the key slogans of reducing human impact on the environment and combating global warming. They will be especially strong in Western Europe.
Vegans cannot wait for victory: obviously, outside the Western world, the fashion for "green" is much weaker. And even the most westernized non-Western countries are not inclined to give up important things for themselves just because they are "green". It is doubtful that vegans will win in a country like the United States: judging by the Trump phenomenon, the local population, especially the inhabitants of the rural hinterland, are generally quite conservative.
Russia, as is often the case, will mostly remain aloof from what is happening, with the exception, of course, of a certain proportion of the population of large cities. Whether you personally fall under the influence of this fashion or not is a purely personal matter. But remember, don't base this decision on the idea that veganism is the most sustainable way to feed humanity.