Numbers Don’t Lie by Vaclav Smil

Rating: 7/10

The collection starts strong, with the ‘People’ and ‘Countries’ sections the most consistently insightful and engaging. However, as the book progresses, the essays become more hit-and-miss, feeling generally less impactful and occasionally drifting into the realm of trivia.

That said, this is an easy and thought-provoking read, with each essay spanning just a few pages. The impressions and knowledge will certainly stay with me for a long time. I’m reminded of classic Jared Diamond books, blending history, geography and science to explain patterns in society. However, unlike those books, there’s no large-scale narrative here, instead it focuses on the quantiative.

For each of the 71 essays, I’ve summarised my main takeaways below. Verbatim notes from the book are bulleted. You can skip to the specific sections using these links: People; Countries; Machines, designs, devices; Fuels and electricity; Transport; Food; and Environment.

Echo the Romans: Festina lente. Make haste slowly.

People: The inhabitants of our world

What happens when we have fewer children? Driven by a large range of factors related to rising living standards, total fertility rates (TFRs) are declining below replacement level in developed countries. Economic power has historically shifted to population centres, and the obvious solution to declining populations (mass immigration) is unlikely.

• A historic pursuit of quantity turned, sometimes rapidly, into the quest for quality
• As is often the case in both social and technical transitions, the pathbreakers took a long time to accomplish the change, while some late adopters completed the process in just two generations. The shift from high to low fertility took about two centuries in Denmark and about 170 years in Sweden. In contrast, South Korean fertility fell from more than 6 TFR to below the replacement level in just 30 years, and even before the introduction of the one-child policy, Chinese fertility had plunged from 6.4 in 1962 to 2.6 in 1980.
• No country has been able to stop the fertility decline at the replacement level and achieve a stationary population.
• This nearly global shift has had enormous demographic, economic, and strategic implications. European importance has diminished (in 1900 the continent had about 18 percent of the world’s population; in 2020 it has only 9.5 percent) and Asia has ascended (60 percent of the world total in 2020), but regional high fertilities guarantee that nearly 75 percent of all births during the 50 years between 2020 and 2070 will be in Africa.
• If the national rates remain close to the replacement (no lower than 1.7; France and Sweden were at 1.8 in 2019), then there is a good chance of possible future rebounds. Once they slip below 1.5, such reversals appear increasingly unlikely

The best indicator of quality of life? Try infant mortality. A lower infant mortality rate directly correlates with higher overall quality of life and better healthcare systems. GDP is problematic, and its replacement (the Human Development Index) is largely correlated to GDP.

• Infant mortality is such a powerful indicator because low rates are impossible to achieve without having a combination of several critical conditions that define good quality of life

The best return on investment: vaccination. Compared to other infant mortality preventative measures, vaccines overwhelmingly provide the best return on investment, both from prevented health care costs, and lost economic costs.

• For every dollar invested in vaccination, $16 is expected to be saved in healthcare costs and the lost wages and lost productivity caused by illness and death.
• And when the analysis went beyond the restricted cost-of-illness approach and looked at broader economic benefits, it found the net benefit-cost ratio was more than twice as high—reaching 44 times

Why it’s difficult to predict how bad a pandemic will be while it is happening. We can know with a high degree of certainty the number of deaths caused by a disease, but identifying the infected population can is difficult and methodologies vary, meaning that the rate itself is extremely difficult (if not impossible) to calculate.

• This is one of the most basic algebraic lessons: you may know the exact numerator, but unless you know the denominator with a comparable certainty, you cannot calculate the precise rate.

Growing taller. Height is correlated to a large range of beneficial health and economic outcomes. A population’s height growth is related to its socio-economic development. To become tall, eat and drink high quality animal protein.

• Better health and better nutrition—above all, greater intakes of high-quality animal protein (milk, dairy products, meat, and eggs)—have driven the shift, and being taller is associated with a surprisingly large number of benefits. These do not include generally higher life expectancy, but a lower risk of cardiovascular diseases, and also higher cognitive ability, higher lifetime earnings, and higher social status.
• CEOs were taller in firms with larger assets!
• The lesson is obvious: the easiest way to improve a child’s chances of growing taller is for them to drink more milk.

Is life expectancy finally topping out? As socio-economic developments increase, so do life expectancy rates. It rises fast, at first, before topping-out at around 90 years old.

• The long-term trajectory of Japanese female life expectancy […] fits a symmetrical logistic curve that is already close to its asymptote of about 90 years.
• There may be no specific genetically programmed limit to lifespan—much as there is no genetic program that limits us to a specific running speed. But lifespan is a bodily characteristic that arises from the interaction of genes with the environment.
• the estimated heritability of lifespan is modest, between 15 and 30 percent. Given that people tend to marry others like themselves—a phenomenon known as assortative mating—the true heritability of human longevity is probably even lower than that.

How sweating improved hunting. Alongside our bipedalism, sweating enabled us to sustainably lose heat when exercising. Not many other big animals sweat, helping us hunt them to exhaustion.

• two great advantages of bipedalism. […] The first advantage is in how we breathe. A quadruped can take only a single breath per locomotive cycle, because its chest must absorb the impact on the front limbs. We, however, can choose other ratios, and that lets us use energy more flexibly. The second (and greater) advantage is in our extraordinary ability to regulate our body temperature
• a human being can easily shed 500 g/m², enough to remove between 550 and 600 watts’ worth of heat. Peak hourly sweating rates can surpass 2 kilograms per square meter, and the highest reported short-term sweating rate is twice that high.
• we have another advantage when we lose water: we don’t have to make up the deficit instantly. Humans can tolerate considerable temporary dehydration providing that we rehydrate in a day or so.
• we humans are neither the fastest nor the most efficient. But thanks to our sweating capability, we are certainly the most persistent.

How many people did it take to build the Great Pyramid? Much less than historic and contemporary estimations (‘slave armies’): likely less than 7,000. Calculated simply by looking at the energy needed to carve, transport and raise the weight of the blocks, plus additions for the logistics.

Why unemployment figures do not tell the whole story. All methodologies for calculating unemployment are significantly flawed. The most reliable might be the labour force participation rate, but even that ignores important factors.

• Many economic statistics are notoriously unreliable, and the reason often has to do with what is included in the measurement and what is left out. Gross domestic product offers a good example of a measure that leaves out key environmental externalities

What makes people happy? Happiness indices are all created with incomparable and “notoriously questionable” indicators and subjective figures. They also rank countries with a meaningless and unnecessary level of precision.

• there is that remarkable lack of correlation between happiness and suicide—plotting the two variables for all European countries shows a complete absence of a relationship. Indeed, some of the happiest countries have relatively high suicide rates, and some rather unhappy places have a very low frequency of suicide.

The rise of megacities. Megacities (those with a population over 10 million) offer huge economies of scale and improved quality of life. They continue to grow, attracting people not only from rural areas, but also smaller cities. They clearly show the rise of Asia.

• In 1800, less than 2 percent of the world’s population lived in cities; by 1900 the share was still only about 5 percent. By 1950 it had reached 30 percent, and 2007 became the first year when more than half of humanity lived in cities.
• This continued concentration of humanity in ever-larger cities has been driven by advantages arising from the agglomeration of people, knowledge, and activities, often due to collocation of kindred companies
• This is why many smaller cities—much like the surrounding countryside—are losing population, but megacities keep growing.
• The growth of megacities offers a perfect illustration of receding Western influence and the rise of Asia.
• Tokyo [has] more people than Canada, and [generates] economic product equal to about half of the German total
• New York [has] the highest share of population born abroad

[top]

Countries: Nations in the Age of Globalization

The First World War’s extended tragedies. WWI was likely the most negatively impactful war of history, despite its static front lines. It led directly to further political instability and brought significant technological developments in arms.

• [WWI’s] enormous carnage scarred the memory of a generation, but its most tragic legacy was the resulting Communist rule in Russia (1917), Fascist rule in Italy (1922), and Nazi rule in Germany (1933). Those developments led to the Second World War, which killed even more people and left direct and indirect legacies—including NATO vs. Russia, and a divided Korea

Is the US really exceptional? American exceptionalism is unfounded. It ranks poorly on most metrics when compared to other rich countries.

• Excusing [America’s] very poor [child mortality] rating by saying that the European countries have homogeneous populations does not work […] What matters more is parental knowledge, good nutrition, the extent of economic inequality, and access to universal healthcare

Why Europe should be more pleased with itself. The Europe Union has achieved significant success in social welfare, economic integration, and quality of life, outperforming many regions in these areas. Despite its problems, compromises should be made by member states in order to keep the union intact. This is more clear to more Eastern members, who lived under Soviet rule.

• The EU has just over 500 million people, less than 7 percent of the global population, but it generates nearly 24 percent of the world’s economic output
• It accounts for nearly 16 percent of global exports of goods
• half of its 27 members are among the top 30 countries in terms of quality of life
• explanations of this new [anti-EU view]: the excessive bureaucratic control exercised from Brussels; the reassertion of national sovereignty; and poor economic and political choices, notably the adoption of a common currency without common fiscal responsibility.

Brexit: Realities that matter most will not change. The UK’s economy is not suited to make a ‘success’ of Brexit, and little will likely change. Food and energy imports are required, the population is ageing, and it is already largely deindustrialised.

Concerns about Japan’s future. Japan rose fast on the international geopolitical stage, but is declining just as fast. Yen devaluation in the 80s sped-up its fall. ITs demographic challenges and economic stagnation threaten prospects.

• In the long run, the fortunes of nations are determined by population trends.
• Japan is not only the world’s fastest-aging major economy […] its population is also declining.
• radical reforms are not easy in a gerrymandered country that still cannot seriously contemplate even moderate-scale immigration and that is yet to make real peace with its neighbors.

How far can China go? While China has grown fast and challenges Western political and economic dominance, it suffers from significant problems which threaten its continued rise. Especially those related to pollution, inequality, and corruption.

India vs. China. India might be better placed to be the dominant Asian power, surpassing China, largely due to it’s democratic political system and its ability to feed its population. However, it also suffers from similar domestic challenges as China.

• At least since the unraveling of the Roman empire, successive Chinese dynasties have ruled over more people than any other government.
• The question is whether [China] will become old before it can become truly rich. Both countries have enormous environmental problems and both will be challenged to feed their populations—but India has about 50 percent more farmland.
• [Himalayan tensions with the nuclear China are not] India’s greatest immediate challenge. More pressing are the need to further lower its fertility rate as rapidly as possible (everything else being equal, that raises per capita income), the challenges of maintaining basic food self-sufficiency (a country of more than 1.4 billion is too large to rely on imports), and finding a way out of the deteriorating relations between the country’s Hindus and Muslims.

Why manufacturing remains important. Manufacturing creates a lot of jobs, many of which are well paid, and helps a country grow its economy.

• manufacturing is still important for the health of a country’s economy, because no other sector can generate nearly as many well-paying jobs.
• Manufacturing creates jobs: only 2 out of the top 10 manufacturing countries have recent unemployment above 5%

Russia and the USA: How things never change. The geopolitical dynamics between Russia and the USA remain relatively consistent over time, driven by enduring strategic rivalries.

Receding empires: Nothing new under the sun. Maintaining an empire is increasingly difficult over time.

• despite the increasing military, technical, and economic capabilities of major nations, keeping large empires for extended periods of time has become more difficult.

[top]

Machines, designs, devices: Inventions that made our modern world

How the 1880s created our modern world. The technological innovations and industrial expansions of the 1880s laid the foundation for modern civilization, with inventions like electric power, telephones, and the internal combustion engine.

How electric motors power modern civilization. Electric motors are “truly indispensable energizers of modern civilization”, driving everything from mobile phone vibrations to industrial machinery. Their efficiency and versatility make them indispensable.

Transformers—the unsung silent, passive devices. Transformers are crucial for efficiently transmitting electricity over long distances, making widespread access to power possible.

Why you shouldn’t write diesel off just yet. Diesel engines, despite their environmental drawbacks, remain critical for heavy transport and industry due to their superior energy efficiency, reliability and affordability compared to gasoline engines.

• today’s diesel engines remain at least 15 to 20 percent more efficient than their gasoline-fueled rivals. Diesels have several advantages: they use fuel of a higher energy density; […] they can burn lower-quality, and hence cheaper, fuel; and [they have] higher efficiencies and cleaner exhaust.
• Today, in the European Union, about 40 percent of all passenger cars are diesels but in the US (which has cheaper gasoline) diesel accounts for just 3 percent.
• Without the low operating costs, high efficiency, high reliability, and great durability of diesel engines, it would have been impossible to reach the extent of globalization that now defines the modern economy.
• There are no readily available mass-mover alternatives that could keep integrating the global economy as affordably, efficiently, and reliably as Diesel’s machines.

Capturing motion—from horses to electrons. The evolution of motion capture technologies has transformed fields ranging from biomechanics to entertainment.

From the phonograph to streaming. The journey from the phonograph to digital streaming represents a dramatic shift in how we consume music.

Inventing integrated circuits. Integrated circuits revolutionised electronics, making it possible to miniaturise and enhance the performance of electronic devices.

Moore’s Curse: Why technical progress takes longer than you think. Moore’s Law has raised impossible expectations for technical progress and innovation generally.

• the doubling time for transistor density is no guide to technical progress generally. Modern life depends on many processes that improve rather slowly, not least the production of food and energy and the transportation of people and goods
• Energy, material, and transportation fundamentals that enable the functioning of modern civilization and that circumscribe its scope of action are improving steadily but slowly. Gains in performance mostly range from 1.5 to 3 percent a year, as do the declines in cost.
• outside the microchip-dominated world, innovation simply does not obey Moore’s Law, proceeding at rates that are lower by an order of magnitude.

The rise of data: Too much too fast. The exponential growth of data, driven by digitalisation, presents both opportunities and challenges, including issues of privacy, storage, data management, and the ability to effectively use vast amounts of information.

• Shakespeare’s plays and poems in their entirety amount to 5 megabytes, the equivalent of just a single high-resolution photograph, or of 30 seconds of high-fidelity sound, or of 8 seconds of streamed high-definition video.
• Printed materials have thus been reduced to a marginal component of overall global information storage. By the year 2000, all books in the Library of Congress held more than 10¹³ bytes (more than 10 terabytes), but that was less than 1 percent of the total collection (10¹⁵ bytes, or about 3 petabytes) once all photographs, maps, movies, and audio recordings were added.
• in 2020, 1.7 megabytes of data is generated every second for every one of the world’s nearly 8 billion people.
• there are fundamental differences between accumulated data, useful information, and insightful knowledge.

Being realistic about innovation. Society prioritises and romanticises loft high-profile innovations, but a more grounded approach to innovation would benefit society more: one that focuses on practical solutions to common problems over the pursuit of grandiosity, that doesn’t always succeed.

[top]

Fuels and electricity

Why gas turbines are the best choice. Gas turbines are highly efficient and versatile, making them the best choice for a range of power generation applications, particularly in combined cycle plants where they are paired with steam turbines for enhanced efficiency.

• The levelized cost of electricity (a measure of the lifetime cost of an energy project) for new capacities entering service in 2023 is forecast to be about $60 per megawatt-hour for coal-fired steam turbogenerators with partial carbon capture, $48/MWh for solar photovoltaics, and $40/MWh for onshore wind—but less than $30/MWh for conventional gas turbines and less than $10/MWh for [combined cycle gas turbine].
• no other combustion machines combine so many advantages as do modern gas turbines. They’re compact, easy to transport and install, and relatively silent, affordable, and efficient, offering nearly instant output and able to operate without water cooling. All this makes them the unrivaled machine to supply both mechanical energy and heat.

Nuclear electricity—an unfulfilled promise. Despite its potential, nuclear power has failed to deliver on its early promises due to high costs, safety concerns, the long-term challenges of waste disposal, and the inability of society to consider long-term energy policies.

• In late 2019, the world had 449 operating reactors (and 53 under construction), many with capacity factors of better than 90 percent. That’s the share of the reactors’ potential output that they averaged year-round, producing more than twice as much electricity as photovoltaic cells and wind turbines combined.

Why you need fossil fuels to get electricity from wind. Wind power depends significantly on fossil fuels for manufacturing, installation, and balancing intermittent supply with stable electricity demand. Steel, a primary component of turbines, is highly polluting to produce.

• in less than a year a well-sited and well-built wind turbine will generate as much energy as it took to produce it. However, all of it will be in the form of intermittent electricity—while its production, installation, and maintenance remain critically dependent on specific fossil energies. Moreover, for most of these energies […] we have no non-fossil substitutes that would be readily available on the requisite large commercial scales.

How big can a wind turbine be? Wind turbines are growing ever larger to increase efficiency and output, but there are physical and logistical limits to their size, including materials strength and transportation challenges.

• Larger turbines must face the inescapable effects of scaling. Turbine power increases with the square of the radius swept by its blades […] But the expansion of the surface swept by the rotor puts a greater strain on the entire assembly, and because blade mass should (at first glance) increase as a cube of blade length, larger designs should be extraordinarily heavy.
• Exploring likely limits of commercial capacity is more useful than forecasting specific maxima for given dates.
• Available wind turbine power is equal to half the density of the air (which is 1.23 kilograms per cubic meter) times the area swept by the blades (pi times the radius squared) times the cube of wind velocity.

The slow rise of photovoltaics. Photovoltaic solar power has seen slow but steady growth, with declining costs and improving efficiency making it an increasingly viable source of renewable energy. By 2030 solar might supply 10% of energy requirements, but this is 70 years since the first PV cells!

Why sunlight is still best. Societal development can be measured by the cost of production of artificial light. But we are a long way from providing the quality of sunlight indoors.

Why we need bigger batteries. As renewable energy becomes more prevalent, the need for large-scale energy storage solutions like bigger batteries becomes critical for balancing supply and demand. The biggest and most effective solution is still ‘pumped storage’: pumping water to a higher point at off peak times, and letting it flow through turbines during peak times.

Why electric container ships are a hard sail. The transition to electric container ships faces significant challenges, including the energy density of batteries, which is currently hugely insufficient for long-haul ocean voyages, especially when compared to diesel engines.

The real cost of electricity. Over time, the cost of a unit of electricity has dropped significantly. However, the increasing reliance on renewable energy has started to raise electricity prices in some countries due to the hidden costs of grid integration and backup systems, highlighting the complexity of accurately assessing electricity costs.

The inevitably slow pace of energy transitions. Energy transitions are slow due to the massive scale, existing infrastructure, and economic factors, meaning that fossil fuels will remain dominant for decades. Some systemic industries still rely on fossil fuels, and there is no viable, scaleable alternative for many of them.

• it has taken a while to accomplish the transition from new carbon (in plant tissues) to old (fossil) carbon in coal, crude oil, and natural gas.
• In [1992], fossil fuels […] provided 86.6 percent of the world’s primary energy. By 2017, they supplied 85.1 percent
• Displacing 10 billion tons of fossil carbon is a fundamentally different challenge than ramping up the sales of small portable electronic devices to more than a billion units a year; the latter feat was achieved in a matter of years, the former one is a task for many decades.

[top]

Transport: How we get around

Shrinking the journey across the Atlantic. Advances in shipping and then aviation have drastically reduced transatlantic travel times. Further significant reductions are unlikely without new technologies.

Engines are older than bicycles! The steam engine predates the modern ‘safety’ bicycle, highlighting the often surprising order of technological development.

The surprising story of inflatable tires. Inflatable tires revolutionised transportation by providing a smoother ride and improving vehicle efficiency, yet they were a late innovation. However, they are polluting to produce and dispose of, with no viable alternatives in sight.

When did the age of the car begin? The car age truly began with the mass production of affordable cars, notably marked by the Ford Model T in the early 20th century.

• Ford stood at the very beginning of manufacturing globalization, using standardized procedures and dispersing car assembly around the world.
• But even though Ford staked much on [the Model T], it didn’t quite become the bestselling vehicle in history. That primacy belongs to the “people’s car” of Germany—the Volkswagen.

Modern cars have a terrible weight-to-payload ratio. Many contemporary cars are inefficiently heavy compared to the payload they carry, unnecessarily wasting energy and resources.

Why electric cars aren’t as great as we think (yet). Electric cars are still limited by battery technology, charging infrastructure, and significant environmental concerns related to battery production.

When did the jet age begin? Arguably in 1958, with the Boeing 707 revolutionising air travel by being an efficient and well-designed jet engine that led to making long-distance travel more accessible.

Why kerosene is king. Kerosene is the dominant fuel for aviation due to its high energy density and efficiency. The only viable alternative is biofuel, but scalability challenges are enormous and potentially not feasible.

• Eliminating kerosene-based jet fuel will be one of the greatest challenges in creating a world without carbon emissions.
• converting to electric drive is much harder for airplanes than for cars and trains.
• Today’s jet fuel […] has a number of advantages. It has a very high energy density […] slightly less than gasoline but it can stay liquid down to –47°C, and it beats gasoline on cost, evaporative losses at high altitude, and risk of fire during handling. No real rivals yet exist.

How safe is flying? Flying is one of the safest modes of transport, with accident rates continuing to decline thanks to technological and regulatory improvements.

Which is more energy efficient—planes, trains, or automobiles? Trains are generally the most energy-efficient mode of transport. Small cars are generally more efficient than full planes, but large SUVs are less so.

• In a rational world—one that valued convenience, time, low energy intensity, and low carbon conversions—the high-speed electric train would always be the first choice for such distances.
• the United States and Canada lack the population density to justify dense networks of these connections, they do have many city pairs that are suited for fast trains. Not a single one of those pairs has a fast train, however.

[top]

Food: Energizing ourselves

The world without synthetic ammonia. Synthetic ammonia is critical for modern agriculture, and without it, the world could not sustain its current population levels. But changes are needed to diet, food waste policies and farming efficiency.

• Traditional farmers supplied the needed nitrogen in two ways: by recycling any available organic materials […] and by rotating grain or oil crops with leguminous plants. […] These plants are able to supply their own nitrogen because bacteria attached to their roots can “fix” nitrogen
• As the demand for staple grains grew with an expanding (and urbanizing) population, it became clear that farmers would not be able to meet future food needs without new, synthetic sources of “fixed” nitrogen—that is, nitrogen available in forms that can be tapped by growing crops.

Multiplying wheat yields. Wheat yields increased massively over time, through improved seeds, fertilisers, and farming techniques. However, yield increases have plateaued, with global gains now best made through minimising food waste.

The inexcusable magnitude of global food waste. A significant portion of food produced globally is wasted, representing a major inefficiency and environmental concern.

• The UN’s Food and Agricultural Organization puts the annual global losses at 40–50 percent for root crops, fruits, and vegetables, 35 percent for fish, 30 percent for cereals, and 20 percent for oilseeds, meat, and dairy products. This means that, globally, at least one-third of all harvested food is wasted.
• Cutting food waste in half would lead the way to a more rational use of food worldwide, and the benefits could be huge: […] a dollar invested in food waste prevention has a 14-fold return in associated benefits.

The slow addio to the Mediterranean diet. The traditional Mediterranean diet is declining, replaced by less healthy, more processed foods, which could have negative health impacts.

• The key traits of the diet are a high intake of carbohydrates (mostly bread, pasta, and rice) complemented by pulses (beans, peas, chickpeas) and nuts, dairy products (mostly cheese and yogurt), fruits and vegetables, seafood, and lightly processed seasonal foods, generally cooked with olive oil. It also includes much more modest quantities of sugar and meat.
• Reasons for this shift have been universal. Higher incomes allow higher meat, fat, and sugar intakes. Traditional families have been replaced by two-income and single-person households that cook less at home and buy more ready-to-eat meals. And busier lifestyles promote snacking and convenience food.

Bluefin tuna: On the way to extinction. Overfishing has driven Bluefin tuna populations to dangerously low levels. Farming of Bluefin is difficult and has resulted in significant fraud.

Why chicken rules. Chicken has become the world’s most popular meat due to its efficiency, affordability, and adaptability in various cuisines. Broilers (chickens reared for consumption) have a higher edible weight ratio, lower saturated fat ratio, and have a feed-to-meat ratio almost four times higher than beef. However, this has resulted in significant animal suffering.

• Recent ratios have been 3–4 units of feed per unit of edible meat for broilers, 9–10 for pork, and 20–30 for beef.

(Not) drinking wine. Wine consumption patterns are shifting, with declining traditional markets and growth in new regions.

• French products are attested to by the fact that they account for 15 percent of the global trade in wines and spirits but 30 percent of the total value.

Rational meat-eating. Moderate meat consumption, particularly from sustainably raised sources, is more ecologically responsible than extreme dietary choices like veganism or carnivorism, especially when adjusting the ratios of chicken, pork, and beef on a global scale.

• animals, particularly cattle, are inefficient converters of feed into meat, and affluent countries have expanded their meat production to such an extent that the principal task of agriculture has become not to grow crops for people but feed for animals. In North America and Europe, about 60 percent of the total crop harvest is now destined for feeding
• The minimum water requirement per kilogram of boneless beef is, indeed, high, on the order of 15,000 liters, but only about half a liter of that ends up incorporated in the meat, with more than 99 percent being water needed for the growth of feed crops which eventually re-enters the atmosphere via evaporation and plant transpiration, and rains down.
• rational meat consumption based on moderate intakes of meat produced with greatly reduced environmental impact. The key components of this global adoption would be to adjust the shares of the three dominant meats. For pork, chicken, and beef respectively they were 40, 37, and 23 percent of the global output of about 300 million tons in 2018; by shifting the split to 40, 50, and 10 percent, we could […] produce easily 30 percent more chicken meat and 20 percent more pork, while more than halving beef’s environmental burden—and still supplying at least 10 percent more meat.

The Japanese diet. Japan’s traditional diet, rich in fish, rice, and vegetables, likely contributes to the country’s high life expectancy, but is not unique in the region. The biggest observable difference is simply in the quantity eaten.

• spirituality rather than religiosity might better describe the Japanese mindset
• perhaps the single most important explanation of Japan’s longevity primacy is quite simple: moderate overall food consumption, the habit expressed in just four kanji characters, 腹八分目 (hara hachi bun me, “belly eight parts [in ten] full”)

Dairy products—the counter-trends. Global dairy consumption patterns are shifting, with rising demand in some traditionally lactase-deficient regions and declines in more historic milk-drinking ones, driven by economic, cultural, and health factors.

• The […] decrease of demand for all dairy products has been slower [than for just milk], in large part because of the still slowly rising consumption of mozzarella via American pizza.
• how have lactase-deficient societies been able to undergo this shift [to milk consumption]? Because lactose intolerance is not universal, and because it is relative rather than absolute. Four-fifths of Japanese have no problems drinking up to a cup of milk a day, and that would translate to annual consumption of more than 70 liters—more than the recent American mean. And fermentation removes progressively more lactose, with fresh cheeses […] retaining less than a third of the lactose present in milk, and hard varieties […] having just a trace. And while yogurt retains nearly all of the original lactose, its bacterial enzymes facilitate the digestion.

[top]

Environment: Damaging and protecting our world

Animals vs. artifacts—which are more diverse? Through a novel taxonomy of man-made artifacts, Smil shows that we have created many more ‘species’ of artifact than there are biological species. However, the utility of this taxonomy is debatable.

Planet of the cows. There are a lot of cows on the planet (1.5 billion in 2020), and even more humans (7.75 billion). But cows weigh a lot more than us (400 vs 50 kg), so their ‘zoomas’ far exceed our ‘anthropomass’ (600 vs 390 million metric tons).

• cattle zoomass is now more than 50 percent larger than the anthropomass

The deaths of elephants. Poaching has drastically reduced elephant populations, threatening their survival and raising ethical and ecological concerns. However, they can also be destructive animals to farmers and herders if not managed appropriately.

Why calls for the Anthropocene era may be premature. While humans have significantly impacted the planet, declaring a new geological era is premature, as such shifts require long-term, widespread changes, which we are yet to make (give it another 10,000 years).

• To be quite clear, there is no doubt about the pervasiveness of our interference in global biogeochemical cycles and the loss of biodiversity attributable to human actions: the mass dumping of our wastes; the large-scale deforestation and accelerated erosion of soils; the global extent of pollution generated by farming, cities, industries, and transportation. In combination, these man-made impacts are unprecedented, and of a scale that may well imperil the future of our species.

Concrete facts. Concrete is an enormously used building material, with growing demand. Its production is highly energy-intensive and environmentally damaging. Furthermore, it will deteriorate over time and in the coming decades billions of tons will start to require replacement.

• Cement is then mixed with water (10–15 percent of the final mass) and aggregates (sand and gravel, making up 60–75 percent of the total mass) to produce concrete, a formable material that is strong under compression but weak in tension. Weakness in tension can be reduced by reinforcement with steel.
• The most impressive illustration of China’s unprecedented construction effort is that in just the last two years the country emplaced more cement (about 4.7 billion tons) than the US did cumulatively throughout the entire 20th century (about 4.6 billion tons)!
• Air pollution (fine dust) from cement production can be captured by fabric filters, but the industry (burning such inferior fuels as low-quality coal and petroleum coke) remains a significant source of carbon dioxide, emitting roughly a ton of the gas per ton of cement. For comparison, producing a ton of steel is associated with emissions of about 1.8 tons of CO₂.

What’s worse for the environment—your car or your phone? It’s a close call. While cars require vastly more energy resources for initial production, due to the almost annual turnover of smartphones, the differences largely even out when compared across their useful lives. Operating energy requirements are also vastly larger for cars, but this does not take into account the growing energy needs to maintain and run the entire telephony network.

Who has better insulation? Despite initial appearances, North American wooden wall construction has superior insulating properties compared to European brick building, thanks to the layering of high R-value materials.

Triple-glazed windows: A see-through energy solution. Triple-glazed windows offer superior insulation, significantly reducing energy loss and improving building energy efficiency over a long period of time.

• Both in the United States and in the European Union, buildings account for about 40 percent of total primary energy consumption (transportation comes second, at 28 percent in the US and about 22 percent in the EU). Heating and air conditioning account for half of residential consumption, which is why the single best thing we could do for the energy budget is to keep the heat in (or out) with better insulation.
• Physics is indisputable, but economics rules.

Improving the efficiency of household heating. Enhancing the efficiency of household heating systems (particularly boilers/furnaces) is a crucial step toward reducing energy consumption and combating climate change. But we’re reaching a plateau of boiler efficiency (≥97%), so future gains needs to come from insulation, heat pumps, and smaller houses.

Running into carbon. Despite global climate agreements, carbon emissions continue to rise, driven by developing economies and the challenges of reducing reliance on fossil fuels, particularly for essential materials.

• we do not have any affordable non-carbon alternatives that could be rapidly deployed on mass scales in order to energize the production of enormous quantities of what I have called the four pillars of modern civilization—ammonia, steel, cement, and plastics—which will be needed in Africa and Asia in the decades to come.

Epilogue

• Even fairly reliable—indeed, even impeccably accurate—numbers need to be seen in wider contexts. An informed judging of absolute values requires some relative, comparative perspectives.
• Rigid ranking based on minuscule differences misleads rather than informs. Rounding and approximation is superior to unwarranted and unnecessary precision. Doubt, caution, and incessant questioning are in order—but so is the insistence on quantifying the complex realities of the modern world.