In Numbers Don’t Lie, Canadian scientist and economist Vaclav Smil argues that numbers, when used correctly, can help us understand the world. But people often misunderstand what certain metrics are saying or use statistics that don’t tell a complete story. To get an accurate view of the world, we must place numbers in the proper context and understand how they were calculated. To figure out what the many numbers and metrics used in the modern world are saying requires a basic understanding of science and statistics. More importantly, however, it requires effort. You must be willing to pay attention, and to look beneath the surface of a simple statistic and try to see what it says about the world.
In this guide, we’ll first look at some commonly used metrics and what they actually say about the world and its inhabitants. Then, we’ll look at the stats about some of the most economically powerful countries and what the numbers say about their futures. Finally, we’ll examine the numbers on humanity’s most pressing environmental issues, such as greenhouse gas emissions, sustainable energy, transportation, and food production.
Metrics on GDP, unemployment, population growth, and happiness levels, to name a few, are used regularly by the media and are often taken at face value by the general public, claims Smil. But what do these numbers actually tell us? And what information do they leave out? Let’s look at a few commonly used metrics and determine their significance.
We should always take reports of a country’s happiness with a grain of salt, as happiness is difficult to measure, writes Smil. He argues against the validity of the World Happiness Report, which the media regularly cites as an accurate measure of the quality of life in different countries.
This report calculates happiness using several variables: GDP per capita, social support, life expectancy, freedom to make life choices, generosity, and perception of corruption. GDP, as we'll discuss further, is not a good indicator of quality of life. Other variables, like freedom of choice and perception of corruption, depend too heavily on subjective answers that are difficult to compare across cultures.
The Use of the World Happiness Report
Since its inception in 2012, the World Happiness Report (WHR) has gained traction among the scientific community, something Smil might disapprove of. The WHR is made every year by experts in economics, psychology, and statistics. Researchers note that the report was created to measure worldwide happiness and to help make important policy decisions. Because happy people live longer, are more productive, and earn more money, the argument goes, when politicians focus on happiness, society as a whole benefits.
We should be careful, however, to not put too much weight on self-reported statistics on happiness, as these statistics can sometimes be misleading. For example, most happiness statistics are based on national averages and don’t account for happiness inequality. A country may have relatively high happiness levels, but there could be a big gap between its most happy and least happy citizens.
Gross Domestic Product (GDP) is the total annual value of all goods and services transacted within a country, and economists often use it to measure standard of living. Smil argues that GDP, while a decent measure of overall economic strength, is an unreliable measure of quality of life because it fails to take many factors into account. For one, GDP doesn’t factor in population size, which means it only looks at overall economic output and not output per citizen—thus, larger countries may have larger GDPs simply because they have more citizens, not because each citizen has a higher standard of living. GDP per capita (total GDP divided by population) would be a better measure to use for this.
But GDP per capita still doesn’t factor in differences in cost of living and exchange rates between countries, making comparisons unhelpful. For that, we’d need to use GDP per capita at purchasing power parity, a measure that uses the prices of goods among different countries to compare currency valuation. Even this metric, however, doesn’t account for income inequality or the availability of social safety nets, huge factors in determining the average standard of living.
What Else GDP Misses
Smil argues that GDP can be misleading as a measure of standard of living because it doesn’t account for income inequality and other social aspects of a country that impact quality of life. In Naked Economics, Charles Wheelan lists some other factors GDP doesn’t take into account:
Unpaid work: Activities like raising your children or taking care of your elderly family members aren’t included in the GDP, yet this is important work that enhances quality of life.
Leisure activities: If people take time off work to do things they enjoy, this is bad for GDP but good for the person’s well-being.
Environmental impact: Though a country may be producing a lot of products and services, thereby raising its GDP, it could come at a major cost to the environment, which is detrimental to quality of life.
According to Smil, another unreliable metric used to broadly measure economic strength is a nation’s unemployment rate. The main reason official unemployment rates don’t paint an accurate portrait of a country’s labor force, he argues, is that they exclude people who aren’t actively seeking employment. A country may have a low official unemployment rate but a high percentage of people who aren’t working because they gave up seeking employment.
The labor force participation rate is a better indicator of a country’s workforce health, as it’s a measure of all people above the age of 16 who are available to work, including those who aren’t looking for work. In the US, the labor force participation rate peaked in 2000 at 67%. As of 2019, it was around 63%. For comparison, the unemployment rate in 2000 peaked at 4.1% and was around 3.5% in 2019. These unemployment rates would indicate that the labor market has improved in that timeframe, but the percentage of people working has actually gone down.
(Shortform note: Another way unemployment rates can be problematic is when using them to compare countries. As pointed out in Basic Economics, social support systems can drastically affect unemployment rates, leading to misinterpretations of economic well-being. France, for example, has generous welfare programs that help remove people from the labor force and reduce unemployment. However, this also means that the country’s labor force participation rate is lower.)
Smil argues that the infant mortality rate is a better indicator of standard of living than GDP per capita. The infant mortality rate is such a powerful indicator because it accounts for factors that GDP ignores, like income inequality, social support, a strong healthcare system, good education, and safe and clean living conditions.
From 2015 to 2020, Finland, Japan, and Slovenia had extremely low infant mortality rates (around two per 1000 live births). The United States, with the highest GDP in the world, had triple that amount at six per 1000, suggesting that the higher GDP of the US fails to capture important quality-of-life factors that those other countries provide their citizens despite their lower GDP.
Wealth Versus Health
Studies that examine the relationship between a country’s wealth and the health of its citizens echo Smil’s argument that GDP is not a good measure of life quality. One way this is shown is in the paradoxical effect of economic recessions on population health. In wealthy countries, mortality rates actually decline during recessions.
This is also true for infant mortality rates, as child health generally improves during economic contractions in the United States. During a recession in prosperous nations, mothers who find themselves out of work generally have more time to prepare food, provide clean water, and visit the doctor, which will decrease infant mortality rates. The opposite is true for underdeveloped countries, however. When a less affluent nation is hit by economic hardships, mothers have less access to healthcare, clean water, and adequate supply of food, which increases mortality rates.
Smil argues that vaccines are the most cost-effective way to increase a country’s standard of living. Vaccines greatly reduce infant mortality rates and save millions of lives, both young and old, every year. The measles vaccine alone is estimated to have saved 14 million lives from 2011 to 2020.
Because they’re so effective at preventing disease, vaccines also have enormous economic benefits. A 2016 study found that for every dollar invested in vaccines, $16 are saved in healthcare costs and prevention of lost wages due to illness. When looking at broader economic benefits, up to $44 are saved for every dollar spent.
Thanks to their economic benefits, increased vaccination rates could go a long way in lifting underdeveloped nations out of poverty, writes Smil. From 2000 to 2016, vaccination rates rose from 50% to 80% among low-income nations. If these increases continue, we could see many more prosperous nations in the 21st century.
Calculating the Economic Benefits of Vaccines
The 2016 study Smil referred to was conducted by Johns Hopkins Bloomberg School of Public Health. Since it’s important to understand how statistics are calculated, here’s how the data was determined:
Researchers used projected vaccination rates from 2011 to 2020 to assess economic benefits among 94 low- and middle-income countries. They looked at two types of savings that could result from higher vaccination rates: First, they measured the “cost-of-illness,” which is the money saved from averted treatment costs, transportation costs, lost wages, and productivity losses when people get vaccinated. Then, they looked at the “full-income approach,” which quantifies the value of people living longer and healthier lives when they get vaccinated.
From 2011 to 2020, the total estimated cost of immunization programs was around $34 billion. The money saved in cost-of-illness expenses was estimated at around $586 billion, and the full-income approach is estimated at around $1.5 trillion in savings. When you divide the $586 billion and $1.5 trillion in savings by the $34 billion in cost of immunization programs, you get $16 and $44 saved in healthcare costs and broader economic benefits, respectively.
Given the effectiveness of the measles vaccine and the rising vaccination rates that Smil references, this all points to better global health and higher savings.
According to Smil, falling fertility rates have the potential to significantly alter global dynamics in the 21st century. Fertility rates, or total births per woman in a given population, have changed drastically in the last century, especially in developed nations. From 1950 to 2000, the global fertility rate dropped from around 5 to 2.6.
To maintain a stable population size, you need a fertility rate of approximately 2.1. Countries with sustained fertility rates below 2.1 will see a gradual population decline, which can have detrimental effects. By 2050, it is estimated that three-quarters of the global population will live in countries with a fertility rate below the replacement level of 2.1. Many developed nations are already well below this level. In 2019, Japan, Spain, Italy, and Romania had fertility rates of 1.3. Japan, Ukraine, Greece, and Croatia sat at 1.4.
If these trends continue, there will be severe economic repercussions, writes Smil: To grow economically, a society needs a young labor force to maintain infrastructure and take care of the elderly. Developed nations with increasingly low fertility rates will likely see a sharp decline in standards of living as the country buckles under the weight of increased healthcare costs, labor shortages, and lower economic output. To combat low fertility rates, many countries will likely implement policies that encourage childbirth and immigration, but it remains to be seen if that will be enough to maintain population size.
New Studies on Population Growth
Recent studies provide more insight into the potential impact of fertility rates and population growth in the 21st century. 2020 population forecasts predict a global peak of 9.7 billion people in 2064, which goes against the common prediction of continued growth throughout the century. By 2100, it’s estimated that the global population will number around 8.8 billion, and 183 out of 195 countries will have fertility rates below 2.1.
Like Smil, researchers suggest that population decline will have dramatic effects on economic, social, and geopolitical issues across the globe. As economic growth stagnates worldwide, experts expect population decline to be a major factor in policy decisions. Many countries will need radical changes in immigration policies, and protecting the sexual and reproductive rights of women will be of increasing importance.
Now that we’ve examined some common metrics, we’ll look specifically at a few prominent countries and what the metrics are for them. Smil argues that the most important measure of success for a country is not its GDP, as many believe, but the well-being of its citizens. The way we over-value economic success can be seen in the top three countries by GDP: the United States, China, and Japan. Though on the surface these countries may seem to thrive, a closer inspection tells a different story. Let’s examine each country.
Smil points out that the US isn’t as exceptional as many think. Though it’s an economic powerhouse, the US is profoundly lacking when measuring the prosperity of its people. Its infant mortality rate, as mentioned above, sits at 6, which ranks 33rd out of 36 nations in the Organisation for Economic Co-operation and Development (OECD). This can largely be attributed to the country’s lack of universal healthcare, which every other wealthy nation has. Furthermore, out of the 36 OECD nations, the US ranks first in obesity percentage and 28th in life expectancy.
Additional Factors GDP Doesn’t Account For
In Caste, Isabel Wilkerson highlights some of the other ways the US’s high GDP also doesn’t capture important quality-of-life factors:
The US has more mass shootings than any other nation, leading in both gun ownership and gun deaths.
The US has the highest incarceration percentage of any country, with over 2.2 million people incarcerated.
Among wealthy nations, the US not only has the highest infant mortality rate but the highest mortality rate of women during pregnancy and childbirth.
Japan saw a tremendous rise in economic and social prosperity in the 20th century, but Smil argues that the country is declining rapidly for a number of reasons.
After World War II, Japan quickly grew to be a global powerhouse. In 1978, Japan became the world’s second-largest economy and continued to flourish throughout the 80s. By 2000, however, Japan’s stock market was half of its 1990 peak, and many of its strongest companies struggled to remain profitable.
Though it still has a low infant mortality rate and good standard of living, there are concerns that Japan will continue to decline in the 21st century. Japan has had to deal with the increasing costs of natural disasters like the 2011 tsunami, and its relations with China and South Korea are worsening. Perhaps most worrying, however, is Japan’s population, which is expected to drop from 127 million to 97 million by 2050. With an aging society, it will be difficult to maintain Japan’s construction, transportation, and healthcare infrastructure.
Japan’s Decline
One expert points to Japan as a leading illustration of modern economic failure, largely because its tax revenues have dropped and its public debt has drastically increased. The combination of decreasing GDP and increasing debt could very well be setting Japan up for an economic collapse.
On top of its aging population, Japan also has one of the strictest immigration policies among wealthy nations. Unlike the US, Japan doesn’t have an influx of young immigrants helping to keep the average age low and population growth steady. Even if the Japanese government does open up its doors to immigrants, it may be too late, because migration is slowing down worldwide as global prosperity increases and people prefer to stay in their home countries.
Though China has grown tremendously in the past 40 years, Smil questions its ability to maintain this growth in the coming decades. Even as its GDP has grown to rival the United States, the average quality of life for Chinese citizens is far from ideal. Its per capita GDP by purchasing power parity ranks 73rd in the world.
Like Japan, China also faces the risks of an aging population, and its economy may not grow quickly enough to make up for it. Its percentage of economically active people peaked in 2010. As the country’s average age increases, its dominant manufacturing and industrial economies are expected to decline without enough young labor to support its growth.
(Shortform note: In addition to a general slowing of economic growth, China’s response to the global pandemic and weakening real estate market severely damaged its economy, and some experts question whether China can continue to grow at its rapid pre-pandemic pace. Historically, China has relied on its property sector, which accounts for around a quarter of its GDP, to drive recovery after an economic downturn. Covid-19 restrictions, however, are preventing this, as new construction projects are being put on hold. By the time construction picks back up, it may be too little too late for the Chinese economy.)
Another factor impacting the well-being of China’s citizens is pollution, which has become a huge problem as the country has grown economically, says Smil. Air quality falls well below health standards in its biggest cities: Beijing averaged 80 particulates per cubic meter of air in 2015, over three times the World Health Organization’s maximum acceptable level of 25. Some Chinese cities regularly exceed 500 particulates per cubic meter. This extreme pollution is expected to increase respiratory and heart disease and decrease expected lifespans.
(Shortform note: A 2017 study quantified how much air pollution is decreasing life expectancy in China. This study found that people in northern China live an average of 3.1 fewer years than those living in the south. With air pollution 46% higher in northern China, these findings imply that every additional 10 micrograms of particulate matter pollution reduce life expectancy by 0.6 years. According to researchers, this data indicates that air pollution is currently the greatest environmental risk to human health.)
Now that we’ve discussed numbers about populations and countries, let’s look at some important numbers about the environment. Smil argues that the main challenge we face in the modern world is how to continue raising standards of living for billions of people while sharply decreasing our carbon emissions.
Unfortunately, when looking at the numbers, this challenge is close to impossible. We simply rely too much on fossil fuels to power the global economy, and the technological advances we would need to make to replace carbon-heavy industries are unlikely to happen in the near future. It’s important, however, to look at the facts and be realistic about the challenges we face. Let’s do that by first examining our carbon emissions and the failure of technology to protect us from environmental degradation. We’ll then look at a variety of areas that impact the environment and the numbers associated with those.
To help understand our environmental challenges, Smil provides the numbers for the amount of carbon we emit through the use of fossil fuels. At the beginning of the 19th century, global carbon emissions were relatively low at around 10 million tons a year. By the end of the century, that number was over half a billion tons. And by 2000, global carbon emissions were over seven billion tons a year. To put it another way, from 1800 to 2000 carbon emissions grew 650-fold while the global population only grew sixfold.
(Shortform note: In Thank You For Being Late, Thomas Friedman provides historical context on the climate change crisis. He argues that global emissions have increased so dramatically, that we’re creating a new epoch: the Anthropocene, a period in which the Earth can’t keep up with the changes humans are causing to the planet. Starting with the Industrial Revolution, the Earth began heating up rapidly due to increased greenhouse gas emissions. In the 1960s and 1970s, as more people gained access to cars, planes, and single-family homes, this heating sped up even further.)
Even as governments and other organizations have started to implement large-scale efforts to curb carbon emissions, global emissions continue to grow, writes Smil. By 2017, emissions had declined in Europe and the United States, but those declines were offset by China, which contributed three billion tons of carbon emissions.
More recently, China’s increase in carbon emissions has slowed, but emissions in India and Africa are expected to continue growing, making any substantial decreases in overall global emissions unlikely. Even if we meet the targets set forth by the Paris Agreement of 2015, an international committee dedicated to reducing carbon emissions, carbon emissions would still be about 50% greater than their 2017 levels.
If we are to avoid environmental disaster, scientists estimate we need to keep global temperatures from increasing more than 1.5 degrees Celsius. According to a 2018 study, the only way to do this is to get to zero net emissions by 2050. Smil claims reaching zero emissions by 2050 will take an unprecedented global effort on a massive scale.
Additional Temperature Forecasts
Many climate scientists believe that meeting the goal of the Paris Climate Agreement is unlikely and provide additional evidence to prove that: The main target of the Paris Agreement is to keep the global temperature rise under two degrees Celsius, preferably under 1.5. A 2017 study found that the chances that global temperatures will rise more than two degrees Celsius this century are around 95%, with a less than 1% chance they rise less than 1.5 degrees. The most likely scenario is that global temperatures will rise between two and 4.9 degrees Celsius by 2100.
The main factors contributing to this increase are population growth and carbon intensity, or the measure of carbon dioxide emitted per unit of gross domestic product. If we wish to keep global temperatures down, we must drastically reduce carbon intensity.
The same research team released another study in 2021, this time looking to determine exactly by how much we need to reduce carbon emissions to keep global temperatures steady. They found that we need emission reductions about 80% greater than the Paris Climate Agreement proposed: Instead of 1% annual reductions in carbon emissions, we’ll need about 1.8%.
Smil argues that many people wrongly believe technology can save us from environmental disaster. This is because they often have unrealistic expectations about the speed at which technology will advance.
These unrealistic expectations are often because people are influenced by the numbers underpinning Moore’s law, which states that the speed and capabilities of computer chips double every two years. This law has largely held true since its inception in 1965, and it has allowed for a great deal of innovation in computers and electronics.
People often assume the same rate of progress applies to other fields—for instance, in environment-related industries—but technological progress happens much more slowly outside of computer-based technologies. For example, corn yields have risen by an average of only about 2% per year since 1950, and fuel efficiency has increased by about 2.5% a year.
Instead of relying on future technologies to save us, we should be searching for realistic and practical solutions, and if a problem can’t be completely and immediately solved, incremental progress is still better than no progress at all, contends Smil.
Can Technology Save Us at All?
A 2017 MIT study found that even in the fields of computers and electronics, where Moore’s law applies, technological advancements still aren’t enough to create a sustainable world. Some scientists believe that as we become more technologically advanced, we’ll use fewer materials and be a more sustainable society. But researchers found that no matter how much more efficiently a product is made, consumers will only demand more of that product and thus produce more material waste.
For example, the amount of material to make a transistor has greatly decreased over the last few decades. This has made computers and smartphones much more powerful and compact, but the increase in demand for these superior products has outpaced further technological improvements to their sustainability.
When researchers looked at materials, goods, and services outside of the electronic and computer industries, they found a similar trend: As products become smaller, better, and cheaper, demand increases, and there is no overall reduction in the amount of material used to make them. The only cases in which significant dematerialization occurs are when a product is replaced by something else (wool with nylon and polyester, for example), or the government intervenes (for instance, by passing laws against asbestos and thallium).
The latter case exemplifies how practical solutions are more effective than reliance on not-yet-discovered technologies: Asbestos was discovered to be hazardous, so the US government passed a law limiting the production and use of asbestos.
A key environmental challenge of the 21st century is transitioning our energy sources away from fossil fuel consumption. Smil argues that we must be realistic about this transition, and understand the numbers behind it if we wish to make meaningful progress.
Energy transitions take time. The transition from wood and charcoal to coal, oil, and gas as the world’s main source of energy took a century. Transitioning away from fuels that currently produce 10 billion tons of annual carbon emissions will be a much more difficult task. While alternative energies like solar, wind, and nuclear are being adopted, they won’t be able to replace fossil fuel consumption any time soon. In this section, we’ll go over each of these energy alternatives and provide further insight into our reliance on fossil fuels.
Many point to nuclear energy as the best possible replacement for fossil fuel energy; when it began to take off in the 1970s, some predicted it would provide virtually all of the world's electricity by 2000. However, Smil argues that it has failed to do so for several reasons.
Catastrophic failures of nuclear power plants occurred at Three Mile Island, Pennsylvania, at Chernobyl, Ukraine, and at Fukushima, Japan, which has made the public and governments more skeptical of nuclear energy. Also, the constructions of many nuclear plants have gone over budget, there is still not a viable option for permanent storage of nuclear waste, and we still haven’t come up with a safer, less expensive design for new reactors.
For these reasons, the prominence of nuclear energy has receded, especially in the Western world, writes Smil. Germany and Sweden are removing nuclear energy entirely, and France, the leading adopter of nuclear energy, is also cutting back. As a result, the percentage of global electricity powered by nuclear energy has gone from 18% in 1996 to 10% in 2018. Though nuclear power still has the potential to drastically reduce carbon emissions, it isn’t on track to do so, as it is estimated to provide only about 12% of electricity by 2040.
Nuclear Energy Continues to Decline
Beyond the publicized failures of nuclear energy Smil mentions, there are other reasons nuclear energy failed to take off, including the low cost of natural gas, the falling cost of renewables, and the fallout and heightened safety requirements caused by the 2011 Fukushima accident. Though scientists believe nuclear energy will play a big role in reducing carbon emissions, 2021 estimates from IAEA project nuclear energy to account for only 6 to 12% of global electricity in 2050.
What’s more, when looking back at previous projections, we see that the estimates for future nuclear energy usage are becoming smaller and smaller: In 2007, the low-end projection for 2030 nuclear energy production was 447 gigawatts. By 2016, the low-end projection was significantly lower at 390 gigawatts. These projections indicate that nuclear energy may not play such a significant role in the reduction of carbon emissions.
According to Smil, numbers don’t suggest that wind turbines will provide an efficient solution to environmental problems, either. The main issue with wind-generated electricity is the amount of fossil fuel required to build wind turbines. Though a wind turbine can generate the energy it took to produce it in less than a year, these turbines only produce energy intermittently, and we need large amounts of steel, oil, and cement to make them. For wind to provide just a quarter of the world’s electricity by 2030, we’d need around 450 million tons of steel, which as of now can only be made using coal and natural gas. Until we can make wind turbines using only renewable resources, we will continue to depend on fossil fuels.
(Shortform note: Though it will indeed be difficult to replace carbon-powered electricity with renewable energy, it is theoretically possible. A 2012 study found that there is enough wind energy to meet global demand. As of 2012, humans used about 18 terawatts of power a year, while more than 400 terawatts of power could be extracted from surface winds every year. Furthermore, wind turbines make up for the carbon emissions of their production in as little as three months.)
Solar energy, though efficient, provides more evidence to Smil’s argument that energy transitions take time: The photovoltaic effect, the generation of electricity when a material is exposed to light, was first discovered in 1876. Yet it wasn’t until the 21st century that solar electricity generation became efficient enough for large-scale usage. In 2000, solar power provided 0.01% of global electricity. In 2010, that number went up to 0.16%. By 2018, it was at 2.2%. This is a sharp rise, and with solar energy becoming more efficient, it could certainly make a dent in global carbon emissions. But it isn’t likely to replace fossil fuels entirely.
(Shortform note: Though it will take significant investment, scientists believe it is possible to shift to 100% renewable energy by 2050 with the help of solar energy. A 2020 study predicted what it would take for the solar energy industry to meet the Paris Agreement targets: Along with other renewable energy sources, we would need a capacity of 70 to 80 terawatts from photovoltaic systems, more than 100 times what we currently have. While this is a drastic increase, it isn’t impossible, as solar energy is expected to become much more cheap and efficient in the coming decades.)
If we hope to provide year-round renewable electricity to big cities through wind and solar power, we’ll need better batteries to store saved-up energy more efficiently, claims Smil. This is because there are gaps in the flow of wind and solar energy: For instance, an unusually cloudy or windless month could render a city’s solar panels or windmills inadequate.
As of now, lithium-ion batteries are the best thing we have, but they are still too inefficient to hold enough power for a city of millions. We’ll probably need something more efficient, like hydrogen-based or compressed air batteries, but the technology for those is still in early development.
(Shortform note: A 2013 study examined how efficient it would be to store surplus solar and wind energy using current battery technologies. It found that when factoring in the energy costs of storing it, this could work for solar energy but not for wind energy. This is because it is more energy-efficient to temporarily shut down a wind turbine than it is to store its surplus energy in batteries. In other words, building the batteries to store the surplus electricity would require too much energy for it to be worth it.)
Statistics show that another significant contributor to carbon emissions is transportation and shipping. Smil argues that it will take a radical change to go carbon-neutral in these industries. From cargo ships to airplanes to cars, the entire world now runs on fossil fuel-powered vehicles. Let’s look at the numbers behind the transportation and shipping industries.
According to Smil, diesel engines are an integral part of the globalized economy. Diesel engines are much more efficient (15 to 20%) than their gasoline-powered counterparts, and they are reliable, durable, and have relatively low operating costs. Because of this, they power virtually every container ship, truck, and freight train, moving our most important commodities (oil, cement, grain) around the world. There is simply no better way to transport the massive amount of materials than diesel engines, and this will remain true for the foreseeable future.
(Shortform note: While we aren’t getting rid of diesel engines any time soon, there are some new technologies that may drastically reduce emissions from the transport sector. A Swedish transport company is using over 50 vehicles that run on HVO 100, a synthetic biodiesel, and they hope to further reduce energy consumption by designing more aerodynamic trucks. Additionally, researchers at MIT have devised a new way of powering trucks using a hybrid engine system that could also sharply reduce pollution.)
Though we’ve successfully built electric trains and cars, Smil points out that building efficient electric container ships will be a monumental task. The first electric container ship, built in the late 2010s, can only carry 120 containers, will travel at a slow speed of six knots, and will only be used for trips of up to 30 nautical miles. In contrast, diesel-powered container ships can carry over 20,000 standard-sized containers, travel at a speed of 16 knots and commonly make trips of over 20,000 kilometers.
To match the production of diesel, container ships would require lithium-ion batteries over 10 times more efficient than what we have today. To put this in perspective, in the last 70 years the efficiency of commercial batteries hasn’t even quadrupled.
(Shortform note: Besides electric container ships, there are other more environmentally friendly ships in the works, but they, too, are a long way from replacing diesel-powered cargo ships. One ship design, Vindskip, is partially powered by wind, and early tests have seen a 63% reduction in carbon emissions. But the earliest these ships could hit the waters is 2025. Another Norwegian ship design is meant to use hybrid propulsion systems to save energy and fuel, but again, these are hardly going to make a dent in near-term carbon emissions.)
Smil argues that the age of the car began on August 12, 1908. This was the day the first Model T was assembled, making cars a much more affordable commodity. The automobile has had an enormous impact on the world but is also a major contributor of carbon emissions. We’ll look at the numbers behind vehicles to explain why they are so inefficient as a means of transportation and why electric cars won’t save us.
According to Smil, the main reason cars are energy-inefficient is their large weight-to-payload ratio—in other words, the weight of the car versus the weight of the people it’s carrying. This means it takes a huge amount of energy simply to move the car itself, not the passengers in it. For comparison, a Ford F-150, the most popular American car, has a ratio of 32, a bike has a weight ratio of 0.1, and a Vespa scooter 1.6 (for an average-sized human).
To make matters worse, in the US, almost three-quarters of Americans commute to work without other passengers, so the weight-to-payload ratio is especially bad. What’s more, the average car size is only increasing, especially with the heavy batteries required for electric cars. And while lighter cars would help, having fewer people drive alone would be the best thing to do to reduce the weight ratio of cars.
(Shortform note: Another factor that adds to the US weight-to-payload problem is the number of US citizens who are overweight. A 2006 study found that the average weight of a US citizen rose 24 pounds from 1960 to 2002. This meant cars were using almost a billion more gallons of gasoline a year due to overweight passengers, or about $2.8 billion annually at $3 a gallon. Interestingly, it seems the amount of driving Americans do could partially cause their overweight problem: A 2012 study found a positive correlation between daily automobile travel and body mass index.)
While electric vehicles (EVs) can help with carbon emissions, Smil argues that they aren’t an effective means of displacing carbon just yet. First, since global electricity still mostly comes from fossil fuels, simply powering EVs will continue to be a source of carbon emissions. Further, as we’ve discussed, building the infrastructure for renewable energy takes fossil fuels, so even getting to the point where many people drive sustainably powered EVs will require a lot of carbon, as will producing the EVs.
To add to this, EV production also creates about three times as much toxicity as a gas-powered car. This is due to the use of more heavy metals, which are more toxic to both humans and our freshwater sources.
(Shortform note: Studies support Smil’s claim that electric vehicles aren’t as environmentally friendly as advertised. A German study compared the carbon footprints of a Tesla Model 3, a Mercedes that runs on diesel, and a Mercedes that runs on natural gas. They found that the Tesla has the highest carbon footprint per kilometer of driving when taking the cars’ entire life cycle into account. The main reason for this is the carbon cost of the EV’s battery production and recycling.)
According to Smil, the numbers show that eliminating the carbon footprint of air traffic will be another great challenge of a transition to a carbon-free world. Airplanes use kerosene-based jet fuel, and there is currently no viable alternative to that. The best alternative may be fuel from organic matter, but to meet the increasing demand for air travel with biofuel, we’d need to cultivate oil-rich crops, which have their own environmental issues (more on this later).
Further, like container ships, making electric airplanes will be difficult, as batteries are heavy and a plane needs to be as light as possible to function properly. Of course, the most practical and effective way to limit airplane emissions would be to limit air traffic, but airplane use is expected to continue growing in the coming years.
(Shortform note: Like Smil, scientists seem to think one of the best ways to curb the carbon emissions of airplanes is to use biofuel. The most promising biofuel for this purpose comes from the camelina plant. In 2009, researchers found that oil from camelina can be converted to a green jet fuel that meets the standards of current petroleum jet fuels. The widespread use of camelina jet fuel could reduce carbon emissions of air traffic by up to 84%. The biggest roadblock to this currently is the cost and availability of growing the camelina crop at the required scale.)
As Smil points out, no mode of transportation is as efficient for medium distances as a high-speed electric train. While high-speed trains can’t replace the intercontinental capacity of planes or the local capacity of cars, they’re the best option for travel between these extremes.
For inter-city travel, trains offer high speeds, convenience, and relatively low energy usage and carbon emissions. A high-speed train can cover 300 kilometers in just under two hours. This is just a little bit longer than an airplane takes at a fraction of the energy usage. While Europe and China have adopted the use of electric trains, the United States is lagging behind: There’s not a single high-speed train connecting major cities in the US.
(Shortform note: A 2021 study on the high-speed rail system in China highlights how much more efficient and environmentally friendly high-speed trains are than airplanes. The study estimates that air travel emits seven times more carbon per passenger than high-speed rail (HSR) travel. The extensive HSR system in China is reducing carbon emissions drastically, as people are switching from plane to HSR travel within China. This switch to HSR has reduced China’s air carbon emissions by approximately 18%, or 12 million metric tons, over the last few years.)
Our food production also plays a big role in climate change, and as the global population continues to rise, Smil argues we must make changes in the way we produce and consume food. We’ll look at the numbers of three key aspects of food production: the use of nitrogen fertilizer, food waste, and meat consumption.
Smil argues that the use of synthetic nitrogen fertilizers impacts the environment in two major ways: It adds to greenhouse gas emissions, and it causes nitrogen to be removed from the soil. Crops need nitrogen, and the traditional ways farmers supplied nitrogen to crops (recycling organic materials and rotating crops) are no longer adequate as the population now reaches close to 8 billion people. To provide nitrogen to crops, we synthesize almost 150 million tons of ammonium a year to make fertilizers, a process that’s environmentally harmful. Let’s look in more detail at fertilizers’ impact on greenhouse gas emissions and soil nitrogen.
(Shortform note: In The Omnivore’s Dilemma, Michael Pollan provides historical context for the proliferation of nitrogen fertilizers in the 20th century and how they paved the way for our damaging agricultural practices. The process that synthesizes nitrogen to make fertilizers can also be used to make explosives. After World War II, the manufacturing plants that made explosives for the war began making nitrogen fertilizers instead. This resulted in massive amounts of nitrogen fertilizer being made and used, which increased crop yields around the world but significantly damaged the environment as we grew more and more crops.)
Though carbon dioxide contributes the most to the heating of the Earth, Smil points out that the next largest contributors are methane and nitrous oxide. The production and use of nitrogenous fertilizers add all three of these gases to the atmosphere. The synthesis of ammonia requires a lot of energy, usually provided by the burning of coal, which emits carbon dioxide, or natural gas, which in turn emits methane. The use of fertilizers also adds nitrous oxide to the atmosphere. Altogether, synthetic nitrogen fertilizers are estimated to account for about 1% of global greenhouse gas emissions.
(Shortform note: A 2014 study examined the effect nitrogen fertilizers have on carbon emissions and found that nitrous oxide emissions could be significantly reduced by simply using the correct amount of fertilizer. According to the study, agriculture accounts for 8 to 14% of global greenhouse gas emissions, and around 80% of nitrous oxide emissions. These numbers could be drastically reduced by limiting the over-fertilization of crops, as using the exact right amount of fertilizer has shown a sharp decrease in nitrous oxide emission.)
According to Smil, nitrogen fertilizers also contribute greatly to nitrogen loss, which affects crop yields and makes us more dependent on synthetic nitrogen. Nitrogen loss happens when the nitrogen naturally found within the soil decreases. As more and more nitrogen is removed from the soil, crop yields become smaller, which could lead to widespread hunger and famine. Because of this, farmers will have to increase their use of synthetic nitrogen fertilizers, further adding to the problem.
To avoid this vicious cycle, we must find a way to reduce the use of nitrogen fertilizers, whether through increased fertilizer efficiency or a more sustainable, natural supply of nitrogen.
(Shortform note: One of the main ways nitrogen leaves soil is through leaching: when nitrogen leaves the soil through drainage water, usually rainwater or irrigation. A 2022 study provided three ways to prevent nitrogen loss caused by leaching. First, farmers can mitigate drainage by carefully managing the amount of irrigation when there is heavy rain. Second, farmers should avoid overfertilizing so that more nitrate isn’t lost to drainage. Third, farmers can plant “cover crops” during times when no cash crop is growing. Rye, for example, can be grown in the winter and helps soak up some of the nitrogen that’s normally washed away during this time.)
Smil argues that reducing global food waste would greatly benefit the environment. The amount of food humans waste is massive. According to the UN, at least a third of all harvested food is wasted. The biggest contributor is the United States, with over 40% of food going to waste—an amount that would be enough to feed about 230 million people annually.
Further, when we waste food, we also waste a great deal of labor and energy while furthering the damage to the environment. If we wasted less food, we’d have less soil erosion, nitrogen loss, and greenhouse gas emissions.
(Shortform note: A Finnish study from 2012 evaluated the impact of food waste on a global scale. Globally, an estimated 614 calories per person are wasted every day. For every person on the planet, we waste around 27 cubic meters of water, 300 square meters of land, and 4 kilograms of fertilizer each year. If we just halved the amount of food waste, we could feed up to a billion more people each year and drastically reduce our use of the planet’s natural resources.)
Another change Smil advocates that could have a great environmental impact is limiting the consumption of meat, especially beef. Reducing all meat consumption would be helpful, but we could make a substantial impact just by eating more chicken and less beef.
One of the main reasons meat is bad for the environment is because of the amount of crops required to feed animals. In North America and Europe, approximately 60% of the total crop harvest is used for feeding livestock. Cows, in particular, require a lot of feed for the amount of meat they provide. Chickens require less than a third of the amount of feed to provide the same amount of edible meat.
(Shortform note: In 2014, a team from the Weizmann Institute of Science compared the environmental costs of the most popular livestock-based foods (beef, pork, poultry, dairy, and eggs). The main takeaway from the study confirms Smil’s argument: that beef has by far the largest environmental impact. Compared with poultry, beef requires about 28 times more land, 11 times more water, 6 times more nitrogen, and releases 5 times the amount of greenhouse gases. The study also found that pork, poultry, eggs, and dairy have relatively similar environmental impacts.)
Based on some of Smil’s metrics about the environmental footprint of transportation, consider steps you can take to reduce the environmental impact of your travel. Because such change will require a collaborative, global effort, think about what you can do as an individual and as a member of a community.
Consider your method of daily and weekly travel. Do you drive to work alone in a vehicle? Do you ever take public transportation, bike, or walk? Jot down some of your common transport methods and how often you use them.
Now consider how you could spend less time driving alone. If you drive to work, could you carpool with a coworker? Or could you use other methods of transportation, such as a bus or a train? Note some possible alternative transportation methods.
Finally, think about if the area you live in has adequate public transportation in the first place. What non-car options are available? If these are lacking, could you take action to improve them? (You might do this by signing petitions, giving feedback to the existing public transit companies, or contacting local representatives.)