In Chapter 3 of How the World Really Works, Smil writes about the four key materials of modern civilization: cement, steel, plastics, and ammonia. These are indispensable for infrastructure, transportation, communication, and other essential functions. Despite their critical role, these materials often receive less attention compared to more intangible aspects like GDP growth or technological advancements.
Ammonia: It's crucial for global food production, used predominantly as a nitrogen fertilizer. Without synthetic ammonia, feeding a significant portion of the world's population would be impossible. Ammonia synthesis, a major scientific breakthrough, was achieved by Fritz Haber and scaled up by Carl Bosch. Today, about 80% of global ammonia production is used for fertilizers, with Asia being the largest consumer.
Plastics: They offer a unique combination of malleability, durability, and light weight. Plastics are derived from crude oils and natural gases and are used in a vast array of products.
Steel: Ubiquitous and irreplaceable, steel is fundamental for energy extraction, food production, shelter, and infrastructure. No other metal can substitute for steel's unique properties.
Cement: Essential for construction, cement is used to make concrete. Its strength, versatility, and durability cannot be matched by other materials like lumber or stone.
These materials are produced in massive quantities: 4.5 billion tons of cement, 1.8 billion tons of steel, 370 million tons of plastics, and 150 million tons of ammonia annually. Their production is heavily reliant on fossil fuels, contributing significantly to global CO2 emissions. Currently, there are no mass-scale, commercially viable alternatives to these production processes.
The chapter also discusses the history and importance of these materials. For instance, ammonia's role in feeding the world is highlighted, with synthetic ammonia being essential for at least 40-50% of the global population. The synthesis of ammonia was a key scientific achievement, enabling the Green Revolution and significantly boosting global food production.
Plastics are a diverse group of synthetic or semisynthetic materials known for their malleability. They are made from monomers like ethylene and propylene, derived from hydrocarbons, and formed into polymers. The production process is energy-intensive, involving high-temperature steam cracking.
Key types of plastics include thermoplastics (soften when heated, harden when cooled) like polyethylene, polypropylene, and PVC, and thermoset plastics (resist softening when heated) like polyurethanes and polyimides. Plastics combine low weight with high strength, making them ideal for various applications, from heavy-duty pipes to car interiors and aircraft components.
The history of plastics dates back to the 19th century with the invention of celluloid and Bakelite. Post-World War II saw a significant expansion in plastic types and uses, including polycarbonates, polyimides, and famous brands like Tyvek®, Lycra®, and Kevlar®. By the end of the 20th century, the market offered 50 different kinds of plastics, with global production skyrocketing from 20,000 tons in 1925 to about 370 million tons by 2019.
Plastics are ubiquitous in daily life, found in consumer electronics, healthcare, transportation, and construction. They are particularly vital in healthcare, used in numerous medical devices and personal protective equipment. The COVID-19 pandemic highlighted the critical role of plastics in healthcare, especially in personal protective equipment.
Despite their indispensability, plastics have raised environmental concerns due to pollution, particularly in oceans and coastal areas. However, it's noted that most microfibers in ocean water are of natural origin, not from synthetic textiles. The chapter emphasizes that while plastic pollution is a serious issue, it should not detract from the proper use and importance of these materials in modern life.
Steels, with over 3,500 varieties, are iron-dominated alloys essential in modern civilization. They are made from cast iron by reducing its carbon content, resulting in a material superior to hard stones and common metals in terms of strength and heat resistance. Steels are categorized into carbon steels, alloy steels, stainless steels, and tool steels, each with specific properties and uses.
Steel is fundamental in construction, transportation, and manufacturing, forming critical components of our world. It is used in everything from household items to large structures like skyscrapers and bridges. Steel's ubiquity extends to transportation, with significant usage in cars, trains, and ships. It also plays a crucial role in electricity generation and is vital in healthcare and military applications.
Iron, the primary component of steel, is abundant in the Earth's crust, ensuring a long-term supply for steel production. Steel is also highly recyclable, with electric arc furnaces melting scrap steel. Recycling rates are high in affluent economies, and steel scrap has become a valuable export commodity.
Primary steelmaking still dominates over recycling, involving energy-intensive processes like blast furnaces and basic oxygen furnaces. Integrated steelmaking is the standard method, with final products formed through continuous casting. The energy demand for steel production is significant, contributing to greenhouse gas emissions. The steel industry is a major contributor to CO2 emissions due to its reliance on coking coal and natural gas.
In summary, steel's versatility, strength, and recyclability make it a cornerstone of modern civilization, used in a vast array of applications. Its production, while essential, poses environmental challenges due to its energy intensity and carbon emissions.
Cement, the key component of concrete, is produced by heating limestone and clay in kilns, resulting in clinker, which is then ground into fine cement. Concrete, primarily made of aggregates and water, is the most widely used material in modern civilization, especially when reinforced with steel. It's essential for urban infrastructure, including buildings, roads, bridges, and transportation systems.
The history of cement dates back to Roman times, but modern cement was patented in 1824 by Joseph Aspdin. The large-scale adoption of concrete in construction became feasible with advances in steel reinforcement. Reinforced concrete is now a staple in large buildings and transportation infrastructure, from skyscrapers to bridges and highways.
China is the world's largest consumer of cement, with its production surpassing the U.S. and contributing significantly to its extensive infrastructure development. The global consumption of cement has grown exponentially, with recent rates around 100 million tons per year in the U.S. and about 2.2 billion tons in China.
However, concrete is not a highly durable material and is subject to environmental damage, leading to deterioration over time. This means that the 21st century will face significant challenges in concrete renewal and removal, especially in China. Concrete structures vary in longevity, with many deteriorating after a few decades, while others last longer.
Concrete can be recycled, but the process is costly. In affluent countries, the primary need is repairing decaying infrastructures, while in poorer regions, replacing mud floors with concrete is essential for improving hygiene and reducing disease.
The abandonment of concrete structures is becoming more common due to aging populations, urban migration, and economic shifts. This trend is evident in the concrete ruins of industrial sites in Detroit, Europe, and former Soviet regions. Other notable concrete relics include defensive bunkers and missile silos.
In summary, while concrete is crucial for modern civilization, its production, use, and eventual deterioration pose significant challenges for sustainability and infrastructure maintenance.
In the first half of the 21st century, global economies should be able to meet the demand for steel, cement, ammonia, and plastics, especially with increased recycling. However, completely eliminating the dependence of these industries on fossil fuels by 2050 is unlikely. This is particularly true for low-income countries undergoing modernization, which will require significant increases in basic materials.
Replicating China's post-1990 material growth in other modernizing countries would lead to substantial increases in the production of these materials. The continued reliance on fossil carbon is the price paid for the benefits derived from steel, cement, ammonia, and plastics. Moreover, the expansion of renewable energy will require not only large quantities of traditional materials but also new materials previously needed in smaller amounts.
Two examples illustrate this growing material dependence:
Wind Turbines: Symbolic of green electricity, wind turbines are large accumulations of steel, cement, and plastics, all embodying fossil fuels. Their construction and maintenance involve significant use of these materials and fossil fuels, contradicting the notion of a dematerialized green economy.
Electric Cars: Electric vehicles represent a new, substantial material dependency. A typical lithium car battery requires processing large amounts of ores, leading to significant extraction and processing of raw materials. The global shift to electric vehicles will dramatically increase the demand for lithium, cobalt, nickel, and other materials, necessitating expanded extraction and processing activities.
The future adoption rates of electric vehicles are uncertain, but projections indicate a significant increase in demand for materials like lithium, cobalt, and nickel. This expansion will require extensive resource exploration and extraction, heavily reliant on fossil fuels and electricity.
Modern economies are intrinsically linked to massive material flows, whether for fertilizers, construction materials, or components for renewable energy technologies and electric vehicles. Until renewable energy sources can fully support the extraction and processing of these materials, civilization will remain fundamentally dependent on fossil fuels. Advanced technologies like AI, apps, and electronic communications won't alter this reliance on essential materials.