Capítulo 1
The Materials That Built Our World
Imagine a world where your smartphone, car, and home simply didn't exist. Not because they hadn't been invented yet, but because humanity lacked the materials to create them. This isn't science fiction-it's the reality our ancestors faced for millennia. In "Making the Modern World," Vaclav Smil, whom Bill Gates calls his favorite author and "the person who has most influenced my understanding of modern civilization," reveals how humanity's relationship with materials has defined our very existence. This interdisciplinary masterpiece has become required reading at leading business schools and tech companies, with Elon Musk citing it as essential for understanding sustainable development. Beyond academic circles, the book has gained a cult following among environmentalists, engineers, and policymakers seeking to balance material prosperity with planetary boundaries.
Capítulo 2
The Human Material Revolution
The story of human civilization is inseparable from our expanding use of materials. While all organisms use materials-termites build mounds weighing 4-7 tons each, and marine organisms sequester roughly 10 gigatonnes of minerals annually-humans stand apart through the extent, specific qualities, and increasing complexity of our material extraction and transformation. This unique relationship with materials has enabled us to reshape our environment and create increasingly sophisticated technologies.
Our material journey began with stone tools 2.6 million years ago, though these early implements weren't remarkable for their quantity but their quality. The first technological breakthrough came 164,000 years ago when humans began heat-treating stones to improve flaking properties. This innovation, combined with expert stone selection and manufacturing techniques, produced ingenious, ergonomic tools that extended human capabilities. Early humans demonstrated remarkable skill in selecting specific types of stone - obsidian, flint, and chert were particularly prized for their predictable fracture patterns and sharp edges.
As societies developed, material use grew more sophisticated. Neolithic communities mastered fired pottery production around 6000 BCE, with Japan's Jomon pottery dating back 12,000 years. These early potters developed complex techniques for controlling clay composition, firing temperatures, and decorative elements. The first textiles appeared even before plant domestication, with flax weaves predating agriculture and wool cloth being spun over 10,000 years ago. Archaeological evidence shows sophisticated weaving techniques, including twill and herringbone patterns, were already in use by 5000 BCE.
Megalithic structures like Stonehenge demonstrated remarkable engineering capabilities, with massive stones transported over great distances without modern equipment. Recent research suggests these stones were moved using wooden sledges over rolling logs, with careful route planning to minimize elevation changes. The builders showed sophisticated understanding of astronomy and geometry in their layouts.
The durability of ancient wooden structures is exemplified by Japan's Horyuji pagoda, the world's oldest surviving wooden building, constructed 1,400 years ago. These structures used no fasteners, relying instead on precise mortise-and-tenon joints that accommodated humidity changes and withstood earthquakes. The central pole in tall pagodas functioned as a massive pendulum-equivalent to modern skyscraper tuned mass damping systems. This sophisticated engineering principle, known as shinbashira, allowed these structures to survive countless earthquakes over centuries.
Stone's permanence made it ideal for enduring monuments. The Egyptian pyramids remain unmatched engineering feats-Khufu's pyramid required 2.5 million stones averaging 2.5 tons each, constructed with remarkable precision. Recent studies have revealed the use of copper chisels, bronze saws, and wooden mallets in their construction, along with sophisticated surveying techniques that achieved near-perfect right angles and level surfaces. Medieval European cathedrals achieved unprecedented heights through modular design principles and on-site experimentation, featuring arched vaults, flying buttresses, and tall spires. While Egypt's largest pyramid took just 20 years (2703-2683 BCE), European cathedrals often required centuries-Notre Dame took nearly 200 years, while Prague's St. Vitus Cathedral, begun in 1344, wasn't completed until 1929. These extended construction periods allowed for technological innovations and adaptations, creating living laboratories for architectural advancement.
Capítulo 3
The Birth of Modern Material Civilization
The early modern era (1500-1800) marked humanity's first significant steps toward mass consumption and materialism. Dutch Golden Age paintings provide vivid evidence of this transformation, depicting comfortable burgher homes equipped with previously rare luxuries: glass windows that allowed natural light while protecting from the elements, decorative tiled floors, sturdy wooden furniture, and imported goods from far-off lands. These paintings reveal not just material affluence but a new middle-class lifestyle emerging well before European industrialization. Consumer goods expanded dramatically, from basic cookware to prized Chinese porcelain, Indian textiles, and exotic spices, creating new patterns of domestic comfort and social display.
Though most housing remained primitive during this period - with rural populations inhabiting basic mud huts and urban dwellers crowded into poorly heated quarters with minimal amenities - a revolutionary cultural shift was underway. People began aspiring to material well-being in unprecedented ways, creating demand for better housing, furnishings, and household goods. This aspiration would become a driving force of economic development.
The nineteenth century transformed these early stirrings through two parallel revolutions in materials: vastly expanded extraction of traditional construction materials and an explosion in metal consumption. Paris's modernization under Baron Haussmann (1853-1870) exemplifies this transformation on an urban scale. The creation of approximately 40,000 new stone buildings required an estimated 25 million tonnes of limestone, while new boulevards demanded vast quantities of paving materials. The project essentially rebuilt an entire city using industrial-scale material flows. Railways, perhaps the century's defining achievement, expanded from just 56km in 1830 to an astounding 775,000km globally by 1900. This expansion required at least 2.5 billion cubic meters of bulk materials for roadbeds and 2 billion tonnes of crushed stone ballast, transforming landscapes worldwide.
The metals revolution fundamentally altered manufacturing capabilities through both expanded traditional metal use and the introduction of new alloys. The crucial breakthrough for inexpensive steel production came in 1856-57 when Henry Bessemer and William Kelly independently patented their decarburization process, which could remove impurities from iron through oxidation. Steel production increased exponentially from 200,000 tons in 1800 to 9.5 Mt by 1900, enabling unprecedented applications from agricultural machinery to bridges and skyscrapers. This new material strength allowed buildings to reach previously impossible heights and machines to operate under intense pressures.
Paper production underwent equally dramatic changes, beginning with the Fourdrinier machine (patented 1799) that enabled continuous paper-making for the first time. Until the 1870s, paper remained relatively expensive as it relied primarily on recycled rags for raw material. However, extensive experimentation with natural fibers, including straw, hemp, and eventually wood pulp, led to wood becoming the dominant raw material, dramatically reducing costs and expanding availability. The textile industry experienced similar revolutionary change through mechanized weaving with power looms and steam engines. Britain's transformation was particularly dramatic, with its mechanical loom count growing from just 2,000 in 1800 to 250,000 by 1857. This industrialization enabled mass ownership of clothing, moving beyond the traditional limitation of a single set of garments to allow for wardrobes that could accommodate different seasons and social occasions.
Capítulo 4
Materials That Shaped the Twentieth Century
The twentieth century witnessed a revolutionary transformation in material production, fundamentally reshaping human civilization through industrialization, transportation, agriculture, and mass consumption. Iron maintained its historical dominance, with global output achieving unprecedented levels by 2000: 1 Gt/year of iron ore extraction and approximately 850 Mt/year of steel production-30 times higher than in 1900. Per capita steel consumption increased dramatically from less than 20 to about 140 kg/year, enabling massive infrastructure projects, from skyscrapers to bridges, and fueling the automotive industry's explosive growth.
Aluminum emerged as the century's signature metal, experiencing a remarkable rise from less than 7000 t to nearly 25 Mt, ultimately surpassing copper production twofold. Despite its advantageous properties-one-third the density of steel while offering comparable tensile strength-aluminum production remains one of the most energy-intensive metallurgical processes. Each ton of cast aluminum ingot requires approximately 5270 kg of bauxite ore and 435 kg of petrol coke and pitch. This energy intensity initially limited aluminum to luxury applications, but advancing technology and increasing scale gradually made it essential in aerospace, packaging, and construction industries.
Plastics revolutionized manufacturing and consumer goods, becoming the quintessential twentieth-century material by rapidly replacing traditional materials in countless applications after World War II. Though synthetic materials originated in the 1870s with John Wesley Hyatt's celluloid, the true breakthrough arrived in 1907 when Leo Baekeland created Bakelite, the first fully synthetic thermoset plastic. The 1930s became the golden era of plastic innovation through systematic research by major chemical firms. DuPont's development of neoprene in 1930 opened new possibilities in synthetic rubber. ICI's creation of polyethylene by 1935 transformed packaging, while Wallace Carothers's patent of Nylon in 1937 revolutionized textiles and industrial applications. Global production experienced exponential growth from under 50,000 tons in the early 1930s to an astounding 265 million tons by 2010-surpassing steel in volume and reaching 18% of steel's weight.
The Haber-Bosch process for ammonia synthesis stands as perhaps the century's most crucial material innovation, fundamentally enabling modern agriculture and population growth. Without this breakthrough in nitrogen fixation, supporting the additional 4.5 billion people who arrived during the century would have been impossible. In 1900, global fertilizer nitrogen consumption was a mere 350,000 tons, meeting only 2% of crop needs. After Fritz Haber's demonstration of catalytic ammonia synthesis in 1909, production underwent explosive growth, rising from 150,000 tons in 1920 to 85.13 million tons by 2000-a staggering 570-fold increase that significantly outpaced both population growth (3.8x) and economic output (20x). This process now produces over 450 million tonnes of nitrogen fertilizer annually, supporting approximately half of global food production and making it one of the most important industrial processes ever developed.
Capítulo 5
The Modern Material Landscape
Today's construction industry continues to evolve through a complex interplay of traditional materials and cutting-edge innovations. Wood maintains its dominance in North American construction, with a typical 200m2 house requiring approximately 28 tons of materials-split evenly between lumber and panel products. Engineered wood products, particularly glued-laminated lumber (Glu-lam), have revolutionized timber construction. These products combine smaller pieces of wood with advanced adhesives under precise pressure and temperature conditions. With a remarkably low density of 0.55-0.7 g/cm3 (compared to steel's 7.8 g/cm3), Glu-lam structures achieve exceptional strength-to-weight ratios, delivering more than twice the strength of traditional sawn timber while matching structural steel's performance per unit mass. This innovation has enabled the construction of increasingly ambitious timber structures, including multi-story buildings and long-span bridges previously impossible with conventional lumber.
Concrete has emerged as the world's most ubiquitous construction material, transforming modern architecture and infrastructure. Contemporary concrete mixtures follow precise formulations: aggregates (60-75%), water (15-20%), and cement (10-15%), with various admixtures for specific properties. The evolution of concrete strength has been remarkable-from modest 25 MPa capabilities in 1900 to today's high-performance mixtures achieving 150-200 MPa, enabling the construction of super-tall skyscrapers and complex infrastructure. China's dominance in cement production, reaching 1.88 Gt in 2010 (55% of global output), reflects the material's critical role in rapid urbanization and infrastructure development.
The environmental footprint of concrete production presents significant challenges. Each ton of cement produced generates approximately one ton of CO2, contributing nearly 5% of global fossil fuel carbon emissions by 2010. The scale is staggering: of the estimated 500 Gt of concrete installed between 1945-2010, 60% was placed in just two decades (1990-2010). This massive infrastructure faces multiple deterioration mechanisms: moisture infiltration, freeze-thaw cycles, biological fouling, acid rain damage, structural vibration, and alkali-silica reactions. These factors create an unprecedented maintenance challenge for future generations.
The steel industry has undergone transformative technological advances. Modern blast furnaces have grown to massive proportions, with the largest exceeding 5000 m3 capacity, enabling economies of scale previously unimaginable. The introduction of Basic Oxygen Furnaces (BOFs) revolutionized steel production, slashing processing times from 9-10 hours to just 35-45 minutes while achieving a thousandfold productivity increase. Electric Arc Furnaces (EAFs) have become increasingly prevalent, particularly in the US where they account for 61% of steel production, offering a more sustainable approach through scrap metal recycling. Continuous casting technology has further optimized production, reducing metal losses from 10% to approximately 1% while cutting energy consumption by 50-75% compared to traditional methods. These advances have made steel production more efficient and environmentally conscious, though challenges remain in reducing its carbon footprint.
Capítulo 6
Tracking the Flow of Materials
Materials move through societies in patterns ranging from simple, linear flows to complex, difficult-to-trace paths. Material flow accounting emerged from environmental concerns that traditional economic thinking ignored the conservation of mass principle. This principle states that matter cannot be created or destroyed, only transformed - a fundamental concept often overlooked in conventional economic analyses. Only in the late 1990s did researchers begin comprehensive studies of national-level material requirements, spurred by growing awareness of resource depletion and environmental impacts.
The greatest challenge in constructing material flow accounts is setting system boundaries. Limiting analysis to direct material inputs greatly underestimates resource demands, especially for trade-dependent economies. Even accounting for net imports is increasingly inadequate as finished products contain materials from complex global supply chains. Modern consumer products like Apple's iPhone exemplify this complexity, with components from nearly 20 companies across a dozen countries using raw materials from many more nations. For instance, a single smartphone contains over 60 different elements, including rare earth metals from China, lithium from South America, and cobalt from the Democratic Republic of Congo.
The United States shows complex patterns in metal consumption and accumulation. By 2002, cumulative aluminum stocks in American structures and products reached 142 Mt, compared to 117 Mt for copper and 4.13 Gt for steel. These metals are embedded in infrastructure, buildings, vehicles, and countless consumer goods, creating vast "urban mines" of potentially recyclable materials. In per capita terms, overall material consumption grew from 1.9 t in 1900 to 12 t by 2000, with construction materials accounting for most of this increase (from 0.7 t to 9 t per capita). This dramatic rise reflects the massive expansion of infrastructure, suburban development, and the interstate highway system. Wood is the only material showing a century-long per capita decline, from 800 kg in 1900 to 300 kg by 2000, primarily due to the shift from wood to other construction materials and heating fuels.
China's modernization represents not just the fastest but the largest economic advance in history, with official growth averaging 9.6% annually-doubling every 7.3 years to reach a 2010 GDP nearly 18 times higher than in 1980. This unprecedented growth has driven massive material consumption. China's construction boom drove a 25-fold increase in construction minerals extraction between 1980-2010, transforming landscapes and creating entirely new cities. Cement production grew from 80 Mt in 1980 to a staggering 1.88 Gt by 2010, supporting the construction of millions of apartments, offices, and infrastructure projects. For perspective, China used more cement in just three years (2008-2010) than the United States used during the entire twentieth century. This intensive material consumption has significant implications for global resource availability, environmental impact, and future recycling potential.
Capítulo 7
The Energy Cost of Materials
The energy required to produce materials varies dramatically. Construction materials generally have low energy costs, with higher requirements only for pyro-processed products like bricks, tiles, glass, and cement. Natural stone products require minimal energy-around 500 MJ/t for quarried blocks, somewhat less for crushed stone. Simple sand mining may require just 100 MJ/t, while gravel sorting typically stays below 500 MJ/t.
Cement production is energy-intensive due to high-temperature processing. World best practice now produces Portland cement with 3.3-3.5 GJ/t total energy input, while fly-ash and blast furnace slag cements require as little as 2.4 and 2.1 GJ/t respectively. Many plants in low-income countries still need around 4.5 GJ/t.
Iron and steel production has seen dramatic efficiency improvements, with global average energy consumption dropping from 60 GJ/t in 1950 to about 20 GJ/t by 2000. Best practices achieve 16.3-18.2 GJ/t for the blast furnace-BOF-continuous casting route, 18.6 GJ/t for direct reduction with EAF steelmaking, and just 6 GJ/t for scrap recycling via EAF.
Aluminum production is extraordinarily energy-intensive, requiring 13-18 MWh/t of electricity for electrolysis, plus 10-13 GJ/t for the Bayer process and 7-8 GJ/t for casting and rolling. The total energy cost reaches about 175 GJ/t-nearly twice copper's intensity and almost 10 times steel's. Secondary aluminum requires only 7.6 GJ/t for remelting.
Electronic-grade silicon is even more energy-intensive. The production chain from quartz to finished wafers requires approximately 2100 kWh/kg of electricity (7.6-20 GJ/kg depending on electricity source), 100-1000 times more energy-intensive than common metals. Material losses compound the energy cost, with 9.4 kg of raw silicon needed per kg of finished wafer.
These energy intensities translate to significant portions of global energy use. In 2010, steel production consumed about 36 EJ (7% of total primary energy supply), plastics 20 EJ (4%), construction materials 15 EJ (3%), paper 10 EJ (2%), and fertilizers under 8 EJ (1.6%). Together, major materials required about 100 EJ or 20% of global energy supply-a remarkable achievement considering that had steel production remained at 1900 energy intensities, 2010 production alone would have required 20% of global energy supply rather than 6%.
Capítulo 8
The Dematerialization Question
Despite declining material intensity in economic output, per capita material consumption continues rising even in affluent societies. What appears to be dematerialization often turns out to be complex material substitution. The shift from paper blueprints to computer-assisted design (CAD) illustrates this perfectly. While eliminating tons of paper drawings (Boeing 747 required 75,000 drawings weighing nearly 8 tons), CAD systems require extensive electronic infrastructures, servers, and reliable electricity supplies.
Material input reductions can be achieved through four main approaches: gradual design improvements without new materials; substituting constituent materials with lighter alternatives; intensified recycling; and introducing entirely new devices that perform functions with a fraction of their predecessors' mass. The soft drink can evolution illustrates both protracted substitution and substantial improvements-from steel containers to aluminum cans that dropped from 85g in their first iteration to just 12.75g by 2011, allowing a 2.3-fold increase in consumption with only a 60% increase in aluminum mass.
However, relative dematerialization has paradoxically increased total material consumption. Despite a 60% improvement in thrust-to-weight ratios of turbofan engines since the 1950s, the aviation industry has shifted toward larger aircraft with more powerful engines. While per-passenger weight decreased 15% (from 494kg to 419kg), this modest improvement was overwhelmed by explosive growth in air travel.
Material substitution often creates unexpected energy tradeoffs. Replacing steel with aluminum in automobiles reduces weight but dramatically increases energy costs. While aluminum is three times lighter than steel, it requires over ten times more energy to produce (218 MJ/kg versus 20 MJ/kg). A typical car's 120kg of aluminum components requires 24 GJ to produce, while the 350kg of steel it replaced needed only 8 GJ-a fourfold energy increase despite the weight reduction.
There is no evidence of widespread substantial dematerialization-absolute or relative-even among the world's richest economies. While material input growth has moderated due to established infrastructure, outsourcing of material-intensive industries, and relative dematerialization, few countries have achieved stabilization or slight declines in overall material inputs. Most high-income economies continue experiencing slowly rising material needs, while modernizing countries have seen unprecedented material demand growth.
Capítulo 9
The Material Future
Despite catastrophist predictions of imminent resource peaks, our civilization faces no imminent danger of running out of any major mineral. Resources represent total material in Earth's crust, while reserves are economically extractable portions that constantly change through investment and technical advances. Even "rare earths" aren't actually rare-China's near-monopolization created temporary supply concerns, but new mines and substitution research are already addressing these issues.
Prospects for new materials, improved varieties of common commodities, and more efficient production methods remain highly encouraging. Intensive R&D is addressing these goals across multiple sectors, with particular focus on materials for energy and environmental protection. Notable innovations include nanomaterials, graphene (a one-atom thick carbon fabric with extraordinary mechanical strength and conductivity), and carbon nanotubes. Traditional materials are also being reimagined, with self-cleaning glass surfaces, bendable concrete incorporating fly-ash and polymer fibers, and self-healing materials that can repair damage and recover functionality.
Despite these innovations, absolute global material consumption will continue increasing. Even conservative forecasts project significant growth by 2050: steel (+70%), aluminum (+33%), cement (+15%), paper (+200%), and plastics (doubling). While affluent countries with declining populations may reduce material consumption, rapidly developing nations with growing populations will drive continued global material demand growth.
The global ban on chlorofluorocarbons, removal of lead from gasoline, reduction of SO2 emissions, and adoption of water treatment represent notable environmental achievements alongside substantial reductions in energy intensities of major industrial products. Yet these impressive relative dematerialization successes haven't translated into absolute declines in global material use.
We face a choice between continuing our unsustainable "river economy" practices or pursuing rational futures of moderated material use that maximize quality of life for a stationary or declining population. Human ingenuity and adaptability must guide us toward the latter path, though this transformation will inevitably be gradual and difficult with uncertain outcomes. The gap between the haves (1.5 billion people) and have-nots (5.5 billion) remains so vast that even modest aspirations among the materially deprived would require generations of continued aggregate material growth. Our challenge is finding a balance that provides dignity and comfort for all while preserving the planet that sustains us.
