The contemporary era is marked by technology that is increasingly sophisticated and the defining feature of each decade is new technology. The history of our era can be described in terms of innovation—the automobile, the airplane, radar, radio, television, computers, the Internet—the list of innovations is endless. In the contemporary era, the term technology has been closely linked with invention (the creation of a new idea) and innovation (the first use of a new idea). The history of the 20th century is a history of social change that new inventions have brought about, and green technology might be the latest in a long series of innovations that include flight (1903), nuclear power (1945), contraception (1955), and the Internet (1965). Social change can also take place over decades. The invention of the contraceptive pill, for example, over decades led to major social changes such as the liberation of women from the drudgery of domestic life and decreasing populations, especially in the West, which faces demographic change, the social impact of which is still unclear.

The 20th century has also seen tremendous environmental impact as a result of technological innovation. Of special relevance to green technology is how a society's responses to its environmental problems always prove significant in averting or leading to collapse. Studying seven cases of collapse—Easter Island, Pitcairn and Henderson Islands, the Anasazi tribe of North America, the Maya in Central America, the Vikings in Iceland, and the Norse in Greenland, author Jared Diamond in his book Collapse (2005) lists eight factors that have historically contributed to the collapse of past societies: deforestation and habitat destruction, poor soil and water management, overhunting, overfishing, the effects of introduced species on native species, overpopulation and the increased per capita impact of people. All of these show how relevant green technology can be to contemporary problems. Diamond also argues that four new factors mark our current era of technologically induced growth: anthropogenic climate change, the buildup of toxins in the environment, energy shortages, and the buildup of greenhouse gases in the atmosphere.

In the field of green technology, one major innovation in the 20th century that led to the end of the biblical plague of famine in most parts of the world was the Green Revolution. Historically, stabilizing a population's food supply has meant improving agricultural methods, harvesting tools, equipment, transportation, and infrastructure, all of which inevitably involve technology. The Green Revolution, which swept the world in the 1950s and 1960s, applied agricultural innovations such as hybrid seeds, chemical fertilizers, pesticides, and irrigation methods. To many—including Norman Borlaug, the American scientist known as the father of the Green Revolution—these technologies were essential to prosperity, though critics charged they were environmentally devastating.

Ironically, green technology is also the answer to one enduring problem that has bedeviled new technology—the rise of new problems when older ones have been solved. To take a specific environmental example, early-19th-century American farmers used a variety of methods to control insects, with biological methods predominating. However, in the

20th century, chemical methods predominated until the publication of Rachel Carson's Silent Spring (1962), which revealed the havoc that chemical methods could wreak on the countryside. Carson's major contribution was the recognition that humans were an integral part of the natural world. In a world that since the 17th century had been used to the Promethean notion that science and technological development would give man ultimate control of nature, this was radical. Since the 1960s, there has been intense interest in technology that is not intrusive and that tries to work with nature rather than against it. This is reflected in interest in technologies that address questions of environmental pollution and public health, community right-to-know legislation, and the personal values embedded in scientific practice. Events in the 1970s, the sharpening of the nuclear arms race, the 1979 near-meltdown of the nuclear reactor at Three Mile Island, and increasing pessimism led to a questioning of the ability of technology and technocrats to control things and an idea that society was not efficiently administered or organized at all that marked a key shift from the belief that science could conquer nature to the realization that science could only work in harmony with nature. Thus, in the 20th century, the growing awareness of the dangers that unbridled technology can cause is one the key changes in social attitudes that directly influenced the quest for green technology, including renewable sources to replace nuclear power plants, green nanotechnology to ensure that nanotechnology will not have an adverse impact on the environment, and technology that is designed to reduce global warming.

Another change in attitudes that is significant to green technology is the growing recognition that there are technologies of the poor that have as much relevance as the technologies of the rich. Earlier notions of scientific progress, epitomized by the modernization paradigm that guided development in most postcolonial states and in Europe after the 18th century, favored heavy resource-intensive and environmentally unfriendly technology such as dams, nuclear power, and huge manufacturing plants. Where social attitudes toward the environment are still subordinate to the lure of economic progress, there is still a preference for such technologies, in spite of the harm that they can cause the environment. Examples of these include the Three Gorges Dam in China, which is the world's largest hydropower project, and the Narmada Dam in India.

Another key element of contemporary social change is that it is global. Manuel Castells, for example, has theorized the existence of a “space of flows,” which Castells uses to explain how technology has enabled a separation of the production process from nation-states, enabling a disjointed patchwork of command and control centers to coexist with geographically diverse centers of production. Applying this concept to modern industrial production, one can delineate a nonhierarchical system that is not geographically bound. This has challenged ideas of the developed West and the underdeveloped East, or such territorially bound definitions as the first world and the third world. Thus, the contemporary world is marked by research and development (R&D) in the highly innovative industrial core areas, skilled fabrication in the core and semi-periphery, semiskilled large-scale assembly and testing work that has shifted to the periphery, and finally the customizing of devices and after-sales maintenance and technical support that is organized in regional centers throughout the globe. However, rather than being territorially defined, the core and the periphery can exist in the same country, for example, R&D for Microsoft that takes place in Bangalore, India, which also hosts a burgeoning service industry that serves the need of the core that is the advanced, industrialized West.

Technological change can be spurred by war, though war is not an essential condition to scientific progress. Two of the greatest periods of human innovation, from the late 19th century to the eve of World War I and the post-1945 period, have seen enormous technological and scientific progress. Wartime innovations have led to major changes in food storage and agriculture, with considerable impact on the environment. For example, the need to supply enormous numbers of troops in Europe and the Far East led to massive U.S. government investment in new preservation techniques such as spray-drying and dehydration. In fact, during the war, while the average American male civilian ate 125 pounds of meat in 1942, a typical soldier was allotted 360 pounds. Through the power of processed foods and new cooking innovations such as the microwave oven, a meal that took one hour to produce in 1965 was shaved down to only 35 minutes by the mid-1990s. Other key innovations were the washing machine, the domestic electric oven, and oral contraception. The greatest impact of such technology that cut down the chores of housekeeping was that it freed women from the household and led to a massive influx of women into the workforce. The social changes that this brought about, most prominently the easing of the economic dependence of women on men, were tremendous.

Technological innovations have traditionally been held to cause sudden and dramatic changes, though explanations for economic growth that favored technological change have now given way to more nuanced studies of the impact of technology on society, especially in the emerging field of science and technology studies. However, while the speed of social change can be debated, the fact that technological innovations starting in the 19th-century Industrial Revolution dramatically altered societies cannot be denied. Thus, coal and coal-using technology so dramatically transformed industry toward the end of the 18th century, transforming Britain from an iron-importing country to one that dominated the world market in wrought iron. The combination of coal technology, steam engines, and heavy industry dramatically transformed Britain. Writers such as Charles Dickens (1812–1870) gave life to the dramatic inequalities that the Industrial Revolution caused in works like Hard Times (1854). William Blake coined the expression dark Satanic Mills to refer to the destruction of nature and human relationships that followed the early Industrial Revolution, which threw traditional and independent craftsmen out of work, especially in the textile industry. They, and many writers like them, gave fictional expression to the tremendous social changes that new technology brought in Britain.

More important was the social thinking that the new technology and its changes gave rise to. They included socialism, which advocated public ownership of the means of production; Marxism, which called for a takeover of the state by the working class; and anarchism, which considered the state superfluous and called for a stateless society, or anarchy. All of these inspired revolutionary movements throughout Europe. There were others, such as industrialist Robert Owen (1771–1858), who experimented with self-sustaining communes, an idea that environmentalists would adopt later, and Henri de Saint Simon (1765–1825), who coined the term socialisme and argued for technocracy and industrial planning.

In the 20th century, these philosophies would lead to social experimentation on a grand scale, but an experimentation that at its core was based on control of technology and the means of production. These include Marxist revolutions, most prominently in Russia (1917) and China (1949), the early-20th-century rise of fascism and Nazism in Italy and Germany, and the emergence of the social welfare state, in varying forms, in postwar Europe. What is important is that all of them advocated some kind of social order that was in the final analysis a product of technology. Thus, Marxist states advocated state-driven industrial planning, and fascism saw the rise of the corporatist state that called for

management of the economy through the state or through privately controlled organizations (corporations). With reference to green technology, fears have been expressed regarding both the power of corporations, especially in the oil, gas, and automobile sectors, to block sustainable but expensive green technology and the tremendous concentration of power in the hands of corporations in areas such as biotechnology.

Often, technology has not brought change in the way that was expected. The history of science and technology is replete with instances where technology did not bring about the social change that it was expected to. When electricity was first introduced, it was predicted that it would make cities green, an outcome that did not occur. The information technology revolution of the last decades of the 20th century also did not bring about expected positive social outcomes. It was hoped that the infrastructure of information and communication technology (ICT) would decentralize production and bring about tremendous social change by enabling work to be done from anywhere in the world. In reality, local, national, and increasingly globalized information and communication networks have broadly inflated a range of social and spatial boundaries, that is, the reach of active social connectivity, yet they remain unmistakably centered in the metropolitan core. Thus, while in theory the Internet is borderless, its core elements are designed and situated in well-defined spaces, where large research, development, software production, mass media, commodity manufacturing, sales and advertising, finance, commerce, state intelligence, and other commanding interests usually gather—and where most strategic decision making and revenue ultimately reside. The first-tier information cities are New York, Tokyo, and London, and secondary nodes can be found in cities such as Bangalore and Shanghai. Socially, this has meant the transfer of jobs such as back-office operations from the West to countries in the East. As a result of the ICT revolution, U.S. firms began to outsource computer and software development to India, exploiting the differential rates of income as a source of profit. Thus, in 2003, while an American engineer earned $50,000 to $60,000, the comparable figure for an Indian engineer was $3,000. Such outsourcing affected customer services, back-office accounting, and even secretarial work with enormous consequences for the poor and working class in advanced nations, especially the United States.

Thus, one of the less salubrious effects of the ICT revolution was the breaking down of the geographical barriers of social inequality. ICT has led to the creation of islands of plenty among poverty, a phenomenon that is as evident in the inner cities of the United States as it is in newly emerging regions such as Shanghai and Bangalore. The Internet, which traces its roots to military research in the United States, ironically broke down the centralization of information in the hands of corporate, government, media, and university authorities. Activists, the most prominent among them the website wikileaks.org , have enabled people to bypass electronic communications media that broadcast centrally determined messages to mass passive audiences and communicate with each other quickly and directly. Information technology also has led to radical changes in the way people communicate in society. Face-to-face interaction, long a staple of human culture, is increasingly replaced by “interface” with technological “terminals” of communication, electronic devices that acquire a life of their own. Games like Second Life enable people to interact virtually and to fulfill various roles. In particular, television has had tremendous social

impact, with critics charging that it disrupts social and family life, allows TV news to exercise great agenda-setting power, and trivializes complex political and social issues.

A key component of technology and social change is its international and transnational nature. While invention, especially in the past, was localized, its spread across borders has led to complex changes. Whether openly or by stealth, nations have always tried to acquire the latest technology. The Venetians tried to obtain the secret of Greek fire from the Byzantine navy during the late Middles Ages and the British, in a precursor of contemporary struggles over intellectual property rights and green technology, tried to prevent the export of their steam engines and textile machinery to rival powers.

The time gap between new technological innovations and the social change they bring about has narrowed from centuries to mere decades, and the coming nano-cogno-bio-info knowledge economy is likely to accelerate this trend. Some futurists argue that new technology will so shape the channels of our experience, transforming our conception of the “real,” redefining what we mean by “community,” and, some would maintain, what we mean by our “selves.” It is likely that in the future, human beings will spend as much time in virtual electronic space as they do in reality. It is likely that humankind is now on the threshold of a posthuman era in which persons merge with intelligent machines. In such a posthuman state, there would be no borders between bodily existence and computer simulation, between cybernetic mechanism and biological organism. One of the key components of this world will be ubiquitous special-purpose chips, “smart” devices, and agents that interact with human beings constantly. Most “computers” will be embedded in wearable micro-devices and implants, blurring the divisions between man and machine.