What is the anthroposphere?

The anthroposphere encompasses the total human presence throughout the Earth system including our culture, technology, built environment, and activities associated with these. The anthroposphere complements the term anthropocene – the age within which the anthroposphere developed. Some mark this with the advent of agriculture, others with the industrial revolution. In physical terms, the anthroposphere is comprised of the cities, villages, energy and transportation networks, farms, mines, ports, as well as the books, software, blueprints, and communication systems – the mark of civilization.

Using a broad definition of the anthroposphere, it extends beyond Earth. For example, our radio and television broadcasts of the 20th and 21st centuries travel at the speed of light as an expanding electromagnetic sphere of human origin into the Milky Way galaxy. Another, more tangible, example are the four NASA probes, Voyagers 1 and 2 and Pioneers 10 and 11, launched in the 1970s and now venturing beyond our Solar System. In the event of an encounter with any other intelligent life, each probe contains images and other artifacts that attempt to convey the basic characteristics of humans and their niche within the universe.

Carajàs Mine, Brazil Nestled deep in remote Amazonia, the Carajàs mine is of world’s largest iron ore mines. In a given year, such as 1997, this mine can produce 296 million metric tons of iron ore. Images like these reveal the vast amounts of resources from nature to supply their ever-growing needs, as well as the capability of humans to reshape the land.

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Message from Mankind. The Pioneer F spacecraft, destined to be the first man made object to escape from the solar system into interstellar space, carries this pictorial plaque. It is designed to show scientifically educated inhabitants of some other star system, who might intercept it millions of years from now, when Pioneer was launched, from where, and by what kind of beings. (With the hope that they would not invade Earth.) The design is etched into a 6 inch by 9 inch gold-anodized aluminum plate, attached to the spacecraft's attenna support struts in a position to help shield it from erosion by interstellar dust. The radiating lines at left represents the positions of 14 pulsars, a cosmic source of radio energy, arranged to indicate our sun as the home star of our civilization. The "1-" symbols at the ends of the lines are binary numbers that represent the frequencies of these pulsars at the time of launch of Pioneer F relative of that to the hydrogen atom shown at the upper left with a "1" unity symbol. The hydrogen atom is thus used as a "universal clock," and the regular decrease in the frequencies of the pulsars will enable another civilization to determine the time that has elapsed since Pioneer F was launched. The hydrogen is also used as a "universal yardstick" for sizing the human figures and outline of the spacecraft shown on the right. The hydrogen wavelength, about 8 inches, multiplied by the binary number representing "8" shown next to the woman gives her height, 64 inches. The figures represent the type of creature that created Pioneer. The man's hand is raised in a gesture of good will. Across the bottom are the planets, ranging outward from the Sun, with the spacecraft trajectory arching away from Earth, passing Mars, and swinging by Jupiter.
Source: NASA.

Why do humans merit a sphere of their own?

For much of our existence, human impact on the environment was comparable to other mammals roaming the Earth. As our numbers grew and our impact on the landscape expanded, we departed from the trajectory common to other mammals. Harnessing fire and tool-making are two critical departures followed by the advent of agriculture and sustained settlements.

Since the start of the industrial revolution in the late 18th century, humans developed the ability to harness the power of fossil fuels, transcending our role from mostly observers of global change. Human dwellings now occupy about 8 percent of ice-free land, but about three-fourths of the land surface has been altered by humans in some way. Additionally, we have significantly altered the biogeochemical cycles of nitrogen, carbon, sulfur, and phosphorus. Alteration of the carbon cycle alone has changed the pH of the oceans and the climate of Earth. Chemical inventions such as chlorinated fluorocarbons (CFCs) have altered the ozone in the stratosphere and the amount of ultraviolet light reaching the Earth’s surface. The footprint of our chemical activities are found in the air, water, land, and biota of Earth in the form of naturally occurring and human created molecules.

World Population. A key attribute of the anthroposphere over the past century has been rapid and sustained population growth. Estimates for world population by 2050 range from 8 to 10.5 billion people. Click to expand.

How does the anthroposphere change?

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World Population. This chart shows the recorded population trend of the past in addition to four estimates of future population. Each of these four projections reflect different assumptions about future fertility rates, mortality rates, and international migration. In this chart, a middle-of-the-road scenario calculates that population will exceed 9 billion people by 2050. Click here to read more about the assumptions underlying these estimates.
Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat, World Population Prospects: The 2008 Revision, http://esa.un.org/unpp.

To make room and to feed these added billions, the anthroposphere has expanded to occupy more land for dwellings and agriculture. In addition, human appropriation of fossil fuel energy and the many technologies it powers have played a major role in amplifying the influence of the anthroposphere in the Earth system. It has enabled humans to cut deep holes into the Earth to extract resources such as iron ore and bauxite, which are used to make up the automobiles, skyscrapers, and countless gadgets integral to modern life. However, these activities have expanded the anthroposphere in subtle ways by infusing pollutants into our water and air, negatively affecting the biosphere and bringing about global warming.

A defining decision for humans this century will be to either maintain a business-as-usual course, which many experts estimate could cause widespread devastation to life on Earth, or alter the nature of human activities in order to insure greater balance between the anthroposphere and the rest of the Earth’s systems.

The Earth at Night. Humans are the only species whose presence is recognizable from space. While humans are distributed throughout most of the land, the contrast between the luminous and dark regions of the continents reveal disparities in human development that exist throughout the globe. (Photo: NASA / Goddard Space Flight Center)