Man and his direct ancestors (hominids) have graced the planet for only about three million years.
For almost all of this period the human population totaled less than 5 to 10 million individuals.
Homo sapiens have increased their numbers exponentially from 1650 to present rising to the current population of 7.4 billion. If this growth continued unabated, the human population would reach 11.2 billion in the year 2100.
Of course, unlimited growth in an environment of finite resources is impossible because growth will eventually deplete the available resources and the population will collapse.
Indeed one of the kindest things that the human species could do for planet Earth is to control the rate of growth of the anthrosphere.
What is the anthroposphere?
The anthroposphere encompasses the total human presence throughout the Earth system including our culture, technology, built environment, and associated activities. The anthroposphere complements the term anthropocene – the age within which the anthroposphere developed. Some mark this age as beginning with the advent of agriculture, others with the industrial revolution. A growing movement within the geological community is considering establishing the anthropocene as a new geologic era, possibly starting around 1950. In physical terms, the anthroposphere is comprised of the cities, villages, energy and transportation networks, farms, mines, and ports. It also encompasses books, software, blueprints, and communication systems - the mark of civilization.
How does the anthroposphere change?
When compared with most natural changes in other spheres, change in the anthroposphere is happening rapidly. This is partly due to the rapid increase in population over the past several centuries but also as a result of the strides in technology and energy that have empowered humans to directly and indirectly affect environmental change. In terms of world population, the number of humans has soared from about 1 billion in 1800 to over 7 billion today.
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)
To make room for 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 extract resources such as iron ore and bauxite, which are used to make up automobiles, skyscrapers, and countless gadgets integral to modern life. However, these activities have expanded the anthroposphere by infusing pollutants into our water and air, negatively affecting the biosphere, and bringing about global warming. As the impacts of global warming unfold, the anthroposphere will be increasingly defined by extreme climate. For example, 2015, 2016, and 2017 were the four hottest years on record, since we started gathering reliable climate data in the late 1800s.
The five hottest years on record since the 1800s have occurred since 2010. (Photo: NOAA)
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.
JOURNAL ACTIVITY
Materials: Notebook, paper and pencil or dedicated computer file where you can keep your work.
Pick one or more of the Anthroposphere Questions.
Write down or sketch your answers based on your own understanding without looking anything up.
Ask a family member, friend, or teacher the same question(s) and write down or sketch their answers.
What are the common ideas in the answers you've collected? Write or sketch the common themes/ideas.
Come up with your own strategy for digging deeper (ask a scientist, check out university and government agency websites like NASA and NOAA, go to the library, design and conduct an experiment, etc.) until you're satisfied the answer makes sense to you.
Summarize what is known and unknown about the subject of the question(s). Also note what evidence there is in supporting what is known and how the evidence was obtained.
Rate the answer you've come up with on a scale of 1 to 10, 1 being weak with lots of uncertainty, 10 being perfect.
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 one of the world’s largest iron ore mines. In a given year, 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.
Why a separate sphere for humans?
World Population. A key attribute of the anthroposphere over the past century has been rapid and sustained population growth. Estimates for world population show between 8 billion and 10.5 billion people living on the Earth by 2050. Click to expand.
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, followed by the advent of agriculture and sustained settlements, are two critical departures from those commonalities.
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 observers to drivers 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 Earth’s surface. The footprint of our chemical activities is found in the air, water, land, and biota of Earth in the form of naturally occurring and human created molecules.
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)
The five hottest years on record since the 1800s have occurred since 2010. (Photo: NOAA)
Carajàs Mine, Brazil. Nestled deep in remote Amazonia, the Carajàs mine is one of the world’s largest iron ore mines. In a given year, 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.
World Population. A key attribute of the anthroposphere over the past century has been rapid and sustained population growth. Estimates for world population show between 8 billion and 10.5 billion people living on the Earth by 2050. Click to expand.
