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 5.5 billion. If this growth continued unabated, the human population would reach 8 billion in the year 2000, 14 billion in the year 2010, 60 billion in the year 2020, and infinity by the year 2023. 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.
Links to other components:
Atmosphere: Industrial and agricultural activities have changed the composition of the atmosphere. For example, we have increased the concentration of carbon dioxide in the atmosphere by 26% and doubled the concentration of methane. The production of chlorofluorocarabons are depleting the earth's ozone layer, our natural defense against ultraviolet radiation. Man has also effected the quality of air (e.g., smog), especially in urban area which results in respiratory problems.
Hydrosphere: Humans have impacted the hydrosphere by withdrawing large amounts of groundwater for agriculture and by contaminating rivers, lakes, groundwater, and oceans by organic and industrial wastes.
Biosphere: Man has clearly altered the natural biosphere through agricultural activities. A prime example is the slash and burn agricultural practice in the tropics where rainforest is cut and burned, and the land is converted to pasture.
Geosphere: Mineral and energy resources from the geosphere have fueled the Industrial Revolution that has permitted the human species to increase so prodigiously in number. For example, the exploitation of fossil fuels has increased our standard of living but an unintended consequence of this action may be climate change and global warming.