For most of the time that humans have inhabited the earth our wastes were only of significance on a local level. In recent decades society has started to take seriously the impact of human actions on the planet in a broader sense. Pollution of the air, land and water comes from a variety of sources and continues to be a major issue for communities and countries across the globe. While measures have been taken to address pollution in various ways across many dimensions – from local waste collection and recycling programs to international hazardous waste protocols -- globalization has magnified the problems as pollution is often exported along with good and services. One of the major challenges of the 21st century is to find ways for a growing human population to reduce the amount and impact of contaminants we discharge to our shared natural resources.
Debris scatters in the Pacific Ocean, possibly heading to United States.
Debris from the tsunami that devastated Japan in March 2011 could reach the United States as early...
Ecosystem services fact sheetLast Updated on 2014-07-09 17:01:53
This ecosystems services fact sheet is intended to provide an overview of the subject of ecosystem services, e.g. the economic consequences to humankind of benefits provided by the natural environment. This fact sheet was originally developed by the Ecological Society of America (ESA).
Have you ever considered that the cereal you eat is brought to you each morning by the wind, or that the glass of clear, cold, clean water drawn from you faucet may have been purified for you by a wetland or perhaps the root system of an entire forest? Trees in your front yard work to trap dust, dirt, and harmful gases from the air you breathe. The bright fire of oak logs you light to keep warm on cold nights and the medicine you take to ease the pain of an ailment come to you from Nature’s warehouse of services. Natural ecosystems perform fundamental life-support services upon which human... More »
PollutionLast Updated on 2014-06-28 18:51:13Pollution is environmental contamination that results in harm or death to living organisms. Most pollution is in the form of chemical additions to air, water or soil; however, in modern times starting in the mid-twentieth century noise and light have been considered as pollution sources. Most pollution is man-made, with natural fluctuations in atmospheric composition, surface water bodies and soil considered temporal gyrations in the Earth's natural history. The chief driver of pollution is the massive growth in human population, which induces the proximate causes of intensive agriculture and extraordinary industrial output. The United Nations and the Blacksmith Institute are two prominent organisations that tabulate locales of the greatest pollution intensity; while their listings do not correspond precisely, the overlap countries that both entities agree are the worst polluted... More »
Causes of extinctionLast Updated on 2014-06-13 19:39:40
Causes of extinction have prehistorically been dominated by natural earth processes such as geological transformation of the Earth's crust and major climatic oscillations, as well as species interactions; however, since the ascent of modern man during the Holocene, the causes of extinction have been dominated by the activities of humans. Rates of species extinction have increased rapidly since the early Holocene epoch, chiefly due to activities of humans; further acceleration of extinction rates began approximately 1600 AD, with the onset of accelerated human population growth and expanded scope of agriculture. Natural causes of extinction are regarded as being an irrelevantly small fraction of present extinction events, but are important to understand for historical and academic context. Darwin was the first to fully articulate the concepts of speciation and... More »
Population EquationLast Updated on 2014-06-11 16:19:48
This article, written by Richard Dahl, appeared first in Environmental Health Perspectives—the peer-reviewed, open access journal of the'National Institute of Environmental Health Sciences.
The article is a verbatim version of the original and is not available for edits or additions by Encyclopedia of Earth editors or authors. Companion articles on the same topic that are editable may exist within the Encyclopedia of Earth.
Planet Earth, now home to about 6.5 billion human beings, has thus far disproved the doomsayers. In 1798, Rev. Thomas Robert Malthus predicted that population would outrun food supply on the assumption that human numbers would increase at a geometric rate while food would be limited to arithmetic increases. Then, in 1968, Stanford University professor Paul R. Ehrlich issued a similar warning in his book The Population Bomb, in which he predicted... More »
Accidental release source termsLast Updated on 2013-12-18 14:53:28
Accidental release source terms are the mathematical equations that quantify the flow rate at which accidental releases of air pollutants into the ambient environment can occur at industrial facilities such as petroleum refineries, natural gas processing plants, petrochemical and chemical plants, oil and gas transportation pipelines, and many other industrial facilities. Accidental releases in such facilities may occur through acts of nature (e.g., floods, hurricanes or earthquakes), operational errors, faulty design or inadequate maintenance.
Governmental regulations in a many countries require that the probability of such accidental releases be analyzed and their quantitative impact upon the environment and human health be determined so that mitigating steps can be planned and implemented.
There are a number of mathematical calculation methods for determining the flow rate... More »
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