As human population grows, the demand for the use of natural resources also increases. More people will need air and water, plants and animals for food, land use for shelter and manufacture of its other needs. As population grows, more forestlands need to be converted to agricultural and industrial use. “The human activities have raised the rate of extinction to 1,000 times its usual rate" (Center for International Environmental Law). This is actually supported by the idea of IPAT (Impact equals Population times Affluence times Technology), an environmental impact formula developed by the physicist John Holdren which directly holds humans accountable for the loss of biodiversity the world is currently facing (Meadows, Donella). IPAT formula computes the environmental impact of human activities as: Impact (I) = Population (P) x Affluence (A) x Technology (T). The author of this formula explained that the pollution that each human being contributes to the environment is determined and measured by “counting what is countable" (M. Meadows). This is especially true because the formula obviously ignores the factors of economy and political power which only suggests that the impact is measured irrespective of his status.
The keyword for pointing to the human specie as primarily responsible for the loss of biodiversity is choice. Man has the choice of which, how and how much of the natural resources and the technology he will use and consume. Therefore man has always the choice and the sense of rationality to consider the consequences of his action. In the latest inventory of biodiversity done by the United Nations, a project entitled “The Millennium Ecosystem Assessment" humans were found to have depleted 60% of the world's grasslands, forests, farmlands, rivers and lakes (Associated Press, April 01, 2005). The report also revealed that one-fifth of the world's coral reefs and on-third of its mangroves have already been destroyed. The said study was a joint effort of 1,360 scientists representing ninety five nations.
As human population grows, the demand for the natural resources necessarily increases and so “over-harvesting" of the earth's produce has been one of the major reasons for the loss of biodiversity. A report made by the World Wide Fund (WWF) revealed that the fishing industry has harvested more than 250% of what the ocean can produce. “Deforestation had not only rendered the land barren and arid, but had also led to the depletion of the ground water level" (Blua, Antoine 2005). The demand for timber, for food and establishment of manufacturing plants led humans to degrade the forest and to deprive all the organisms that depend on it of their natural habitats. Soil degradation has dramatically reduced crop productivity which challenges food production and its ability to feed 1.5 billion people in the next 20 years according to the International Food Policy Research Institute (IFPRI) and the World Resources Institute (WRI).
Pollution due to the introduction and development of technology and industries played an important role in the destruction of biodiversity. Tourism is just one of the newest industries which contributed a vast amount of pollutants through air emissions, solid waste, litter, noise, oil and chemical and sewage. World Wide Fund reported that tourism now accounts for more than 60% of air travel. Coalmines release tons and tons of carbon dioxide causing global warming and sulfur dioxide which causes acid rain. Coal burning has been reported to have increased eight times from 1971 to 1995 brought about by electricity generation in Asia alone (WWF, October 19, 2006). Excessive use of fertilizers, flame-retardants, plasticizers and phenols posed a major concern in the for air pollution (Portal for Plastic Industry, 2004). Human intervention in the nitrogen cycle has also caused considerably vast damage of the earth's biodiversity. The oversupply of nitrogen is caused by industrial processes that produce nitrogen fertilizers, the combustion of fossil fuels, and the cultivation of soybeans, peas, and other crops that host symbiotic nitrogen-fixing bacteria (Vituosek, Peter M et. al. ) Such nitrogen overproduction has also been analyzed by scientists to be the cause of the dramatic shift in the dominant species. As population also increases, more and more people are going to use vehicles and industrial technologies which in turn will increase the emission of carbon dioxide and other greenhouse gases more the atmosphere can contain. Human beings are although aware that
Humans have all the capacity and the ability to destroy the natural environment. Deforestation and degradation have been the major human activities which contributed to the destruction of natural habitats. In crisis are forests and fisheries which accommodate vast variety of species. The World Resources Institute (WRI) reported that there are about one-fifth of the earth's original forest cover which remains intact. What is threatening is that humans continue to degrade such areas to give way with the demands of globalization. There are already about 180 million hectares deforested in developing countries between 1980 and 1995 (WRI, February 14, 2001). Deforestation caused diverse species to flee as forests are home to 50-90% of terrestrial species. Human beings are also affected as forests provide services to human beings in forms of carbon storage and flood prevention. Indigenous people also were deprived of their natural homes by forest conversion and destruction. Reports by the Food and Agriculture Organization revealed that over-fishing, destructive fishing techniques have destroyed the marine ecosystem. The said UN wing estimated that nearly two-thirds of ocean fisheries are exploited at our beyond capacity, affecting over one billion people, mostly in developing countries, depend on fish as their primary source of animal protein (IPCC, 2001).
The introduction of invasive new species into a certain habitat has caused the loss of biodiversity. Such human activities are initially intended to increase local biodiversity but also caused significant eradication of other species. Experts estimate that an average of three new species per year should be produced with the consideration of biological factors including climate change. “Changes in the biological systems such as start and end of breeding season, shifts in migration patterns, shifts in animal and plant distributions to higher elevations and towards the poles, and changes in body size and population numbers are but proven effects of global warming caused by human activities" (IPCC, 2001). Considering that there are specie extinctions caused by nature as with the case of the extinction of dinosaurs, it is still made clear by studies and researchers that humans have played a major role in the alteration of the natural process in the ecosystem.