Human Impact on Biodiversity


Trisha Hostetter

Biology Senior Seminar

November 21, 2005



Thesis: Humans affect biodiversity on many levels and it is important to realize these effects on an individual, societal, and government level and attempt to minimize them in order to ensure a future for humanity.  

I.                   Introduction

II.                Biodiversity Defined and Why It Is Important

III.             Extinction of Species

a.      Rates of Extinction

a.      Cause of Extinction

IV.              Human Actions

a.      How to Determine Impact

b.      Drivers

c.       Human Population

d.       Agriculture

e.      Climate Change Problems

V.                 Poverty and Biodiversity

a.      Logging in Malawi

b.      Rich vs. Poor

c.       Education

VI.              Government Actions

a.      President Bush

b.      Kyoto Protocol

c.       Regional Greenhouse Gas Initiative

d.      Debt for Nature Swap

VII.           Conclusion




Many individuals do not think about the damage they are causing on biodiversity. However, it is important as humans to realize the impact we have on biodiversity because without it, there would be no human existence.  If no changes are made in the ways humans use resources on earth, there will continue to be a degradation of biodiversity until human lives can no longer be sustained. Humans affect biodiversity by their population numbers, use of land, and their lifestyles, causing damage to habitats for species. It is important for humans to realize how their actions affect biodiversity and the importance of maintaining what biodiversity is left on the earth. Through proper education, and by demanding that governments make decisions to preserve biodiversity, the human population will be able to sustain life on earth longer.


Biodiversity Defined and Why It Is Important

Biodiversity is the term that is given to describe the variety of life on earth and the natural patterns it forms. It is the result of evolution, natural processes, and human influence. (Secretariat, 2000) Biodiversity involves diversity of genes within a species, of species within ecosystems, and of ecosystems in the biosphere (Frequently, 2005).  Biodiversity is not determined by only one factor, but rather many factors that differ spatially and temporally (Climate, 2005).

            Although many humans may not realize how important biodiversity is to them, it is clear that without it humans would not be able to exist. Each day humans use 40,000 species, most of which go totally unnoticed (Eldredge, 2000). Even though only a minority of humans realize it, biodiversity provides humans with food, water, oxygen, energy, detoxification of waste, stabilization of earth’s climate, medicine, opportunities for recreation and tourism, and many more things (Secretariat, 2000). Simply put, there would be no population of humans without biodiversity. 


Extinction of Species

            The most obvious indicator of biodiversity is the number of species on the planet. Currently there are 1.75 million species that have been identified; however, some speculate that there are at least 10 million living species on earth (Eldredge, 2000). To look at the loss of biodiversity, the number of extinctions of species should be examined. Rates of extinction are currently up to 40,000 species per year (that’s 100 per day or 4 per hour) (Wood, 2000).  This rate is 50 -100 times the natural rate of extinction and is expected to increase in the coming years (Sherbinin, 2002). The extinction rate is of great concern because once a species is extinct, there is no chance of ever getting that species back on the planet.

Three main problems that cause species extinction are: habitat loss, degradation, and fragmentation (Noss et al, 2005). Habitat loss is described as the complete destruction of a habitat. An example of habitat loss would be logging of a forest. Habitat degradation is when a habitat diminishes to a point where it can no longer support biological communities (Effects, 2005). An example of this would be habitats that are polluted by industry.  Habitat fragmentation is described as a habitat that is broken into smaller discontinuous segments of land for development (Mapping, 2005). An example of this would be putting a road in the middle of a habitat. All three of these problems that result in species extinction are directly related to human influence. 


Human Actions

There is no clear way of determining the total impact that humans are making on biodiversity; however, it is obvious that many actions by humans are causing a decrease in biodiversity. To determine the total impact that humans are making on a given environment, the area of productive land and water needed to produce the item that is being consumed and the need to account for the waste being generated by humanity must all be taken into account according to management and production practices in use during that time (Wackernagel et al., 2002).

Direct or indirect actions by humans have resulted in the decrease of biodiversity. The Convention of Biological Diversity states that there are both indirect and direct human drivers. Some of the indirect human drivers are demographic, economic, sociopolitical, scientific and technological, and cultural and religious factors.  Some of the direct human drivers are changes in local land use and land cover, species introductions or removals, external inputs, harvesting, air and water pollution, and climate change (Climate, 2005).

Human activity has substantially changed one-third to one-half of the world’s surface (Frequently, 2005). In the next 50 years it is expected that humans will seriously impact 50-90 percent of land in developing countries. This is a result of growth in population and in over consumption of natural resources (Mapping, 2005). The population of humans is, what many consider, the root of the biodiversity problem (Eldredge, 2000). The number of humans on earth, as of July 2005, is at 6.4 billion (World, 2005). The increase in human inhabitants causes a problem because with it comes a need to convert natural habitats to land for human consumption.

One way that the humans have been able to sustain their growth is by converting natural habitats to fields where foods can be produced. At least 23 percent of the earth’s land is being used for agriculture (31 percent of all land is unfarmable). In the United States there is a direct relationship between the loss of forests to the increase in cropland (Dobson, 1996). Internationally, there is half a hectare of tropical forest disappearing to farmland every second. One of the potential dangers of decreasing the amount of natural habitats remaining is that species will no longer be present on earth. This directly affects agriculture because many of the species that are being destroyed for croplands may have been used for genetically enhancing crop products (Frequently, 2005). In this manner, the increase in agricultural land actually harms our agricultural future.

Human actions have also played a role in climate change, which is also causing great danger for biodiversity. The change in climate is due to increased atmospheric concentrations of carbon dioxide, which causes increased land and ocean temperatures, and changes in precipitation and sea level rise. With the change in climate also comes a change in species. Climate affects the timing of reproduction and migration, the length of growing seasons, species distributions and population size, and the frequency of pest and disease outbreaks. It is also expected that the change in climate in the 21st century will have a much higher rate than the past 10,000 years and create an even bigger impact on biodiversity (Climate, 2005). It is expected that 80 percent of biologically rich regions will suffer great losses of plant and animal species because of global warming. The rate of change of habitats is expected to increase up to ten times due to global warming (Sherbinin, 2002). 


Poverty and Biodiversity

Biodiversity affects everyone to varying degrees. People that live in poverty depend heavily upon nature to provide them with resources to live. In third world countries logging has become a common activity of the poor. It is a huge problem in many developing countries because it is destroying natural habitats, yet it seems to be one of the only ways that people can make enough money to support their families. The New York Times recently ran an article about individuals in Malawi illegally cutting down trees in order to make enough money for food. One individual states, "We have no money to raise our families. We have nowhere to run, nothing else to do. So we have to cut the trees to feed our families." However, even when the individuals cut down trees and sell the wood they still do not always have enough money to support their families. The current rate of deforestation in Malawi is 2.8 percent and 23 species that are found in their forests are considered endangered. (Wines, 2005)

The degradation of the environment will affect both poor and industrialized nations. However, The developing nations will be the ones that are affected the most by the degradation of the environment by increasing poverty, reducing labor productivity, and exacerbating the current economic social crisis (Mapping, 2005). Developing nations do not have the resources to help their citizens find an alternative to use nature for survival. 

Educating individuals in developing countries about the need to preserve biodiversity is a must for ensuring human survival. Educating locals on the impact people are making on the environment and showing people how they can live in equilibrium with nature, will help preserve biodiversity without causing further oppression. Many times individuals do not realize that there are alternative ways of obtaining money that do not put the environment into jeopardy. For example, in the case in Malawi, if the locals were to obtain honey from beehives found in the forests they would be able to make more money than they would by selling wood (Wines, 2005).

General education in developing countries is very important to biodiversity even if it does not focus directly on sustainable living. There have been significant studies that have shown that educating and empowering women lead to a decrease in birthrates which would make a huge impact on population growth, especially since developing nations have a higher birthrate compared to industrialized nations. Simply educating individuals, all individuals, not just impoverished ones, about their impacts on biodiversity is a step in the right direction. (Eldredge, 2000)


Governmental Actions

             Although there are actions individuals can make that can assist in helping the biodiversity problem, it is important for governments to take actions that will provide a larger scale effect on saving biodiversity. The George W. Bush administration is not known for protecting the environment. President Bush has eliminated the roadless rule, which was a rule that kept logging and roads from being present in 60 million acres of national forests. Bush has also cut 42 million acres of critical habitat from the 83 million acres that are needed for threatened and endangered species. There has been a great decrease in the amount of designated wilderness in the United States. Bush designated 530,000 acres as wilderness areas compared to 9.5 million under the Clinton administration, 10.6 million acres under the Reagan administration, and 66.3 million acres under the Carter administration. There has also been a decrease in the number of species that were added to the endangered species list; Bush has added 31 species, Reagan 253, Bush Senior 228, and Clinton 521. (Wetsone et al., 2005)

            Bush made another decision against the environment by not ratifying the Kyoto protocol. The Kyoto protocol is a treaty that agrees to manage climate change on earth by reducing the amount of carbon dioxide and other greenhouse gasses from entering the atmosphere or to employ emissions trading (when governments provide an incentive for individuals to reduce the amount of emissions) (Kyoto, 2005). Al Gore signed the Kyoto protocol in 1998, however this agreement was not binding until it was ratified (Kyoto Protocol A, 2005, Kyoto Protocol B  2005). The United States did not support the signing of the agreement because they thought it “would result in serious harm to the economy of the United States.” (Kyoto Protocol A, 2005) The United States did not ratify the agreement and has no intention of doing so at this time (Kyoto Protocol B, 2005). Bush stated that he didn’t agree with the treaty because it did not include every nation, especially ones that were releasing great amounts of greenhouse gasses, for example China. The United States has agreed to reduce their carbon intensity to 18 percent by 2012; however, this is actually an increase in overall emissions (Kyoto Protocol A, 2005). 

            Some local governments are not in agreement with the United States’ decision not to sign the Kyoto protocol. The northeastern states in the United States (Connecticut, Delaware, Maine, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island and Vermont with Pennsylvania, Maryland, District of Columbia, and Eastern Canadian Provinces observing) decided that there needed to be a reduction of emissions and created the Regional Greenhouse Gas Initiative, RGGI. The goal of RGGI is to bringing the northeast region of the United States together to discuss a regional cap-and-trade program that deals with carbon dioxide and other greenhouse gasses emissions that are released from their power plants. The cap and trade program works by allowing a certain amount of emissions from each company, but if a company has been able to limit its emissions and has not reached the maximum level allowed, they are able to sell the permits for the emissions to companies who cannot keep within their maximum allowance for emissions (Regional, 2005).  RGGI will cap the program by taking the average emission between the years of 2000 to 2004 and not allowing a greater amount than this average to occur from 2009 to 2015. Through the years 2015 to 2020 the RGGI wishes to start the reduction of emissions by 10 percent (US, 2005).

            Although there is much evidence that the Bush administration does not truly care about the environment, they have made a few contributions that are beneficial to the environment. Bush has made a debt for nature swap, which is when a country’s debt is redeemed by supplying land reserves and salaries for people to monitor and protect reserves (Dobson, 1996). There are two ways in which debt for nature swaps can occur. The first way is through bilateral debt swap, which occurs between the two governments. The second way is through commercial debt swap, this occurs when a nongovernmental organization purchases the debt at a discount from the creditor government. The nongovernmental organization then organizes the conservation project with the debtor government. (World Wildlife, 2002)



            Biodiversity is an issue that affects everyone and therefore everyone should be aware of their effect on biodiversity. As biodiversity decreases on earth, so do the chances of human survival. Therefore, it is important to educate people on living in equilibrium with the environment. It is also important to make sure that the government is making laws that will ensure biodiversity for the future and not focus on shortsighted economics. If humans become extinct, it will likely be a result of their own action or lack of action. Hopefully humans will realize this before it is too late.


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