The purpose of this blog entry is to explain to the readers the causes and the effects the human population growth has on the environment.

The current number of humans existing on the Earth is around 6.9 billon. Scientists predict that the population will reach 7 billion in 2011.

The human population is accelerating as a very fast rate . It is growing exponentially and therefore the problem scientists face is determining when the Earth will reach its carrying capacity. According to the current human population graph, it has been predicted and calculated that even by 2025 the population of the Earth is going to continue growing at an amazing speed.

Human population's exponential growth (Source 6)

There are several causes which contribute to the increase of the human population over the last century. Technological advances, better health systems and sanitation, increased food production are some of the reasons why there are so many people on Earth today. In general, better and modernized lifestyle allowed humans to spread rapidly.

 Different theories regarding the Earth’s sustainability – Cornucopians vs. Cassandras

Regarding the human population growth, the Cornucopians believe that the human population, because of its technological advances will be able to overcome any hardship in the future. They also state that humans will never run out of resources because the more human there are on Earth the more they will be to utilize and acquire those very resources.

On the other hand, the Casandras also know as the “Doomsayers” predict that the Earth will not be able to sustain the human population growth for much longer. They state that the Earth can only support so many people and there are only so many resources available. They predict famine and and source depletion, which cannot be replaced in the future.

In our opinion, current society has a very serious problem. The human population’s exponential growth is causing many short – term and long – term problems for both the future and the present generations. Our stand on this issue is a balance between the views of the Cornucopians and the Casandras. We believe that in order to fix this problem we should work on reaching the Earth’s carrying capacity as soon as possible. However, we also believe that if our technology is used accordingly and if the resources are distributed equally we will be able to overcome this looming problem. (2)

Paul Ehlich

Paul Ehrlich (Source 1)

Paul Ehrlich (born 1932) is American biologist and professor atStanfordUniversity. He is also an entomologist who specializes in studies of butterflies. However he is more famous for releasing the controversial book “Population Bomb” in 1968.

Ehrlich’s predicted that rapid growth of human population will result in famine and a substantial increase in the global death rate.

Part of his predictions came true, seeing as how even in today’s world the continent ofAfricasuffered greatly from famine, malnourishment and impressive mortality rate. Moreover, the population has been growing even faster that Ehrlich had predicted. However some of his predictions didn’t come true. He predicted that some countries such asIndiaandBangladeshwill suffer from famine the most, however over the past few years their harvest has doubled and tripled. (1, 2, 3)

The IPAT Model

 I = P x A x T

 The IPAT equation describes the contribution of multiple factors to the human impact on the environment. Factors include:

  1. Population (P)
  2. Affluence (A)
  3. Technology (T).

Sometimes, sensitivity factor (S) is added to the equation so as to present the sensitivity of a given environment to the human impact. (2)

IPAT model applied in different countries

In today’s world, the rates of annual growth of the population vary from country to country. At this moment, the 2 leading countries in terms of the IPAT model areUSAandChina.

 USA (307,006,550 people)

In theUSA, the 2 dominant factors which contribute to its impact on the environment are the affluence and the technology. Scientists came to an amazing statistic which states that if the world consumed as much food as the American, Canadian, and Australian there would be only enough sources to feed 2.5 billion people. This fact This fact tells us a lot about the great impact theUSand its citizens have on the environment today.

China (1,332,460,000 people) 

In China, all 3 factors of the IPAT model (population, affluence, and technology) have impact on the environment.Chinahas the largest population on Earth and therefore they needed to solve the problem of rapid population increase in order to be able t feed and place its citizens. They introduced the controversial one child policy in 1978 which prevented the birth of millions of Chinese babies per year since. However,Chinastill hasn’t solved its problem of the large population’s influence on the environment.

Serbia (7,319,712 people)

 In our country, the mortality rate is higher than the natality rate. Therefore, the issueSerbianeeds to overcome is to increase the birth rate and decrease the mortality rate. It is a very important problem that needs to be dealt with as soon as possible because the nation’s population is decreasing more and more every year unless some drastic measures are taken. Additionally,Serbiais a developing country whose level of technological advancement is very low and whose citizens are not using the sources available adequately or equally.


 Hans Rosling

Hans Rosling (Source 5)


Hans Rosling (born 1948) is a Swedish medical doctor, statistician, professor, and public speaker. He has given many speeches and presentations around the world on issues such as economic development, agriculture, poverty and health in Africa, Asia, andLatin America. He uses a specific software called Trendalyzer to present today’s world situation in terms of population growth and famine.

The statement from his speech that impressed us the most was the explanation that all countries progress and expand in the same way in terms of both the economic and population growth. TheUSAbeing the country that is furthest ahead of most countries but the ones left behind such asIndia,China,Mexico, andBrazilare rapidly catching up. (4)

My partner in this assignment was Dina from the other group.


1. Tackles Cultural Evolution. “Population Bomb” (Dec 3, 2008). Retrieved May 7th, 2011 from

2. Withgott, J. & Brennan, S. (2010). Environment: The science behind the stories. Fourth Ed. San Francisco: Pearson Education.

3. Wikipedia. “Paul Ehrlich”. Retreived May 7th, 2011 from

4. Wikipedia. “Hans Rosling”. Retreived May 7th, 2011 from

5. Growth Through Technology. “Technology in Business Conference” (2007). Retrieved May 7th, 2011 from

6. Earth Orbit. “The national Conversation on Alternative Energy” (Oct 18, 2010). Retrieved May 7th, 2011  from