The purpose of this post is to provide some clues of the population growth impact on the environment.

Background information.

Nowadays the total human population on the Earth is currently estimated to be 6.92 billion. Human population is increasing with tremendous growth rate and scientists believed that in 50 years the number will reach to 10 billion as we can see on the graph below. So with the limited carrying capacity of the earth the problem of the overpopulation is obviously unavoidable. Carrying capacity is the maximum population size of the species that the environment can sustain.


Causes that increase the human population.

The basic factors that can determine the population growth are the birth and immigration rates that increase the size of the population and on the other side the death and emigration rates that decrease the size. So an easy way to calculate these rates is the specific formula:

Population Growth = Birth rates – Death rates + Immigration – Emigration.

(PG=B-D+I-E)                                                                                               (2)

Population growth theories.

Cornucopians are futurist who believe that human through the continued progress and the advances in technology will manage to face the problem of the over-population. Fundamentally they believe that there is enough matter and energy on the Earth to provide for the estimated peak population of about 9.22 billion in 2075.

Cassandras on the other side they believe that the overpopulation of the earth in the future will bring the world to an end. The earth will not be able to sustain the size of the population and unavoidably will have the extinction of the natural resources such as food and water and so on the end of the human species.

Now as far as my opinion, I believe that indeed humanity will face the problem of the overpopulation in the future and this will yield two different problems. The first is the matter of extinction of the natural sources and the second is the matter of extinction of space. So I think the problem of natural sources will be overcome with the rapidly growth of the technology. For example the creation of artificial products without the use of the natural materials such as pills that will replace the need of food and water by the human. But on the other side I believe that the matter of space extinction on the earth can be a vital problem in the future. The uncontrolled population growth will limited the space of living for every individual. Even nowadays we have extremely overcrowded cities that people face the problem of limited space and this will be even worst with the continuous population growth.

Paul Ehrlich.

Paul Ralph Ehrlich is an American biologist and educator who is the Bing Professor of Population Studies in the department of Biological Sciences at Stanford University and president of Stanford’s Center for Conservation Biology. He is known better as an ecologist and a demographer, specifically for his warnings about unrestricted population growth and limited resources. Ehrlich became well-known after publication of his controversial 1968 book The Population Bomb. (3) Ehrlich through his book focused to the mass starvation of humans in the 1970s and 1980s due to overpopulation, and advocated immediate action to limit population growth. The book has been criticized in recent decades for its alarmist tone and inaccurate predictions. Ehrlich stand by the basic ideas in the book, stating in 2009 that “perhaps the most serious flaw in The Bomb was that it was much too optimistic about the future” and believe that it achieved their goals because “it alerted people to the importance of environmental issues and brought human numbers into the debate on the human future.” (4)  However Ehrlich made a number of specific predictions that did not come to pass, for which he have received criticism. He have acknowledged that some predictions were incorrect but maintain that his general argument remains intact, that his predictions were merely illustrative, that his warnings caused preventive action, or that many of his predictions may yet come true.

(5)                                                                                                                                        (6)

     <–   The Author


The Book  –>




The I PAT equation.

I=PAT is the lettering of a formula put forward to describe the impact of human activity on the environment.

I = P × A × T

In words:

Human Impact (I) on the environment equals the product of P= Population, A= Affluence, T= Technology. This describes how our growing population, affluence, and technology contribute toward our environmental impact.

The equation was developed in the 1970s during the course of a debate between Barry Commoner, Paul R. Ehrlich and John Holdren. Commoner argued that environmental impacts in the United States were caused primarily by changes in its production technology following World War II, while Ehrlich and Holdren argued that all three factors were important and emphasized in particular the role of population growth. The equation can aid in understanding some of the factors affecting human impacts on the environment. (7)

How The  IPAT equation applies in various countries.


United States – The US with a population around 300 millions has a huge impact on the environment. The two major factors of the US is technology and affluence. By having these two factors on the highest grade, a developed country like the US can determine and influence the formation of the environment. Especially if the country’s consumption rate is as big as the US.

China – China being the most populated country in the world, having more than 1.4 billions, it is obvious that can affect in a big percentage the environment. China faces the problem of the overpopulation and that’s why is used strict governmental policies to reduce the growth of the population. The one child policy that China uses is an effective way to stabilize and control the population growth. So despite the huge technological growth that China has, the decrease of the population will eventually decrease China’s impact on the environment.

Greece – Greece’s population reaches around to 11 billion and in connection to a low affluence and even lower technological progress means that the impact of the country on the environment is balance between the average   and under the average rate.



Hans Rosling.

Hans Rosling is a Swedish medical doctor, academic, statistician and public speaker. He is Professor of International Health at Karolinska Institute and co-founder and chairman of the Gapminder Foundation, which developed the Trendalyzer software system. Rosling’s research has also focused on different links between economic development, agriculture, poverty and health in Africa, Asia and Latin America. He has been health adviser to WHO, UNICEF and several aid agencies. Also as chairman of Karolinska International Research and Training Committee (1998–2004) he started health research collaborations with universities in Asia, Africa, the Middle East and Latin America. He started new courses on Global Health and co-authored a textbook on Global Health that promotes a fact-based world view. (8)

Hans Rosling using the Trendalyzer software.

Hans Rosling using the Trendalyzer software. (9)

However it is interesting also to mention how Rosling presents and mixed many factors that contribute to the development of a country such as of economy, health and education.Rosling also aim on the interrelation of the developing countries with the developed and how these different economies are set up to achieve the specific progress. Such as the example of China that first developed a health policy before the economical growth that china has nowadays.