Archive for the ‘Assignment 7’ Category

The purpose of this post is to raise our awareness on the issue of population growth and its impact on Earth, but also to familiarize us with the content explained in class and the use of formulas such as the IPAT model.

It is not a secret that the human population has increased with an extremely high rate during the last decades. Some people don’t see any problems and are sure that Earth can support a lot more people. However, others believe that the human population should be strictly controlled or it could lead to catastrophic outcomes.

Fig. 1: The graph above represents the human population growth. Source: (1)

According to the U.S. Census Bureau the current human population already exceeds 6.18 billion people and is steadily moving to 7 billion. This means that we are overestimating Earth’s carrying capacity by around 30%. (2) Some of the causes that resulted in rapid population growth are the development of science and technology, increase in food production and distribution, improvements in public health and disease conquest. The use of technology resulted in expansion of food production and distribution. Besides, the access to safe drinking water and the pressure to provide adequate hosing led to progress in public health. Moreover, scientists have found ways to prevent and cure numerous diseases and reduced the death rate. (3)  All this factors, altogether, have resulted in the increase of the world population.

There are two different views on the issue of population growth.  The first one, the Cassandras’ view, predicts doom for the Earth. Most Cassandras agree with Ehrlich’s view, who” predicted that population growth would unleash famine and conflict that would consume civilization by the end of 20th century.” This didn’t happen the way he predicted, but there is some truth in what he said. Although our civilization was not destroyed, population growth has contributed to famine, disease and conflict, but whether this will lead to complete destruction is yet to be seen.
The second view on this issue, which opposes the Cassandras’ view, is the Cournucopians’ view. Many of the people who hold this view are economists, and they believe that population growth does not pose any threats if new resources can be found or created to replace the depleted ones.(4)

In my opinion the rapid growth of human population is clearly a source of problems and is a threat for the existence of our civilization. It is known that the amount of resources is limited and it is obvious that we will face serious problems if we don’t apply certain methods to reduce the growth of the human population. The growth will certainly come to an end either by the destruction of nature and the society or by right decisions that will stop the rapid growth and stabilize the population.  

Paul Ehrlich and the IPAT model

Picture 1: Paul Ehrlich


Paul Ehrlich is a biologist and a professor at Stanford University. In 1968 he wrote the book “The Population Bomb”, which predicted the end of civilization by the end of 20th century. He and another professor, John Holdren of Harvard University, are also known for a formula called the IPAT. This formula is a way to calculate the impact of population and other factors on the environment. “The IPAT model represents how our total impact (I) on the environment results from the interaction among population (P), affluence (A), and technology (T). (6)

In his book, “The Population Bomb”, Paul Ehrlich predicted that population growth would lead to famine and war, which would finally bring our civilization to an end. As population growth continued in high rates, he predicted that, more resources would be depleted, and there would be less food for the people. Less food would then lead to starvation, and this could lead to war. All of these combined together, would finally lead to the destruction of our society. Although, on the one hand, his predictions that our society would be destructed by the end of the 20th century did not come true in the complete sense, during the end of the 20th century and the beginning of 21st century many parts of the world were faced with famine, disease and war, which created many problems for the world as a whole. On the other hand, during these years our world was faced with a very rapid growth in technology and the Green Revolution happened, which probably made it possible for humans to escape the doom predicted by Ehrlich, or maybe just lengthen this process.

Taking into consideration the IPAT model, The United States of America have a very big influence on Earth’s environment as they have a very advanced technology and high affluence. In addition to this, even though the US’ population is not as big as China’s or India’s it is still very big and has a big influence in the environment.
Being the country with the highest population, China, without doubt has a very big impact on our Earth. The other thing contributing to these high impact levels is its rapid growth of affluence and eventually the use of technology nowadays contributes to this impact.
Finally, both Armenia and Kosovo, being countries with a population of about 3.2 and 2.5 million respectively, having small amounts of production (very few, small factories) and not very advanced technology and its use, have a much smaller impact on the environment compared to bigger, more developed countries.

Another scientist that deals with population growth is Hans Rosling. He is a professor at the Karolinska Institute in Sweden, and is the co-founder of Gapminder Foundation. What we liked more about his presentation is his method of presenting the information using the moving bubbles, which allowed us to better understand everything he was talking about. Another thing that caught our attention is his statement about using the term “developing countries”, when today some of them are even more developed that the so-called “developed countries”.

Fig. 2: Gapminder World Chart (2006) Source: (7)

Video 1: A short video explaining population growth: Source: (8)


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(1) Agrilandsales,“World Population Growth”(2008),Retrieved May 9,2011 from

(2) International Programs. (n.d.). Census Bureau Home Page. Retrieved May 9, 2011, from

(3) Kinder, C. (n.d.). The Population Explosion: Causes and Consequences. Yale University. Retrieved May 9, 2011, from

(4)   Withgott, J., & Brennan, S. R. (2008). Environment: the science behind the stories. (4th ed.). San Francisco: Pearson Benjamin Cummings.

(5) Keim, B. (2008). Paul Ehrlich. Retrieved May 9, 2011 from

(6)  Withgott, J., & Brennan, S. R. (2008). Environment: the science behind the stories. (4th ed.). San Francisco: Pearson Benjamin Cummings.

(7) N.d. (2008). Gapminder World Chart 2006. Retrieved May 9, 2011 from

(8)  EconomistMagazine,“The seventh billion”(Nov 25,2010),Retrieved May 9, 2011, from