New Studies on Urban Heat Island Effect

by SRZaouali on November 27, 2015 - 11:42pm

          In the article “Urban 'Heat Island' Effect is Only a Small Contributor to Global Warming, and White Roofs Don't Help to Solve the Problem, say Stanford Researchers” by Louis Bergeron, the author presents a new perspective to urban development. The purpose of this article is to establish a relation between urban heat islands and global warming. Based on new scientific researches done by Mark Jacobson, a professor of civil and environmental engineering who led the study, it was found that urban heat islands only had a minor impact on the overall global warming. His research was the first to demonstrate the consequences of urban heat island effect on sea ice, atmospheric stability, global sea-surface temperature, gas concentrations, precipitation and clouds. He characterized urban surface around the world at a resolution of one kilometer, making his simulation extremely detailed and globally comprehensive.

          However, the author highlights an important point to retain concerning Jacobson’s study. Even if the researcher suggests that urban heat island is only a minor contribution to global warming, he thinks that it is still important to reduce the impacts of heat islands to slow down the rise of global temperature.   

          Bergeron defines the urban heat island effect, an important concept of urbanisation as a phenomena where soil and vegetation are replaced by sidewalks, paved roads and buildings. Paving prevents evaporation of water from the soil and plant leaves. Since evaporation is a cooling process, reducing evaporation warms cities. Additionally, the darker colors of some roads and buildings absorb more sunlight, heating a city further. However, based on Jacobson’s study, the author suggests that painting roofs a reflective white is not a solution for reducing the impacts of urban heat islands. Instead, it cools urban surfaces. That is, the author concludes by suggesting that new alternatives to reduce those increase of temperature need to be found.  

         I found this article particularly interesting because it brings up a different perspective on the impacts of urbanisation. As mentioned in the article, people usually believe that when there is an urban heat island, it necessarily has significant impacts on global warming. However, based on studies, the author challenges believes on this phenomena of urbanisation. Therefore, I think it would be interesting to further develop the impacts of those urban heat islands and see how the increase in temperature created by those areas can be reduced. 

Bergeron, L. (2011, October 19). Urban 'Heat Island' Effect is Only a Small Contributor to Global Warming, and White Roofs Don't Help to Solve the Problem, say Stanford Researchers. Standford News. Retrieved from


While reading your first paragraph I was already thinking to myself "every little bit counts!!" and you said exactly that in your second paragraph. I think that this article was really interesting and I'm glad that you shared it. living in canada, we only experience heat for a few months, and even then it is rarely extreme. many other countries around the world experience this extreme heat every single day. having buildings that reflect sunlight back is very crucial in order to keep cool year round. while you mention that these reflective buildings are not the solution that the world needs, i would like to hear your thoughts on what solutions might be feasible? in the article i found ( it mentions green roofs and the need for vegetation.

Great post! Really interesting as I think that this is an important issue as more and more cities are being erected in developing countries. New, initiative ideas need to be created and implemented in order to negate the negative effects of urban heat islands. All data shows that temperatures decrease significantly when vegetation is present. Permalink offered a great solution which is green roofs. This would keep the urban areas cooler as the vegetation absorbs some solar radiation. Also, the implementation of trees and other forms of vegetation on the ground would be good options. This could be done by incorporating more parks into certain cities, or creating suburban residential communities throughout the city to increase the amount of vegetation. The urban sprawl and density of the city, as well as the use of 'green space' can support the ideas that were stated above.


Interesting post! I only knew a little bit about urban heat islands before reading your article and you now I am extremely curious to know more about them. I also have the same opinion as you do about those urban heat islands. Even though they are not a major factor of global warming, it doesn't mean that we have to ignore them. I thought that a way to solve this issue would to paint all the building roofs white, but after reading more about the subject, I found out that if all the roofs in urban areas were painted white, it would actually increase global warming. "The increased sunlight reflected back into the atmosphere by white roofs in turn increased absorption of light by dark pollutants such as black carbon, which further increased heating of the atmosphere."

I strongly believe that we still need to find a solution in order to solve the urban heat island effect on global warming.


Quite nice! You say that people tend to believe that as soon as there is an urban heat island it means that it is going to have significant impact on global warming. It is true, but if we were to regroup all of the cities and their urban area we would find this extremely big. You said that the author of your article mentions that every bit counts. He is totally right! We need to address a problem as soon as it is identified. If we do not do so, it will grow and grow and then it will become an unsolvable problem. We do not want this to happen. I believe that sensitizing people to the situation is required in that case. We need to stop urban heat island growth. I do not understand why painting the roof with reflective paint would not work though. It is quite sad that the author did not mention why.

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