Month: January 2015

Save our water and food supply!

Fast food

Solar dimming can be a double-edged sword. It is essential for life on Earth because it maintains the planet’s surface temperature, mitigates the initial effects of global warming, and provides plants with the appropriate amount of solar radiation for important processes like photosynthesis. However, too much of the phenomenon can bring unfortunate events like droughts.

In recent news at the Northern Hemisphere, air pollution caused by aerosols was believed to have resulted in an increase in river flow. The pollutants prevent proper sunlight form reaching the Earth and thus reduced evaporation and rise in river flow by as much as 25% (Passary, 2015). The study was led by Nicola Gedney from the British Met Office and it found that the impacts mostly occurred in Europe’s industrial regions. This corresponds with the previous blog post on urbanization and it being a main contributor of aerosol pollutants.

Going back to the effects of solar dimming, its reversal could result in a reduction in river water level due to the fall in river flows. This in turn produces a cause of concern for estimation of future water supplies. As mentioned by Gedney, “With water shortages likely to be one of the biggest impacts of climate change in the future, these findings are important in making projections for the future” (Passary, 2015).

From the above issue we can see that global dimming, albeit not a well-known issue, ties in with the security of our water supplies. This thus stresses on the importance of understanding it and its interactions with global warming so that adequate solutions can be proposed and carried out. Mitigation and adaptation measures to ensure food security need to be paid close attention to too (FAO, 2012) since weather ad climate are crucial determinants of the issue.

References

FAO (2012). Climate change adaptation and mitigation: Challenges and opportunities in the food sector. Food And Agriculture Organization Of The United Nations.

Passary, S. (2015). Air pollution increases river flow in Northern Hemisphere: StudyTech Times. Retrieved 30 January 2015, from http://www.techtimes.com/articles/17348/20141008/air-pollution-increases-river-flow-in-northern-hemisphere-study.htm

Urbanization’s Contribution to Global Dimming

NY Urban

Global dimming is said to be one of the most prominent examples indicative of athropogenic disturbances. This phenomenon is mostly dominant in large urban sites as studies have shown that large cities with a population greater than 0.1 million, when compared to sparsely populated sites, are in general steady sources of anthropogenic pollutants like fossil fuels, nitrates, sulfates, and soot (Alpert, 2005). The paper by Alpert (2005) aims to investigate if global dimming is a local or global phenomenon.

However, I feel that urban development produces other effects too that can contribute to the changes in solar radiation and it is not solely the fault of anthropogenic aerosols. Some examples include the urban heat island effect, deforestation, and changes in surface albedo. Moreover, people tend to settle near coastal areas which further contribute to the uncertainty of the study.

(3) rural vs urban pop

Figure 1. (World Urbanization Prospects, 2014)

The above figure demonstrates the varying levels of urbanization across regions. Nevertheless, they have one thing in common and that is that the urban population is increasing. Over the decades, the level of urbanization is expected to increase in all regions with Africa and Asia doing so at a faster rate than the rest.

Hence, in my opinion, it is not so much an issue of whether global dimming is a global or local phenomenon because with most parts of the world catching up with the trend on urbanization, it will soon be a global concern.

References

Alpert, P. (2005). Global dimming or local dimming?: Effect of urbanization on sunlight availability. Geophysical Research Letters32(17).

World Urbanization Prospects. (2014). World Urbanization Prospects, the 2014 revision. Retrieved 23 January 2015, from http://esa.un.org/unpd/wup/Highlights/WUP2014-Highlights.pdf

New Aerosol Study

aerosol study

I came across this article that reveals a possibility of countering the natural aerosol emissions with man-made ones. The study, published in Proceedings of the National Academy of Sciences, was conducted by Professor Sally Ng from the School of Chemical and Biomolecular Engineering, her students, as well as researchers from institutions throughout the Southeast. The natural emissions from trees that undergo oxidation to form aerosols and they can then interact with the anthropogenic emissions, eventually releasing even more aerosols in the environment.

The study then suggests a solution to this problem by using the knowledge of a strong correlation between aerosols and carbon monoxide (a man-made emission) as well as the fact that most aerosols originate from organic sources rather than directly from vehicles and industries. In the paper, they explain “the chemical mechanisms by which man-made pollutants cause greater production of organic aerosols, effectively solving the paradox” (Marino, 2015).

Such studies on pollutants are particularly important for understanding the climate and human health at a greater depth. Aerosols can be beneficial in cooling our environment, especially with global warming today, but it is seen as harmful according to the World Health Organization because it is classified as carcinogenic. This demonstrates that there is a trade-off when using aerosols to counter the effects of global warming since it may cause more damage to human health.

Even though we should not be too complacent and must still recognize the fact that anthropogenic emissions of aerosols have greatly distorted the mechanisms of natural emissions today. This thus creates an imbalance that we should aim to remove, as mentioned in my first blog post. There is always a threshold for all things and I strongly feel that once that threshold is crossed, the ability to live comfortably as before would be compromised.

References
Marino, K. (2015). Professor Ng presents new aerosol study. Technique. Retrieved 22 January 2015, from http://nique.net/life/2015/01/09/professor-ng-presents-new-aerosol-study/

What is Global Dimming?

Global dimming is the opposite of global warming. It is defined as the reduced amounts of solar radiation reaching the surface of the Earth. When we put it that way, by right, global dimming should be seen as a good thing to us since it counters the warming effects. However, upon more research, this seemingly ‘helpful’ environmental phenomenon has actually caused devastating effects on both the living and the environment.

How is this so? Global dimming is caused mainly by the by-products of burning fossil fuels, and an example would be aerosols. They reflect sunlight away from the Earth’s surface and hence decreases the amount of solar radiation entering, producing a cooling effect. This effect has caused the water in the northern hemisphere to turn colder, leading to a slower evaporation rate and lesser water droplet generation. With that, there would thence be many fewer occasions of rainfall, resulting in droughts and famines. An example would be the situation in Sahel in sub-Saharan Africa during the 1970s where thousands of people suffered during the drought due to global dimming (Kukreja, 2015).

Today, the concern of this environmental issue falls more on Asian monsoons where half of the world’s annual rainfall derive from. The decrease in solar radiation can also have a huge impact on the productivity of plants.

Since global dimming counteracts the effects of global warming, actions that drastically impact any one of them such that there is an imbalance could distort global temperatures which would then spell disaster. Hence, attempts to maintain, or restore, the harmony between global dimming and warming should aim to reduce emissions of both greenhouse gases as well as particulate matter.

References
Kukreja, R. (2015). What is Global Dimming?. Conserve Energy Future. Retrieved 18 January 2015, from http://www.conserve-energy-future.com/causes-and-effects-of-global-dimming.php#sthash.a76HGeRr.dpuf

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