By Aditi Gupta
Abstract
Air pollution is slowing down global warming (with a little help from the ocean!). In the summers, if the sun shines down a little less than it should, thank air pollution-the aerosols we release into the atmosphere give clouds a power boost and helps them keep a little more heat out. But, the dense fog that weighs down during winters isn’t just dangerous to drive in, it’s equally (if not more) dangerous to breathe in. Wearing a mask might be your best bet this winter - the reason being that all that air pollution comes down along with the fog.
The Industrial Revolution was just the beginning and the global warming hiatus during the 20th century gave way to a steep incline in temperatures since the turn of the century. Three major reasons contributed to the decline, out of which we may be able to manipulate one-aerosols.
Aerosols are colloidal suspension of fine solid or liquid particles dispersed in air or gas. They have long been considered as atmospheric pollutants, made popular by the media during the late 20th century to refer to spray cans that released ozone-damaging CFCs. These particles are the main culprits of the ozone hole as they are found in the troposphere.
In the winter, aerosols grow to form polar stratospheric clouds, acting as the ideal platform for chemical reactions to take place, hence their harmful effect on the ozone layer. Barring their pernicious effects during the winters, they have been found doing some good too. Turns out, by burning fossil fuels, mankind has managed to somewhat detain the damage done for a short period of time!
The Cloud Albedo Effect
Scientists have observed that the aerosols, both natural and artificial, were causing a phenomenon called as the Cloud Albedo Effect. The effect is that for the same cloud water or ice content, more but smaller cloud particles can reflect more solar radiation, therefore causing a ‘cooling effect’.
Aerosols hold the power to change the composition and properties of clouds and are reflective in nature. The effect was noticed due to the several volcanic eruptions that occurred in the 20th century and the release of particles (natural & anthropogenic in origin) into the atmosphere. The dominant aerosol layer is formed by sulfur dioxide gas which converts into droplets of sulfuric acid in the stratosphere over the course of weeks or months. The sulfate particles have a life of about 3-5 days and do not absorb solar radiation.
According to NASA, as a direct effect, the aerosols scatter sunlight directly back into space. As an indirect effect, aerosols in the lower atmosphere can modify the size of cloud particles, changing how the clouds reflect and absorb sunlight, thereby affecting the Earth's energy budget [1]. Assisting the aerosols were the longer than usual solar minimum cycle, relatively low amounts of water vapor in the stratosphere and variability of the Earth’s natural climate, which helped transfer excess heat from the Earth’s surface into the deep ocean.
What’s Next?
Researchers have been investigating the case of the semi-helpful aerosols and are still looking for a way to exploit them by maximizing the potential they hold and minimizing environmental hazards.
The global warming hiatus is over and the 21st century needs to do something about it and fast. Although the ozone hole is beginning to heal, it is not enough to simply let it run its course.
With rising temperatures, developing nanotechnology which can effectively either replicate or utilize the already-present aerosols in a manner that doesn’t pose a hazard even during the cold winters.
Using climatic phenomena and enhancing them by adding a technological add-on is the key to solving many issues; global warming is just one of many. In fact, Eoin Colfer, author of the popular Artemis Fowl series, touches upon one such idea in one of his books. Through the protagonist, Artemis Fowl, he suggests engineering artificial & environmental-friendly ‘snowflakes’ which could reflect solar radiation and be distributed via clouds.
A low-key example of this is the shade ball-experiment that took place in L.A, 2015, where thousands of black plastic ‘shade balls’ were released into water bodies to cover the surface and hence prevent loss of gallons of water via evaporation. Although the court ordered the removal of these balls, federal rules mandate that all bodies of drinking water be covered and shade-balls have been replaced by floating covers; providing a more complete barrier to air contaminants and solar radiation.
The Earth needs our help and we need the Earth to survive! A breakthrough is coming; the question is will it come from scientists or students?
References
[1]Allen, Bob. (08/07/2017). Atmospheric Aerosols: What Are They, and Why Are They So Important? nasa.gov . https://www.nasa.gov/centers/langley/news/factsheets/Aerosols.html | Retrieved: (10/05/2018)