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Cycles Upon Cycles: The Mechanisms of Climate Change

Author: Ellie Wang

Editors: Rachel Chen, Eric Lin, and Emily Yu

Artist: Alvina Zheng

You may have learned that climate change is caused by the greenhouse effect, which is the process in which various greenhouse gases in the atmosphere trap heat near the Earth’s surface. Greenhouse gases are essential to keeping the planet warm enough for life; without carbon dioxide in the atmosphere, Earth’s global temperature would decrease by about 33°C, or 59°F. However, since the Industrial Revolution, humans have been releasing an excessive amount of these gases into the atmosphere by using fossil fuels. As a result, the earth is warming at an unprecedented level, deviating from Earth’s natural temperature cycle. But climate change is complex; carbon dioxide is not the only contributing factor to global warming, nor is global warming the only outcome of excessive carbon dioxide.

While carbon dioxide is the most commonly known greenhouse gas, there is another that also poses a significant threat: water vapor. Although it is not the main cause of global warming, water vapor is responsible for approximately half of the Earth’s greenhouse effect. The Clausius-Clapeyron relationship dictates that because the vapor pressure of liquids will exponentially increase as the temperature rises, more water vapor will enter the atmosphere. This is because a higher vapor pressure makes it easier for more water molecules to overcome the intermolecular forces that hold them in a liquid phase to instead become a gas and enter the atmosphere. The addition of water vapor in the atmosphere sets off a greater greenhouse effect, thus triggering a positive feedback loop in which more vapor will be released into the air. Thus, water vapor amplifies the greenhouse effect caused by carbon dioxide, increasing the impact of climate change.

Greenhouse gases also cause more than just global temperature changes. Carbon dioxide is unique from other greenhouse gases in that it exists not only in the atmosphere but also on land and in the ocean. The effects it has upon the ocean in particular cannot be overlooked. 25% of all carbon dioxide emissions are absorbed by the ocean, greatly reducing the severity of global warming at the cost of the ocean’s acidity. When carbon dioxide dissolves into water, it undergoes a chemical reaction that releases the H atoms from H2O atoms as H+ ions. The H+ ions increase the acidity of the ocean, as well as decrease the number of carbonate ions through bonding. Shellfish, crustaceans, and coral require carbonate ions in order to build their shells, exoskeletons, and skeletons. The decrease in this resource forces these calcifying organisms to exert more energy to build their shells, threatening their survival.

These examples merely scratch the surface of the climate crisis. The more informed people are about the complexities of climate change, the better we can understand and take action against the human activities that are causing it. 


P.S.: (If you want to learn some more about the oceanic effects of climate change, read my article on the effects of slowing ocean currents in ScienceHolic’s Winter 2023 Edition, pages 38-39).

 

Citations:

Buis, Alan. “Steamy Relationships: How Atmospheric Water Vapor Amplifies Earth'S

Greenhouse Effect.” Climate Change: Vital Signs of the Planet, 22 Aug. 2022,

“FAQ: What Is the Greenhouse Effect?” Climate Change: Vital Signs of the Planet,

Libretexts. “Clausius-Clapeyron Equation.” Chemistry LibreTexts, 24 Feb. 2023,

United Nations. “The Ocean – the World’s Greatest Ally Against Climate Change | United

What Is Ocean Acidification? oceanservice.noaa.gov/facts/acidification.html.

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