Assessing Ocean Acidification at Popular Tourist Islands

Before you book a post-pandemic vacation, learn about the current trends of major islands’ ocean climates.

It is heard almost every day that our planet is going through climate change with vast effects. One of those effects, due to increased carbon emissions, is an increase in ocean acidification. This process hurts marine wildlife, especially coral reef ecosystems, as it depletes key nutrients from the waters.

Nearly a third of carbon emissions get trapped in the ocean, which creates high levels of carbonic acid and thus starts the process of acidification¹. Acidity is measure on a pH scale of 0 to 14 (where 7 is neutral) and based on powers of 10. To see this process in real life, we can look at three popular islands: Hawaii, Bermuda, and the Canary Islands.

A historical trend of ocean pH levels around these islands show that all of their waters are becoming much more acidic over time even while being on opposite sides of the world. This can also be seen in increasing trends of ocean partial pressure of CO². The Canary Islands seem to have consistently high pH and pCO² levels, indicating that local variables might be adding onto global pollution.


It would be interesting to see if we can find correlations of these trends from within local economies. Looking at each island’s GDP over time, there are similar increases to each of the three locations.

We can then plot each of these GDP data against their corresponding ocean acidification. This will provide us with a general sense of the correlation between the two variables.

The first chart of Hawaii’s economic-acidification levels appears somewhat reminiscent of a Pareto efficiency curve. This would mean that acidity and economic fortune are both dependent upon each other and decrease when the other resource is increased. While this needs further statistical analysis to be proven, it does not seem to be the case for Bermuda and the Canary Islands. These plots decrease at a relatively linear pace, though, which still means that local GDP and pH levels are negatively correlated.


We can now dive deeper into local economies and key in on a major component: tourism. Using historical tourism data, we are able to plot yearly tourist volume against pH and pCO² levels.

If annual tourism is bad for the environment, we should see a negative trend on the pH graphs (top) and a positive trend on the pCO² graphs (bottom). This seems to be true for all destinations except for the Canary Islands. This Atlantic group of islands has an opposite correlation.

How could increased tourism be associated with low ocean acidification levels? It was seen earlier that GDP has relatively strong correlations with increased acidity. While I’m not an environmental scientist, there may be an explanation.

The Canary Islands are owned by Spain, which committed to the Kyoto protocol in 2003 for reducing CO² emissions. This caps the amount of development for the local economy. Although development of the island itself may have been halted, the tourism demand remained high on a yearly basis. Therefore, as we saw local CO² emissions decrease while GDP decreased, tourism continued to grow. This could be a factor in the Canary Islands’ unique environmental/economic situation.

Overall, though, tourism and increased production run counter to the local marine environment. So if you’re looking to travel to an island resort, please realize that you are likely contributing to increased acidity of their oceans, thus hurting the ecosystem that attracted you in the first place.


About the Author: Mike Doulong is a senior at the Wharton School of Business.

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