The impact of climate change on Puerto Rico — The basics
Retired engineer Cade Johnson explains related challenges for the island.
This is the first in a series of articles providing readers with an overview of a complex topic, much in the news, but that remains dauntingly broad and laden with inhuman immensities. We can be heartened to know that the government of Puerto Rico has been diligently considering climate change.
In April 2024, the Department of Natural and Environmental Resources (DRNA, in Spanish) released an updated draft report of risk assessments and recommendations, referred to as the “PR Climate Plan.” Enthusiasts of this topic can find these articles on the department’s website (in Spanish).
Essentially, humanity’s use of fossil fuels, or carbon that was once part of the biosphere that became fossilized and stored in the Earth’s crust, has released large quantities of carbon dioxide into the atmosphere over a relatively short amount of time. This excess carbon dioxide slows the rate of heat loss to space, raising the temperature of the atmosphere and increasing its moisture content (which further raises the temperature).
The United Nations Intergovernmental Panel on Climate Change (IPCC) has issued a series of reports since 1990 predicting how the climate would respond to the surge in carbon dioxide and how humanity could respond to the situation to reduce the consequences. While the climate change projections have increasingly proven accurate, the proposed response scenarios have not been widely implemented, and the situation has steadily worsened.
Climate change caused by greenhouse heating — the trapping of solar energy by carbon dioxide and water vapor — is a global issue that manifests in varied ways in different places, such as changing atmospheric and ocean circulations. The PR Climate Plan describes in great detail the impacts we can anticipate in Puerto Rico, including temperature extremes, changes in rainfall, increased storm frequency, rising sea levels, and acidification and heating of the ocean. Let’s look at the details.
The average temperature in Puerto Rico is slowly rising — about 1 degree Celsius (2 degrees Fahrenheit) every 50 years. But extreme heat events, when temperatures hover near or exceed the historic maximums, have roughly doubled over the past 50 years. These are events.
Along with rising temperatures, we are predicted to experience more severe droughts as well as prolonged and heavier rains. Just this past year, most of the island began 2024 in drought conditions and ended with above-average rainfall.
As with last year, over the past 30 years, annual average rainfall has decreased in several parts of the island while increasing in others. But overall, the trend points to gradually less rainfall in the future — how much less depends on how the world reacts to the climate crisis.
In the past 25 years, there has been a slight increase in the number of hurricanes and their lesser cousins, tropical storms and depressions, near Puerto Rico. This is consistent with climatologists’ predictions that higher sea surface temperatures and greater moisture content in the air contribute to more frequent and intense hurricanes.
So far, we have “gained” less than one additional hurricane per year on average, which is not too surprising because the Caribbean sea surface temperature has risen by only about 1°C (just like the average air temperature in Puerto Rico — not a coincidence!). Before going on, pause to consider this immense feat: Humanity has managed to warm up the entire ocean! And we are not done — it will get warmer and warm faster.
This same warming that increases large weather systems is also increasing the number of tornadoes, particularly along the north and west coasts of Puerto Rico. In the 20th century, tornadoes were virtually unheard of in Puerto Rico but one per year is no longer surprising.
Changes in the weather are not the only consequence of higher carbon dioxide in the atmosphere. In the next article, we will take up other effects of climate change and begin to explore how Puerto Rico can adapt to them.
Author Cade Johnson is a retired chemical engineer (Georgia Tech ’83) and a volunteer with the 501(c)(3) Exaquest Carbon in California. He has been involved with various climate response organizations for nearly 10 years and he has lived in the Caribbean since 2001 — currently residing in Naranjito, Puerto Rico. Send comments to [email protected].
Paragraph 6 ending “These are events.” defining extreme temperature events, should be “These are events when the temperature hovers near, or exceeds the historic maximum.”
Great article! Can’t wait to see the rest of the series!