Climate Stories Part 3: We’re all in hot water - increased ocean temperatures

Mary Cozy — Extension Intern

This is the third in a series of seven blog posts that communicates about climate change through personal stories. Over the course of three months, UCSD student Caitlin Crowe interviewed seven long-term beach goers in San Diego County on their personal connections with climate change effects. In this post we cover increased ocean temperatures.

A sunset over Sunset Beach in Huntington Beach, CA. Image courtesy of project interviewees.

Average air temperatures on Earth are projected to increase by 5°F to 10°F by the end of the century, coupled with longer and more severe heat waves. The average global ocean temperature is also expected to increase by 1.8°F to 7.2°F in the same amount of time. Ocean temperatures are rising at an unprecedented rate with the five warmest years on record all happening since 2015, 2019 being the highest. With the increasingly humid weather that comes with warming trends, this past August has also brought record breaking ocean temperatures off of San Diego - 79.5 degrees F; a record that tied with one set just two years ago. 

Most of the long-time beach goers interviewed did not report seeing a trend in either direction in regards to ocean temperature, simply stating that the temperature changes a lot from year to year. One person noted, “Things that swimmers care about are water temperature and surf. Some years we get colder water than others, some winters stay warmer. It just comes and goes.” The two people who did notice a change spoke to the fact that they felt the water was warming. One said “The water temperature appears to be getting a little bit warmer. I remember a lot of surfing in the [19]50s, and the water temperature seems to be warmer nowadays…the temperature rarely drops below 60 [℉].” It’s not surprising that a majority of people wouldn’t notice an increase in ocean temperature, especially if they aren’t in the water every day at the same time of day. Ocean temperature change is a long-term trend and it can be hard to observe that trend within the daily and seasonal ups and downs. Some days are still going to be cooler or hotter. It's only when the data are plotted over time that a pattern can be observed.

Even though the change in ocean temperatures may seem small or slow, there are a lot of threats that come with this increase. Rising temperatures can threaten food security through the loss or shifting of marine fisheries and reduced fishing opportunities associated with fishery changes or warm-weather induced storms. It can also increase the prevalence of diseases, and contribute to more extreme weather events. What this will look like for most people is a loss in products from the oceans, whether that be food or otherwise, and a severe increase in food prices. 

Although there are still a lot of unknowns about the direct impacts of ocean temperature increases within both science and in discourse for those who are not climate scientists, one thing is certain- its ramifications and consequences could end up being very severe. Marine heat waves are happening much more frequently than they ever have in the past and there is a need to get better about informing the public and preparing them for what’s to come.

There are many resources currently available for individuals to visualize trends in changing ocean temperatures such as IUCN’s Annual Ocean Warming Report and the US EPA. The best way for individuals to help mitigate the impacts of rising ocean temperatures is to begin researching and understanding these rising ocean temperature trends and the potential impacts they may have. Additionally, individuals can contribute to healthy oceans by being active in restoration and enhancement, including clean-up, of marine and coastal ecosystems. You can also encourage local, state and federal representatives to support science-based, collaborative decision-making processes surrounding the responsible management of our ocean’s resources. More than ever, it will be crucial to balance the protection and the use of resources if we want to ensure access to healthy ecosystems and food now and for generations to come.


IUCN’S Ocean warming Report

Climate Change Indicators: Sea Surface Temperature | US EPA

California 4th Climate Assessment 

San Diego 4th Climate Assessment