CA - Gary Griggs, Our Ocean Backyard | Ocean warming raises concerns

Living along the coast next to the Pacific Ocean provides us with a temperature buffer or moderating effect. Yet we have had snow on the beach in Santa Cruz on several occasions and also had some very sweltering days here.

The hottest day ever recorded in Santa Cruz took place on Aug. 1, 1900, when the thermometer hit 108 degrees. But the warmest continuous spell took place in late June 1976, in the middle what was our most extreme two-year drought. On June 23, the temperature reached 100 degrees, and for the next five days, the thermometers hit 106, 105, 103, 105 and then cooled slightly to 103 degrees on June 28. This is not typical or normal, but as the planet continues to warm, these temperatures will likely occur more frequently.

While the offshore ocean acts as our natural air conditioner, the oceans are also heating up. Two weeks ago, a new study reported that the surface temperatures of the world’s oceans reached their warmest levels in modern history this year, exceeding climate forecasts.

These increasing temperatures, particularly this spring, are concerning the scientists who study ocean warming and global climate. The ocean has been a major recipient of the huge amounts of carbon dioxide generated by humans over the past 150 or so years since the Industrial Revolution. Ocean water has absorbed about 90% of the increased heat with the top few meters of the ocean storing as much heat as the Earth’s entire atmosphere.


Gary Griggs is a Distinguished Professor of Earth and Planetary Sciences at UC Santa Cruz. He can be reached at For past Ocean Backyard columns, visit

In 2021, global emissions of carbon dioxide from fossil fuel combustion, as well as from the production of cement and the burning of vegetation, reached 40.7 billion tons and were projected to rise nearly 1% more in 2022. On the positive side, the United States has made some progress in actually decreasing our carbon dioxide emissions slightly, cutting them back by 8% from 1990 to 2020. It’s important to celebrate our progress, but in 2021, despite having just 4.5% of the global population, we emitted 14% of the planet’s carbon dioxide.

We have a whole lot more to do in order to reduce our emissions, and in the meantime, as each day and month goes by, the oceans are continuing to get warmer. You might ask – wouldn’t that be a good thing? It would seem so around Monterey Bay where I’m certain that anyone who spends any time at all in the ocean here would be delighted to have warmer water.

This week the water off Santa Cruz has been about 52 degrees, and at its warmest, in late summer, it can get up to about 66 degrees. The generally accepted range in water temperatures for comfortable ocean swimming, however, is about 77 to 82 degrees. We aren’t even close.

Most marine life is adjusted to the ocean temperatures they live in. Marine mammals such as whales, seals, sea lions and dolphins, for example, have a healthy thickness of blubber insulting them from cold water. Sea otters do not, but they have an important coating of very fine fur that, as long as it’s clean, can hold air that insulates them. For most of us, however, we don’t have either.

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