Environmental hot water? Local ocean temperatures hitting historic highs


A wave crashes along the Encinitas coast. (Photo by Ian McDonnell, iStock Getty Images)

On Aug. 2, Scripps Institution of Oceanography measured the sea-surface temperature of local waters at 78.6 degrees, which was the highest temperature taken in the 102 years since the institute started taking measurements.

The last time the sea was that warm was in 1931, when the temperature hit 78.4 degrees.

The new record, taken at Scripps Pier in La Jolla, was then broken again a day later on Aug. 3 at 78.8 degrees and continued to rise to around 79 degrees on Aug. 7.

La Jolla hasn’t been the only area to witness such ocean temperatures this month.

Some beaches, such as Solana Beach, recorded water temperatures up to 81 degrees, according to reports, leading the area’s popular coastlines to be even busier than most observers have seen in recent memory.

“It has definitely been, probably, the busiest summer I can remember in my lifeguarding career,” said Jason Shook, the marine safety captain for Solana Beach who has been a lifeguard for 24 years.

“I would definitely say that the water temp has brought more people to the beaches,” said Larry Giles, the marine safety captain for the city of Encinitas.

Giles then referenced a beach counter system that tracked a record high of about 25,000 people who came to Encinitas beaches in one day.

Shook and Giles also said that the warm water and air temperatures have even contributed to increasing visitors’ “duration of usage” of the beach, meaning that beachgoers are getting to the beach earlier and staying longer into the early night.

Unusually warm coastal water: Anomaly or trend?

Why are these ocean water temperatures so high? How long are they going to last? How often are they going to arrive? How could they affect future storms and climate?

Art Miller, the head of the Oceans and Atmospheric section of Scripps Institution, said that the warm water temperatures are partially due to a high pressure system that is blocking northwesterly winds that cause upwelling, or the mixing of the cooler deep water with the warmer water at the surface.

He said that this warm water is only a thin layer of 10 to 30 meters deep “just sitting out there,” and even though there is colder water underneath, it is “just not mixing up.”

Miller said that “it’s not too surprising that we start to see more and more of these events” where the region experiences a sustained period of high temperatures.

What is abnormal is how long this period has continued, as “it is the preponderance” of the temperatures over the “past weeks, months and decades” that matter more than one record-breaking temperature.

The recent warm temperatures also brought the topic of climate change into the discussion.

Miller said that the modes of natural variability that are known to cause these fluctuations in temperature, such as El Niño, are being replaced by rising greenhouse gases that force global warming. This particular warming in San Diego is a “regional meteorological event,” however.

In fact, Santa Barbara’s water temperatures are actually cooler than normal, “so it is really a local effect,” Miller said.

This does not mean that climate change is not connected to this trend, as Miller pointed out that natural variability is rising on a background that is slowly warming.

Eventually, this rise will shift the means where “typical warm events will be a little bit warmer” and “colder events will be warmer, too,” and that there will be more anomalous warm events like the one the region is experiencing now, and they will become more intense.

Tropical storm systems: A more serious threat?

Could the recent warmer ocean water lead hurricanes to wander up the coast to San Diego?

Hurricanes are exceedingly rare in California, and San Diego specifically, but there is evidence of a hurricane that hit the region in 1858, which caused property damage.

Miller and National Weather Service Meteorologist Samantha Connolly concur that the chances of a hurricane coming up the coast and making landfall in San Diego are “vanishingly small” due to the fact that hurricanes from Central America would need intense winds and even warmer water than what the region is seeing now, the kind of warm water that reaches deeper down in order to sustain such a storm.

The hurricane that hit San Diego in 1858 was not really a hurricane like that seen to the south and did not make direct landfall, according to Miller.

The one caveat to this is that even though San Diego’s chances of seeing a hurricane are small, the region’s increasingly warmer periods do increase the risks of feeling other effects of storms to the south — more moisture, humidity and rain rather than destruction.

The potential negative effects of this warm water could extend to the local food web as the lack of upwelling could deprive phytoplankton, or as Miller described as “the grass of the sea,” of nutrients from below and could inhibit its growth. If this persists, the food web could be harmed in the long term.

Warm water also favors harmful toxic algae blooms that are absorbed by shellfish, crabs and squid, which itself is a “cornerstone” of the food web.

Looking to the fall and winter: El Niño on the way?

While Giles, his lifeguards and the beachgoing public have enjoyed their time with the warm water, it will not continue far into fall, according to Connolly at the National Weather Service.

Temperatures will cool into the fall months, but there is “around 70 percent chance” of an El Niño hitting in winter. What we can expect from this is more rain, moisture and warmer water.

Even though this warm period will not last and climate watchers do not know exactly when such an event will return, what is certain is that the future will hold more of these warming events.

So this record-breaking temperature season could likely be broken again and the region will see another warming period similar to this — but the next time might not take 102 years.

Cameron Niven is a North County freelance writer