Ocean Water Has Record Temperature Off San Diego Coast

Speaker 1: 00:00 A stretch of high temperatures in the eighties and nineties in San Diego is not that unusual in August, but with humidity's also near 80%, that is not typical San Diego weather. However, it might be something we're going to have to get used to the heat and humidity we've been experiencing for the past two weeks can be traced back to changes in the Earth's climate and those uncomfortable conditions could become more frequent in the coming years. Joining me is Alexander Gershwin of he is a climate scientist with the Scripps institution of oceanography and Alexander Sasha. Welcome to the program. Speaker 2: 00:38 Thanks Maureen. Nice to be back with you. Speaker 1: 00:40 Now, we've heard that this heat wave is being caused by a heat dome. That's been covering a large section of the Western States, but what is causing the humidity? Speaker 2: 00:51 The humidity and heat waves in California has been increasing over a decade since the eighties, pretty much, uh, in the summertime heat waves because of the warming of the ocean. Speaker 1: 01:06 What part of the ocean in particular, do we know Speaker 2: 01:10 It's really the Pacific ocean West of Bucca, California. That's been warming more than, uh, than most other parts of the global ocean. The global ocean has been warming as well, but there are these bullseyes of accelerated warming and that's one of them. And, uh, when, uh, that air is delivered to California, it's a, it tends to be warmer, but, but much more humid, the amount of humidity that the air can hold really depends, um, exponentially on temperature. So if it's a little bit warmer and you've got saturated there, sitting over the ocean is going to be a lot more human. Speaker 1: 01:48 No, the water temperature recorded at Scripps pier last week. It was more than 77 degrees and only a few weeks ago, it was in the fifties. Is that evidence that, of that warmer water being pulled in our direction. Speaker 2: 02:02 I was talking specifically of the air. That's been sitting over that warmer water being pulled in our direction, but certainly, you know, when our coastal waters, you know, just off the coast of the California bite is warmer. We feel the humidity very directly. We don't even need to have a heat wave for that. And, and certainly, um, the water temperature, uh, right here of our coast has been jumping around a lot, uh, this, this summer so far, you know, in, uh, uh, in mid-July over a period of one day, it went from a repeat for that day, uh, to record cold, uh, for the next day. Wow. Speaker 1: 02:47 Wow. We've been hearing for years that climate change will have the effect of making California warmer, but also dryer. So where does this access of humidity fit into that picture? So basically the dry season Speaker 2: 03:01 Is getting longer with climate change because the expanding subtropical belt basically makes our dry season longer and the wet season gets squeezed into the peak of winter. Speaker 1: 03:16 Now we all know that a wet heat is more uncomfortable than a dry heat, but why is it more uncomfortable? Speaker 2: 03:22 Well, when it gets really hot, then, um, uh, we start cooling off more efficiently by sweating. When the sweat evaporates from our skin, it calls the skin down. Actually the same thing happens on the global level when, when water evaporates from the ocean or from, or from a human surface, when there's more humidity in the air that sweat just doesn't evaporate as efficiently. And we've all felt when it's humid, the, uh, the sweat runs off, it stays on our scan and it just makes us wet, but not, uh, cool. Speaker 1: 03:56 Can this kind of heat cause people to get sick, Speaker 2: 03:59 Certainly. And especially since we're not really acclimated to humid heat in this part of the world. And, uh, you know, the other thing that the humidity in the air does is it prevents the temperature from cooling down at night. So the nights remain much hotter, uh, than they would be during dry heat waves. And we don't get the respect from the heat people with preexisting conditions, especially that make them more vulnerable to heat, begin to get sick. And, uh, some people die. Speaker 1: 04:31 Now, if we're going to be seeing more of these stretches of hot and humid weather in the summer, how do you think San Diego needs to prepare for them? Speaker 2: 04:39 I think that during the time of COVID specifically, we can't really tell people to crowd into a cooling centers. So some adjustment needs to be made in that respect. Also, when a nights are hot during this humid heat waves, cooling centers are closed, then there's gotta be some other way that we intervene to reduce the health impacts of this humid heat. Speaker 1: 05:09 I read that you were thinking that maybe we could adjust electricity rates for people who need to run their AC a little bit longer. Speaker 2: 05:17 Of course. Yeah. We're thinking about, um, you know, these crises, uh, uh, piling up on top of each other, you know, there's a health crisis with COVID, there's an economic crisis also related to COVID locked down and, um, uh, you know, people, even if they have air conditioning, they, they may be less likely to, uh, turn it on if they're unemployed and can't afford it. Uh, health and extreme weather events have to be considered in the context of everything else that's going on. Speaker 1: 05:50 I've been speaking with Alexander Goshen off. He is a climate scientist with this Scripps institution of oceanography. And thank you so much for joining us, Speaker 2: 06:00 Maureen.