Why Have Ocean Temperatures Spiked?

11:51 minutes

A view of the ocean, nothing but the waves and the horizon
Credit: Ant Rozetsky, Unsplash

Sea surface temperatures in the North Atlantic have risen dramatically in recent weeks, to as much as 0.5 degrees Celsius warmer than the previous record—and over 1 degree C warmer than average temperatures from 1982 to 2011. 

The reason for the unusually toasty waters isn’t entirely clear. Some climatologists attribute part of the rise to an El Niño ocean circulation pattern this year, replacing the La Niña pattern that had been suppressing temperatures. Other factors may include a decline in atmospheric dust from the Sahara, and atmospheric circulation patterns that are allowing warm surface water to stay in place longer.

The warmer temperatures aren’t just limited to the North Atlantic, however—for the past three months, global average sea surface temperatures have also been reaching new highs. Casey Crownhart, a climate reporter at MIT Technology Review, joins Ira to talk about the warming trend, and other stories from the week in science, including accusations of body part sales from the Harvard Medical School morgue, studies of the economics of heat pumps, and a lawsuit brought by youth in Montana over global warming.

Segment Guests

Casey Crownhart

Casey Crownhart is a climate reporter for MIT Technology Review in New York, New York.

Segment Transcript

IRA FLATOW: This is Science Friday. I am Ira Flatow. Later in the hour, our annual summertime reading picks. Do you have a science book to recommend for vacation reading? We’ve got a bunch to give you so give us a call. Our number 844-724-8255, that’s 844-SCI-TALK, or tweet us SciFri.

But first, the approaching summer means rising temperatures for most of our northern oceans, but this year they’re surprisingly warm and researchers aren’t entirely sure why. Joining me now to talk about that and other top science news of the week is Casey Crownhart, climate reporter for the MIT Technology Review. She’s here with me live in our New York studio. Welcome back, Casey.

CASEY CROWNHART: Thanks so much for having me back.

IRA FLATOW: It’s nice to have you. First on these warming temperatures, how warm are we talking about here? Unusually warm?

CASEY CROWNHART: Yes, definitely unusually warm. So we just got data back from the month of May, and it was the warmest May since records started being kept in 1850, about 1.5 degrees Fahrenheit higher than normal, which is pretty significant when we’re talking about ocean temperatures.

IRA FLATOW: And this is all over the place or just one place?

CASEY CROWNHART: It’s all over the place. We’re seeing more of a temperature increase in some parts of the oceans. The North Atlantic is looking especially warm for some reason this year, but this is really a worldwide thing.

IRA FLATOW: And we don’t know why?

CASEY CROWNHART: There are a lot of theories–

IRA FLATOW: Climate change, global warming.

CASEY CROWNHART: It’s– we’re not totally sure. It’s probably maybe a little bit something to do with climate change. Maybe there’s some natural variation, but there’s a lot of controversial takes right now.

IRA FLATOW: Is there a number how much warmer it is?

CASEY CROWNHART: So in total it’s about 0.8 degrees C above normal or 1.5 degrees Fahrenheit. So it’s a lot. That’s definitely something to be concerned about because warmer ocean temperatures can mean more powerful hurricanes. It can mean consequences for wildlife, so it can be a pretty big deal.

IRA FLATOW: Yeah, well, I like that that lives there. Let’s go to other climate news. There’s an unusual lawsuit going on in Montana. Tell us about that.

CASEY CROWNHART: Yeah, so a group of 16 young residents are suing the state of Montana over climate change. They’re basically arguing that some of the state’s laws that prop up fossil fuels violate their constitutional rights.

IRA FLATOW: Oh, wait. You’re going to have to– what’s the basis? Tell me more about that.

CASEY CROWNHART: Yeah. The– they’re– in the Montana State Constitution, there’s a line that says that the state will maintain a, quote, clean and healthful environment for present and future generations. And so basically the plaintiffs argue that there are a couple of laws on the books. One is the state’s energy policy which directs how the state produces and uses energy, and then the other one is the Montana Environmental Policy Act. And so the plaintiffs are saying that these laws by promoting fossil fuel use are contributing to climate change, which obviously isn’t always aligned with a safe and healthful environment.

IRA FLATOW: Yeah, because it said about future generations also. So we want to make sure they’re safe for our kids. What’s that old phrase? We’re borrowing time from our kids or future generations.


IRA FLATOW: And if they win, could that lead to similar suits in other states possibly?

CASEY CROWNHART: It could. And actually we’ve already seen that some suits are ongoing in other states already. So the nonprofit law firm that is involved in this suit is already involved in some other suits. One is in Hawaii. That one could go to trial as soon as this fall.



IRA FLATOW: So are– is anybody giving odds on how successful this might be?

CASEY CROWNHART: It’s really hard to say because it’s really the first lawsuit of its kind. I will say that the state has tried to get the case thrown out and then tried to get the trial delayed, and in both cases, the judge said, nope, we’re going to trial. And so we’re going to see another week of testimony, and then we could see a decision soon after that.

IRA FLATOW: That’s interesting. On one route to reducing your personal climate impact, of course, is moving away from things like oil or gas furnaces to heat pumps, one of my favorite topics. I want to hear more because I know you’ve written a lot about heat pumps, so let’s talk about that.

CASEY CROWNHART: Yes. I always want to talk more about heat pumps. And so basically– so some background here– new consumer climate technologies like solar panels, electric vehicles, we know that they can help cut emissions. They can also help people save money. They also can come with health benefits. But typically these technologies and their benefits are much more likely to be accessible to wealthier people that can afford them.

And so this week, I wrote a story about some new data which was from a 2020 survey that suggests that heat pumps don’t follow this trend, that at least in the US, they’re pretty evenly distributed–

IRA FLATOW: Is that right?

CASEY CROWNHART: Among the lowest and the highest income groups. Right about 15% of Americans use a heat pump as their primary heating technology.

IRA FLATOW: I didn’t– actually I didn’t even think that was that high, 15%.

CASEY CROWNHART: So it’s really geographic specific. So the southeastern US much more likely to have a heat pump. I’m from Alabama. Forty percent of homes in Alabama are heated with a heat pump.

IRA FLATOW: No– really?



CASEY CROWNHART: So it’s this overlap between places where electricity is cheap and where– a lot of places where the winters are a little bit milder. So in those places, heat pumps are already a no brainer because they’re cheaper than getting central air conditioning and heating system in a lot of cases.

IRA FLATOW: For people who don’t know, what’s the basic setup of a heat pump.

CASEY CROWNHART: Yeah, sorry. I skipped over that. I was so excited. Heat pumps use electricity to cool and heat your home. So they work similarly to an air conditioner, but they can heat and often they can do both, heat and cool.

IRA FLATOW: So you don’t have to install two units. Do you have one unit that turns into an air conditioner in the summer and turns into a heater in the wintertime?

CASEY CROWNHART: Correct, yeah. Not all heat pumps can do both, but a lot of them can.

IRA FLATOW: Yeah. And this is a technology that there are credits and incentives for?

CASEY CROWNHART: Mmm hmm. And so I want to emphasize that a lot of the folks that I talked to for this story did say that even though we do see a pretty even distribution right now, it’s really important moving forward that having these kinds of credits and doing them well will help these technologies be accessible to a lot of– a wide array of people moving forward.

IRA FLATOW: Yeah, yeah.

CASEY CROWNHART: Yeah. And so there– the tax credits in the Inflation Reduction Act, there’s $2,000 towards the sale of a heat pump. Some state rebate programs can go up to $8,000. So the Department of Energy actually just put out a new tool that you can use to see if you’re eligible for this kind of thing. It’s called the Energy Savings Hub, so you can check out see if you can get your very own heat pump.

IRA FLATOW: Yeah because when I was– my heater is about 20 years old. It was 20 years old, and I was talking about replacing it with a high efficiency unit. And my company said, well, no, go with the heat pump because–


IRA FLATOW: You can save money on the installation, and there are these tax incentives.

CASEY CROWNHART: Absolutely. And the time to do it is before your heater goes out because it’s harder to do it when you really need to get the system replaced right away.

IRA FLATOW: And it’s amazing how much money you can save with these things. I have solar panels, which make my electric bill $9 a month as opposed to $300 as it used to be, and we got heat pumps then. I love that. I’m going to move to that next.

Let’s– I can talk about this a lot more as you can tell. I’m sure you could. Let’s move on to some exciting news this week that found water from Saturn’s moon Enceladus and it had a really interesting chemical in it because they have little geysers sprouting out of it, that moon, right?

CASEY CROWNHART: Yes. This moon sounds absolutely wild. A lot of the stories that I saw referred to this ocean on this moon as a soda ocean because it’s very fizzy.


CASEY CROWNHART: But, yeah, so scientists, when they look for life on other planets, they look for a few key ingredients that we know all life on Earth or most life on Earth has, carbon hydrogen. One of those things is phosphorous, and so they found in some of these icy shards that come out of these geysers on this moon of Saturn that there’s phosphorus in that.


CASEY CROWNHART: So this is the last of the six ingredients that they were looking for on this planet, so it means that all the ingredients for life are on this moon in Saturn.

IRA FLATOW: Yeah, because there’s an ocean under this crust, this icy crust–


IRA FLATOW: And maybe who knows?


IRA FLATOW: We’ve got all the ingredients.

CASEY CROWNHART: Gotta go back.

IRA FLATOW: Let’s go.


Let me move on to some darker news. There’s a very strange story this week about people being accused of selling body parts from the Harvard Medical School morgue.

CASEY CROWNHART: Yes. It’s really– like you said a really dark story. So the morgue manager at Harvard Medical School was accused of stealing and selling body parts. Medical schools often use human remains that are donated for research, for teaching purposes, but the morgue manager and then a few other people were arrested this week for a scheme that went from 2018 until just earlier this year. It looks like they were taking parts from cadavers that were set to be cremated. So Harvard says that they’re working with investigators to figure out what happened and which donors may have been affected by this.

IRA FLATOW: It sounds like something out of the 18th century, 19th century, some sort of Frankenstein–


IRA FLATOW: Kind of thing.

CASEY CROWNHART: I know. It’s terrible.

IRA FLATOW: But it’s really– and they just discovered it had been going on for a while.

CASEY CROWNHART: Mmm hmm, years.

IRA FLATOW: Wow. We recently talked on this program about the body mass index or the BMI, and this week the American Medical Association called for doctors to change how they use the BMI because when you go to the doctor, they take this body mass index and say, well, you’re overweight, you’re not overweight, right?

CASEY CROWNHART: Mmm hmm. Yeah. So as your listeners probably know, BMI is a ratio of your weight to your height. There are a lot of problems with using it as a measure to diagnose people. Number one, it’s not a very good way to measure your body fat because you can be really muscular and have the same BMI as somebody who maybe has more body fat.


CASEY CROWNHART: But also it’s not a good way to measure health at the individual level. So we saw this week like you said that this association voted for doctors to de-emphasize its use in clinical practice.

IRA FLATOW: Yeah. And the AMA, the American Medical Association, carries a lot of weight with doctors so no pun intended.


CASEY CROWNHART: Yeah, it is one of the largest medical groups in the country, so it’ll be really interesting to see how this changes the field and practice and if doctors start to change how they talk to people.

IRA FLATOW: Finally, on a existential note, there are flies that experience death that may age faster. I’m just going to let you go with this because I have no idea how this works.

CASEY CROWNHART: Existential is exactly the word for this one. So scientists were looking to understand whether flies might undergo some physical changes after they were around sick flies– so if their immune systems would kick into gear or something– and they started to notice that flies would undergo changes but after the flies that they were with had died.


CASEY CROWNHART: And so it’s a really weird finding, but they found that these flies would lose their stored fat and that they would die sooner than other flies did.

IRA FLATOW: And there’s no way to extrapolate this to people yet? It’s just flies.

CASEY CROWNHART: It’s really hard to say what exactly this means or even what is going on and what the pathway is but–



IRA FLATOW: Wow. It’s very weird. We love you bringing weird stuff.

CASEY CROWNHART: It’s my favorite thing to bring, Ira.

IRA FLATOW: Glad to hear it. You’re always welcome back. With Casey Crownhart, climber reporter for MIT Technology Review here live with me in our New York studios. Thanks for coming in.

CASEY CROWNHART: Thanks so much for having me.

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