How Changing Ocean Temperatures Could Upend Life on Earth

from The New York Times I'm Katherine. benold this is the. [Music]. da many of the effects of climate change. are already with us heat waves droughts. wildfires flooding but some of the most. alarming consequences are hiding beneath. the surface of the ocean today my. colleagues David gallis and raymon Jong. on just how close we might be to a. Tipping Point. [Applause].

[Applause]. [Music]. it's Tuesday May. 7th David you've been writing about. different aspects of climate change for. years and I'm definitely no stranger to. distressing news about a warming Planet. but something about ocean temperatures. seems particularly distressing what's. going on starting last year scientists. started noting something alarming.

happening in oceans all around the world. it was warm in the oceans but it started. to get really hot in ways that they had. never seen before and for the last year. plus I've been checking in with. scientists and they are increasingly. concerned perplexed even with what. they're seeing and when you say oceans. are getting hotter can you just give me. a sense of how much the oceans are. warming and how fast well if you look at.

a chart that shows say the last two or. three decades of average sea surface. temperatures you'll see a gradual. warming Trend but starting last March we. didn't see another gradual increase we. saw this big jump and from March of 2023. on it stayed hot and it's just getting. hotter and we began 2024 at this much. higher level than we've ever seen before. and we're still there and in parts of.

the world the temperatures are still. going up as we head into summer and that. has scientists really concerned and you. said earlier that none of the scientists. that you've been checking in with and. none of these very sophisticated climate. models that they're operating with can. explain this big jump and I guess I have. to ask at this point why are these. scientists so surprised I mean we've. seen record breaking heat waves for the. past several years it seems like every. single year is hotter than the last why. is it any Sur surpris that the ocean is.

no different well they're not surprised. that the ocean's warming they have. understood for many years now that the. overall man-made global warming that. we're experiencing all over the world in. all these different ways is going to. affect the oceans water is very. absorbent for heat and a lot of the. extra heat that we're producing from the. burning of fossil fuels a lot of the. extra heat that's being caused in the. atmosphere as a result of that is just. getting sucked in to the ocean and bit.

by bit over the last many decades the. oceans have gotten warmer so even after. the air cools say in Winter or something. the ocean holds on to a portion of that. heat that's right even when it's cold. outside the oceans year after year have. been getting a little warmer as a result. of climate change but that on its own. does not account for the kind of warming. that we're seeing right now not even. close so what else do they think could. be going on well for the last year or so.

the Pacific Ocean has been going through. an elino cycle which is when a lot of. excess heat is released from the ocean. and in addition to making the Pacific. Ocean hotter it has sort of an overall. warming nudge a little boost for warmth. in Ocean heat around the world but even. that doesn't explain the big jumps we've. seen and there's another. counterintuitive factor that scientists. believe is playing a role here as well. and that has everything to do with the. pollution.

being emitted by big ocean liners by Big. Ships traveling across the. Atlantic so in 2020 some shipping. regulations changed and they required. that the emissions from the fuel being. used in big ocean. tankers become much cleaner and as a. result of that there was less sulfur. dioxide in the shipping. emissions that's a good thing for many.

reasons sulfur dioxide is a pollutant it. can have really adverse health effects. on humans but one of the things that was. also doing was refracting sunlight away. from the. oceans and so what we've seen over the. last recent Years is as there was less. sulfur dioxide in the North Atlantic as. less and less of that parate matter was. in the atmosphere and able to bounce the. sun's energy back into space.

more and more of the sun's energy more. and more of the sun's heat was making. its way into the. oceans and that scientists are now. understanding likely played a warming. role as. [Music]. well so basically lower emissions in. these shipping lanes means less kind of. smoggy cloud cover and therefore more. direct sunlight hitting the ocean. surface and heating it up which actually. kind of rings the bell because we talked. about this in the show recently in.

relation to scientists wanting to. artificially create more potent clown. cover to cool down the planet it's a. little ironic that scientists are now. trying to engineer the very thing we. were trying to stop doing it talk about. unintended consequences that's right and. this is one of those instances where. there are these very tough tradeoffs. right it's great yes that we have less. pollution that's going to be good for. Public Health on the other hand it may. have allowed yet more warming in the. oceans that's having Cascade cing.

effects across all sorts of ecosystems. that we're only just beginning to. understand yeah let's let's talk about. that for a moment what are the effects. of this mysterious warming you mentioned. ecosystems well there are a lot of. effects when the oceans get this hot. this fast but perhaps the most immediate. concern among people all over the world. is the fact that in dozens and dozens of. countries all over the world we're. experiencing a wreck wave of coral.

bleaching which is to say that coral. reefs these vitally important parts of. the ocean ecosystems are just dying at a. rate we've never really seen before and. that's going to have all sorts of. negative effects for Fisheries all over. the globe why are coral reefs so. important well they matter for a lot. more than just snorkeling yes they're. beautiful and yes they are the center of. a lot of tourist activity but they're. also sort of this fun fundamental.

foundational part of the marine food. chain and so when we think about all of. the life that coral reefs sustain that. all allows for smaller fish to flourish. and go out into the ocean and those. smaller fish contribute to the lives and. the ecosystems of bigger fish and when. we think back to you know the food chain. that we learned about when we were in. elementary school coral reefs are right. at the bottom of that and if we lose.

that it's going to have devastating. effects for marine ecosystems all over. the world is there any hope to save the. Coral at this point or are they doomed. my colleague Ka Einhorn has been doing a. lot of great reporting on the situation. with corals and she's highlighted some. of the efforts underway to try to save. them to grow more resilient corals but. the truth is the scale we're seeing with. bleaching events happening All Around.

the World in something like 56 countries. it's just not possible to stop it. entirely at this point so it's one of. these dominoes in our ecosystem that can. set up a whole range of problems and. actually result in major losses to. biodiversity and just to come back to. the mystery of it all we just don't know. what happens when those dominoes start. to fall and it's not just corals that. are being impacted here the weather. could well change as a result of these. warmer oceans as well and I'm.

particularly thinking about the upcoming. Atlantic hurricane season warm water is. a key ingredient to hurricanes when you. think about hurricanes and how strong. they get and how fast they intensify one. of the most important factors in both of. those Dynamics is how hot the water is. and when we see all this warm water. hanging out in the Atlantic ocean that. is leading forecasters to predict a.

potentially record-breaking hurricane. season that is right around the corner. in the North Atlantic and that could. affect the Caribbean North America and. Beyond what's striking to me is that you. know we know that the oceans are getting. much hotter we don't fully know why and. we can't fully explain what the impact. will be which really doesn't sound great. but if we don't fully understand what's. going on then how can we even hope to do.

something about. it well I've been asking scientists this. very question right like what is there. to be done and the tough answer is. there's no easy way to turn down the. thermostat of the oceans this warming is. happening and our job now is to live. with it as best we. can and we haven't even talked about. what some people regard as the biggest. threat of all.

as the oceans warm they're contributing. to The Melting of glaciers and the loss. of Arctic sea ice and as that happens. many people are worried not just about. rising sea levels but also about the. disruption to a vitally important ocean. current and if that happens it could. have massive ramifications for the. entire planet it could change just about. everything we know about life on.

[Music]. Earth after the break my colleague. Raymond Jong talks about the possibility. of that ocean current. [Music]. collapsing we'll be right. back Raymond before the break our. colleague David gallis told us all about.

this alarming trend of the ocean heating. up and some of the very worrying. consequences of of that but you are here. to tell us about something else that may. be happening in the ocean something to. do with ocean currents and if I'm honest. it sounds like something straight out of. a science fiction movie can you explain. sure Katherine and and actually you're. right it is something from a science. fiction. movie I'm here at the global warming. conference in New Delhi where if you can. believe your eyes it's snowing.

about 20 years ago a movie called The. Day After Tomorrow came out the only. Force strong enough to affect global. weather is the Sun what about the North. Atlantic current I got a call last night. from Professor rapson at the Headland. Center he thinks the current is. changed come on Jack how could that be. and the plot of that movie is that. there's this major ocean current in the. Atlantic that suddenly stops moving it. collapses and it sets off this Cascade.

of natural disasters in Nova Scotia. earlier today the Ocean Rose by 25 ft in. a matter of seconds what you're seeing. are two actual tornadoes striking Los. Angeles International Airport it's a mob. scene here at Grand Central Station over. half the platforms are flooded and. service has been suspended on all trains. that ultimately plunged the planet into. a new Ice Age what can we do. [Music]. save as many as you.

can I guess my question to you Raymond. given what we're talking about here is. which part of that movie is science. fiction and which part is actual science. I'd say most of the movie is pretty. purely fiction but there is a kernel of. Truth in the science which is that this. vital ocean current in the Atlantic is. very real and just like in the movie. scientists are worried about what. happens if it shuts down okay so tell me.

about this current scientists have given. it a very very unwieldy. name they call it the Atlantic. meridianal overturning circulation but. most people just use the acronym amoc. amok amok okay think of it as a giant. conveyor belt of water that loops around. the Atlantic Ocean and it starts near. the equator goes up through the. Caribbean around the east coast of the.

US up toward northern Europe and then. back. again scientists have come to realize. how important amok is for a lot of the. climate that we enjoy today a lot of. Northern Europe Britain Iceland. Scandinavia is habitable today really. because of amok it's because this system. transports Heat from the equator and.

very generously drops it off uh in. northern Europe that even though it's so. far from the equator it it's not as. uninhabitable as say far Northern Canada. or. Siberia and let me just ask you is this. amoc current the same thing as the Gulf. Stream which people write about in a. worried about a lot these days yeah the. Gulf Stream is a similar system of. currents but amok sort of the full loop.

the Gulf Stream is just one part of it. but amok is really what's important for. the climate Okay so before we talk about. amok shutting down or collapsing can you. actually kind of give me a a quick. science 101 explanation of how this. thing works like there's this massive. Loop of water like a sort of I guess an. underwater river that you described. which kind of. transports warm water up towards the. North and then comes back as cold water. what keeps this thing running how does a. current just stay in constant motion and.

loop around like that it has to do. primarily with differences in. temperature and salinity basically. fluids want to keep moving in a. particular direction and it's driven by. this balance between warm water cold. water salty water fresh water heavier. water wants to sink lighter water wants. to rise and so the temperature and. salinity of the water is sort of what. determines how densities and this.

density and differences in density keeps. this giant Loop moving it's something. that explorers noted in the Atlantic. hundreds of years ago they noticed that. deep water was was very cold it was. unexpected and so I think as people have. started studying the oceans more and and. science has advanced they've realized. there's a very delicate system of. differences and temperature and salinity. that keeps this conveyor belt moving. that's really fascinating I mean I've. always known we had these currents and.

that they were really important but I. never really appreciated and understood. what it takes to keep them going so okay. tell me why scientists are so worried. about amok shutting. down as the planet warms there's. something that might be significantly. affecting this delicate balance and. that's the melting of the Greenland ice. sheet with the melting of the ice. there's this big infusion of fresh water. into the North Northern Atlantic and.

because that affects the salinity of the. northern Atlantic it sort of changes the. balance of salinity and temperature. potentially enough to knock this Loop. off course and there's signs already. that this is happening that at least the. current is slowing down and one major. piece of evidence is this cold blob. that's appeared in the northern Atlantic. a cold blob a cold blob that's right. with most almost everywhere on the. planet getting warmer because of the.

greenhouse gases that we're putting into. the atmosphere there's a conspicuous. blob in the North Atlantic near. Greenland that is getting cooler and. it's exactly the place that scientists. would expect to be getting cooler if. amok were slowing down okay so the. Greenland ice sheet is melting due to. climate change and that seems to be. disrupting this current so as a result. less warm water is being transported nor. North and that's why we have this cold.

blop that scientists have noticed in the. North Atlantic that's right and do we. know what would happen if the current. collapsed today so the best source of. information we have about what happens. when amok collapses comes from about. 12,800 years. [Music]. ago which is as far as scientists know. the last major time this happened. basically the climate changed really. really quickly at least by geological. time it was it was sort of less than 100.

years as far as scientists know much of. the northern hemisphere got cold. again the temperature in parts of. Greenland probably fell by about 18° fah. forests were replaced by Tundra ice. sheets grew. again as far away as California and the. southwestern us you had evidence of. cooler drier conditions and as far as. scientists can tell this may even have. contributed to The Disappearance of some.

of our early hunter gatherer. civilizations some of our ancestors were. probably pushing into new territory as. the aits retreated and were suddenly. confronted with another blast of. cold wow okay so the last time this. happened this current shutdown the world. was basically plunged into an ice age. and wiped out part of humanity. is that the scenario we're looking at.

today I think scientists are careful. about not being too precise about what. it would look like if it happened again. the world after all is still warming and. so in a lot of ways the climate is. already quite different from the one. that was around at the time but. certainly I think scientists expect. northern Europe the UK Iceland. Scandinavia to become a much colder. place even than it was 200 years ago. before Industrial Revolution before.

humans started adding greenhouse gases. to the atmosphere How cold are we. talking you mentioned the UK I'm in the. UK right now I mean would Britain. suddenly look like the frozen tundra it. would be significantly colder it's far. north enough to really be almost Arctic. and I think an amok collapse could bring. much stronger winter storms deep cold in. the winter that would be extremely. dangerous but at the same time that cold. around the North Atlantic doesn't just.

translate straightforwardly into cold. everywhere basically if you don't have. amok you have more heat that stays. around the tropics and the equator a. warm ocean around the equator gives the. fuel to storms around the equator and. rainfall around the Equator so it's not. just about getting that warm water from. the tropics to Europe it's also getting. that warm water away from the tropics to. avoid things like extreme weather events. that's right and it's not just about the.

temperatures people would experience. it's also about agriculture and. especially in vulnerable places like. Africa big shifts in rainfall big shifts. in temperature could really affect food. chains Food Supplies our ability to feed. ourselves and what does that mean for. humans living in these places like you. were saying that 13,000 years ago. northern Europe basically wasn't. inhabitable. anymore would humans still be able to. live in these places we as a. civilization ation as a species.

obviously have some ability to withstand. a range of temperatures a range of. weather conditions but we really haven't. seen in our recent history at least. changes as fast as the ones scientists. imagine anoch collapse would bring it's. really hard to say is Northern Europe. ready for a much colder climate than it. is right now if for instance sea level. rise accelerates on the east coast of. the US are cities there prepared that's. another consequence of amok that.

scientists are worried about and it's. obviously already happening and you can. see the effects of seil rise in places. like the Gulf Coast North Carolina. Florida even New York but certainly it. would be a test for countries societies. around the northern Atlantic that they. haven't seen before okay that that's a. very scary Prospect with everything that. goes with it you know Mass floods and. displacement of people climate migration. everything that you can sort of Imagine.

when do scientists predict that this. could actually happen based on the data. they have and and assuming of course. current human behavior and Emissions. don't change as best of scientists can. tell right now they know amok is. weakening they expect it to continue. weakening whether a collapse is imminent. whether it's far away is still really. really hard to say but it couldn't. quickly be reversed once you sort of. started on this process the the system. just keeps moving in that direction like.

a point of no return that's right so if. we're already seeing signs that this. current is weakening does that mean. we're possibly already past that point. of no return is it no longer a matter of. if but when the really short answer is. we just don't know the best guess is. that it's not going to shut down this. Century but plenty of scientists are. worried it's something that a lot of. them are focused very intensely just.

because we do think the consequences if. amok did shut down could be so. catastrophic if that current collapsed. though like is there anything we could. do to bring it back like it did come. back 13,000 years ago after that last. ice age what happened short answer again. nobody is quite sure it seems to have. abruptly grown warm again over 40 50. years but it's pretty clear why and I.

think as far as what would happen today. to bring it. back scientists would still say cutting. greenhouse gas emissions and preventing. the planet from overheating is probably. the only thing we have in our control. that could influence the climate on that. scale I mean it's sort of where we land. at the end of every episode about. climate change and it's sort of. interesting I mean probably like a lot. of people listening to you I find all. this pretty scary and dystopian and.

worrying it's kind of crazy to think. actually that scientists have warned. about this for decades that there was. even a science fiction movie made 20. years ago which you know in some ways. predicted what might be the real. consequences of this current shutting. down it's not like we humans lack the. imagination of like all the terrible. things we're we're risking here but when. it comes to protecting ourselves and the. planet against this existential threat. we are clearly unwilling to do what it.

takes yeah scientists have been thinking. about amok and had a pretty good grasp. of what amok looked like decades ago as. early as the 80s and 90s scientists made. this connection between the warming that. humans were bringing about and. consequences like an amok collapse and. other things as. well it was one of the scientists who. wrote about amok in the 880s who said. the climate system is an angry beast and. we are poking it with sticks and that's.

still true. today well raymon thank you very much. thank you. [Music]. Katherine we'll be right back. here's what else you need to know today.

on Monday the judge in Donald Trump's. hush money trial held the former. president in contempt for repeatedly. violating a gag order and threatened to. jail him the judge told Trump that the. last thing he wanted to do is to put him. in jail but at the end of the day he had. a job to do and would seriously consider. it and Israel stepped up its attack on. the southern city of Rafa in Gaza hours. after Hamas said it was ready to accept. a cease by a proposal The Proposal was.

put forward by Egyptian and Qatari. mediators but Israel responded by saying. that it failed to meet its demands the. prime minister's office said it would. still send a delegation to talk about. how to reach an acceptable. deal today's episode was produced by. Carlos prto Michael Simon Johnson Alex. Stern and Diana win it was edited by. Devon Taylor contains original music by. Rowan neimo and Mar Lozano our theme. music is by Jim brunberg and Ben.

lansberg of. wanderly that's it for the daily I'm. Katherine benold see you tomorrow. [Music].