WEBVTT 00:00:00.000 --> 00:00:03.259 Welcome to Meteorology Matters. Today we're looking 00:00:03.259 --> 00:00:05.820 at something really quite strange, a real climate 00:00:05.820 --> 00:00:09.439 puzzle. Imagine this, a huge part of the Atlantic 00:00:09.439 --> 00:00:12.179 Ocean is a little cold. And it's actually getting 00:00:12.179 --> 00:00:15.199 colder, even while the planet overall is hitting 00:00:15.199 --> 00:00:17.660 record high temperatures. It does sound completely 00:00:17.660 --> 00:00:20.420 counterintuitive, doesn't it? Like finding an 00:00:20.420 --> 00:00:23.679 ice cube floating in a hot bath. Exactly. And 00:00:23.679 --> 00:00:25.839 understanding this cold spot is, well, it turns 00:00:25.839 --> 00:00:27.600 out it's pretty key to understanding the bigger 00:00:27.600 --> 00:00:30.399 climate picture. So in this Meteorology Matters 00:00:30.399 --> 00:00:33.420 podcast, we're going to explore these surprising 00:00:33.420 --> 00:00:35.299 connections. Why is this happening? What does 00:00:35.299 --> 00:00:38.100 it mean for our weather? And really, why should 00:00:38.100 --> 00:00:40.579 you care about it? That's a great topic. For 00:00:40.579 --> 00:00:43.280 years, this was a genuine scientific head -scratcher, 00:00:43.479 --> 00:00:46.640 a real anomaly. But recent work, some really 00:00:46.640 --> 00:00:48.420 intensive research has started to piece it together. 00:00:48.899 --> 00:00:51.479 This cold blob, as people call it. It's a specific 00:00:51.479 --> 00:00:54.439 spot in the sub -polar Atlantic south of Greenland. 00:00:54.960 --> 00:00:57.219 And measurements show it's cooled maybe by up 00:00:57.219 --> 00:00:59.960 to 0 .3 degrees Celsius over the last century 00:00:59.960 --> 00:01:02.710 or so, while everywhere else is warming up. Right, 00:01:02.929 --> 00:01:05.189 0 .3 Celsius or about half a degree Fahrenheit. 00:01:05.469 --> 00:01:08.010 That's not tiny, especially when the waters right 00:01:08.010 --> 00:01:09.950 next to it are warming. And like you said, there 00:01:09.950 --> 00:01:11.810 was this debate for a while, wasn't there? Was 00:01:11.810 --> 00:01:15.049 it just ocean circulation doing this or was the 00:01:15.049 --> 00:01:17.790 atmosphere somehow involved too? Well, the latest 00:01:17.790 --> 00:01:20.329 thinking, the newest research points pretty clearly 00:01:20.329 --> 00:01:23.870 to both. It seems ocean and atmospheric processes 00:01:23.870 --> 00:01:27.659 are. pretty much equally responsible. Okay, both. 00:01:27.939 --> 00:01:30.920 And understanding that mix is vital because this 00:01:30.920 --> 00:01:33.200 isn't just some local quirk. This cold patch 00:01:33.200 --> 00:01:35.840 can actually disrupt things like the jet stream 00:01:35.840 --> 00:01:38.459 and that affects storm tracks, you know, big 00:01:38.459 --> 00:01:40.439 time. Okay, so let's break that down. The ocean 00:01:40.439 --> 00:01:43.480 part. Yeah. That involves the AMOC, right? The 00:01:43.480 --> 00:01:45.900 Atlantic Meridional Overturning Circulation. 00:01:45.920 --> 00:01:48.540 That's the one. The AMOC is this absolutely enormous 00:01:48.540 --> 00:01:50.920 system of ocean currents. Like a giant conveyor 00:01:50.920 --> 00:01:53.459 belt moving water around the Atlantic. Precisely. 00:01:53.609 --> 00:01:56.329 It brings warm, salty water up from the tropics 00:01:56.329 --> 00:01:58.670 towards the north. Where it cools down. It cools, 00:01:58.750 --> 00:02:00.469 gets denser because it's salty and cold, and 00:02:00.469 --> 00:02:03.810 then it sinks, deep down. And then it flows back 00:02:03.810 --> 00:02:06.189 south again, deep underwater. And this whole 00:02:06.189 --> 00:02:08.610 circulation, this conveyor belt, is massively 00:02:08.610 --> 00:02:10.849 important for climate, especially here in Europe 00:02:10.849 --> 00:02:13.289 and North America? Hugely important. It helps 00:02:13.289 --> 00:02:16.650 regulate temperatures, distributes heat. It's 00:02:16.650 --> 00:02:18.930 a major climate driver. And the origin of this 00:02:18.930 --> 00:02:22.020 cold blob... It's directly linked to a slowdown 00:02:22.020 --> 00:02:25.340 in the AMOC. Ah, okay. So why is it slowing down? 00:02:25.740 --> 00:02:28.599 The main culprit seems to be freshwater. Lots 00:02:28.599 --> 00:02:31.360 of it. Melting ice from Greenland, mostly. This 00:02:31.360 --> 00:02:33.319 freshwater pours into the North Atlantic and 00:02:33.319 --> 00:02:35.620 it dilutes the salty ocean water. Making it less 00:02:35.620 --> 00:02:38.680 salty and less dense. Exactly. Less dense water 00:02:38.680 --> 00:02:40.780 doesn't sink as readily. So that sinking part 00:02:40.780 --> 00:02:42.699 of the conveyor belt, the engine driving it, 00:02:42.960 --> 00:02:45.069 it weakens. The whole system slows down. And 00:02:45.069 --> 00:02:47.710 less heat gets transported north, leading to 00:02:47.710 --> 00:02:50.289 that cooling south of Greenland. That's the mechanism. 00:02:50.389 --> 00:02:54.430 And we have data going back over 100 years showing 00:02:54.430 --> 00:02:56.669 this long -term weakening trend in the AMOC. 00:02:56.870 --> 00:02:59.289 Plus, the climate models really back this up. 00:02:59.610 --> 00:03:02.629 Only the models that simulate a weaker AMOC can 00:03:02.629 --> 00:03:05.469 actually reproduce the cooling and the freshening, 00:03:05.509 --> 00:03:07.590 the lower salinity that we've observed in that 00:03:07.590 --> 00:03:09.729 specific region. OK, so that covers the ocean 00:03:09.729 --> 00:03:12.000 side. But you said the atmosphere is equally 00:03:12.000 --> 00:03:14.939 involved. How does a colder ocean surface affect 00:03:14.939 --> 00:03:17.500 the air above it? Is it just, like, locally cooler 00:03:17.500 --> 00:03:20.120 air? It's more than just cooling the air directly. 00:03:20.199 --> 00:03:22.620 It's about moisture. Colder water means less 00:03:22.620 --> 00:03:25.360 evaporation. Right. Less water turning into vapor. 00:03:25.659 --> 00:03:27.620 And less water vapor in the atmosphere means, 00:03:28.039 --> 00:03:29.960 well, water vapor is a greenhouse gas, isn't 00:03:29.960 --> 00:03:32.900 it? It traps heat. Ah, I see. So less water vapor 00:03:32.900 --> 00:03:35.479 means less trap heat locally. Precisely. You 00:03:35.479 --> 00:03:38.110 get a drier... cooler atmosphere right above 00:03:38.110 --> 00:03:41.870 that cold patch. And this drier, cooler air then 00:03:41.870 --> 00:03:44.129 feeds back onto the ocean, helping to keep it 00:03:44.129 --> 00:03:45.930 cool, maybe even making it a bit cooler still. 00:03:46.090 --> 00:03:48.229 So it's feedback loop. The cold ocean makes the 00:03:48.229 --> 00:03:50.689 air cooler and drier, which then helps keep the 00:03:50.689 --> 00:03:54.229 ocean cold. Exactly. It amplifies and sort of 00:03:54.229 --> 00:03:56.129 locks in the cold. It's like turning down the 00:03:56.129 --> 00:03:58.689 local greenhouse effect just in that area. It 00:03:58.689 --> 00:04:01.069 really shows just how tightly interwoven the 00:04:01.069 --> 00:04:03.349 ocean and atmosphere are. It's such a delicate 00:04:03.349 --> 00:04:08.000 balance. OK, so. Bringing this back, why should 00:04:08.000 --> 00:04:10.740 someone listening right now, maybe miles away 00:04:10.740 --> 00:04:12.960 from the Atlantic, why should they be concerned 00:04:12.960 --> 00:04:15.699 about this cold blob? What are the real -world 00:04:15.699 --> 00:04:18.339 impacts? Well, they're quite significant, potentially. 00:04:18.800 --> 00:04:21.019 First, as I mentioned, messing with the AMOC 00:04:21.019 --> 00:04:23.519 and creating this cold spot disrupts the jet 00:04:23.519 --> 00:04:26.259 stream. That directly influences weather patterns, 00:04:26.379 --> 00:04:29.180 where storms go, how much rain falls across North 00:04:29.180 --> 00:04:31.879 America and Europe. Think extreme weather events. 00:04:31.980 --> 00:04:34.529 Okay, so more unpredictable weather. Potentially, 00:04:34.829 --> 00:04:38.189 yes. And then, if the MOC were to weaken drastically, 00:04:38.889 --> 00:04:41.550 or in a worst -case scenario, collapse. That 00:04:41.550 --> 00:04:43.470 could trigger a really sharp temperature drop, 00:04:43.829 --> 00:04:45.649 especially across northern Europe. We're talking 00:04:45.649 --> 00:04:48.329 major changes. Wow. OK. What else? There's sea 00:04:48.329 --> 00:04:50.589 level rise. Changes that AMOC can actually affect 00:04:50.589 --> 00:04:52.870 sea level heights, potentially making sea level 00:04:52.870 --> 00:04:55.389 rise worse along the US East Coast. Really? How 00:04:55.389 --> 00:04:58.189 does that work? It's complex, related to ocean 00:04:58.189 --> 00:05:00.269 dynamics and how the currents pile up water. 00:05:00.910 --> 00:05:03.550 But a weaker AMOC can allow coastal sea levels 00:05:03.550 --> 00:05:05.829 to rise more on the western side of the Atlantic. 00:05:06.490 --> 00:05:08.569 And of course, changing water temperature and 00:05:08.569 --> 00:05:11.660 salinity has huge impacts on marine life. fish 00:05:11.660 --> 00:05:15.139 stocks, ecosystems. They're all sensitive to 00:05:15.139 --> 00:05:18.000 these shifts. So understanding all this helps 00:05:18.000 --> 00:05:20.699 predict future climate changes better, especially 00:05:20.699 --> 00:05:22.680 for places like Europe. Definitely. Improving 00:05:22.680 --> 00:05:24.680 our climate models with this understanding is 00:05:24.680 --> 00:05:27.199 crucial for forecasting, especially regionally. 00:05:27.339 --> 00:05:28.579 You know, just when it sounds like we're heading 00:05:28.579 --> 00:05:31.980 towards a potentially concerning slowdown... 00:05:31.759 --> 00:05:34.540 There's this other twist, right? Something about 00:05:34.540 --> 00:05:38.500 a possible backup system in the Arctic. Ah, yes. 00:05:39.000 --> 00:05:41.339 That's a really interesting, fairly recent line 00:05:41.339 --> 00:05:44.019 of research. The idea of some resilience in the 00:05:44.019 --> 00:05:45.800 system. So what's happening there? Researchers 00:05:45.800 --> 00:05:47.720 are observing something called Atlantification 00:05:47.720 --> 00:05:50.459 in the Arctic Ocean. Atlantification, meaning 00:05:50.459 --> 00:05:52.819 it's becoming more like the Atlantic. In a way, 00:05:52.980 --> 00:05:55.160 yes. The Arctic is generally becoming warmer. 00:05:55.389 --> 00:05:58.949 less ice covered, and warmer, saltier Atlantic 00:05:58.949 --> 00:06:01.449 water is pushing further and further into the 00:06:01.449 --> 00:06:03.810 Arctic Ocean each year. Where is this happening 00:06:03.810 --> 00:06:06.629 most? We see it strongly in places like the Barents 00:06:06.629 --> 00:06:09.370 Sea. That's actually expected to be the first 00:06:09.370 --> 00:06:12.089 part of the Arctic to become ice free year round 00:06:12.089 --> 00:06:14.910 and also north of Svalbard. OK, so the Arctic 00:06:14.910 --> 00:06:17.170 is getting more Atlantic like. How does that 00:06:17.170 --> 00:06:20.790 help the AMC, which relies on cold, dense water 00:06:20.790 --> 00:06:23.970 sinking way further south? Well, the twist is 00:06:24.089 --> 00:06:26.509 As this warmer Atlantic water interacts with 00:06:26.509 --> 00:06:28.610 the Arctic conditions, and particularly as sea 00:06:28.610 --> 00:06:31.290 ice forms in winter, the remaining water becomes 00:06:31.290 --> 00:06:33.970 saltier and denser. And it turns out the Arctic, 00:06:34.449 --> 00:06:36.449 through this atlantification process, might actually 00:06:36.449 --> 00:06:38.089 be starting to produce more dense water than 00:06:38.089 --> 00:06:40.389 it used to. Oh, interesting. So it's creating 00:06:40.389 --> 00:06:43.610 dense water in a new place. Kind of. It seems 00:06:43.610 --> 00:06:45.949 to be partly compensating for the slowdown in 00:06:45.949 --> 00:06:47.970 dense water formation in the traditional areas, 00:06:48.230 --> 00:06:50.430 like the Greenland and Norwegian seas. So like 00:06:50.430 --> 00:06:52.649 a backup generator kicking in? That's one way 00:06:52.649 --> 00:06:54.490 to think about it. It suggests the system might 00:06:54.490 --> 00:06:57.370 have more resilience than we thought. But, and 00:06:57.370 --> 00:06:59.670 it's a big but, we need more research. There 00:06:59.670 --> 00:07:02.050 are still questions about whether the dense water 00:07:02.050 --> 00:07:05.060 formed in the Arctic is... quite dense enough, 00:07:05.540 --> 00:07:08.300 or if it can effectively replace the really deep, 00:07:08.500 --> 00:07:10.420 dense water formation that historically happened 00:07:10.420 --> 00:07:13.019 in the Nordic seas and powered the strongest 00:07:13.019 --> 00:07:16.160 AMO circulation. Maybe some resilience, but the 00:07:16.160 --> 00:07:18.779 jury's still out on how much. Precisely. It's 00:07:18.779 --> 00:07:21.199 an active area of study. So wrapping this up, 00:07:21.360 --> 00:07:24.660 it's clear this seemingly simple cold spot in 00:07:24.660 --> 00:07:28.100 the Atlantic is tied into these huge complex 00:07:28.100 --> 00:07:31.360 planetary systems, ocean currents, the atmosphere, 00:07:31.600 --> 00:07:34.139 melting ice. It's a really powerful reminder 00:07:34.139 --> 00:07:36.560 of how interconnected and frankly how delicately 00:07:36.560 --> 00:07:39.399 balanced Earth's climate really is. Absolutely. 00:07:39.519 --> 00:07:41.540 And our understanding is clearly still evolving, 00:07:41.600 --> 00:07:43.560 which hopefully helps us anticipate what's coming. 00:07:44.170 --> 00:07:46.149 makes you wonder, doesn't it? What else are we 00:07:46.149 --> 00:07:48.149 going to discover that shifts our perspective 00:07:48.149 --> 00:07:50.389 on how all this works? That's the fascinating 00:07:50.389 --> 00:07:53.329 part. This research really drives home that even 00:07:53.329 --> 00:07:56.129 with global warming as the big picture, these 00:07:56.129 --> 00:07:58.569 regional variations, these anomalies like the 00:07:58.569 --> 00:08:01.350 cold blob, offer vital clues. They show us the 00:08:01.350 --> 00:08:03.290 nuances, the intricate ways the planet responds. 00:08:03.769 --> 00:08:05.790 It really underscores, I think, why we need to 00:08:05.790 --> 00:08:08.389 keep digging, keep asking questions, and be open 00:08:08.389 --> 00:08:11.269 to complex answers in this changing world. Indeed. 00:08:11.829 --> 00:08:14.430 Well, this Meteorology Matters podcast is a collaboration 00:08:14.430 --> 00:08:16.870 with meteorologist Rob Jones. You can follow 00:08:16.870 --> 00:08:19.009 Rob's work. He's on Instagram at Meteorologist. 00:08:19.089 --> 00:08:22.329 That's M -E -T -E -O -R -O -L -O -G -I -S -T. 00:08:22.550 --> 00:08:25.509 On TikTok, look for TV Meteorologist. And over 00:08:25.509 --> 00:08:28.050 on YouTube, search for Rob Jones Hurricane. That's 00:08:28.050 --> 00:08:30.189 Rob Jones Hurricane, all one word. And you'll 00:08:30.189 --> 00:08:32.309 also find the Meteorology Matters podcast playlist 00:08:32.309 --> 00:08:34.389 there. Thank you so much for joining us today 00:08:34.389 --> 00:08:36.929 as we explored this piece of the Earth's amazing, 00:08:37.009 --> 00:08:38.389 intricate climate puzzle.