subscribing<\/a>. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\nThanks so much for coming on to chat with us.<\/p>\n
Andrea Thompson: Thanks for having me.<\/p>\n
Feltman: So we\u2019ve talked, briefly, about this year\u2019s El Ni\u00f1o in a couple other episodes. But let\u2019s start with the basics just to refresh our listeners\u2019 memories. What exactly is El Ni\u00f1o?<\/p>\n
Thompson: Right. So it\u2019s this, sort of, cyclical climate phenomenon. Its epicenter is in the tropical Pacific Ocean. And so basically in, sort of, normal times or on average, trade winds blow from east to west and across the tropical Pacific, and that, sort of, piles warm water up around Indonesia.<\/p>\n
But in El Ni\u00f1o times, those winds weaken or can even reverse, and that means all of that warm water, sort of, sloshes back over toward the eastern tropical Pacific. And that can have really big impacts because that heat isn\u2019t just limited to the ocean; it\u2019s releasing out into the atmosphere. And that changes where clouds and storms form, which has, sort of, this domino effect in the atmosphere that can change major weather circulation patterns.<\/p>\n
And, for example, it tends to quash hurricane activity in the Atlantic because you get a lot of what we call wind shear, so sort of cross-cutting winds, whereas in the Pacific Ocean, it tends to ramp up hurricane activity, which we\u2019ve seen both of those play out over this hurricane season with really not a lot happening in the Atlantic and then whole bunch of flurry of storms in the Pacific.<\/p>\n
And this particular El Ni\u00f1o is really, really strong; so the, the warm waters in the Eastern Pacific right now are just record-breakingly hot in terms of basically any El Ni\u00f1o we\u2019ve seen in our lifetimes.<\/p>\n
Feltman: Well and we\u2019ve heard a lot about how this year\u2019s El Ni\u00f1o is so intense. So I guess, a few questions there that we can tackle one at a time. How intense is it? How do we know? And then: What kinds of impacts are we gonna see because of that? So let\u2019s start with just, you know, what do we mean by saying this is such a powerful El Ni\u00f1o, and how does it compare to previous years?<\/p>\n
Thompson: Right. So we mainly measure that based on the sea surface temperatures in a specific part of the Pacific Ocean. And we, sort of, monitor what those temperatures are doing. If they reach a certain threshold, that\u2019s when we say, \u201cWe\u2019re in an El Ni\u00f1o,\u201d and then if they get, you know, really high, then you could say, \u201cThis is a very strong El Ni\u00f1o.\u201d<\/p>\n
And these have been breaking records since September. I talk to climate scientists who are, kind of, just aghast at how strong this one is. Right now, temperatures in the, sort of, core part of the Pacific where we monitor El Ni\u00f1o are about 3.5 degrees Celsius above normal. That is astounding. They could reach four degrees Celsius above normal, when this event, sort of, peaks, which typically happens in the November-December timeframe for El Ni\u00f1os. And those just, sort of, absolutely smash any heat records we have, at least with direct temperature measurements. Those go back to, into the 19th century, and the, sort of, the record we have was set by an El Ni\u00f1o in 1877.<\/p>\n
We can also estimate sea surface temperatures going further back than, you know, direct temperature measurements based on things like tree growth rings, coral growth rings, and those tree rings tell us how El Ni\u00f1o\u2013related precipitation changes happened. And then coral growth rings are actually a little bit more direct. How the coral grows is related to sea surface temperatures. And so those we can build out an estimate going back to around the year 1100, and this would probably set records even going back that far. So this is a truly astounding event.<\/p>\n
Feltman: Wow. And do we know why this is happening?<\/p>\n
Thompson: It can be hard to say. So, you know, El Ni\u00f1o and especially really big El Ni\u00f1os are still relatively rare events, and so you don\u2019t quite have enough data to really be able to piece out why they happen when they happen. Anytime data is rare, it\u2019s very hard to find a trend. There is some new research that indicates that climate change may be pushing us more toward these really strong El Ni\u00f1os. That\u2019s based also in coral records. So it could be that we\u2019re seeing more of these in part because of climate change.<\/p>\n
But some of it\u2019s also probably just the chaos of the Earth\u2019s system that, you know, sometimes you\u2019re gonna get one, and sometimes you aren\u2019t. And of course, there\u2019s a baseline warming of the world\u2019s oceans that\u2019s feeding into this a little bit, but even, sort of, subtracting that from the ocean temperatures, this El Ni\u00f1o is still outstanding.<\/p>\n
Feltman: Right. Well, and so segueing into the impacts we can expect, you know, even though we can\u2019t necessarily pin this on climate change, the fact that climate change is happening and global temperatures are already warmer and weather is already weirder probably means that a really extreme El Ni\u00f1o is maybe more worrying than it would\u2019ve been a couple decades ago. Would you say that that\u2019s correct?<\/p>\n
Thompson: Definitely can, because for an example, El Ni\u00f1o tends to bring drought conditions to the Amazon. And the Amazon is already in a weakened state, both in part because of a previous strong El Ni\u00f1o that caused drought and contributed to wildfires as well as climate change acting on that and exacerbating those droughts. And then other, of course, land-use change happening in parts of the Amazon. So you don\u2019t just have the effects of this El Ni\u00f1o, you have all those other things playing in.<\/p>\n
And then we have various what are called teleconnections in scientific parlance, where El Ni\u00f1o has certain effects in certain places. And generally these are more robust when you have a very strong El Ni\u00f1o just because you have more input into the system from the El Ni\u00f1o. So, you know, you have the effects on hurricanes in the Atlantic and the Pacific, where we\u2019ve seen almost no hurricane activity in the Atlantic this year and a flurry of storms especially around Hawaii and the Pacific. You\u2019ve also seen a major drought and wildfires in Indonesia. That is a hallmark of El Ni\u00f1os.<\/p>\n
And generally, the closer places are to where El Ni\u00f1o is, sort of, happening, the stronger the impacts are, which makes sense. But they can reach really far afield too, so you know, there are teleconnections in Africa. You tend to have more rainfall and flooding in the Horn of Africa but less rainfall and drought in, sort of, South Africa. And it\u2019s going to be particularly interesting to watch this winter.<\/p>\n
So, you know, with the climate being warmer than it was in the past, you know, it\u2019s unclear how much of the precipitation from these storms may fall as rain instead of snow when what you want in the West is snow because that snowpack is, sort of, what gives you the water that lasts you through spring, summer and fall.<\/p>\n
These storms also bring a lot of coastal waves, we already have exceptionally high sea levels off the coast of California right now \u2019cause it\u2019s very warm there, too, and we have these, sort of, pulses of warm water that can come up from the main El Ni\u00f1o region called Kelvin waves, which I know we talked about before. And so all of that together could mean we have a lot of major coastal flooding in California this winter.<\/p>\n
Feltman: Right. So how much do we know about how long the El Ni\u00f1o is gonna last?<\/p>\n
Thompson: So we have a pretty good understanding of, sort of, the cadence of El Ni\u00f1o. It tends to always peak in the November\/December\/January timeframe. This one has ramped up a lot faster than ones we\u2019ve seen in the past, so it got warm very quickly.<\/p>\n
It\u2019s a little unclear exactly how high it\u2019s going to peak, and that might determine how long temperatures stay really elevated. If it peaks higher, it may take longer for them to come down. After it peaks, it\u2019ll, sort of, slowly come down through the winter.<\/p>\n
But winter is typically the time where we see the biggest impacts, at least in the Northern Hemisphere, in the U.S. It\u2019s gonna last several more months. Eventually it will, sort of, exhaust itself, and ocean temperatures will get back to, sort of, more typical levels, and then we\u2019ll be in what\u2019s called, sort of, neutral conditions.<\/p>\n
But the heat of an El Ni\u00f1o in the atmosphere always lags the heat in the ocean, the heat in the ocean peaks November\/December-ish. Heat in the atmosphere follows a few months behind. So we\u2019re going to see global temperatures stay elevated for longer. Right now it\u2019s a little unclear if 2026 is going to be the hottest year on record. Very well could be. It\u2019s definitely going to be up there, which is pretty remarkable because we started this year in, sort of, a weak La Ni\u00f1a state, so …<\/p>\n
Feltman: Which brings temperatures down?<\/p>\n
Thompson: Down, yeah. So no one was expecting that this was going to be a contender. It will definitely be 1.5 degrees Celsius above preindustrial this year, which would be the second year that\u2019s ever happened after 2024.<\/p>\n
[The year] 2027 [is] almost certainly going to be the warmest year on record because of that heat lag. And it will also be warmer than 1.5 C. And one thing I\u2019ve talked to with some scientists is the question of: Do we come back down from that, or are we, sort of, at 1.5 C from now on? Now, that still wouldn\u2019t technically breach the climate agreement \u2019cause that\u2019s considered an average over many, many years, but it\u2019s possible.<\/p>\n
Now, if we swing over to La Ni\u00f1a, maybe we come back down below 1.5 C above preindustrial. It\u2019s a little hard to tell. But, you know, this is definitely not going in the direction we want things to go in, for sure<\/p>\n
Feltman: Yeah. I remember years ago, at this point, an expert I talked to said, you know, \u201cWe\u2019re on an escalator. El Ni\u00f1o is us getting up on our tippy-toes, and La Ni\u00f1a is us ducking down, but the escalator keeps going up.\u201d And that has really stuck with me all these years.<\/p>\n
Thompson: Right. Yeah, and typically, sort of, El Ni\u00f1o\u2019s temperature effects on the globe are temporary. Eventually that heat is radiated back to space. But what a couple climate scientists pointed out to me is that the same, sort of, feedbacks that happen with climate change, where you have sea ice melts or permafrost thawings that can, sort of, exacerbate it, those are sort of agnostic to where that additional heat comes from. So if you have more heat coming from El Ni\u00f1o, those might also ramp up those feedbacks and, sort of, effectively lock some of the El Ni\u00f1o heat into the system instead of it just being temporary.<\/p>\n
Feltman: Well, not necessarily the most fun topic to discuss but always a pleasure to have you on. Thanks for talking us through this.<\/p>\n
Thompson: Yeah, absolutely. Thanks for having me.<\/p>\n
Feltman: That\u2019s all for today\u2019s episode. If you\u2019ve got any burning weather-related questions that you\u2019d like Andrea to help us answer for you, send them on over to sciencequickly@sciam.com<\/a>. We\u2019ll be back on Friday to dig into some surprising new perspectives on the science of stuttering.<\/p>\nScience Quickly is produced by me, Rachel Feltman, along with Fonda Mwangi, Sushmita Pathak, Allison Rodgers and Jeff DelViscio. This episode was edited by Alex Sugiura. Marielle Issa and Aaron Shattuck fact-check our show. Our theme music was composed by Dominic Smith. Subscribe to Scientific American for more up-to-date and in-depth science news.<\/p>\n
For Scientific American\u2019s Science Quickly, this is Rachel Feltman. See you next time!<\/p>\n","protected":false},"excerpt":{"rendered":"Rachel Feltman: For Scientific American\u2019s Science Quickly, I\u2019m Rachel Feltman. You\u2019ve probably heard by now, possibly even on…\n","protected":false},"author":2,"featured_media":960912,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[64,63,75,128],"class_list":["post-960911","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-au","tag-australia","tag-environment","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/960911","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=960911"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/960911\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/960912"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=960911"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=960911"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=960911"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}