Why Are There More Floods? | Neil deGrasse Tyson and Radley Horton Explain...

[Music] chuck another explainer yes yeah except we're running out of stuff that i'm an expert in so we gotta we gotta reach for other places now okay yeah i think i'm i'm tapping we're striking yeah the whole universe i got the universe covered but earth that's another thing so what there's such intriguing disastrous news about catastrophic flooding in the world recently and places that that that are that we've never seen it before and i just thought you know is there someone nearby and of course columbia university has has very rich traditions in thinking about uh climate not only with the nasa a branch of nasa that's there the goddard institute for space studies but hold departments on this and so we found a professor where this is what he does uh radley horton bradley welcome to star talk thank you it's great to be here again you tell me tell me your official title so i'm a climate scientist at the lamont dougherty earth observatory located a little north of colombia's main campus i'm also part of colombia's emerging interdisciplinary climate school which is going to be on the main campus an exciting new initiative to blend earth science with impacts and solutions to these challenges and and your specialty is what within climate science climate prediction extreme weather events extreme weather and adaptation okay so you're the main you got the hottest thing going right that's right chuck he's the man he's the man other events yeah so so so rally floods are nothing new i mean there's the flood legend in gilgamesh in the bible and so so why should anyone think differently about recent flooding than we've ever thought about flooding in the past yeah well you're right i mean flooding is one of the most fundamental dangers that the climate system presents us with but as we're experiencing global warming temperatures are rising by one or two degrees which doesn't sound like much it means that that atmosphere is capable of holding more moisture and as a result when conditions are right we're seeing much heavier rain events than we've when conditions are wrong okay there you go thanks for correcting me on that wrong statement no i mean just to give a sense of this um over the eastern half of the united states just in the last 50 years or so there's evidence that that sort of worst heaviest rain event per year now provides about 50 percent more rain than it did two generations ago right when we built a lot of our critical infrastructure right so the infrastructure that's a good point because when you when you create cities you say how big should the sewer pipe be how high should the flood wall be how how how uh what's the slope of the street towards the drain so good engineers civil engineers calculating all this and they would have no idea what future challenges would that they would confront with their design yeah the statistics of these events have changed in a way that those designers couldn't foresee back then and what's really you know distressing about it is let's just say you increase the rain by 20 percent um that doesn't mean twenty percent more flooding it might mean three hundred percent more flooding right because it's like you don't flood at all up until a certain point and then boom things can get out of control uh in a hurry and put on top of that a lot of this infrastructure is aging right it's beyond its intended lifetime or we haven't invested enough to to maintain it so it's a it's a challenging situation we never invest enough to maintain or to take preventative measures but we always have enough money to pay for the damage which runs normally five to ten times more than the investment an ounce of prevention right a dollar towards yeah no that's right okay so hold the cities aside for the moment could you tell me what is physically happening in a flood normally when it rains the water just goes into the soil if it rains a little more why doesn't it go into the soil a little more i don't see the problem yeah right so maybe just to back it up even more just to remind folks the difference between rainfall and flooding right rainfall stating the obvious here is what's coming out of the atmosphere could in theory be snow but you know most of the time it's rain not all rain events turn into floods so what determines whether it's a flood certainly that's my question yeah yeah is this sorry is the rate of the rainfall um but then we also have to turn to things like what is the land surface like have we replaced these soils which might have been pretty good with strip malls yes parking lots um you know that's going to increase these flood rates dramatically when we see regions that have experienced deforestation or maybe forest fires during drier times uh eliminating some of this vegetation that can set the stage when it does rain again for moisture not getting taken up by the the soil which gets sort of a firm surface to the root systems of trees right exactly yeah these aren't there to take up that moisture anymore um so we get more extreme flood events largely due to these longer lasting rain events and more intense rainfall per hour right that because that's sort of worst hour worst rate of rain that matters the most but there's these other components too how we're changing the landscape and decisions we make about things like dams too right also have and water management also have have implications we've seen footage the most what i've seen most recently is flooding in las vegas where it hardly ever rains there so i guess there's a difference between heavy rain where it has rained before and heavy rain where no one has any clue what to do about it because all the roofs were leaking into the interior because no one checks if the roof has holes if it never rains right absolutely there was water flooding out of the lamp the light fixtures and the ceiling going on all the the craft tables and and the and the the bedding machines and i just thought to myself wow this is something predicted yeah well you you would have predicted it you predict nope maybe i'd like to like to say i would have i don't know if i would it's these things are happening so much faster what happened in pakistan update me on that okay so though you know i was looking into that recently we're over a thousand deaths now as a result of these rain events is pakistan in the in the monsoon zone or not pakistan is in the monsoon monsoon is flooding and they get that every year so why is this different it does they're really at the extreme sort of western edge of the monsoon zone and what that means is the monsoon on average arrives later it's a relatively short monsoon season and it can vary quite a bit year to year sometimes it doesn't make it all the way into extreme parts of pakistan um but this is a so there's high variability generally there in the month but it's been really extreme this year since they started keeping records in roughly 1961 a little while after partition this is the worst year in terms of the amount of right the partition between india and pakistan yeah it's actually about a decade later but you know 1961 i think was was when the record started um and you know we're talking about five to ten times as much rainfall as the typical year um depending on depending on where you're where you're looking at and this is you know to generalize about the country a lot of mountainous areas right a lot of dependence on these river valleys where people are concentrated into low areas and rivers the infrastructure is there populations are there crops are there so when you get that water being channeled through these mountain valleys the people everything is concentrated in a way where the recipe is there for really extreme suffering we're seeing that by some estimates i think two million homes roughly damaged or destroyed prop systems you know extremely affected um 33 million people uh by one estimate you know experiencing so here we have a case where pakistan is not one of the big carbon footprint emitters of the world yet they're suffering badly from the inaction of other nations that are and that's that's tragic it's tragic and it's not fair right just as it's not fair that uh young people who haven't been responsible for for emissions are going to be the ones who who suffer the most inherit the mess yeah yeah but you know hey here on the upside guess what we're going to suffer too so oh that's the upside thank you chuck for that thank you yeah i mean you know so so in a flood what what is what is the primary cause of death is it fast-moving waters or is it it's the standing water that becomes uh germ-infested yeah disease disease and waterborne illnesses yeah what is the more typical way of flood causes flood deaths yeah i don't i'm not sure the answer to that question my first thought it's probably the depth of the water and how quickly the water is moving that tends to be the most important certainly in the short term but i think it's an open question that you're raising which is are we accurately counting the long-term damages whether it's mold in a building right whether it's groundwater pollution um you know as as chemical sites or you know right you have sewage backing up because now there's a liquid liquid pathway between your sewage treatment your your sewers and your roads and homes that's right and thinking about this now i'm thinking now about the pakistan example that damage to these crops right what's that going to mean in a country where there's a lot of people who are food insecure mental health issues of flooding and you know losing your home and your and your livelihood so it may actually really be an open question of of which aspect of the flooding is the most detrimental so are there parts of the world that are particularly at risk that you can warn the world about or do you they just kind of show up and so it's kind of not to sort of uh make this a contest but if you after the fact say see i told you so well did you really did you say pakistan was at risk no you said the world is at risk and then it shows up in pakistan do do your models allow you some precision of time and place that was weren't available previously to planners yet climate models are improving i would say you know the climate models help us do these long-term predictions what are the statistics of heat waves and temperature going that's just not helpful if i want to plan for tomorrow's flood and i don't know it's going to flood tomorrow yeah so we have weather models too which are you know what are used to forecast what's going to happen to a hurricane for example next week those certainly are improved but just to distinguish you have climate which is long-term averages and you have weather which is what's happening in your weather forecast right yes yeah and those those forecasting models have improved just a general statement you hear sometimes is that weather forecasting of today is as successful looking at about five days as weather forecasting was a generation ago when looking out three days right or even one day no i remember you didn't know if it was going to rain tomorrow you had to your picnic would be on hold until you know that morning and unless unless your grandfather's bursitis was acting though rheumatism on the porch you got to be on the porch we're in for a big one i'm letting you know chuck one day i want to meet all your relatives okay sorry bradley what about the bursitis predictive forces do you have an old man on your porch that's a question i've never gotten before i'm stumped yeah right so just tell me let's get back to what i asked um are you do you have what kind of precision do you have about certain regions that are highest at risk yeah so yeah for in the sort of time scale of the weather forecasting you know we're getting better at this one thing you're hearing more and more about now is these atmospheric river events these plumes of moisture sometimes referred to as the pineapple express because they often originate generally speaking near hawaii right with all it's with all its pineapples under the right conditions you will get a narrow ribbon in the atmosphere of moisture essentially a river that can flow right into land and then sometimes if the topography is right topography is a huge part of flooding start to rise up say this sierra mountains in california dumping out all their moisture rapidly we're seeing instances now where some of these events can be predicted a week or so in advance roughly that's definitely progress longer term you know how good is how strong is the monsoon season gonna be for pakistan next year a year or two from now we're making progress but there's still a lot of uncertainty and i think a lot of surprises a lot of areas have to assume that things that they didn't plan for could happen it would just be helpful with all the naysayers if you could say you know in the next two years this region's going to have a catastrophic flood and then it does right yeah and then they'll shut up finally and listen to you guys but one one thing you can say without in without any reservation is that uh we have seen an intensification of all weather events due to climate change and the climate crisis and with that in mind if you look at the worst thing that has happened to you historically you can count on that happening again and or something worse or something much worse yes is that a fair statement that's what you should be that's what you should be um preparing for that is a fair statement and any time we go beyond one city or one season we have more statistical power so if we start talking about a nation as a whole the world as a whole or an average over five or ten years here the statistics are totally compelling right we're clearly seeing those heavier rain events more extreme heat waves fewer cold air outbreaks and more drought right and some people do need to plant at those scales right your insurers your reinsurers your emergency management officials they need they should be need to be looking at that whole picture as they balance their their resources and geopolitically you could have climate refugees when they're what some nations in the in the south pacific where this the average is was a meter above sea level or something or less and yeah no right we've been focusing on the the sort of flooding that's coming from rain events but let's keep in mind too as sea levels rise as you know coastal flooding right these these storms that are piling water up through their winds along the coast are going to cause that water to go much further inland than it did in the past even if the storms don't get any stronger and the winds don't get any stronger just because the bathtub is higher right sea levels higher right and for places like you know where where we're sitting in new york during a certain storm it might be the blend of all three higher sea levels a stronger storm pushing more water on the coast and heavier rain events yeah exactly that was uh that was uh the remnants they call it the remnant of hurricane ida so without the wind we had a larger storm surge than a hurricane the most rainfall that ever happened in the shortest period of time which resulted in greater flooding that was in manhattan right that was in manhattan right right side of the suburban city here right right so it's this idea of like the compound risks the multiple risks a lot of city planners have said how strong might the storm be how high might the sea level rise be how much rain might we get you got to put it all together how are the risks of of all these things occurring what's what phase of the moon does does it have does it hit your shores right yeah that's right yeah man what phase and what time of day it's crazy that's great well one thing that you said bradley that uh everybody should take into account uh which is insurance companies if you want to realize how real this problem is there is not one insurance company on earth that does not have climate crisis contingencies and uh prediction predictive models in their business plan going forward for the next 50 years they in the military are the leading major agencies that are not climate deniers in this that's right in this equation and of course radley [Laughter] yeah but you know bradley's getting all that sweet sweet government money oh that's why he's doing it yeah you know they're making it rain on him so he's got to say this is going to happen yeah of course of course a big science conspiracy we all get together that's right right it's crazy guys we got to end our our explainer here but this is fascinating radley uh this is it's it's not every day we just get a behind the scenes on what's going on not only in the world but in the models that predict it so think we'd love to get you back on and because we'll we'll find other excuses to do this again because this is not your only bit of expertise you can share with us with your permission we'll keep you on the rolodex and young ends look up rolodex google it you'll know what a rolodex is bradley uh how do we find you on social media um i'm on twitter uh at radley horton radley horton okay we'll find you there chuck your chuck nice comic as always everywhere thank you yes telling people your comic because they didn't otherwise know is that by you well you know what can i say i i like to reinforce what people make okay you repeat it enough they'll believe it right is that what it is [Laughter] neil degrasse tyson has been another star talk explainer this one on flux as always keep looking up [Music]

Channel: StarTalk

Views: 190,959

Keywords: startalk, star talk, startalk radio, neil degrasse tyson, neil tyson, science, space, astrophysics, astronomy, podcast, space podcast, science podcast, astronomy podcast, niel degrasse tyson, physics, floods, flooding, extreme weather, climate change

Id: D1eN-kfYVGY

Length: 18min 58sec (1138 seconds)

Published: Tue Sep 13 2022