Climate Threatens Food Supplies Even With Adaption, with Andrew Hultgren

[00:00:00] Speaker 1: and welcome to climate chat i'm your host dan miller and today we have a special guest professor andy holprin from the university of illinois urbana champaign and we're going to get to him in just a moment but first i want to just give a little bit of a heads up up some upcoming programs on climate chat on sunday july 13th we have sanjay waggle and we're going to be talking about uh investment opportunities in climate adaption it's a subject you don't actually hear a lot about although today's program is is on that um and then on thursday july 17th so it's a special day thursday not sunday matthew england who we've had on before on the early days of climate chat and we'll be talking about his kind of important paper about an alternative explanation or perhaps a complementary explanation for the recent accelerated warming that we've been seeing and then on sunday july 20th ben santer a well-known climate scientist who's done work on uh the sort of the climate fingerprint how we know that climate change is caused by humans and then also on thursday and again a special day on july 31st uh we have uh former u.s energy secretary stephen chu also nobel prize winner stephen chu and a professor at stanford and um i met uh steve a long time ago when he was actually giving a climate talk um really long time ago and so anyway all of that is upcoming and don't forget to like and subscribe and hit the notification bell so that you don't miss out and remember a couple of these programs are not at our regular time so you really probably want to hit that notification bell so that you don't miss them so without that out of the way um let's get on and first of all let me just tell you that that andy is an environmental and industrial organization economist studying the economics of environmental regulation his research interests include firm behavior under regulatory uncertainty and quantifying the economic impacts of climate change which is what we'll be talking about today he is an assistant professor at the department of agriculture and consumer economics at the university of illinois urbana champaign he is also a faculty affiliate at the national center for supercomputing application and is a member of the climate impact lab so with that andy welcome and maybe you could just start off in telling us just a little bit more about your background and how you came about to be study uh to focus on climate change oh sure yeah um [00:02:57] Andy: thanks stan for having me on the program i'm honored to be included in such like a light of illustrious uh i guess that's that's amazing um uh yeah i i have a weird background uh for an economist uh i was a chemical engineer uh kind of early in life that was my undergraduate degree was in uh and i and i worked in especially especially chemicals uh inkjet ink r d for for several years after after graduating actually um so my interest in climate change really started uh in the mid 2000s when it sort of became apparent you know i would just kind of follow information online and it became apparent that the world was warming and the impacts of climate change were happening much faster than climate scientists had thought they would um this was kind of when that when that was uh that realization was happening was getting out into the public conversation um so that made me uh more and more interested in working on climate change and my background in chemical engineering helped me think a little bit about energy balance in the atmosphere and heat transfer and things like that um so so i was able to sort of follow things along but i wanted to work on climate policy so i went to the gulden school of public policy at uc berkeley to get my master's in public policy and then i thought i would go work in a think tank working on climate policy or or work for a legislator or something like that um and i met um some researchers at uc berkeley faculty at uc berkeley in particular solomon shun chum and and also max offheimer who would go on to become my dissertation advisors and they essentially um really opened up a world of research that was providing inputs to policy making that seemed really important right understanding what is the magnitude of the economic impacts of of climate change right which was um something that we're trying to wrap our heads around now right there's the physical impacts of climate change how much the world might warm or something like that how precipitation trends might change and then there's the economic implications of that and and if you want to talk to policy makers and if you want to um uh think about climate policy uh uh those economic impacts are really important important part of that conversation um but they're hard to quantify right and so that's how i got into this work i went on to get my phd and have continued [00:05:25] Speaker 1: working on this ever since okay well that is interesting from that to agriculture um yeah yeah so tell us a little bit about this paper but first start off by telling us like how it's structured you know what kind of study this is yeah and what you did you gathered an incredible amount of information as part of this and then we'll get into what what the results are yeah yeah so um it [00:05:54] Andy: is not a mystery that climate change is going to affect agriculture right agriculture if you pick a sector of the economy agriculture is probably the most weather exposed sector you know farmers like understand very clearly that weather is an input into their into their productivity right on their farm uh what what what is not clearly understood and this really motivated how we approached the paper is how farmers will adapt to climate change right so you have like a set of studies that essentially look at heat shocks and and uh sort of methodologically don't consider farmer adaptation that effectively means that farmers don't adapt right by assumption and impacts to climate change look really really bad under sort of that that set of um assumptions there's another set of studies that essentially assume that farmers are able to adapt uh costlessly right and as much as they want uh and things are much more muted impacts of climate change are much more muted under that set of assumptions what we want to do is look at how look at how actual producers around the world right in rich places in the world in poor places in the world where farmers sometimes even today can't get as much fertilizer as they want much less other inputs like mechanization uh in dry places in wet places and hot places cold places we got as much data from as many places we could and we want to look at how what that data of historical climate exposure can tell us about farmer adaptation so that's what we've set out to do and as you mentioned that motivated us going and getting a wide variety of sub-national right so high resolution data on actual crop yields from as many different global contexts as we could uh and so that's what motivated the study our approach is a statistical approach so we're not running um like a detailed model of a crops biology which would be a process-based model approach rather we're running a statistical approach looking at how weather shocks in different parts of the world affect the same crop differently right so if i have like a hot day like a like a 30 c day right uh uh uh that weather shock to corn yields maze yields you know depending on what part of the world you live in um has a differential effect depending on where it happens right so the example that uh i like to give because i'm born i was born raised in minnesota so you know i like to talk i like to work in minnesota into my examples so the example i like to give is you know you have a corn farmer in minnesota and you have a corn farmer in say south texas right the corn farmer in minnesota is growing the crop in a relatively temperate place right it's relatively cool minnesota summers can get plenty hot but you know on on relative scales it's relatively cool uh and so you get that 30 degrees c day a hot day and that's not that doesn't happen very often during the growing season it's much less frequent right and when it happens you have large yield losses so a single 24-hour period at 30c can drive down corn yields in a place like minnesota by on the order of you know six to six to seven percent of total growing season yields for just that one 24-hour exposure these are very large losses in south texas farmers there understand that they're going to get very many of those 30c days right and so what we see is that same 30c day has a much more muted impact on yields right so we see yield losses an order of two percent for a 24-hour period at 30c in south texas so so that's a if you think of like a declining you know slope in yields with extreme heat exposure that slope is much more muted it's less steep in south texas there what we're doing is we're statistically uncovering adaptation is that because they're going to have lower overall yield [00:09:42] Speaker 1: because texas is just hotter in general so you're starting from a lower point or does texas per acre get the same as minnesota on a normal no you you hit the nail on the head exactly right so we want to [00:09:55] Andy: think about farmers adaptation and their costs and your question gets at their costs right so what do farmers actually do right a lot a big part of what they do is they make choices over the varietal of say corn that they're going to grow right and there are some varietals that are mature quickly right and so then you can get them out of the ground and just miss avoid all of that late season extreme temperature exposure right so one adaptation mechanism is okay i'm going to plant a variety of corn that just matures faster i'm going to harvest it earlier i'm just going to avoid all that late season growing uh that that late season extreme heat exposure right that manifests then as like zero impact for all that late season extreme heat because the crop is out of the ground already that's an adaptation mechanism now the minnesota farmer could choose to plant that varietal and avoid all that late season heat exposure too and the minnesota farmer is not making a mistake by planting the longer maturing varietal the trade-off and this is getting to your question the trade-off is the longer maturing varietal even though it has more late season heat exposure right and that's that's potentially bad it also has higher yields on average because it has there's more time for the grain to fill in right and so you literally just get more yield out of a given uh plant uh with that longer maturing varietal and so there's a trade-off right farmers can choose to adapt through say this varietal selection right and they'll avoid some of that late season heat exposure but they'll have lower yields on average to your point and that is an adaptation cost okay and so we track both of these things and by the [00:11:32] Speaker 1: way i'm gonna try to let me get the show a picture of your uh there we go oh yeah but we should be on there so let's see let's try to get us here um there we go so this is your uh it cuts it off i don't know how to do there we go okay so that's that's your by the way let me make a point to everyone that um links to the paper are in the video description on youtube so go there and you can read along if you'd like um so all right so that's how you set it up and you found some interesting things so why don't you tell us like high level what the results of this paper are and then we can we'll dig into some of the details [00:12:23] Andy: yeah yeah so i kind of um painted this picture of two different uh more extreme assumptions about farmer adaptation you know in that of existing literature one that let's see where are my hands here one that farmers don't uh maybe don't adapt at all and one that farmers can sort of perfectly and cautiously adapt right maybe unsurprisingly you know we find that the truth lies between those those two extremes so farmers do adapt that adaptation is important it reduces yield losses on the order of like 34 percent like a third by a third uh uh under a high warming emissions future relative to if adaptation hadn't happened at all right so so mitigating 34 of overall losses is is valuable right and that's important and um uh we want to note that but of course that means that two-thirds of losses are not mitigated right and and you essentially have uh persistent losses even after accounting for farmer adaptation uh the losses are on the order of um 24 percent for a higher a higher emissions future and about half that about 11 percent if we're on a more moderate uh emissions future um and those are global aggregate productivity losses and either there are implications for higher prices for consumers of course those higher prices are partially protective for farmers but farmers are facing [00:13:47] Speaker 1: revenue losses in that scenario as well so what so one of the um i guess big things so so i'm getting less productivity yeah therefore i'm supplying less food but there's there's a demand in the market for food right right so isn't the and i don't know how you handle this in terms of quote adoption but one thing that will happen is farmers will plant more land you know they'll plant more food right right right will that happen or is there something that will prevent that or anything like [00:14:17] Andy: that it's been no no no of course right that that will that will absolutely happen on the margin right um uh uh and there's a literature uh that we don't dive into studying you know sort of you know as you expand land into more marginal lands do you get the same productivities you know for the lands we're currently using is expanded and marginal lands and there's an open question about that but that will that will absolutely happen um we model uh we model a social cost of carbon so the value the economic value of these lost yields from emissions and co of co2 today right so you have a pulse of co2 that gets emitted today yeah that co2 persists in the atmosphere for a very long time and then we assign an economic value to the yield losses that are associated with that additional pulse of warming as that co2 persists in the atmosphere through that process we allow for farmer adjustments in land use planted uh to your question uh in determining sort of you know a rough model of where prices will clear in markets and things like that that is an important part of the process we still find um uh uh sort of a uh an economically uh positive contribution you know if you will like losses damages from emissions today on on the stream of of economic value out of the agricultural sector going forward [00:15:37] Speaker 1: i'm sorry say that one day i said i mean there's like a reverse thing there so you you find that for every ton of co2 emitted there's a negative impact on what on the cost or the available losses there's [00:15:51] Andy: there's economic losses right so you essentially have um yields go down right so that that shifts the supply of calories into the global market down uh uh prices go up right so consumers are harmed by the higher prices producers are helped by the higher prices but both producers and consumers are overall they're not going to be the higher prices but they're not going to be the higher prices so they're [00:16:14] Speaker 1: all worse off uh uh in the future and we quantify those economic damages yeah and what what social [00:16:17] Andy: cost of carbon are you using there there was you came up uh uh we we we're very hands-off on sort of um uh you know so if you've had other people on i don't know have you talked about the social cost of carbon on this show right they just know how you the time value of damages matters a lot right uh so the most straight straightforward thing is probably to um uh do what's called ramsey discounting right where you account for um uh you you essentially account for the uh the wealth of nations going forward right as as income growth happens and the timing of damages associated with that uh and i can pull up the figures for ramsey discounting but i think yes [00:16:57] Speaker 1: it's the order of 15 a ton for that 15 just so you know one of our first climate chat programs which was audio back then and and it's it's available on youtube with david archer he calculated the social cost of carbon if you didn't do discounting and yeah yeah yeah 27 000 a ton of co2 if you don't do if you don't do discounting yes if you're not going to sacrifice your grandchildren then yeah then how much is it cost you know it costs a lot more than you think and by the way it the damage continues for 500 000 years yeah so it's not like so it adds up over no it's totally fair totally fair totally fair [00:17:35] Andy: yeah so um and and at several thousand you know several thousand dollars a ton you know if that's um right there are welfare issues your impact is that right sorry so it's so yeah so it's just agriculture okay for a moderate emission scenario it's 17 for a higher emission scenario it's 20 right uh that's just 22 agriculture so it's just the food right and and i'll say um uh uh our group's estimates including the agriculture sector but also other sectors of the economy um uh were employed by the uh biden era uh environmental protection agency to update the social cost of carbon and that that update was 190 dollars a ton which um which includes everything becomes economically pretty meaningful in terms of you know what policies are uh you know rational uh under under that scale of damages so so these are not small you know these are not small numbers and and they matter for for [00:18:29] Speaker 1: policy making for sure yeah yeah it's a little bit like what's the economic value of putting another bullet in the chamber when you're playing russian roulette i don't know some of these numbers are uh anyway but that's that is a whole other program hey so so you've uh a certain level of climate change yeah so can you just tell us what you assumed because this is going through the end of the century right yeah yeah what kind of temperature profiles and uh yeah assume because we talk a lot about that [00:18:59] Andy: on this program absolutely absolutely so it is not clear what emissions trajectory and your viewers probably know this very well it's not clear what emissions trajectory we're on right now right so we're probably somewhere between rcp 4.5 which is a moderate emissions trajectory and enforcing trajectory and rcp 8.5 which is very high emissions enforcing trajectory i don't think we're on rcp 8.5 i think we're below it uh i don't really think we're on rcp 4.5 personally either i think we're above it um and i'm not entirely sure where we are in between so we do those two trajectories as sort of um bookends right say like that this is you know one end of the spectrum this is the other end of the spectrum uh and then and then we just report both numbers uh uh and so that's why i said um you know losses even accounting for adaptation are on the order of 24 under the high emissions rcp 8.5 and about half that 11 under 4.5 right so um that's the those are the two trajectories there are two things to note kind of within those one and this is really important we um and if your viewers can see it there's figure 3d we trace yeah yeah yeah a damage function with warming let's see if we can oh yeah so if you yeah so you can just like scroll down it should just be there yeah no i was looking at 3d yes uh yeah yeah okay yeah yeah that's it there it is the dots the one on the right there with the dots the colored dots right so so the blue dots are rcp 4.5 and the red dots rcp 8.5 oh okay the y-axis is caloric output loss the x-axis is global mean surface temperature yeah this says this [00:20:42] Speaker 1: people can't maybe because this is two four six eight c above by the way the 2001 to 2010 so that would be already built in one c so this would really be a little bit less yeah we see from pre-industrial four [00:20:59] Andy: five yeah i think it i think it might be i think it might be 0.6 uh if i remember i think it might be i could be wrong that sounds a little wrong about that i think that might that's the number that i have in my head okay okay uh so so between between 0.6 and 1c uh um uh sort of you want to go to pre-industrial so um and then this is end of century warming right yeah so i wanted to pull this one up [00:21:25] Speaker 1: for a future question so let's talk about it now yeah great first of all um our my understanding is you're talking about emissions scenarios like 8.5 that's a very high emission scenario yeah but that translates to a climate forcing scenario yeah yeah and so my understanding we're not at 8.5 emissions but we are at 8.5 forcing so the climate is following 8.5 yeah yeah so that's warmer than everyone thinks and we've covered that a lot on this program that's one of the main uncertainties [00:21:59] Andy: because you know rcp 8.5 that forcing 8.5 watts per meter squared is derived from a high emission scenario but a lot of gc did and you know you have climate scientists on here they should talk about this but my understanding is a lot of gcms there are a number of feedbacks that are just not modeled because we don't have the capacity model currently right so we could be on a lower emission scenario but a higher warming scenario and those are not inconsistent with each other but your but in this [00:22:25] Speaker 1: graph since the bottom is the temperature you can just plot in what you think the warming scenario is going to be and then look up right exactly so we're on a path clearly now and by the way james hansen says it's uh ecs is 4.5 not three so that's like 50 percent more warming right and we're on path for let's say four uh c which would be three no that would be wait since we're already at one and you're starting at one ish so that would be about here i think yeah if you look up here on the reds okay this is this would say yeah 25 percent right maybe that's what you're saying 25 but this is a spread and if you're not lucky like you're playing russian roulette and you just come down here to 25 percentile or something you're over at minus 50 percent ish yeah yeah yeah right yeah so so these that mean what i think it means does that yes no you're characterizing each acre of land is generating half as much food at the end of the century as it does now i mean you know it's not it's not right [00:23:34] Andy: yeah yeah so let's let's unpack this a little bit this is this is great this is i'm really glad you're bringing this up okay so one high level thing that i want to highlight because this is really important part of this figure and i make sure want to make sure we don't miss it you can see that black fitted line has a small amount of curvature but it's almost linear that essentially applies that no matter what emissions trajectory you think we're on no matter which rcp you think we're facing right the marginal amount uh the marginal damage the marginal caloric output loss associated with one degree centigrade of global mean surface temperature warming is the same right so a one degree increase in the global mean surface temperature has the same marginal effect on caloric output or rough the same marginal effect on caloric output whether you think we're on rcp 8.5 or rcp 4.5 or somewhere yeah yeah because that's just right the temperature right right so but but you know people get hung up on like you know which rcp are we on and it really matters and it does matter right but but the point here is that actually for agricultural output it looks like it actually doesn't matter as much right just it which whatever scenario you just give me a scenario whatever scenario you think we're on right increase the temperature by one degree uh c the global mean surface temperature by one degree c you have the same output loss right on the margin associated with that right so that's an important point and i think that's worth highlighting now to your question the dots here represent uh monte carlo draws of the statistical uncertainty in how each individual crop differentially responds to a given temperature shock and a given precipitation shock right so we we do a statistical model that statistical model has uncertainty from it we draw from that uncertainty and then we push that uncertainty through a suite of climate models so so each dot represents both the statistic draw from the that economic uncertainty that statistical uncertainty as well as push through a different gcm one of 33 different gcm's across these two different rcps so like 66 gcm's total gcm rcm global climate model by the way for global yeah yes that's right global climate models those global climate models all have different spatial patterns of warming right so uh and then those all hit cropped regions of the world differently so each of those dots represents a different spatial pattern of warming and a different statistical response for a given crop to that spatial pattern of warming in each location so there's a lot of information embedded sure right think of an entire global map embedded in one of those dots and then think of another entire global map embedded in another one of those dots and then we aggregate each of those with caloric weights across crops so think of actually each dot having six global maps behind it one for maize one for soybean right rice wheat cassava and sorghum right so there's a lot of information embedded in those dots and now to your question yes the 25th percentile for example means that across that range of uncertainty right so spatial patterns of warming overall magnitude of warming uh and statistical uncertainty in our uh relationship between uh crop yields and weather shocks right across those spatial those those uh uh uh various forms of uncertainty the 25th percentile represents uh sort of like you know the the bottom [00:27:00] Speaker 1: quartile worst well that's the darker darker gray is 25 and the lighter gray spread here is is 1090 [00:27:09] Andy: is the 10 is the 1090 spread the 10th quantile to the 90 90 percent yeah and the middle is what again uh i think that's the interquartile range yeah okay all right and that's the interquartile range around the damage function right so each of those dots is essentially like a data point if there it's a projected data point that we then fit this uh this curve through and so the gray bands represent uncertainty around that um that slope and i would i would suggest i would [00:27:38] Speaker 1: think that you would suggest we don't go hit 8c warming here oh i mean you look at you know you mentioned like you mentioned like russian i don't think there'll be any food being grown then by the [00:27:47] Andy: way you you look at some of these maps right and you just look at it and you just you just say to yourself i hope this doesn't happen right that's all you can that's all you can say right uh yeah yeah no we don't want to do i mean 8c warming would be um well because this is end of century so that's that's uh you know in the tail of the probability distribution um well that's also the the comparable [00:28:12] Speaker 1: to the largest mass extinction on earth when 90 of all life on earth perished it would be it would be very bad that happened over thousands and thousands of years yeah not over 200 years you know so yeah we we don't want to go that's game over i i i think i'm pretty safe in saying that that's a game over [00:28:30] Andy: scenario yeah and and note at the bottom there's there's a distribution of warming there's a blue distribution and yeah exactly right so the blue distribution is the distribution warming under rcp 4.5 the red distribution is the distribution of warming under rcp 8.5 so these high the higher emissions scenario has essentially a tail probability of very high levels of warming even by oh i see for end of [00:28:52] Speaker 1: century yeah oh i see so this is saying that the the peak probability is a little bit less than four about three and a half yeah yeah three and a half but if you're not so lucky and by the way everything we're learning so far is that it's it's you know the actual the actual warming well speak speaking of that the actual warming versus predicted warming there's also actual losses today due to climate change yeah um versus um predicted losses like what you're coming up with and i and i mentioned to you previously that there's this paper from stanford uh yeah very recently in may of this year a half century of climate change in major agriculture regions and this talks about uh the losses already this is not right predicting this is trying to figure out what they are and it's um i uh see i thought the numbers are in here um yeah uh 10 13 lower wheat maize barley 10 4 and 13 lower than they would otherwise had been already so so first of all what do you think of a study like this does that sound credible and were you using this kind of information you know of existing losses existing adaption to to to make your study [00:30:12] Andy: yeah yeah there's a um a high level similar motivation in terms of fitting a statistical model uh to crop yields which is what they do to get at this losses number now i you know first of all my congrats to david and stephanian on this publication i think this was david's um publication associated with his um uh uh phd uh no no no no he's he's been publishing this space for a very long time yeah and david and i know each other uh uh being uh uh elected to the national academy of sciences oh wow uh uh so um uh david's you know we we cite david's work and david labell by very quickly david labell yeah yeah professor labell yes um uh and uh and so at a high level yes but primarily actually what they do and what they spend most of the paper focusing on is measures of weather exposure that matter for crops during the growing season how do climate models do at replicating historical trends right and so what they find is that climate models do a particularly bad job of replicating vapor pressure deficit right is essentially the water need that a crop has because of sort of uh atmospheric shortage shortage of humidity essentially right so the what the crop if it's very dry the crop needs to transpire more water bring more water up through the roots and it goes out through the leaves uh and that puts water stress on the crop if there's not enough water in the ground right so that's what that's my favorite pressure deficit measure is uh and they find that global climate models have done particularly um just they have a hard time replicating that uh particular phenomenon and it matters quite a bit for crop yields yeah yeah uh uh and and so that's i would say you know that is the central thrust of the paper it's a very interesting finding and that's one of the key drivers of these differences it has implications for uh and they have a really nice discussion of uh the implications for the adaptation that is assumed in these um crop in these crop models these process-based crop models uh where essentially the crop models uh take the gcm the global climate model vapor pressure deficit um uh projections as given because you know you have to look what else are you going to use uh so that you know that just is what it is but but because these global climate models are essentially under predicting the vapor pressure deficit they're saying there's gonna be more moisture than there will be that's a very interesting finding i think it merits you know there's a there's a lot more to be done there uh but but i think it's a very provocative and interesting and important finding so by the way i [00:33:01] Speaker 1: should mention that one of the very first climate chats on youtube we we were on uh clubhouse before that but when the first movie one of the very first one so you can see it somewhere on this on the home page there uh is uh on vapor pressure deficit and why the world started stopped greening 20 years ago was the the article on that interest and i learned all about vapor but so vapor pressure deficit is like a really important thing that almost no one knows about i mean yeah it's just not talked about so my question is is your study you are incorporating vapor pressure deficit so we do yeah we do this like [00:33:42] Andy: machine learning thing and essentially one of the things that i was actually a bit surprised about um is we find that for most crops if you do really fine fine scaled measures of non-linearities and temperature exposure and non-linearities and precipitation exposure once you do that vapor pressure deficit doesn't add a lot more information that's some but not a lot more right so so we're essentially accounting for it through high dimensional measures of non-linear temperature exposure and precipitation exposure because climate models don't so so so this is this is a problem with um precipitation resolution in global climate models this is very hard to resolve precipitation events okay um a climate scientist will understand this better than i do but my understanding is essentially right you have a giant grid of the atmospheric earth system right which is already very complicated and then you have precipitation events that resolve at a spatial scale that's much smaller than a grid cell and involves like chaotic convection processes coming into play and that's very hard to uh model at global scale and have your model run faster than like actual time right so have your model do predictions that you know uh are computed faster than your your little the actual clock in your room moves right so so it's computationally difficult um and so and so the gcms have trouble resolving these precipitation events so there are a number of measures of weather extremes that we would like to project into the future but we don't because the gcms themselves don't do a good job of capturing those measures so for example measures of growing season drought right is something that we have some climate scientists in our team and they basically told us like even for some crops they're important but they're like we can't project these things because the gcms don't uh don't do a good job with them right but so we statistically model them but then we don't carry them forward because into projections uh because essentially our climate scientists and our team were like we're going to be going to add potentially add more noise to our projections than meaningful information [00:35:57] Speaker 1: but let me ask you the question then so droughts yeah are they in the numbers you said we're going to lose uh you know 10 percent 25 of our productivity food per acre calories per acre um does that or does that [00:36:16] Andy: not include the impact of droughts so uh yes and no is is the answer the yes is we account for non-linear areas and precipitation so if you have a month with no precipitation that shows up in our impacts right so that that would sort of be at the scale of a drought however for some crops not all for crops but for some crops we find that even conditional on like you know if you have three months say that have no precipitation right each of those three months has a large yield loss associated with like 20% loss associated with permits right it's a fairly large loss for some crops over and above that additive effect there is an additional effect of having many months of no rain right and that that's a that's a term that we call drought right so over and above just the monthly effect of no rainfall there's an additional effect where it's even worse if you have multiple months without rain versus one month right so that that additional effect is is like an additional drought effect that is not in our projections now for many crops the monthly individual effects sufficiently describe the yield losses associated with the growing season and so that's fine for some crops that drought measure is really important so rice you know understandably that drought measure is going to be important it's the most water intensive crop in the set surprisingly cassava which is grown on marginal lands and known for its resilience actually also has a large contribution from this drought measure that we don't protect right and if you're worried about subsistence farmers and the global poor cassava is not a major source of global caloric uh input right like global calories wise it's not a major source but for subsistence farmers and such here in africa south america central america uh southeast asia and oceana uh cassava is an important source of household calories right and we already there's already food security concerns associated with cassava farming for these groups and we don't include this drought measure that ends up being really important for cassava as well which [00:38:29] Speaker 1: probably would make things worse but so i've seen like um a long time ago from n cars like a study of what's going to happen to drought situation around the world in the 2060s they had uh in across the most of the united states well certainly the western united states food basket for the united states and the world uh drought conditions at the palmer index i think it was like nine it was purple color yeah and three is was the dust bowl so this was something that would make the dust bowl look like a walk in the park you know yeah not long from now and i would think that that would utterly devastate agriculture if we had drought conditions like that and you're saying that's not included so like this is not like uh [00:39:22] Andy: yours is not a best case so it's yeah so ours is not a best case scenario um i will say from for for many crops like you know maize uh uh that additive drought measure doesn't do a whole lot once you've once you've conditioned on the monthly sort of losses of precipitation right so i'd say we get most of that kind of effect but but no not all of it and so it is conservative in that sense that's right [00:39:48] Speaker 1: okay i'm not going to ask you a question that maybe you can answer or not i don't know but sure yeah you talk about um calorie loss and it makes it sound like i think some of the articles but like you're going to have no breakfast in 20 years or something because you're going to lose that many calories of the average breakfast i can't remember exactly what the number yeah yeah yeah yeah but in reality it won't be us that's not having breakfast it'll be cows that are not having breakfast because doesn't it something like 60 percent of all the food we grow go to domesticated animals not to humans um so uh what first of all uh one of the adaptions instead of growing more food uh more land is to get rid of cows what what do you think the and many people say that getting rid of cows would be the ultimate climate solution what's your feeling on um yeah cow impact on agriculture yeah i mean i think i [00:40:46] Andy: think this stuff will manifest through prices right so uh if so in a high warming future right in a high emissions future that's where you get sort of these numbers of like by end of century it's like everyone forgoing breakfast right that's you know three degrees sea warming from from uh the the 2000s baseline uh uh you sort of get like uh 360 keel cows per person per day right that's roughly equivalent to what we eat breakfast like like you said uh that probably won't manifest as you know at least us in the in the in the in wealthier parts of the world not eating breakfast it'll manifest as higher prices right so that'll be higher prices for the grains that translates to higher prices for meats right if the cows are fed grains you know that's higher input cost for those farmers right that's going to transfer higher prices uh uh in the grocery store and consumers then are going to adjust purchasing habits based on those price responses right so that's probably what that looks like in the u.s and if you know price for beef goes up quite a bit yeah i mean i would imagine that people would substitute away from beef and into other sources of protein or maybe just into grains directly right like i would imagine that sort of substitution will happen for sure um in poorer parts of the world those price shocks could be destabilizing right if if if and we've seen this sort of thing happen right where essentially if i just can't afford to buy food for my family right protest becomes um a pretty good looking option because what else am i going to do right uh so we don't we don't go there in this study but um uh it's entirely possible that you know in a high warming future if you have this kind of caloric output loss that we're talking about um there are sort of knock-on uh effects in terms of [00:42:36] Speaker 1: political destabilization there's a there's an mit study from long ago that that correlated the price of food with civil unrest around the world for any reason yeah and it's correlated it was like very [00:42:49] Andy: yeah it is not yeah yeah it is not the only driver of civil unrest by far no no no but it can be a [00:42:55] Speaker 1: tipping point factor yeah yeah yeah yeah yeah and it won't be that people will just forgo beef i mean people will forego living in especially in some of these countries where there's you know food shortages and speaking of food shortage that's the concern yeah uh one of the concerns is not just that there will be a drop in agriculture productivity in a certain region because of that but there will be synchronized food uh uh red basket failures so yeah we had the war in ukraine but other places could step up and produce more food but what happens when right this happens simultaneous did your paper [00:43:33] Andy: shed any insight on synchronized crop failures uh fantastic question i asked myself the same question and i'm working on i'm working with student one of my colleagues uh bob cop on trying to get at exactly sort of the the scale of these singer that synchronized losses because we don't we don't look at that here it's a it's a great question uh and i i want to know the answer to it um i i think you know it's uh some synchronization of losses is obviously going to to happen right uh um uh and the question is how much uh and and what is the probability of large global yield loss events start to look like like all happening in the same year yeah yeah okay um well actually why don't you tell us kind of [00:44:17] Speaker 1: speaking of that what what else what are you working on what what what's coming next yeah i mean that [00:44:22] Andy: paper um uh is an important one uh i i look at a i look at a lot of different so i'm working with one student looking at um health outcome uh so global health outcome for uh for infants uh exposed to climate shocks right and that may be operating through an agricultural channel or it may be operating through a disease channel we're trying to figure that out right now um uh so that's that's an interesting one um and then the with the climate impact lab looking forward one of our main objectives now is trying to figure out what do modes of adaptation look like right so this study the one that we've been talking about is with this group called the climate impact lab which is a fantastic set of people to work with across a number of research institutions um and one of the the key strategic objectives that we have now looking forward is we we've measured some of these reduced form adaptation gains like what i've talked about here these statistical measures of adaptation gains and now we want to dig in and see okay what's driving those adaptation gains and are there ways that we can we want to be able to bring in and we want to be able to we want to be able to build these capacities in the development world um although you know one of the things that i didn't mention but it's really important about this paper is actually um it's u.s and other breadbasket farmers that are hit the hardest in this right um so there's scope for that in the u.s as well i think yeah the the city's that efficient [00:45:53] Speaker 1: yeah so yeah so your study found it was surprisingly that going through these scenarios of uh climate impacting agriculture the the folks hit the most are the developed world not not not the poor folks in africa and i guess it's because they're already dealing with crappy conditions and harsh things and the american farmers have everyone your developed country farmers have everything optimized perfectly for maximum yield and so when you change conditions on them they get hurt the most although they have more productivity obviously than the other guys but their percentage fall is it's their percentage [00:46:33] Andy: falls much larger right so if you look yeah yeah and that's exactly right and that is not what i expected to see going into it right we've consistently seen across sectors of the of the economy that um the developed world tends to be in cooler places so it's like less exposed to warming and is richer and has more capacity to adapt right whereas the the poorer parts of the world just bear the burden we've seen that a lot across different sectors i expected to see that here we saw the opposite right we saw like the u.s corn belt in a high emissions future has yield losses on the order of 50 to 40 40 to 50 percent for corn and soybeans like wow you sort of wonder if those crops are going to be viable in the midwest like if the corn belt is going to be the corn belt in a high warming future right so those are very large losses uh uh and and the pattern of winners and losers globally is is striking here um so you're like u.s farmers lose right high latitude farmers like canada russia very northern europe they win from warming yeah yeah yeah i mean it's you know it's better to be warmer if you're in some area like that's probably objectively true uh uh interestingly rice growing regions uh win right so south southeast asia regions that focus on rice growing rice is kind of one of the most adaptable crops we find uh with with minimum losses accounting for adaptation uh and so rice growing regions win uh and and so the global distribution of winners and losers is also also very very interesting sub-saharan and africa does not do well in future warming um right uh uh unsurprisingly uh unfortunately [00:48:08] Speaker 1: and and and it could be that we're actually on now now one question i'll just ask you about i don't think you'll maybe have studied this but what we talk a lot about solar radiation management on this program because yeah we're headed to four degrees and that collapse of civilization territory right there for a lot of reasons um uh so one way to stop that is solar radiation management have you looked at yeah yeah the impact of solar radiation management on crop yields you have people aware you're going to [00:48:36] Andy: block a little bit of of the sun but it gets right right right right right i haven't um my my colleague jonathan proctor uh is a is is a great person to to talk to you about that question um and so he's looked at you know you know diffuse fractions right he's he's looked at clouds and crop yields but i think and he's also looked at solar radiation management uh uh impacts to crop yields um uh so he he's a great person to talk to about that you you might uh uh yeah so uh yeah yeah yeah exactly exactly um uh so i think that's important to look at solar radiation management may also potentially shift precipitation patterns and ways that are hard to predict right so there could be um uh bad side effects associated with that that are unknowns right uh and that's a really important question sure uh uh um but uh yeah i mean [00:49:34] Speaker 1: but if we're getting from your work it's better not doing it has really negative consequences exactly by the way one thing about corn you could take half i understand you could take half the acreage used just for corn ethanol in the united states so not corn corn ethanol take half of that put solar panels [00:49:56] Andy: on there and you could power the entire united states i was not aware of that uh that's that that's [00:50:03] Speaker 1: a lot of solar power uh yeah but a lot of a lot of acreage for corn because corn corn ethanol might be half a percent efficient in terms of turning sunlight maybe less okay the solar panels are 20 25 percent right anyway uh let's we're gonna go to our uh comod stacy here and then she has a question and welcome [00:50:25] Speaker 3: stacy great to see you hi great to see you dan and andy thanks for being here um we've had a lot of good questions and comments um okay mine um i think you answered partly um and it's what a lot of the buzz was it's around the trade-off of how much food we produce how many people we produce what is the carrying capacity of our home planet and um you know i think a lot about food waste and is there a is there a way to do things more efficiently and effectively um and then the last piece of it is um i grew up in a very small town that was a farming community um in pennsylvania and it took a number of years till i realized all those fields around me weren't growing any food for me they were growing food for the cows and um i would love to see a lot less um food for cows and cows as food so i don't know how about it [00:51:38] Andy: yeah yeah yeah so some of this is getting into sort of the ethics of the food system oh sorry go ahead [00:51:45] Speaker 1: dan no no no i just realized i had me on the big screen and you should be sorry about that no it's [00:51:51] Andy: fine it's fine uh so a lot of this is getting into the ethics of the food system uh that is not my area of expertise i will say uh so my colleague mark buddolfson uh has written books he's a philosopher by training but interacts with with uh climate facts quite a bit uh in full disclosure he's also my stepbrother uh wonderful human being uh wow yeah that has written books on this subject right so i would recommend readers uh check out mark buddolson uh b-u-d buddol b-u-d-o-u-l oh i'm gonna get it wrong buddolce s oh good lord now you're in trouble now mark's gonna now mark's gonna tease me this this summer when i see him uh uh uh i'll um i'll uh i'll i'll send it to you and you can post it in the [00:52:39] Speaker 3: b-u-d-o-l-f-s-o-n we'll put it we'll put it in the comments later yeah yeah that's that actually [00:52:44] Andy: sounded right yes yes sorry uh okay great thank you stacy i appreciate that uh so check out his work in that space um he's also thought about um philosophical questions about sort of population right i you know i'm gonna you know let people choose to have babies however they want to have a big piece uh i i don't i don't want to um make um uh ethical distinctions about that because i think that's that's it's a difficult question mark is a philosopher he has some training to to engage in that in a rigorous way uh i don't um i will say to your point stacy uh there is a lot of food waste in the system right and one thing that we might just see is higher prices induce less waste right so if prices are higher people just it's just the the opportunity cost that is involved in having thrown food away is larger right and so people might just do less of that uh uh and maybe there are ways that you know we can all think more carefully about food waste uh i think that's important um uh you know to to cattle uh yeah you know again like there's ethics and sort of like our food system uh and and um cattle production uh and and other sort of animal production and consumption um personally sure i'm very much in favor of of animals having uh uh happy wives um uh but that's like a personal um a personal viewpoint uh that's not me as you know an economist uh uh or or a scientist you know making any any statements at all uh and and and i and i do you know i do i'll be full disclosure i do eat sort of sustainably grown meat uh uh uh so i you know i hope that's not very disappointing to your viewers um uh uh um i do think and and i'll put out there sort of as a proposition for the larger social conflict conversation um uh if uh sort of folks very engaged in climate change sort of try to bundle that message with sort of a lot of lifestyle choices that we sort of like tell people what to do that can be very um off-putting i think uh and and i've i've just sort of historically found that to be off-putting in my own experience so you know end of one right you know zero statistical confidence intervals on that statement but i've historically found it to be off-putting my own experience um uh uh um so uh although you can have policy for for what it's worth like control all of these things yeah but you know like if you imagine you know so imagine putting up for legislation uh you're not allowed to eat beef right or something like that that sounds like the fastest way to get voted out of office that that i can imagine right but [00:55:30] Speaker 3: instead what if we just stopped subsidizing corn as much as we do i mean the amount that we put into one crop that is going towards ethanol which is a whole boondoggle in and of itself and as someone mentioned in the chat we can't drink ethanol you know um the amount of water and resources that we're wasting that way um and also that so much of it is for feed rather than um to produce food for us [00:55:56] Speaker 1: it's like we're dumb you know well it also gives us uh you know so if if this all happens and we lose let's say 50 of our crop that's a nice path that we can stop feeding the cows and start keep feeding ourselves so there's an advantage there so it's it's weight well it's not wasted but it's we could [00:56:16] Andy: argue it's wasted food no i think these are like all components yeah i think these are all components of really robust social conversations so like if you've traveled in france for example france as a nation values having farmers right and they've just decided socially they value having farmers so you go out of the cities and you have these functioning farms and they're they're beautiful um uh and uh you know they have uh uh high value for like well good quality wheat that they use to make their breads and you know all these sorts of things right so that's part of their social values right um i think there's a conversation there's an you know do it are ethanol mandates sort of like a value of having farmers in the u.s or what does that look like like i don't know uh i think that's an open question um uh are there other ways that we can do that right like i think these are all well uh components like a really good robust social conversation uh uh uh but you know probably i i would imagine and this is i'm uh i know uh for being in an agricultural economics department i know less about agricultural economics than probably i should uh i'm trained as environmental economist um uh not an agriculture so uh which my my department knows this is not surprising to them uh uh and uh so i would imagine right that removal of uh the ethanol program uh would cause a lot of financial distress for a lot of farmers right and so there's there is some social conversation around like you know uh you know what we as a society as a whole sort of like value for the livelihoods of um you know uh the people that the people are engaged in [00:57:56] Speaker 1: right and like uh it's all very short-term thinking though right because it's it's not a question of uh maintaining the status quo of ethanol it's it's it's like passing on three degrees to our children you know and yeah yeah everything changes like all the stuff we we think is status quo it just goes out the window and but yeah humans are not very good at uh thinking about the future i mean yeah thank you for doing the work you're doing to help us understand no that's exactly okay that's a great point dan like [00:58:28] Andy: one of the goals that i have with this paper is to provoke exactly this conversation right we paint two pictures we paint a picture of a high warming future and a more moderate warming future and just you know this is clear to you guys but to make clear to everyone right the co2 that we emit today stays in the atmosphere for hundreds of years right and so the emissions decisions that we make today put us on these different pathways move us along these different pathways right and so we do try to paint that picture of the trade-offs that humans that we as a society are making over a very long time period based on our emissions decisions today you know whether that looks like all of the us midwest is covered in solar panels right it's like trying to you know right now we're having a social conversation around whether can we just expand renewables output like at all right much less covering the us midwest and solar panels right so so the the current state of the social conversation i think is not to the point where you know we're having this question of you know do we cover most like a huge swaths of land and solar panels right uh we're um but uh but i think it's important to highlight that these decisions even that we are having now have consequences for decades and even hundreds of years uh well yeah consequences for the [00:59:49] Speaker 1: end of civilization too i mean we're getting pretty serious here hey let's go to eli another commod and with a question and then we'll go on to leon with a question then stacy we'll get back to the youtube okay uh well let me hold on a second uh okay hi eli you should be there now hi um so first question of [01:00:10] Speaker 4: two um you talk about one of the modes of adaptation being uh cultivating more land um we know that uh land use is a driver of both uh uh more uh climate feedbacks as well as accelerating mega extinction um have in in your paper did you consider that feedback at all uh in terms of how it might affect climate and uh do you have any further thoughts beyond what went in your paper yeah great great [01:00:45] Andy: question eli so um uh yeah so we take the climate models as as given essentially and so anything about land use change that might happen and sort of like uh you know when we estimate economic damages overall is not going to feed back into the climate models because those we're just inheriting from uh the cement five modelers are the ones that we use so so that feedback is not in there that land use change feedback i think that land use change that feedback is real uh so that's a that's a great point and and that would be an area where our estimates are conservative uh it's probably not very large uh relative to other global sources of emissions unless you talk about cutting it on the amazon which is the second part of your question around uh biodiversity loss uh we we don't study biodiversity loss other studies have our attack are tackling that question it's a very socially important question so just because we don't study it doesn't mean it's not important it just means it's not something that we can cover in this paper so the extent that the amazon for example is being deforested or parts of indonesia and the rainforest there are being deforested right to make use for more land to produce more calories that is not something that we're capturing and it's a great point okay you know you had a [01:01:58] Speaker 4: second question you know you got a second i think that might have been yeah so um in china oh okay [01:02:08] Speaker 1: can oh can you hear me all right we can hear you yeah we can all right we can hear you okay you're [01:02:14] Speaker 4: getting that go but we're not hearing i know they've noticed that uh the the increased uh um uh deployment of greenhouses has actually had a measure effect on uh albedo and locally can actually reduce temperatures um that can presumably also help a great deal with vapor pressure deficit um so [01:02:44] Andy: uh i think we lost you eli any uh you just disappeared but i think i got the gist of the question though right like um this is where thinking about adaptation cost is important right so if we can deploy greenhouses costlessly over massive areas of land right i can imagine the physical mechanism by which that um increases albedo and so um reduces planetary warming that's a good thing uh you can control humidity in the greenhouse very well because you don't have to worry about evaporation to the larger atmosphere that's a good thing uh but of course covering large surfaces of glass is costly uh uh and so you know there's gains from adaptation to be have there it sounds like but there's of course also costs and the question is whether the costs that way the benefits uh and i don't i don't know the answer to that particular question uh but but certainly you can't just look at the gains and say okay this is what would happen you have to account for the fact that you would have to save invest in the infrastructure [01:03:46] Speaker 3: to build those greenhouses okay i'm short-circuiting dan this is usually one of your points the cost what is the cost of not doing these things you know what i mean if that's food yeah i mean less food i mean it's like every every bit of co2 that we put up there is a problem every bit of methane we put up there is a problem so it's like we should be doing absolutely everything it's not so the sorry i don't want to poo-poo economists you know but it's like we're we're beyond the point that this was 10 15 years ago go ahead do your cost analysis what's the best way to spend the money now it is just like [01:04:28] Andy: you know triage i i yeah i feel personally yeah yeah no no no that's a fair point right um uh it would be better if this had been done sooner like i i completely agree uh 100 agree um uh if you take say you know 190 dollars per ton of co2 right the recent biden era estimates of the of the damages associated with co2 emissions the the usefulness the the social kind of usefulness of that number is that anything that reduces co2 emissions that costs less than 190 dollars per ton of co2 to implement is socially beneficial right and so it's a metric that lets you choose among a wide range of things that you could do right we can install solar panels we can install uh uh wind turbines we can install greenhouses over the surface of the earth we can do electric battery vehicles there are many things that we can do we can electrify household appliances there are many things we can do to reduce present emissions and the question is sort of which ones are uh essentially going to give us the biggest bang for the buck right uh uh and uh a metric like a social cost of carbon lets you sort of like draw a line in the sand and say these ones are going to be socially beneficial and these ones maybe we don't want to do because yes they will reduce emissions but they're going to be very very costly to to implement although now i will say 190 per ton of co2 of many things pass a benefit cost test at that at that level right uh uh so um the real conversation now is sort of is their political will to to engage in that right and that's less clear in the present moment um but but i think the economic case is not [01:06:18] Speaker 1: is not the barrier uh at the end of the day although i would say i speaking of this is because this is really the essence of the economic analysis of climate you know the idea of discount is that i uh would might prefer one pizza now instead of two pizzas next week yeah i got a 50 you know discount rate or whatever you know for the yeah yeah okay and that's totally fine because that's me making the choice but that's not what we're talking about here we're talking about us having pizzas now so our children don't have any pizzas so when you're doing intergenerational discounting you're saying screw you i'm taking it all now and yeah and so it's not like there's f there's ethics thrown in here that is not incorporated into a discount rate that's why i think the real number is what david archer came up with it's 27 000 a ton and uh because we're talking about the end of civilization we're not talking [01:07:18] Andy: about pizzas and your personal eating yeah yeah so there's two high level points i i agree there's two high level points that i would make one a portion of the discounting measure is called a pure rate of time preference that is sort of like preferences over when i consume my pizzas like you were saying that parameter we set to near zero for exactly the reason that you highlight right that it's like very weird for me to say well you know i want to consume my emissions now and have other generations pay the cost right 100 100 agree the only reason it's near zero not actually zero is you know there's like some low probability of the like civilization ending events sort of happening over the coming centuries right and so you're pretty high uh external like other to other than you know like some asteroid impact or like something like that right like uh so so that's why it's near zero but not actually zero but but it but it doesn't contribute very much to the overall uh or or sorry changing it doesn't contribute very much to the overall social question um there's another factor which is essentially that sort of like everyone's going to be richer in the future right uh and so the the marginal utility like the marginal gains that one gets from eating pizzas like is lower right when you're very very wealthy like from the next pizza like if you're starving right and you get that first pizza right that first pizza is like amazing right it's it's saving it's you know getting you through you know the next week or whatever right uh uh whereas if you're very very wealthy then you know the pizzas for like okay you know whatever i have a pizza i don't have a pizza i don't really care right so that change in the gains from consuming uh uh is is i think real uh uh and so and so that gets accounted for in discounting now now that's so that's one point the other point i'll say is at this point again i think the economics uh uh make it clear that um we need to decarbonize right uh at this point i think decarbonization is consistent with the economic analyses that have been produced and that is not the barrier anymore right the choice of discounting parameter is uh you know apart from choosing something that's really really crazy right is not really the barrier anymore uh uh the barrier is you know what's the political will uh in sort of u.s society and global society uh uh and uh and [01:09:41] Speaker 1: and that that's the bigger question right of course uh william nordhaus got a nobel prize for his economic analysis that said the optimal temperature we should hit is like 3.7 degrees celsius which would lead to collapse of civilization so yeah i would see so i would suggest that not like analysis is done [01:10:00] Andy: correctly yeah he he he got the nobel prize for doing groundbreaking work and sort of like integrating these economic analyses in the earth systems it was very early and uh there wasn't a lot of data and so people are still using that uh as a yeah so so that's why that that's why the work that we've been doing is significant right we we and others have been doing is significant um uh uh so there's there's sort of like our uh we we have this um decent model the uh of um a climate economy and and then there's a there's a give model uh out of uh our uc berkeley and researchers for the future uh uh which is another sort of independent model of these impacts they both find very large economic losses they're both tied to like actual data uh uh right so they're they're um uh they're much more advanced uh and and they both justify a high level of economic investment and action on this problem uh so we are i think actively changing that conversation but it is true that the early impact assessment models and and there was an early version of give that was one of those models all found much much lower losses uh and and and that was in part associated with just a lack of empirical information on what the actual losses were uh and that literature has since exploded and we're contributing to that literature and we're [01:11:22] Speaker 1: trying to leverage it and once you do you find a very different story so let's uh let's bring in leon simon another host here and welcome leon from the netherlands and great to have you here [01:11:35] Speaker 5: what's your question for andy hi andy thank you uh great to hear that you know what the earth energy imbalance is i think many economists don't um and uh really insightful uh conversation um i have two questions um one is about uh also related to the earth energy imbalance we see that it has now more than doubled um so what are the economic costs for like we're facing now for example we already have now in the coming three days in netherlands will be 30 degrees uh celsius um and choose 35 right so um and and we have to adapt to that and and for southern europe it's even worse so have you looked at that [01:12:22] Andy: or it's mainly on 2100 so this paper great question man um this paper is mainly about future impacts if you look at david david lobel's paper uh and his co-author paper that we were just talking about uh that paper for example looks at historical impacts of these climate shifts on yield output today right so that would be a good resource there there are other papers that i'm sure as you well know have tried to disentangle the climate signal the climate change signal on the economic side that's that's a very nascent um and evolving uh research space getting into the into the economic impacts side right so climate scientists have worked on disentangling the climate the climate change signal from historical noise for some time now and that's a much more robust literature we're now trying to take to learn from that literature to disentangle that signal on the economic side right so that's a nascent and growing field david's paper is a nice early contribution in that space others working on it as well i have co-authors who are who are working on that for a human mortality signal right so disentangling the uh the climate change signal and human mortality uh uh and i think that's that that's a a range sort of a really important and useful metrics that we need to develop that don't largely exist yet thanks and another [01:13:42] Speaker 5: question i think that there's a relationship to the uh mainly to the developing world so you mentioned that you you don't see uh and i'm paraphrasing here uh much impact in in rice production um have you looked at uh the and does it does the model include changes in the in the tropical convection zone in the monsoon systems and rain bands how we how they are changing and really related to that um because it's also very very important these rainfall patterns in the tropics are very important for the poor poor people um have you looked at uh not just hunger and not just at calories but also at hidden hunger so at all at [01:14:27] Andy: nutrients from food right right right so um we basically have like a one sentence disclaimer into paper which especially related to co2 fertilization which we haven't really talked about here but higher carbon dioxide levels in the atmosphere help um different plants grow faster essentially because plants breathe carbon dioxide uh there may be nutrition uh impacts negative nutrition impacts associated with that that's not something we're going to we don't study nutrition sort of impacts overall so leon you're right that's a that's another uh avenue of impact in our food system and and that's not something that we study here in part because really good global nutrition content data that we can do robust statistical analysis on isn't really available to my knowledge right so um uh if uh if we can sort of broadly collect that information through uh fao surveys or something like that right that that would be extremely useful to researchers like me to then be able to systematically study that uh uh so so we don't have information on that in terms of sort of rain bands and things like that uh to the extent that those rain band shifts shifting of of the heavy convection cell for example are incorporated in the global climate models that we use then they are incorporated in the results uh uh that we project so we don't directly project those sorts of shifts we borrow from the cement five suite of models uh uh and at least some of them do incorporate those rain branches i don't know what they do for the indian monsoon is a great question and i'm just not sure that would be something that are like we have climate scientists that are uh part of the co-author team and uh i am not a climate scientist uh so um i'm not sure uh but but it would be something that would be again if it's in a cement five suite of gcms then it would be included to the extent that it's not then it's not i will say to my earlier point the gcms do have trouble resolving these individual precipitation events so like monsoon onset for example i would imagine i'm not sure but i would imagine that they have trouble getting the monsoon onset right that is empirically sort of very important for indian farmers right it can even be determinative of whether they get one growing season or two growing seasons in depending if the onset is later earlier right so uh uh so so those things i'm guessing are not well captured in our [01:16:46] Speaker 5: projected results great another question you said yeah no thank you it was quite very insightful [01:16:53] Speaker 3: thanks great and stacy do we have more from uh yeah yep i have well the one thing i wanted to suggest is you could consider renaming your paper a tale of two cornfields i like that that's catchy yeah yeah um so our first one is from eric and it's what percentage of farmers think they're doing adaptation for climate change oh you know i do not know the answer to that [01:17:24] Andy: um that would require surveying farmers might so so here's here's the thing right um climate change is sort of like a unfortunately um just a politically loaded term right so uh i did an interview with um one news outlet that i won't name uh where basically they were like my readership you know i can't talk about climate change so i actually had to give like i well i didn't have to but i gave a brief very very brief synopsis of the physics of global warming right trying to avoid the term climate change and just communicate it in ways you know like co2 is in the atmosphere physically it absorbs heat this acts like a greenhouse the glass in a greenhouse right like i just broke it down that way uh uh so and and and the farming community there are farmers who are just very skeptical of the term climate change because of the poll because of the way that it has been politicized i don't think it's you know that's that's not um anyone on this call's fault or anything like that it's just sort of the state of the world unfortunately in the us at least uh so whether farmers would say they adapt to climate change i don't know but farmers are very attuned to the weather right they very clearly understand that the weather impacts their choices right so when i look and i can statistically see that a farmer located in a northern latitude right where it's cooler has large losses associated with extreme heat when it happens that is a hundred percent consistent with adaptation behaviors right so i would say that all farmers right i would venture like all or the vast majority of farmers are adapted to their local climate and they are adapting right they understand their given weather and they're not going to make bad investment decisions by ignoring their local weather but whether they would say whether they would say they're adapted to climate change because of the terminology is probably much more of a mixed bag does that make sense [01:19:31] Speaker 3: yeah no it doesn't make sense it's crazy but okay i'll go with it [01:19:37] Speaker 1: no i spent a lot of time with farmers in california and they know they know it's changing but they also don't accept climate change so it's kind of a weird thing it's a little cognitive dissonance i think is what there is a little bit of cognitive yeah [01:19:52] Speaker 3: yeah so maybe one more uh youtube yeah um what are your thoughts on high heat night temperatures is it accurate that night time high heat over three to five days it is what stops the plant's processes for growth [01:20:11] Andy: yeah so um empirically we find that high heat nighttime temperatures are most important for rice and wheat and they're just less important for the other crops once you've done um really fine scale measures of heat exposure that we use uh okay so that's first of all that's a great question um uh um uh jean john uh six four five three uh that's a great question uh um so empirically we find those high heat nighttime temperatures once you do um really really fine tuned measures of both nighttime and daytime heat exposure uh on sort of a continuous scale uh those high heat nighttime measures independently matter really for rice and wheat and less so for the other crops uh for rice they're most important and for most of the places that rice is grown in the world those high heat nighttime temperatures are harmful to yields for rice that is grown in very wet locations in a high input environment so wet locations in relatively wealthy areas of the world there are gains from increases in nighttime temperatures now what's driving that most likely is switching into varietals of rice that are cold sensitive so so cold nighttime temperatures warming is beneficial and that's primarily what that's picking up now very high nighttime heat temperatures say over 30 c or something like that are going to be in the range of these sort of extreme heat exposures and it doesn't matter when well maybe it matters when they happen but regardless it's in the range of these extreme heat exposures that just drive down yields across crops and that's true for rice as well so jean i hope that i hope that answers your question but essentially there's a mixed bag effect right if it's if you have colder nighttime temperatures and you're able to lose those through warming that's beneficial for rice in these high precipitation high input uh environments uh but if you get to very high temperatures say over 30 c or something like [01:22:14] Speaker 3: that then those temperatures are quite detrimental uh dan just one more thing here um i especially since i saw our friend albert had joined um is there any lemonade to be made from massive crop failure in terms of um taking the spoiled material and biochar and using it to enrich the fields so that they might be more um resistant and resilient um for next year you know biochar i think is super interesting uh uh i think um [01:22:51] Andy: um i'm and i i'm sort of familiar with it as a as a concept i think technology as a technology it sounds like a very interesting technology for both um soil health and carbon sequestration um and so sure it is entirely possible uh uh that one could do that now i think you'd want to do the and and am i right and if i remember the the process of producing biochar involves process at very high temperatures and so you have [01:23:17] Speaker 1: very without oxygen yeah you just you turn it into charcoal by uh yeah it's not oxygen i see a very [01:23:23] Andy: little air pollution in particular is that right because india for example does widespread burning of crops in the field which is not biocharges right right right right and that causes massive air pollution problems so we would want to make sure we avoid that right so that would involve people so so yeah i mean that is that is possible uh i think that's interesting uh definitely interesting to think [01:23:42] Speaker 1: about very good well i want to uh andy i want to thank you for your time today learned a lot and we covered a lot of different things um i guess in general we're learning i mean as we kind of know that climate change is not going to be good for agriculture and it's going to cause lots of impacts and lots of lots of adaption uh in many different ways beyond even what you were looking at here not just what the farmers do for sure for sure yeah yeah so i want to thank you and and and good luck with your uh future research as well and uh i think really exciting uh stuff you're doing i want to remind everyone uh to please like and subscribe we don't really talk as much as other youtubers do here about do it but it really helps to spread the word and we're doing this to inform the public about climate change uh this is not like a money-making exercise at all and uh so please do your part by helping us out and uh and spreading the word by liking subscribing hitting the notification bell and also just to remind everyone of upcoming programs if you tuned in late sunday july 13th sanjay woggle we're going to talk about uh uh investment opportunities in climate adoption uh thursday special day july 17th matthew england talking about his alternative explanation for the very rapid warming we've seen recently which is a very interesting uh subject and we've had him on before talked about amok impacts and things like that uh sunday july 20th ben santer talking about the how we know climate change is caused by humans and uh thursday a special day again july 31st stephen chu former energy secretary nobel prize winner and stanford professor and lots of other things as well so anyway so looking forward to all of that and again andy thanks so much for your time really appreciate it and we'll see everybody uh next time take care dan and stacy it's been an honor