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we're going to begin this point being called rethinking sustainability and first speaker the Tom Murphy associate professor or physics University of California San Diego the title of his talk is growth has an expiration date Tom right so it the first slide My name is Tom Murphy and I am a a physics professor at UCSD my day job is seeing a laser to moon abroad the green leaves with me just to have one of these prompts and measuring the distance to one millimeter precision as they tested in relativity it's on the cutting edge of the US and abroad to be but don't worry that's when we're talking about today we're talking about something that made the inside more important which is the notion of growth and help what more constraints we can say about this from a certain physics analytical point of view I'm I can I don't have the power to tell you what that day is but you get some hints along the way um you know that the theme of today's sustainability so this will beg the question of you know what the sustainable mean let's try to get her head around that concept so um growth in general we assessing the progress we have a marvelous technological society as a result and we have better quality of life medical care all these things are fantastic said growth was this it is a very positive influence in our lives at first email and restrict their attention to physical growth on energy as a proxy for this and the part that is because um you know about energy we would not have this um this technological society and its at the surplus energy beyond the subsistence level of energy it's the surplus energy that's made more food available that's created a population of surge and the planet lead to more industry and economic growth and adjacent to the foundation behind all that truly today we use energy in the world at a rate of twelve terawatts steps the the rate of electricity and onlookers total energy use up and historically that's grown the two to three percent for year so what's this mean if we keep expanding and just to show that the growth history this is the United States the blue dots for the data from sixteen fifty to the present and what you see the red one is an exponential that I'm at two point nine percent for your fits quite well what's more astounding to me is that you go to logarithmic plot so that this is the same data but now in its financial is a straight line in the slog of the top and look how amazingly straight that trade this for centuries it's breathtaking that were on this exponential trajectory that's a two point nine percent for year three ok so what if we continue this this see where this is going at twelve terawatts today and time into the future this is a actually slightly less steep curve of two point three percent for your ID that for its mathematical typing this because that means a factor in every hundred years but many cases slightly less than what we've seen what that does is in three hundred and thirty six years from now we are using as much power as all the solar energy the hits all the continents of the landowner so we had hundred percent coverage of the land not piece of dirt to be seen from the sun hundred percent efficiency of solar panels are meant to mimic when possible where three min thirty six years but you know we've got more than that without the ocean the buzz is just a little bit more time um if we want to keep going and put solar panels all we are in the sun we get up to fourteen hundred years but in our stars of the owners are sons of the list are we had a hundred billion such stars in the galaxy twenty five hundred years from now are using as much energy is all the stars and milk the Galaxy at a modest two point three percent growth rate this is the devastation of its financial affairs so if you're stuck in the mindset of exponential growth you have to realize what the consequences are I say we know we're doing twenty five hundred years ago I can claim from this that I know of were not going to be doing twenty five hundred years and were not going to continue this trajectory up incidentally there of thermodynamics limits to that energy production if you let say you not use the sun and solar energy as up as the example established through let's see that's the magic few sooner you know even a word that we have yet for some energy production process on earth um you know in fourteen hundred years were using as much as the entire sense that means we would have to have as much energy as the sun is pretty now in some fantastical device on earth it's gonna get hot ok and because it's smaller than some and effective incarnate son and we can play this game even if as this would you be the same numbers basically that we're starting with the global average temperature of fifty nine degrees Fahrenheit and all this waste he has to get into space as a radiance this it's the only way off the planet and so in something like I don't know why the spacing get screwed up when the sun computer by law I'm ninety nine for her body temperature loss of four hundred years from now we boil the water on the surface of the planet in the mirror you know four hundred and thirty years or something then you know we keep going and burn paper melt steel and you now can we get the sun surface temperature less than a thousand years and this just their mundane and skinny physicists would tell you the same thing given that the problem set up this way by comparison global warming this is a lot of skills that some of the CD as a very minor it from this I'm not talking about global warming and sea or two done talking about thermodynamics heat loss from the earth the waist the removal of waste it so you know what this should tell any reasonable person as that the premise here is ridiculous it's absurd to spend Pascoe the premise that we would continue due to its absolute knots bunkers will not happen there are lots of reasons why we're not going to do that I mean obviously are not cooked ourselves but um you know population growth will presumably saturate now it's going to take off some pressure for energy profit cetera I'm instantly and fun at fossil fuels were not in a go much further along Mr so the lesson is that a future president in energy ok I'm most planning Commission's economists etc countries this bill that in this assumption expected to grow so does St my work and short term but you know it's harder on there that we just expect will grow because everybody we've met and everybody that they've met has experienced this world of cross it's been going for a few years now and we tend to think that even if ok things to level off the population levels awful lot more energy um we can still manage growth and certain economic sense because we can still bring up standards of living we can have efficiency gains technology innovations of these kinds of things to keep marching along but I'm going to make the point and it's maybe a little subtle but those things cannot become the whole economy ok there's an energy base underneath all this fundamentally were were physical beings living in a physical world where the tide energy and divorcing our economy entirely this decoupling from and she is not the best fantasy in me it's not even academically on us so let's just look at a snapshot of growth over the last entry the dots are the data for the gross world product his entire world and for the first half of this entry regret about two point nine percent growth rate which it was from the striking that's the same rate at which energy growth occurred and since nineteen fifteen we had economic growth faster than energy which is maybe often taken as an evidence for this decoupling that we can grow without energy and we can in fact because on him this is considered something of a triumph on but the gap you know and understand what's in that gap it's partly increased interest efficiency do more with less um any other part is growth in things that are less energy intensive which upon the service sector so you know innovation clerical work real estate um I guess it's um in all the other things that don't really require a lot of energy on psychotherapy we have to have to cope with this crazy world I'm so it's clear that low energy Act it is this not in it for a second and that those things don't exist and that they can increase on but how much can the sufficiency of improved let's look at the efficiency part in storage listen to any examples like refrigerators in cars that have increased by a factor to inefficiency over thirty five years it's been passed a law for this I'm back to two percent for your improvement discovered the scale not all examples of such tiny most things in fact don't grow that fast these are the shining examples of Carpenter travel something like one percent for your analyze things are just not going to change its all is going to take to kill a calorie of energy to heat a liter of water one degree C physics tell you now you not in the door for cheaper than that a lot of things electric motors party at eighty nine percent efficiency how much more can you improve those I'm living a family down the road at freeway speeds are always can be fun here that's an answer to that standard cost um you know trusted Carson single file notwithstanding up and so efficiency is also good to have willingly be one or two bunnies left in him and we will pull these buttons on a hat on but we can expect that forever casino we have a hundred percent cap in the end and you know we can maybe get a factor to cross the board I don't think we should anticipate more than about a factor too and someone in Europe the toy model work with a one percent efficiency improvement for your time for another factor to and this is just a graphic showing up airplane efficiency um in energy consumption per passenger kilometer for instance overtime and its engine prop planes are here Jets actually initially work less efficiently prop planes patrolling be squeezing turboprop planes were on and that's a one percent the year improvement now here's a toy model ok this is the data it's the year but the toy model has energy flattening out does the above image scale for energy as fighting off but we boost the available energy be useful in Dubai efficiency gains is to have more than were actually the right and you're good but if we want to keep the economy growing five percent there's a growing gap ok and so some fraction than increasing fraction of your economy has to be based on low energy activities real estate the sky of things and at some point this red dot is over and read index is the percent of the economy it's in the service it does have to grow and grow until it approaches a hundred percent and meal of apartments from here to the top is how much of your economy depends on energy food manufacturing friends for all those things and so my claim is that you're not going to end up tending towards zero UNICEF tree it and that's when economic growth last stop the case of physical growth isn't that redundant there are viable mechanisms for growth that doesn't require physical growth non art and after lots of examples the reach is limited you're not going to tend toward zero in the energy sector which means that would become free effectively if if this much of your economy nine point nine nine nine nine percent of the economy isn't on energy your energy is basically free it's hardly anything I just don't that's not the world with them especially for resource that limited that set them free ok I'm so economic growth will actually also in insulation acts which have a model for steady state economy it be twice first to do so so to stick with what the population law group that scale over a very long baseline for a long time we threw in a modest rate the two thousand are doubling time but look at this hockey stick that what's happened is the hockey stick and a lover of the plot which is super scary okay um I mean normally I'm just this line would look like a hockey stick in the linear plot it's been a super fit super experimental set near doubling time in recent times us break that down a little closer and see their sem break points that are interesting on the first break point on the street corners around time in the investor revolution which well if you've been to call revolution it's not a renovation at school um does anybody know what the first use of the steam engine was the first major employment of steam and wanted to do so that pumped water and one seeking a more call this so it was very much a cold driven enterprise then we had the green revolution in agriculture which is really just the way to put oil in two and other fossil fuels the fertilizer and an increase of the streets and what you know you produce more food to produce more people said all talk listen to him is it's just a reflection to me are of the fossil fuel bill and if we look at fossil fuels over a long term this is sort of cartoon we had slaves animals and firewood for energy before then we ran into fossil fuels we don't know what comes after but that the point is that word a very special moment in the history of humanity and we found the hearse battering plugged up Las Vegas from spinning as fast and possibly can um and treating the last two hundred year history as normal and extrapolating ruthlessly from that as a very perilous it it was an analysis now this is housing prices up over the last century and Tweed heads and boom and bust cycles and holy cow look of this thing um I have I bought a house and when the mood to send me a ride back here maybe on the curve singer rocketing up a better day then and then I get really nervous because the Red Center in one of quantitative analysis what's in the hand way the analysis at all real estate will never be a learning phase of the new now um it's not a bubble um same Diego intricately around that house prices will go down to such a desirable market I sold my house right there started drinking and turn out the whys and so here we are on a similar part of the trajectory and fossil fuels we have all this hubris it's a new now it's a new world I don't know him he could be announcing its not but let's not get ahead of ourselves and assume that we're going to solve this problem because we assume that were in a song that were not working on it that's that's the danger is this complacency now a lot of people really object when I say that this could be it anything like that every phase and calm that we could potentially even consider returning today on a more primitive future this must be what saves someone to enter yours now our life joining us now is so unimaginable us just like people in the team owner could not have a man to Overton today and so why should we you know they're trying to bring humility this argument that we shouldn't assume that we can even comprehend the world who are just now I'm totally great um let's say that that future joining us now with love each other over the heads with half the bones for protecting your food supply comp who today here in this room would have possibly conceive the second half right based on where we are in our trajectory so I'm all about humility in the future let's not make it on and justifiably asymmetric based on our recent history um on a finite resource but let's say that we manage the transition to renewable resource and we can level at our energy ok leveling out actually means that we have to live in about fifth of us entered the living today and I say that because the US has five percent world's population twenty five percent of the energy and inequalities are difficult to justify in the statistic world that Islam is not growth you can say well the people of the bottom hem growth opportunity once you realize that's not true inequality becomes a moral issue are difficult to maintain but could we even sustained today's visible through prayer I mean we got twisted promise to trees degradation a rain forests are being top soil calling were losing into aquifers being pumped out mineral asked me some energy is not the only part of a story here and if you want to accomplished the dream of ever buying world lives like Americans do today it about a ten times increase in our our group and five times just to have today's population that today's standards but Brenna had growth in population and today's standards in the end of the world so that's a fact of ten total and compelling but you guys are nice people and get a discount knock a bike and five because we're going to have some official gains whatever but isn't what it looks like it makes the fossil fuel era look like it and significant black and some people say will exact with such just the kick start the B cell um but what makes us think we can do this when we're not maintaining at one times very well so an example a kid might really want a pony morning eating one of twenty twenty to twenty all your boss Tony has partnered with say ok well let's get it terrible to see and take everything you feed it to clean its cage if you manage that you get a cat it's more work the litter box it's more needy if you can miss that though we get a puppy we'll give you a copy and no more working on a walk it if you can manage that upgrade to go to a democratic to take care of in the room was like a farmer if you can be the go then you get the pony but that's a responsible approach and the problem I see is that were having difficulty right no one excuse for not taking care of our journal we have shown that we can take care of a durable and so what makes this think that we deserve a pony our wee deluding ourselves but talk about Tony Tony Tony Tony that's what we talk back so on do we deserve to be using the word sustainable also because we haven't really understood what it means or what level we can expect to operate sustainably and it's an open question so I think in my mind the fossil fueled to a right that we experience has better judgment we think that were clever or smart will really you know with a monkey the stock at stake into that Brown became dripping with honey or oil and we were very pleased with ourselves but you know it's this the innards that's what minutes people were doing now one very quick hit on something that I think is a real shorter term were at talked about long term problems of maintaining growth but let's say that we did do I begin to decline in in fossil fuels which I believe for oil happen in the next decade will start to decline in oil content oil availability if we want to build a new energy infrastructure to build our way out of this problem with their smarts and our technology that requires an upfront energy investment to build the infrastructure that's exactly what we're reading short time so we have to intentionally exacerbate make the problem worse too umm to start down that path and that's politically very difficult to do just to put some numbers on it if you develop a resource for the forty year lifetime the windmill solar panel nuclear plant and it delivers something like the fact of ten of the energy they use in but you get a return that's ten times when you put in to the pool value for say the solar panels wind might be twenty one but it's in this neighborhood if you want one energy for your innards unit for your out of this the cost of four units up front Stoops the ratio of those two things and the promised there's no energy financing in nature you can build a windmill on promised energy you gotta have the energy of fraud it so that you actually steep than the decline and once you start such a program if you are bold enough to do that abandoning that program is always can be too tempting the next politician can repeal the program and why constantly gets better for the short term so it's very tempting split with heart I'm not going to go over the summary in the helm of literature and time but you know I just wanna point out again that you know growth when we should really think about steady state economics in a serious way I've been in the notions of growth as the only way things can go on we have observed a pony have we deserve use the word sustainable um there are some real promise with this tender trap but let's not be led by scientists assumed that we can get past his promise as if we just assume that we cannot we don't put the real recesses wheel mitigate the actual risks that could happen ok I'm so when you look at Casa de and sustainability ask is this an idea based on continued growth does this abuse the word sustainable um does this help secure merger will or is it just more promise up for a pony so on all stop their work or not I've got a new blogger must ease um ideas are expressed there it's fairly recent but it's got him to repeat he's so you can add to that an experiment thank you the equipment about one one question but it's a question and one and it is not a formal but thank you very much it