corrupt activity is al qaeda. this is an incorrect notion that has even planted itself in certain quarters of the united states congress. and i think it is well worth keeping in mind that for many, many, many years, ten, to be precise, there has been a network of strong connections between the syrian regime and al qaeda in iraq, connections originally used to facilitate the movement of these characters through syria in to iraq, connections which i strongly suspect still exist. >> with that i want to thank fred and matt. i want to congratulate that once again, i urge everyone here to buy a copy of the book on the way out and really wish this goes to the top of the new york times best-seller list of what a week is done. congratulations. [inaudible conversations] to ten .. yet environment reporter. this week environmental leadership program founder paul sabin and his latest book the bet paul ehrlich julian simon and our gambol over earth's future. he analyzes of the 30-year-old wager between an economist and biologist for the long-term effects of depleting natural resources and examines the opposing perspectives at the heart of the climate change to date. the program is about an hour. >> thanks so much for coming to talk about your book of "the bet." i found it fascinating as a reporter that covers climate change, but by reading but i could not help but have a sense of de ja vu. i heard this argument many times in putting in the current congress. but i want to ask you kind of at the beginning which is where did the idea for this book come from? was it an idea that you always had that became light because of the current political context? which was it? >> as it starts with an interest looking back at the 1970's trying to understand what were the successes and the accomplishments of that era of environmental activism and legislation and what are some of the limitations and constraints. i've been interested enough for a very long time and when i was with looking around for a new book topic decided i was looking for a good story and would make me think that would challenge me so that's how i ended up with that particular topic that is too strong individuals. paul ehrlich, famous biologist and julian simon, an interesting iconoclastic economist. looking at the two of them in their lives and then relating that to the larger trend is happening within the environmental movement and the backlash against it and also within the country in a clash between liberals and conservatives suggested a right story to be told. >> host: when you look at what kind of happening currently in the congress or a out of the obama administrations, what lessons do you think the stories of paul ehrlich and julian simon hold for this generation today? >> guest: there are a number of different kinds of lessons and they are the lessons itself. maybe i should tell you quickly what the that was and what they are. so, paul ehrlich, the author of the book, the population bomb which famously predicted that we are in danger of a global famine and ecological disaster and more fair as a result of overpopulation and julian simon was a critic who emerged questioning this saying that affect human ingenuity and creativity in the markets what allowed us to ever to these kind of threats and in fact more people had more mind to bear on their problems. he actually made a bet about the metals and with the decreases were going to go up and down the next ten years and so that was a proxy for the vision of the future or population growth would bring disaster and humans would be a bill to adapt. ehrlich lost the bet and that is what makes it interesting for me is a background on in the environmental background that simon one that is what made it interesting for the lesson of the net. one when sen used to make the relationship between the human society and environmental change are not that simple. they are not a linear relationship and that people are creative, adaptable and able to adjust to changing circumstances so the rising prices for energy resources and oil don't necessarily lead to our running out of oil but rather different kinds of adjustments and fuels coming into play and explorations coming into conservation measures. so that is one important lesson has an appreciation for the adaptability of people and then to understand this juncture. these are the real changes that the scientists like paul ehrlich documented and human welfare so those two things are really did what they are not directly -- they are not always just moving in lockstep with each other. so that as a second important point is about this bet which has become in the last two decades since it was result in '91. the current debate over climate change show the traveling in rot's i guess that were established by the previous debate and put additional growth and resource scarcity. i think to really understand what exists between environmentalists and the conservative critics if you go back and tend to these earlier battles over population growth and resource scarcity. >> host: you also make the point to go back to the debt for a minute that it really was the wrong bet to make because the prices of these metals really didn't do anything to solve the divide between simon and ehrlich because they viewed the world and measured progress in the normal change in very different ways. so, if they were going to do that again, do you think there would be any kind of measure that would at least get them respect for each other? they are still far apart. >> guest: they see something about the debt itself which is leading the debt itself they chose these five metals, chromium, copper and nickel these are important metals in the economy and the question is whether the price would go up and down and whether that would then signal that more people, 800 million people or so were added to the population over the course of the decade but it wasn't the population growth would lead to the price increases because there would be more demand on the resources. and i think so one of the lessons of the debt is these are simplistic measures that do not account for the broad changes in the economy or within the environment. and then there is another complicated aspects of this which is that many people who like to talk about the debt and talk about victory don't necessarily taken to the fact simon really did get kind of lucky in the dates that the chose and when the economists had run the numbers over the last century or more they found that early actually would have one down on these more times than he would have lost. as a taking this one example is that it doesn't really prove the prices are always going to go down. >> host: it reminds me if you bet on all oil prices. weeks before this bill when the president talk about expanding the offshore building and a major disaster that would throw off any kind of wager that you would have on the commodities. >> guest: that is one of the important things to understand about how markets work for commodities and resources is that they are dependent on the factors so in the 1980's there are macroeconomic factors related to the oil crisis and economic slowdowns and also everyday market factors. they were in danger and in that kind of an agreement fell apart and also collapse were you have the introduction of the new substitutions for copper, fiber-optic cable, satellites, things like that. all of this then led to in addition the increased production that led to higher prices that then led to the copper prices going down. >> host: would there have been a better way to get into the book made you can explain this in the audience the bet that ehrlich and steve snyder tried to strike a new bet that they thought was a better measure of the point that they were trying to make. can you talk a little bit about that and then maybe comment on what you think -- if there was an ideal bet to be made between simon and woo-hoo erlich? >> guest: he was very proud of that and went out to california, or i guess he wrote an op-ed for the san francisco chronicle challenging him to the letter that everything was getting the environmental indicators are getting better and to avenging to him or al gore so then ehrlich and his colleagues who passed away recently came up with some other metrics that would be better than the metal prices and would prove that simon was wrong and that the indicators were better. the show's 15 different metrics and put in concentration of carbon dioxide, the state of the ozone layer and environmental indicators that they thought would get worse over the coming period of time. and simon refused to take the bet and he said these indicators, you know what do they show? they just show that the world is changing and they do not necessarily mean that humans are going to suffer. so as part of his idea that people adapt to the changing planet and that is what really needs to be measured as a human right expectancy or the size of the ozone hole they were adopting tough things and that really captures the gap between the two ways of looking at the problem. if simon was very focused on human welfare and ehrlich was focused on the environmental relationship and the two of those it was very difficult to establish because in fact both of them the other assertions could in fact be true. the ozone layer could be a diminishing of the same time and we could come up with various ways to adapt that and prevent skin cancer rates from going up and things like that. so, they were unable to agree on a metric and i think that really symbolizes their inability to have a conversation with each other. a conversation in which they were talking about the same terms to find a mutual agreement and a mutual measure. so what would be a better measure that is difficult to come up with because you have to figure out a way to measure both -- first you have to decide do you want to measure environmental changes or do you want to measure the welfare of human societies? and those can be related but also -- >> host: one of the things that keeps coming up and as someone that has covered this very closely is obviously you hear a lot of what the sign in's of the world say in present day is they are going to kill jobs and kill the environment, it's going to be tremendous for the economy and the response to that by the administration and the supporters has been well, if you look at the sweep of the environmental regulation, these are all the things that you have done with air pollution. g.d. he has set a steadily gone up even as we have curbed the air pollution. what simon has said i agree with that what is the response for that counter argument because that is the one that is used over and over again on the hill in the testimony for the supporters that the gdp has gone up as we have worked on our environmental issue. the >> guest: is hard to put words in his mouth but the other is the counterfactual to try to figure know what would gdp be if the regulations hadn't been in place and why ellen view is that the assertions of the cost of the regulations often not very well substantiated going back all the way to the 1970's and part of that actually has to do with the very points that simon made about the human adaptability because not only can people of that the changing environment but also to the changing regulatory scheme. and so the assertion that a change in the regulatory structure that governs economic activity is going to lead to a cascading series of disasters including unemployment and stagnating economic growth, that assumes people can't figure out how to admit less pollution and that really runs counter to the evidence of the last 40 years. >> host: i'm not going to see this eloquently but ehrlich was always concerned about reaching the limit. the population would reach a level that we reach a limit in the resources that we need to have portable water and what have you. adenosine's that simon was saying as we get closer to this one at people get smart and extend the limit out further. there are so many examples of that. you look at natural gas today with hydraulic fracturing where we are now talking about the debate about exporting natural gas and we have so much of it. but i guess from a policy standpoint, i guess if the question is whether you believe it is always going to happen and whether the yardstick is going to keep moving and if you have to kind of say do we really want to risk this to see if we can push it more >> that is the question that we should be asking now and some of the implications of the story how the current debates about climate and also about energy development so there are a couple points to make about that. one is we can't assume just because we have had success in the past that we will necessarily have success in the future. so we are able to adapt to the growing population doesn't necessarily mean climate change is not a problem and they are very different things so the climate change is not population growth. population growth is a more diffuse occurrence that leads to the ramifications throughout the economy and society. that consumption as well. in the of population growth is much more diffuse than the ability to adjust as simon argued. climate changes and match different question that involves the specific phenomena of putting more gas in the atmosphere that has specific consequences for the planet and i think that the scientists have very well documented that this is happening and people are causing this to happen and so i guess it is quite different from population growth. so actually if this gets to sign in's own arguments which were that -- he made the claim that the problems were to divide solutions that ultimately would lead the society better off but one of the unnecessary things would have to happen for the problem solving to occur that has to be a willingness to recognize the problems exist, and i think that is the problem with today's climate conversation that there are many people on willing to accept the existence of the problem so in some ways it is going against the ideas that simon was advocating which is that we should apply our human ingenuity to adapt and it just to the changing planet around us that if we don't recognize it is changing we cannot apply our own innovations. >> host: you mentioned these ruts and i think that it's a dead on to describe what is happening in the political issue. i mean, is there -- if ehrlich is still living who ehrlich and simon today? you mentioned al gore and earth and the balance in the latter half of the book, but even al gore seems to kind of have after the stand on the hill on occasion has kind of not been so out there as she has been in the past. i mean, is there a contemporary counterpart today from sign in this kind of representing their respective rot if you will -- rut if you will? perhaps james hansen on the ehrlich side who is a scientist who i think kind of has this portion of both where ehrlich basically says it is the scientist's duty to kind of call people out. >> guest: he does take on the role as a scientist intervenor in the public policy process. they have made assertions with a broad collapse -- ehrlich's of the day is saying it's about to collapse and millions of billions of people are about to die and this is eminent as opposed to thinking about how the civilization is going to get out to change. but on the other side, it is one of the more prominent people like -- but with hansen it's different. she's coming out with the nuclear power and various kinds of adaptations that people should be taking to adjust to the climate problem. >> host: you mentioned at the outset your initial interest of matter was about the 70's and i'm a child of the 70's so before out honest. the big battle that is going on i think that he is going to excel as a way up there in terms of kind of a line that is being set in the sand. what differences and what similarities do you see in the 70's. in today's context around earth day and out of the formation of the epa and almost unanimously the environmental law to talk about a mandate to tell us what light bulbs to put in our house. so, where do you put the health of the environmental movement today versus the movement which is the 1970's. >> guest: this is a good topic -- >> host: i know. [laughter] >> guest: there have been different elements to this. the environmental movement today is split in some ways by a set of larger and more abstract claims about the future of society and civilization that actually the keystone pipeline is the symbolic issue in that debate and the more pragmatic aspect of environmentalism having apple local level, state level and the new creation of green businesses and the penetration of environmental concern every aspect of the society. so on the one hand, the country is divided. there is a goal but in the two parties and what to do about environmental policies and the national level to find common ground and pass legislation, and at the same time the country is moving forward to the we are more environmental. states are moving forward and businesses have embraced environmental assets of the brand as being a strategic and vantage. i don't want to misrepresent the environmental movement as the one thing or just being the national conversation about climate is one component of that battle or the struggle around the environmental issue. so that is one point that i would make on that and so then the secondary point is just all the other activities you see the tremendous success of the environmental movement over the last 40 ways with aspects of society's. >> host: one thing to go back in the current, to go back to my prior question about the ehrlich of the day the other name that came up was perhaps phil mckibben who was leading the charge on keystone and the liberty bell toward -- liberty.org. there are different backgrounds but is there any similarity? >> guest: i think there are similarities. he's been concerned about population. a very strong concern of mckibben's and he also tends to speak eloquently about the end of nature was his first book and the danger to the civilization collapsed a different aspect of civilizations. so he is a modern-day ehrlich type of person but one interesting difference about mckibben that i admire about his work is the way that he has tried to shift the conversation to be about our values about the future and what we care about. so the idea of building a climate that is more of a cultural movement about our social priorities. and that is really part of the conclusion of this book for me is the need to move away from the idea that the biology tells us what to do and economics tells us what to do and what ehrlich and simon who thought that we need to learn from science and economics and then we have to figure out how to weed out the risks and the uncertainty that we want to live in so that this kind of the ultimate conclusion to the extent people like mckibben and others can shift the conversation to be about the values and the choices in the world that we are creating. the environmental movement would be on a stronger foundation and that is the goal of the book for me. what i am hoping for is to establish a stronger foundation for thinking about these issues. >> host: he makes the point that is an interesting one. as a biologist, all of the data in the world on the biology side of things. people don't believe it, they simply don't believe it is quite the overall evidence and despite the numerous bodies saying this is happening is going to convince the people to get out of their rut triet >> guest: they say leave the science and that doesn't persuade them, but i guess to get another step forward which is the science doesn't actually tell us what to do. it tells us what we think is going to happen and then we have to make choices about that. the implications of the argument is weak the societies can adapt in many ways and the problem may be something we can add up to and if you take that idea that these societies can adapt it leaves us with a question of even if we can adapt is this the kind of world we want to live with this drought and the sea level rise. so many things the weekend about are being endangered by the changes that are happening and we do have a choice about this. that is the fundamental question that we face today. if we go back and look at the end of the body of ehrlich the assignment to make that second that they are not bringing the two ideas together trying to make them into a whole. and ultimately that is around the question of social values and choices. >> host: is their anyone bridging that gap? as an observer of obama and environmental energy policies, it seems that he is trying to make that case. it is whether the climate had a change and he is talking a little bit about the morals and this response to the to the future generations and his personal conviction. he's trying to make that case. or what does he have to do to think to the american public which is really what it's going to take to get something happening. >> guest: to persuade the american public of problems for the climate change obama is trying to strike the right note to combine the environmental concerns with the wing of the economic opportunity and the new businesses and what is the kind of country that we want to have, so i admire your those efforts and setting than in the framework of the value so that is a good way to talk about it to be a >> host: i want to add to this question so badly when i was reading this book where does he sit on the ehrlich sign in spectrum because he doesn't seem very obama fashion to be on either camp. he seems to be a combination of both. when he looks at the climate policy is about mitigation and about reducing the emission. yet he is also pushing and all of the above strategy on energy. or to you can do carter and reagan. kind of like part carter and part ronald reagan and kind of molding the two halves together to real-life hurt your comment on it and kind of where he is in the midst of this bet. >> guest: he has the different perspectives and i guess another element of his program that i think is admirable is a separation of the short term from long term which he has taken on a number of issues but the idea that in the short term perhaps we still want to be developing different types of energy sources and that we don't necessarily know what is going to work out in the future, so we should be exploring many avenues. but in the long term we want to be reducing the carbon emissions. so by the cap-and-trade or by carbon taxes with a variety of mechanisms that may be out there or regulating power plants in the executive action, you have a long term goal. it is similar in some ways to the deficit, approach to the deficit which is a long-term objective and short term. so i think that is the right way to think about it. >> host: one of the points that you made is people sort of have to suck it up for lack of a better word and make temporary adjustments for longer term benefits and it seems we have made tentative rate changes. so, for example would be in the kind of cap-and-trade with the electricity prices potentially doubling up and that is the cost we have to temporarily there now for a longer term change in the strategy. you mentioned this in the context of ehrlich's believe and he is widely quoted as that they necessarily have to skyrocket and that backfires politically. so how do you kind of get -- what would paul ehrlich say to that? because it seems like when you talk to the polling at the ap and everybody is on his side they want a better planet, you know they don't want people burdening the planet and then we talk about what you have to do to solve the problem people started dropping off like flies and they don't want to kind of you with the high gasoline prices and job losses with of the plants to shut down if they do not feel switch those things. >> guest: that is one of the interesting limitations to be a i was interested in going back to study the inside and also limitations in the earlier environmental issues one of the people like him who was an unwillingness to recognize that there were costs to the actions that they were calling for. and so, he wrote at the end of the population bomb for instance that if i might come and if i'm wrong then we will still be better off. and i think that this a little misleading. where the conversation gets interesting and where they want to be moving the conversation about energy and climate is to this area of trade off and priorities short verses long term, how much -- if we were going to put the carbon tax on, how much should it be as opposed to leader. this is where a more pragmatic approach to addressing the problem is where it's not satisfying to people on either side either ideologically but it is where the united states is accomplished things in this more pragmatic area. >> host: that is a perfect segue because i think that one of the things i came away with in the book was hell do you get past this. every that the that what is how the town has worked and then kind of how entrenched the two camps are on this, it offers a solution in this value in the different type of conversation, that in a practical way it means how do you get out of these routes and the has been happening now for a long -- as a reader i was like i am not covering the news. this has been happening since the days of carter and reagan. it's like we are on this merry-go-round's and the same rhetoric as coming back whenever we talk about the environmental regulation or we are trying to solve this problem so how do we get off the merry go round and get people off their camp and even talking about these things. >> guest: there are many factors in play and no one is going to solve that problem in washington. but the goal of my book was to really try to help both sides to really understand each other and to see that there are merits. there were significant in sites that were worth listening to and that all we need to do is have a conversation instead of yelling at each other and that if we try to understand what are the insights that were important in terms of the role of the ecosystems in our economy that are the human dependent on the nature and the way in which things are changing and the ozone is being depleted and economists like assignment that people can act and that regulations can pose burdens a variety of insights that if we can try to understand them and have more of a conversation, then i think that would perhaps lead people back to the middle ground. i don't want to be too optimistic that this is going to happen in the 24 hour news cycle and all of the pressures of the political structure. but i do think that is a key element of it. so part of it i guess is really i think both sides in this divided tend to say it's the other one's fault and what i am arguing in this book is the gulf between the two parties is mutually created over time and we have to find our way back into a conversation with. >> host: as a journalist how do you think the popular press has covered these two runs and this divided and how can they do a better job? we dhaka this as reporters when we are talking about a climate policy where we are trying to be fair and balanced and how do you balance two sides that are not even really speaking the same language at the end of the day? you don't want my job obviously. [laughter] >> guest: that's a challenge. that's a challenge. i mean i don't think that balance necessarily means just taking both sides at face value. that is particularly related to the science also waiting to whether the climate change is happening whether it is time for the press to move on as many of the press outlets i think have done to server for accepting the consensus that the world is changing. climate is changing and so now we need to move on to a conversation about what we are going to do about that and what that means. that is the extent the press can help move us towards that conversations and i think that is what is going to be important. >> host: moving back to the common ground question for a little bit, one of simon's people that he had fired is a person that talked about the pollution of a commodity. and obviously cap-and-trade is a market-based system. i know what did he have a position on that in terms of the price on pollution? that seems like something that conservatives back in the day would have supported the trading of the public idea. i know the people on the hill would say the bill corrupted the market in ways and that is why they opposed that legislation. but what simon see any of the merits to the pricing of carbon of the solution to the problem? >> guest: i did that if he were alive today he would have a different view even in the early 90's when he i think was skeptical of the climate science about the level of the alarm many environmental scientists were expressing. but i think that today he did like many other conservatives might have changed and evolved in his attitude towards the science because he was a man that was focused on the data and was interested in the the the fact so to say that for the case if he would have the fault or not he might have actually been skeptical of the cap-and-trade bill as a structure for addressing the cost of the carbon. but he like many other economists may well have been favorable to the idea of taxation where the economists would lead. the tax on carbon even with a rebate of the returning of that to the american people to the lower payroll taxes sending it back. i think many of the economists and liberals see that is the place to start the would lead to the types of adaptation simon advocated would respond to the price signals and people what a just and that there would be an evolution in the economy in this production. >> host: simon was a proponent of the ingenuity of technology trying to solve these issues. and, you know, to put that in the present context, you know, the president speaks and talks about how we have to kind of be in charge of technology and the alternative energy like solar and wind and geothermal and getting fuel from algae, you name it. this means the conservatives are against the subsidies that help those along. plus and be where they are on that or would he support basically a way to kind of jump start that ingenuity or does that engine devotee have to be for lack of a better word organic? >> guest: i think that he would have tended to be skeptical about the idea of a state of driven investment strategy that would choose winners and losers because often the government isn't necessarily the best risktaker so to the extent as he would have been more basic scientific research and that type of support from the government for research that might lead ultimately to new technology that the actual choosing of a specific technology is the kind of thing that he would have been more in favor of the idea that the social cost of carvin should be the carbon tax that allow the marketplace to work its way out. i think that he would have favored it and there are many conservatives today who might favor that as well. this is where the conversation gets interesting as well because there are important insights on both sides of the question certainly going back in time you can find many examples for the government investment and technology and again there are merits on both sides of the date and we have to find of where we want to end up and that is where the conversation gets interesting. >> host: where is he today? i've covered things pretty closely. he's really up front on these issues. where is he today and is he still kind that in the same fight with? where does he stand on these issues? >> guest: i think that he has been very essence sufficient in his convictions and vantage points that he has taken and i think that he does feel that society is on the path to ruin some kind of collapse of civilization that he feels is undermining the natural systems of support for the society. so i think that he still feels that way and is mostly sticking to his guns and he's gotten very interested in the idea their needs to be the kind of cultural evolution to help the society to become more sensitive to its own peril i guess is his interest. >> host: does he claim that now? >> guest: like the species' extinction he has been interested in the toxics in the environment and climate change i would say is one of the main focuses that increasing populations lead to increased global greenhouse gas emissions and also the rising consumption has that kind of affect. >> host: does he have other types for solving it? >> guest: he believes population growth is at the heart of it and in the last decade or so which he has made trying to a suit would be the ultimate population of the world and it's come up with numbers along the line of 1.5 billion people. we ought to see a significant reduction in the numbers of people that we have today so the population i don't want to miss characterize he is a complex tanker and recognizes the technology and consumption and affluence and a variety of different factors but i do think that he does still have the basic idea that people need to be in for a medal consequences. the way that goes back into its original research and the idea of sort of the growth of the population butterfly's leading to the crash of the population and this is the origin that have translations from other types of species and to the human population and that was ehrlich's idea of the natural cycle of all of the population and humans are no different that we are animals like other animals and i guess this is a sort of fundamental question people like sign and who say they are different from other animals and we have the capacity to set up in the way that butterflies and other types of things do. >> host: to members of the team are mentioned in the book and one is john who is obviously science adviser and john which i didn't know was very tight with ehrlich. >> guest: close best friends. >> host: spending time in colorado together. obviously it is very in synch from the viewpoint that the population is a major problem that had to be addressed. without going into the specific policies like me and it out in the administration. was he picked to be a part of obama's team and part of his scientific advisory people in his view it has evolved or do you think that he holds that view and it doesn't really talk about it as forcefully as his body does? >> guest: i think that they have evolved as a way that they communicate about these issues and in the 1970's to talk about the idea of the development and came to realize. they didn't have some of the predictions about how exactly the population is going to lead to problems and trying not to talk about the population numbers as much. the conversation shifted more as a discussion of climate change as being the central issue of our time. in some ways perhaps evolution thinking that it's more of a pollution evolution and realizing what is she was working and what are less salient. >> host: the reason i ask the question is to go back to the obama question a little bit because obviously holdren is a name in the administration that seems to be embracing not only solving the root causes of the problem when it comes to climate which is obviously the emissions path but also talking about adaptation and technological fixes to the problem. and it seems that holdren that was hanging out with ehrlich back in the day would talk about the technological fixes much as solving really what they thought the root problem was which was population, to many people, too much pressure on the plan at. >> guest: this is the important shift that needs to occur more generally from the abstract arguments about the population and resource scarcity to the more pragmatic approach is to figuring out how to solve problems. so maybe that is the evolution that occurs when one owns this and to the government and responsibility and is trying to bring together in the form of the actual policies and programs things that are going to work both politically and practically so that me be one component of that. going back to the evolution of the idea that this i guess is an example of the evolution is an idea in which the way the rut is still significant when he was up for his confirmation hearing he faced the whole barrage of questions about his relationship with ehrlich and did he believe that climate change is going to lead to billions of people dying within the next five, ten, 15 years and backed away from those kind of predictions saying it was less conclusive and a little bit uncertain about what was likely to happen. >> host: the other person in here that had a role in obama's administration is larry summers who is on the short list i believe and obviously is mentioned very briefly. basically he seems to be on assignment's side of thing and talks about the limit of growth and how the kind of model for those are bologna. in my reading that right? >> guest: fun in the relationship of julian simon and the economics, and then went further than many economists in the claims that he talked about population growth and we have more people that can be living why is, but his basic critique of the idea of limits to growth and i think ehrlich is very widely shared among the heart of the economics profession. the idea of the human at that devotee of the role of markets and any one people to adjust to various problems and i think there is a lot of criticism going back to the early 70's. people say in who can focus on the pragmatic problems of the sulfur emissions and of legislation now that if we are focused on the apocalypse being declared by the computer making forecasts in the book. it i think summers fits into that school of fought and it's clearly in the terms of how things are going to play out. but like many other economists, he favors i don't know who the specific policy missions but many economists favor the carbon taxes and the need to incorporate the social cost of carbon into the cost of doing business. so i think in that sense and more pragmatic path will be the path that many economists would want to take. >> host: there were some interesting things highlighted in the book that drew my attention and one is that you have to man that have very different views of the world. the have sort of similar upbringings. they were both jewish, they both grew up in my home state of new jersey in my new jersey suburb. and you make this -- talk about this in the case of ehrlich, into the suburbs it was like nobody's going to believe this about my home state. he started getting a butterfly and he saw this massive development. >> guest: ehrlich as representative of the process after world war ii of people moving out to the suburbs and moving to be closer to nature and so he would wander the fields around me poletti and he came to be fascinated by butterflies and a half aquariums and all -- >> host: and they did like you say that have a bed rooms that were kind of like smithsonian -- >> guest: i don't think sign in quite had that in his bedroom that he was an eagle scout interested in nature but i did what happened with someone like ehrlich this is a fascinating story of the suburban nature but also threatens the very nature that they were becoming close to some she was seeing the other divisions going up around where he was with the ddt to control mosquitoes and this nature he was becoming so passionate about john hart, one of his friends who was the third member who joined the debt that ehrlich made with sidemen the cuff simon with ravee suburban foundation of their environmental ideas and the passion for the environment. >> host: and 96 on the radical environmental movement in general. and a lot of the people that are involved in that and like the earth latch yourself on two things movement come from suburbia which i think it's fascinating. the other thing i thought was fascinating is you mentioned that julian simon suffered from depression. get in this book he is the optimist. he is a glass half full kind of guy and if ehrlich who is the apocalyptic glass is half empty kind of guy you and i thought that was an interesting -- dtca and yet we are going to get out of this. >> guest: a couple interesting things about that. one is that it's hard to prove psychology with someone like sieminski distance after -- what extent is sort of a euphoric attitude towards the idea that things are getting better and come from his own determination. things were not so bad. there may have been a link because there was a passion that he brought to his euphoria. now actually i think that paul would actually say, he would actually say that he's an optimistic person and the reason why is because he believes that there is still hope and the whole reason why he is so passionate and has devoted his life to try to inform and educate and mobilize people is that he thinks there is still time to change. so i think that's true. he's very pessimistic about the direction that we are going but he still holds out some hope that it can change. >> host: does he have a new deadline? from 2,000? >> guest: there are a series of different deadlines and when there would be fannin and different things and he would push them back several decades. but the idea that there is going to be one of a variety of different things to happen in the world why the disease of outbreaks and warfare, the collapse of the ecosystem and the social collapse -- >> host: you can clarify for people. we talk about climate change as a kind of building issue whether it is accumulation in the atmosphere with a long time frame. but ehrlich has always sought it's going to be sutphen -- sudden. >> guest: the biologist that studies the eruption of the population and then the crash. biologists often talk about the crash part of that cycle and so he did that but the human population as well. i think that the idea of a nuclear warfare or a massive disease outbreak are more of the sudden responses that he predicted. i think that he would say that -- i guess around point changing the focus on the idea of a to pinpoint the there is going to be t