mean vonn step for science for the public and i welcome you to tonight's contemporary science issues and innovations program concern is growing about a possible six math extinction this one the st brought about by human negligence our guest andrew know the fisher professor of natural history and professor of earth and planetary sciences at harvard university is an international authority on how evolution responds to mass extinctions tonight he explains how the geological record of past extinctions can help us understand the prospects for future life on earth dr noll is a member of the national academy of sciences and the royal society and the winner of numerous awards including one of the most prestigious natural science awards the international prize for biology conferred in tokyo in the presence of the emperor an empress of japan dr no appeared on this program a few years ago to discuss his book on evolution and he'll talk about his forthcoming book later in tonight's program we're very honored to welcome andrew no welcome sir thank you glad to be here and we're delighted that you're going to give us this background because there is a bit of confusion around what we're enduring at this time and what the future holds for us could you start us with of a little bit of the background about the previous extinction since you've done so much on those that well it's interesting that until about one thousand nine hundred and eighty there wasn't a lot of work on geological mass extinctions or interest in them and then two things happened one was water alvarez a geologist from berkeley found evidence of a meteor impact right at the point of the record where the dinosaurs disappear and that stoked a lot of interest in the phenomena of mass extinction and at the same time on the same time scale at least the late jackson kosky went to the library and simply tabulated the st and last appearances of different taxa in the oceans through time and what jack found was that diversity initially goes up and it collapses and it goes up and it collapses and in fact it easy every time it has to write hits their action but in fact there's only evidence that that happened once and that was sixty six million years ago when the dinosaurs and many other species disappeared the biggest mass extinction which happened two hundred and fifty two million years ago is i think at this point clearly known to have been caused by massive vulcanism that is volcanoes a one million times larger than anything ever experienced by humans and so yes there's a variety of causes each of them carries a certain type of selectivity in that the end cretaceous extinction was harder on some groups  permian one and waste versa that's one of the most important points that you make is this evolutionary thing so we tend to think of evolution is linear and that if it's going to fade it will come back in the same way know for one hundred and fifty million years before the end cretaceous impact dinosaurs ruled terrestrial communities and most mammals were little shrew like things that you know lived in at night once all the dinosaurs disappeared they didn't come back they were extinct but within about ten million years all of the orders of mammals that we see today had evolved so in some ways mass extinction is a refresher and it gives new opportunities on the other hand we should take no confort from that because the timescale is millions of years ok and in each case there was this an increase in diversity it sounded like or it seems like is that true from over time that i guess after the permian then you have this start to evolve so on well there's an overall increase in diversity i always tell my students that at least at the beginning of the last century there were probably more species on land in the oceans than there had been at any other time in but it isn't linear and it isn't simply a response to extinction one of the things that we found and we've just published a paper on this recently is that we can quantify the ecological impact of these extinctions and commonly what will happen is the fabric of ecology breaks down because so many species disappear and then when it reassembles it reassembles with different types and how she's and they may or may not allow you to have more diversity than you did before ok well i was thinking was that it seemed to be a development for more mammals of which our ancestors were part that made the world a different place than it had been for ok then in the present situation in the past extinctions these are all brought about by natural forces and i wonder if we can say the same that you know the prospects are the same for say evolution we bounding and  that having that resilience when this kind of an extinction in progress is brought about by man made factors that have poisoned the environment and so on they don't break down in the same way yeah there's there's two aspects to that and you're absolutely right that in each of the geologically induced mass extinctions in the past diversity did recover but it recovered at a time scale of millions of years ye so if you're concerned about your great grandchildren forget it the other thing is that you know it was a terrible day when a meteorite hit the earth sixty six million years ago but the next day the earth began heal what we are doing now doesn't necessarily carry the promise of immediate healing that unless we change our way yes ok so there's that factor and i to come back to that one as well in terms of evolution of just as being a process that has shown enormous resilience at the rate of die off right now i'm thinking of the corals i'm thinking in australia this massive die off of animals and so on the organisms the insect loss and so on you have pointed out that i think that it depends on what gets hit you know perhaps at different times how well nature can respond what do you think about this present situation well it's interesting that what is happening in the st century has a distant mare and that is what happened two hundred and fifty two million years ago when massive vulcanism spewed large amounts of carbon dioxide into the atmosphere at that point there was global warming you have the earth got warmer because the earth got warmer the oceans are warmer they can't carry as much oxygen so oxygen was depleted in the oceans and because so much of that c o two got dissolved in the oceans and one of the things that we did probably twenty years ago now at a time when people had just started to identify geological correlates of extinction very few people were trying to us study the pattern of selectivity what survived what died and so my friend dick bach and i simply spent months in the library and looking at the physiological consequences of increased c o two and we made sort of a you know a checklist of what kind of organisms should be tolerant and what kinds should not be and it turned out that was a very good description of what actually and now in the st century that pattern of extinction at the end of the permian is proving to provide a pretty good road map for the vulnerabilities of populations at least in the oceans today ok now that's in is right right right no that was really very interesting because he could be able to predict what might survive in an ocean environment in you i assume that you're taking this  forward for like land as well let me add another thing there since we have a human factor now all over the planet and one of the big problems is that with the rising sea level places to live are disappearing while the population keeps increasing and so on what is the effect of something like that do you have can you squeeze that into that kind of model in a sense you can in that we have a good really quantitative idea of the relationship between habitable area aha and how many species there are now it has to be said that the kind of sea level change we're talking about over the next century the direct effects of that on biological diversity will be small effects on miami bangkok rattus bangladesh are going to be catastrophic right but i think in terms poor that's so critical to launch a cool system just in general i think in any oceans right so many other creatures depend on if you lose that is there a kind of you know a spill of fact from that in other words a whole bunch of other things go as a result of the loss of that and did that come in your model as you know there's an ecologist at the harvard forest in central massachusetts named aaron ellison and aaron has talked about what he calls foundation species things that we usually don't worry about in terms of extinction because they're common you know the beech trees and morrison massachusetts or corals but everything else in the ecosystem depends on the health of the species so without question since corals are vulnerable to a number of environmental changes and don't come back real fast right well this is an interesting i think we are in some danger of having catastrophic loss of the regions and as you pointed out that will not only affect corals but these are hotspots of biological diversity and many of the things that simply depend on the corals for the physical structure of their environment will be in in  jeopardy has this continuing impact so that you can do something basic you pointed out that even trees particular trees that ecology depends on this it's kind of a root force the or dying on something else the physical structure of the environment will change dramatically if those species are no longer ok ok is there a parallel back in these earlier times essentially no animal built reefs for several one million years there after on the other hand in the permian most of the changes that i mentioned with ocean acidification loss of oxygen are things that peculiar to the oceans yes so the effects on life in the sea was devastating perhaps not so devastating on land whereas at the end of the cretaceous period a majority of right now we seem to have both in the oceans and on land so i was curious about the loss of insects we hear about the the the b the honey bees for instance when we depend on these things to to for pollinating and the a lot of other insects that are a base food for many other creatures is this similar to what has happened before in anothe where we have both sea and land species threatened yes and it's distinct in the sense that and this will not make you feel any better about it that most of the changes in the biota on land and sea that we read about are not the direct result of global change at least up till now that is there are very good censuses of vertebra down to most on land and populations seem to populations seem to have plummeted there have been a loss of i forget the exact figures but about twenty five percent of the living corals on the great barrier reef all of that was due to human influences but most of it was not a direct result of changing climate now the bad news is that we're continuing to influence natural populations in all the ways that we have done before but now superimposed on that the environment is changing at a geologically high rate and so it's a double whammy ok we have to be doubly concerned about what we need to do to vouchsafe our diversity for our grandchildren i could you expand a little bit on that kind of x so abraded climate change thing because i think there's a great deal of confusion about that people think well there are these little cycles and stuff but geologists and biologists have pointed out this is a little faster than what is new and that's an important point  the difference is that organisms respond or don't respond mostly to the rate of change and the rate of change in the environment for example the amount of carbon the environment has increased by about a rd since i was born and that is not something that is characteristic of business as usual in the geologic record we know that that has happened evolution as a process is it cannot be resilient quite resilient enough that even now what are the parameters there for it to respond adequately to something that is excel aerated that what makes populations vulnerable to extinction is loss of population and so from that perspective we should be concerned for any number of plant or that them will species it's also the case that in some ways the landscape of evolution changes in a human world there's a lot of evolution happening now because of our use perhaps even overuse of antibiotics  eagles population size sizes and geographic ranges have declined enough that i think many of these species need our help ok alright then it's not evolution itself evolution keeps responding as it is selective in terms of what can proceed what can survive this is not the idea so so then what extinct there are you know again when i was born there were fewer than three billion humans on this planet now they are seven and a half one billion yeah i know it is growing up so i think that humans will be abundant and and an important planetary force two hundred years from now what will change however if we choose to allow it to change is our environment i mean i i find myself heartsick when i think that my grandchildren might never get to see around us right now like right and part of that's a static you know part of it goes back to the sense that for better or for worse we are the stewards of the planet and what will be here two hundred years from now is going to be based on decisions that we make so i can i can imagine that there's plenty of humans all over the planet but living in a in a world that is impoverished from the standpoint of the diversity of life and that i think in many ways has aesthetic consequences but also made more an environment that's made more vulnerable by having loss of the kind of diversity that makes ecosystem zero bus so we put ourselves into an impoverished and therefore more vulnerable state of the earth system if we choose to ignore what's happening now ok which is the next point what do you think we should do in here bring this up because people feel like they would like to shut it all out they are you know it's it is very daunting with bad news all the time and people feel isolated and they don't know what to do and what's your take on this we can't shut it out you know the lot of climate models predict stronger hurricanes  loss of rainfall in the midwest where a lot of our crops are grown so you know putting your head in the sand doesn't change anything at all so i think there are a number of things that we can choose to do and i hope we will choose to do one is the the root cause of climate change which we know for a fact i should say is predominantly saturday i fly in airplanes and that i think it's going to be difficult to simply stop doing those things but we can do them in with engineering that uses less you generate less c o two for the x o different kinds of cars electric cars hybrids are good and airplane engines have become far more efficient over the last twenty years so i think we can get more bang for our buck in the fossil fuels we do baron i thought the same time i think overwhelmingly we will go toward renewable fuels and in part that's go be forced on us i mean the most optimistic predictions for coil for oil and gas suggest that you know in the lifetime of your great grandchildren they better be using something else because you're going to run out of those things step by step change the way we do business which is useful we do not as yet have effective engineering solutions to global change  although i can imagine i would almost predict and i certainly hope that within my children's lifetime there will be reasonably inexpensive ways to actually scrub c o two from a r that is there's a lot of research going on in that we're not there yet but one could hope so all the things that change the environment we can actually influence through the choices we we make both as individuals and as as voters and then at the same time there are all these other things that we do we exploit species the reason that rhinoceroses are going extinct to guard against pollution there are all sorts of choices that we can make and i think have to be made for our own sake you know not only for the sake of right officers but the sake of our our own environment and collectively if we now as individuals as residents of massachusetts as americans and as global citizens can get behind efforts to make the world a better place i think we can but it's high time we get going there does come a point after which it will be very difficult right i think that is one of the problems that you need governments to be doing this it at the end of the day and there has been a reluctance to really do things what has to be done and there is still a lot of power from the oil industry and so on in terms of determining how long we can drag our feet but the if people can be motivated to get out there and demand change then that might be a good thing and in addition all the renewable energy creates a whole lot of jobs and a just healthier environment and everything it in your view are if we time move say now next twenty years then can we preserve life adequately on if we sort of rethink the way we produce neat the way we do you know the way we use our resources and so on i think we can preserve much of the diversity we have today i think there are things that are consigned to extinction yeah i've happy to say i do want to go back to the point about governments it's easy to blame things on governments but you know in this country the people who are in power in government are people we voted for yeah so if you don't like it yeah it's time to get out and vote yes yes it's very important thing and to be an intelligent voter another thing that is happening is a lot of appointments are being made that are damaging the science  agencies and so on that we do not have control over but the that if people made enough noise then that might change absolutely it's true that voters need to grow up and do their their proper thing dr no i would like in the last few minutes to talk about your forthcoming book and also this fabulous award should be a noble and that start with this book that is coming st if we may so once again we had life on a young planet which is a wonderful book but i understand you're undertaking something a little different in the new one and we hope to have an event around that too so you know i'm writing a book in part for the reasons that we just discussed you know every one of us is tethered to the earth by gravity we're always in contact with  the book that i am writing is really an attempt to bring the story of the earth how it works what its history is to all people yes really not just stem programs oh that's and i think we can only hope that people would will act responsibly as citizens if they understand the earth and its vulnerabilities and its opportunities and so that's that's really the aim to just sort of give people a sense of this wonderful planet we live on as a four billion year history we are the product of that history and we will determine the next chapters in the history they write that's so great and i hope it will bring about as here in your work is very famous for the the integration the geological the chemical the biological that these things are absolutely interdependent and that i think we don't have a very good understanding of that in the public that geology is over in that department and biology is over in this of that but i hope it will come out in this book a little bit too to make people understand that this stuff all goes together and that we have to appreciate it let your heart relay yes so we'll look forward to that book and the movie that goes with that and so i thought i can't resist asking about this at a level award would you please tell us a little about that so you've had loads of awards but this must have been a wee bit different splits the name of it and what happened ok the award is the international prize for biology it's one of those things that i don't think you would ever think about sometimes nice things just fall surprised you yes and it is something that i think i was the th laureate of this and some of the people i admire most like yeah saying that you did ok it's a little more than the opportunity actually to meet him converse with the emperor and empress is not one that ever happened to this pennsylvania dutch boy and probably will not again so yes it was just it is just something that happens once in your lifetime yes but not to everybody so i'm not sure i don't how many americans have received the award  either for that matter but it's about half i think really no american science is pretty rich yes yes yes but i think it must have been pretty swell  neat thing to be during and so we were coming to the end i just want to make sure that the our viewers understand there's a forthcoming book will keep you posted on this and we talked to you that maybe we could have an event around this public lecture or something like that to talk about that book when that one comes out and you said that is to be my summers work is cut out for me but i think my expectation is that i will have finished you know the text of the book by the end of the year which i always tend to think is the beginning of the end we wish you the very best that we preach eate the enormous amount of work that you have done not only professionally but in trying to bring this to the public as well again i recommend this book this is a wonderful read and i sure the next one will be also but dr no has done so much in terms of showing the importance between the type of the extinction and particular affects on life selected i should say as babies selected effects and how evolution works in that manner thank you ever so much for your enormous contribution my pleasure