 I'm a paleontologist. I study things that happened tens of millions of years ago. And yet, here I am at a World Economic Forum conference that focuses on the impact of the fourth industrial revolution, your business people, and scientists of various sorts. And I think probably most of you are focused on next year or five years from now and aren't particularly often thinking about the deep past. I'm going to try to convince you that's a good thing to do. There have been enormous developments in understanding the past and in thinking about the past. And of course, nearly everyone understands that humans now have a global impact. So what I want to do is help you make use of that information and that perspective that we have from looking into the geologic past. But before I start, I need to admit that when I started looking at fossils, I wasn't thinking about anything except having a good time. This is my first field season, 1972, Wyoming. I'm the, I can stand next to myself here. I've changed a little bit since then. But this is when I discovered that collecting fossils was an enormous amount of fun. The discovery, an incredible thrill. And that summer we found fossil mammals, dawn horses, fossil alligators, fossil primates. And also began to find these incredibly delicate leaf fossils that hadn't seen the light of day in 50 million years or more. That was an incredible thrill, the thrill of discovery. And also it was just an incredibly beautiful place to work, a desolate landscape, nobody on it, living in a tent for weeks at a time, bombing around the badlands in an old truck and spending hot days digging up fossils and discovering these new things. I could really have spent my whole life doing nothing but that and just enjoying it. This affected my brain and my perception of time because walking up and down these layered hillsides, you really feel you can transport yourself through time just by taking a step up or a step down. And it changed in 1990 when a couple of my climate science colleagues published this paper with a map in it. This map is generated by a computer simulation of climate 50 million years ago. And what caught my attention about the map were these big gray areas in the middles of the continents at high latitudes where the winter temperature was far below freezing as just the average temperature for the coldest month. And the reason that caught my attention was because it absolutely had to be wrong. The reason it had to be wrong was because we paleontologists have been collecting fossils from these places for over a century, even at this time. And those fossils told us that the winters were really mild, the climate was very warm. This is a forest of dawn redwood trees growing on the shores of the Arctic Ocean, not much more than 1,000 kilometers from the North Pole 50 million years ago. Places where we had evidence for vegetation like what grows along the southeast coast of the United States today or the east coast of China in places where today the ground is frozen year round. There were palm fossils. We had fossil palms from less than 200 kilometers south of the Arctic Circle and all down the coast of Alaska and in the middle of North America in the Rocky Mountain region, palm trees. In Wyoming where it's bitter cold in the winter today, there were alligator fossils. So clearly something was wrong with the model. That led me to think, well, what could be wrong with the model? Well, the model was a simulation based on boundary conditions that were put into the model. So the positions of the coastlines and the continents, the amount of energy coming from the sun, all these were stipulated to begin with and then the climate was calculated from understanding of basic physics and chemistry of the atmosphere. So there were several reasons why the map looked different to a paleontologist and a climate scientist. One might be that we paleontologists were misinterpreting the fossils. We didn't think that was true. We had lots of lines of evidence that we were right. Another possibility was that the boundary conditions were wrong. So maybe the continents were a little bit in the wrong position or the coastlines were represented incorrectly. The climate modelers assured us that the models were not that sensitive to the boundary conditions and we didn't think they were terribly wrong anyway. A third possibility was that there were things missing or misrepresented in the climate model and that's when the light sort of dawned on me. I thought, wait a minute. If the climate model can't reproduce this very warm climate, we know existed 50 million or 60 million years ago and it's the same kind of model we're using to predict the future. How do we know we're gonna do a good job of predicting the future? 25 years have gone by since this paper was published and there's been this very fertile argument back and forth between climate scientists and paleontologists and geologists and today's climate models do a much better approximation of the paleontological reconstruction of climate. They still tend to be too cold. So there's still areas where it's below freezing for the average temperature of the coldest month of the year but they're much better. They're better because the spatial resolution of the model is higher. They're better because there's a much better representation of the water cycle, of clouds, of the effects of vegetation on climate. So many improvements have been made. Over that 25 years, there's also been another development and that is a better understanding of the history. So we have this wonderful situation where we're able to test, use history to test models and it's really important that we're able to test them without waiting for the future to come. So you can run your climate model and into the future and then you have to wait decades or centuries to find out whether the model of the future is correct. Here's a way we can sort of short-circuit that process and find out right away by modeling things that have already happened. But another thing that was happening through this same time interval is an improved understanding of the climate history of the planet and that's best represented by this graph which shows the temperature history of the last 66 million years as read from deep sea sediments and it's represented here in deviation from the modern. So you can see that most of this time the Earth has been much warmer than it is now. We already knew that but one thing that we didn't know about were very short events. We call them hyperthermals. These are planetary heat waves that lasted for tens of thousands or hundreds of thousands of years. And the biggest of these planetary heat waves is called the Paleocene Eocene Thermal Maximum or PETM for short. The PETM happened 56 million years ago. It was kicked off by a release of carbon of 5,000 billion tons of carbon just to give you a sense of how much that is. It's about what would be released if we burned the entire fossil fuel reservoir. So it's a huge amount of carbon. It happened in just a few thousand years and that approximately doubled the amount of CO2 in the atmosphere. It raised planetary temperature by five to eight degrees Celsius. It caused acidification of the ocean. It also initiated a bunch of feedbacks. So the initial carbon came from methane in the ocean floor but the climate warmed that made soils warmer. The soils had organic matter in them which was decayed at a faster rate, putting more CO2 back in the atmosphere and prolonging the warming. So the event was kicked off very suddenly but it lasted for 150,000 years, 75 times longer than the common era that we live in now. An event also that has a lot of resonance with the present obviously with the carbon addition and the acidification. The other thing that happened when the PETM occurred was a huge transition in ecological communities. So in the deep sea, there was about a 50% extinction of small marine organisms in at the high latitudes. There were species of plants and animals that were able to move back and forth between the continents between Asia, North America and Europe. And at mid latitudes, the climate changed so fast that there was extirpation of plant populations and replacement by different kinds of plants. So we start off in Wyoming with something like the vegetation that you would see today around Savannah, Georgia or the north part of Florida. During the height of the PETM, it looks much more like the vegetation of dry tropical Mexico or Costa Rica. And then as the event tails off 150,000 years later, we get a return back to the kind of vegetation we started with. There were also effects higher up the food chain. These are photographs of leaves showing fossilized insect bites on fossil leaves, which is a pretty amazing thing that they're preserved at all. The amount of insect damage on plants rose dramatically during the PETM because of the increased temperature, but also probably because the higher CO2 in the atmosphere, plants have been observed today to make less protein when there's more CO2 in the atmosphere. And that forces the insects to eat more in order to get the same amount of nutrition. There are also effects on mammals. These are teeth of some of the earliest horses. And you can see this jaw here is from the very earliest part of the PETM. This is approximately the very first horse in North America or anywhere. And this one comes from the height of the PETM when the temperatures were warmest. This animal was about 40% smaller than that one. So the mammals dwarfed probably also related to increasing temperature and food that was less nutritious. Let's bring this forward to the present day and think about that. We have this event that's really useful in thinking about the present. There are also ways in which it's very different from the present. The ways in which it's different from the present, frankly, are kind of scary. The PETM took place in a world without ice caps. There were no ice caps before the PETM. Today we have ice caps. And as a result of that, as the climate warms, you melt polar ice caps, you expose new ground that warms because it absorbs more solar radiation and you accelerate the warming trend. In the PETM, that wasn't true. You also, of course, raised sea levels. A climate system like we have now is actually probably more sensitive to a big carbon release than the climate system of the PETM was. The other big difference between the PETM and today is us. We know what we're doing. We're releasing carbon to the atmosphere and we can control that. This puts our current state in a little bit longer context than probably most of you are used to thinking about. It's a record of carbon dioxide in the atmosphere that comes from air bubbles in the Antarctic ice cap. It goes back 800,000 years. You can see that there are fluctuations with the highs being around 300 parts per million, the lows being about 190 parts per million in the atmosphere. These look like small fluctuations, but these climates are more or less like today's climates. In these climates, there's a mile-thick ice sheet on Boston. Very big fluctuations in climate. They have a huge effect. So here we are now in 2016. Since the beginning of the Industrial Revolution, the amount of carbon in the atmosphere has gone up by about 40%. And in a business as usual scenario, it will more than triple by the year 2100. This is like the PETM on steroids. It's a bigger relative increase in CO2 happening maybe 10 times faster than the onset of the PETM. But this graph still doesn't give you a sense of what happens going forward. And this is really my big message. It doesn't think into the future as far as we need to be thinking into the future. Here's a little bit longer view into the future. This is a projection of temperature change to about the year 2250, showing two scenarios, one in which carbon release into the atmosphere, carbon emissions, reach a peak in the next decade or so, and then decline and go and stop entirely by the end of the 21st century. In this simulation, we have sort of business as usual. In one, you get a little bit over a degree Celsius of global warming. In the other, six or seven degrees Celsius warming. So big differences in the amount of warming, but what's really amazing is to bring those projections forward. And what we see is that with the high emission scenario, if we go out to the year 7000 in the common era, 5,000 years from now, we still have over five degrees Celsius of global warming with the high emission scenario. We've looked back to see what happened with the PTEM. If we push that lesson forward, it's quite likely that it would take nearly 100,000 years for the temperature of the planet to drop back to its pre-industrial levels. So this is the scale on which we're operating now. So we've learned a lot from the past in the last 20 or 30 years. We've learned that it's a great place to test our ideas about how the planet works. It's also a place where we can find out about events that we never knew happened, didn't know could happen, and now we have to think about those. We now study the past with an eye on the future, which was not true until fairly recently. I think many people kind of go immediately from where I am now to a kind of apocalyptic view. They say, oh, we're going to destroy the planet. We're going to drive ourselves extinct. But I actually think those are just excuses for not thinking harder about the future and thinking farther ahead. We learned from the past that there's always change, but that the changes we're making now are very rapid and they are going to last a very long time. We need to expand our brains and our concept of time. Most cultures have somewhere in them this idea that human history is an important guide to making decisions that are political or military. We are a geological force. We need to use geological history to guide our actions in the same way that we have used human history. If we're going to act on the scale of geology, we have to include a planetary time scale, a geological time scale in our thinking, not just a human time scale. We have to stop doing crisis management and start doing planet management. For those of you who are in the business of changing minds and economies, my hope is that people look back on us a thousand years from now and say, ah, this was the time when humans began to factor in their own power and the durability of the changes they were making. Thank you. Thank you.