For over three decades, drilling into mountain glaciers ice that has remained frozen for thousands of years. The ice cores they retrieve contain a perfectly preserved record of the earths past climate. Looking toward the future, chris field has crted a time machine in a Northern California grassland. The jasper ridge Global Change experiment is subjecting an entire ecosystem to the predicted climate conditions possible 50 to 75 years in the future. Both Research Programs one looking into the past and the other toward the future will ultimately provide us with better ways to predict and cope with earths changing climate. [ wind whipping ] man ie climbed a t of mountains, and ive been told that i hold the worlds record for the amount of time a human being has spent above 18,000 feet, which is 3 1 2 years of my life. But ive always had a purpose for going up there. And unlike mountaineers, i am always looking for the simplest, safest way we can get our crew up there and all of our equipment, cause we have to move 6 tons of equipment to these mountaintops. And unlike a mountaineer, we set up camp and we live there for six weeks or two months, and we bring four tons of frozen ice back down. And the reason we drill at such high elevations is that were trying to get to the coldest place in those ice fields. And if you go up to where the temperature is below freezing, no melting occurs, and you have the best archive of the parameters that we want to measure. Narrator Lonnie Thompson is a glaciologist who researches the earths climate history by reading information trapped in ice. He drills ice cores hundreds of feet deep all the way to bedrock, at elevations above 18,000 feet places where the air is very thin and extremely cold. Even in the tropics, the temperature at this altitude remains below freezing yearround, so the snow that fell centuries ago has never melted and is buried under newer layers. When the ice is drilled out, it can be read back in time, much like the rings of a tree. Here. Here. Here. Thompson the beauty of the ice is it records anything thats in the atmosphere at the time that that snow falls. If youre at the top of the himalayas, you can see the development of industry in india. You can see when lead was put into gasoline. You can see when legislation was passed to remove it. Anything thats in the air gets recorded. And perhaps, with the ice cores, probably the thing that really makes them unique is that they record the history of the earths atmosphere. And you can see how the earths atmosphere has changed through time. And our limitations is just interpreting how that recorder is working. When i came to ohio state university, i was prettyonvinced i was going to become a coal geologist. Because, having grown up in west virginia, i could see one of the reasons of going to college was to get a job. And i could see the application there. In my First Quarter here, i got a little note in my mailbox that said, how would you like to work for a Research Program in the institute of polar studies, looking at ice cores . And so i took this position. It took me about a year, year and a half, to really start to realize what was archived in those ice cores, or the potential. And at that time, all the work was being done in the polar regions. Narrator during the 1950s and 60s, ambitious drilling programs in the remote ice caps of antarctica and greenland provided an impressive record of past climate, such as ice ages and warming events, going back hundreds of thousands of years. But these records only provided part of the climates history. As a young man, thompsons interests lay outside the arctic. He set a goal to drill ice where no one had ever drilled before. In the polar regions at the time, there was a lot of competition, and no one was looking anywhere else. And so im thinking, well, heres the rest of the world. Why not . And then, of course, if you start thinking about it, you realize that we got 6. 5 billion people on the planet. 70 of them live in the tropics. And then you also realize a lot of the big weather phenomena that impact people el nino, monsoons those are tropical phenomena. And if you really wanted to look at the history of those, you need records from that part of the world. And i will never forget a rebuff when we proposed to drill the quelccaya ice cap. And it basically said, the ice cap is too high for human beings, and the technology does not exist to drill it. And toward the end of the season, i got a telex from the program manager. He said that he had funded all of his real science projects and he had 7,000 left what could we do on that tropical glacier for 7,000 . And i remember telexing back and saying, i think we can get there. The idea was to bring a drill from antarctica and fly this thing up to the summit, drill the core, put the cores in a helicopter, fly it out. This helicopter wed be flying along at 19,000 feet, and it would just fall like a rock. I mean, its clear air. And the pilots eyes were big. Im sure ours were, too. After two attempts, they said, theres no way. We cant even get close to the ice cap. You just couldnt do it. So we failed in our mission to drill the ice field. And thats when we came up with the idea of solar power. The beauty of that is that theyre panels. And you can put six panels to a horse, and you can transport your power supply to the edge of the ice, carry it up on the summit, assemble the array, and power your drill. Turned out that that solar power was just beautiful. The fact is, we actually drilled not one but two cores to bedrock using that solarpowered drill. And we couldnt have chosen a better ice field on earth to do this, because the record was so straightforward. Quelccaya was annually layered. You could see it. And you could see it in the dust measurements. It was couldnt have made a better choice. Narrator the ice cores lonnies team recovered on the quelccaya ice cap became a major step forward in climate History Research because their annual layers could be dated so accurately. The tropics have alternating wet and dry seasons every year, and these alternating seasons are clearly marked in the ice, containing Vital Information about the weather in the region, such as monsoons, droughts, and el nino. Each year, the wet season brings a thick snow layer, followed by a darker layer created by dryseason dust carried by winds up the mountain. These alternating wet and dry layers can then be linked to historic atmospheric events, such as volcanic eruptions, giving a precise annual record. Thompson and so that gives you your calendar. You can see it on the margin of the ice cap, and you can see it in the ice cores when you drill, and you can see it in the analysis when its done in the lab. And if you want to talk about rates of change, you need that annual calendar. And we now know, probably 25 years later, that that ice cap contains the highest resolution, the longest annual record, that we will ever find in the tropics. Narrator the peruvian expeditions were the beginning of an ambitious worldwide drilling program. Over the next 30 years, lonnie and his team continued to make technical improvements to better retrieve highresolution ice cores from extreme locations. To create a global archive of past climate, lonnie has made more than 50 expeditions to africa, antarctica, bolivia, china, greenland, peru, russia, and the united states. At the end of every expedition, the ice is rushed back to the cold room at ohio state university, where it is preserved in a frozen library, waiting to be deciphered. Thompson and we now have 7,000 meters of core we store at minus 30. And it turns out now that its the only tropical archive of ice cores on earth. Narrator these cores are crucial links in the history of climate, connecting the polar regions to the tropics. By analyzing this archive and comparing it to other climate records, a global understanding of past climate is emerging. Woman what we want to do is get it back to the lab and start working on it as quickly as possible, because everybodys really curious to see what kind of information it has. As a matter of fact, as were drilling this, were often talking about what information this record might hold and how it might fit in with all the other records. Its another piece of a global puzzle, and we feel that every one of these pieces is critical. Narrator in the lab, lonnies team analyzes the ice cores. Oxygen isotope ratios provide a proxy for the temperature when the ice was formed. These records are consistent with other studies that reveal, going back 1,000 years, a longterm warming trend, beginning about 150 years ago Carbon Dioxide measurements. Taken directly from bubbles trapped in the ice reveal everincreasing concentrations of co2 over this same time period. Adding to this wealth of information, lonnies team can detect droughts by measuring chemical traces in the ice, blown in from dry lake beds. Dr. Davis well, thats what i was just wondering about. One of the easiest Historic Records to track in an ice core are drought events. So anywhere you see sulfates indicate that the environment got very dry. Here it is. Right here was a drought. In calcium, there was an increase here in the 60s. And then you go down. Heres another increase in the 30s. It was contemporaneous with our dust bowl period. Actually, you know what that is . Thats these. Thompson were now finding that the real story of Climate Change is not in the science or nature paper that comes from the single site, but its in the connection, putting these records together, that you see things that you could have never found in one or two sites. Narrator connecting lonnies tropical icecore data with cores taken from the polar regions, a record of the earths temperature and Carbon Dioxide levels can be established, going back 650,000 years into the past. Over this time period, each rise in Carbon Dioxide levels is accompanied by a rise in temperature. In the most recent period, Carbon Dioxide levels have been rising to an alltime high. Thompson having that record now that goes back 650,000 years and knowing that co2 in the Natural World has varied between 180, 190 parts per million by volume during the cold periods when we have lots of ice on the earth, to 280, 290 parts per million by volume when these glaciers retreat and during the warm periods, and were now at 380 parts per million by volume there is no analogue in 650,000 years. And the co2 is rising at 2 parts per million by volume each year and not be concerned about that. Narrator icecore data is persuasive on its own, but lonnie has witnessed the clearest evidence of a warming planet with his own eyes. The tropical glaciers are melting. This evidence is critical because the tropics, unlike the rest of the planet, naturally experience very little temperature variation. Glaciers they dont have a political agenda. They just kind of sum up whats going on out there, and they respond to it. And they are giving us a very strong signal that the planet is warming. And the glaciers are disappearing. Like looking at an area like this. You may have known where you were, but. We first went to kilimanjaro in 1999. And in 2000, we had aerial photographs flown so that we could make a map of the ice on the mountain in 2000. And its when we started comparing the results of that map with all the other maps that had been made from the mountain, going back to 1912, that you could really see the loss of ice that has occurred there. And some of the skeptics will look at a mountain like kilimanjaro, and they say, well, how do you know that its not landuse changes, changes in moisture supply droughts and the like . And the answer to that is that its not just kilimanjaro. Its mount kenya. Its the ruwenzoris. Its all the glaciers in the andes of south america and throughout the himalayas that are giving the same message. So the confidence comes from this large scale evidence that all points in the same direction. To me and particularly the tropical glaciers are kind of our canaries in a coal mine. So the fact that every tropical glacier is retreating, i think, is our warning that the system is changing. Its in looking at this huge system and having the opportunity to work in 15 Different Countries and observe the glaciers and many times on an annual basis to see how rapidly that change is taking place, that i think you have to be concerned about what you see. Narrator while thompsons work is documenting the global Climate Change that is already well underway, one of the great unknowns is what will be the effects of these changes on ecosystems. Outdoor Carbon Dioxide enrichment experiments around the world are subjecting ecosystems to the kind of environmental conditions that scientists predict 50 to 75ears in the future. A stones throw from Stanford Universitys main campus, chris fields jasper ridge Global Change experiment is one of the longestrunning and most comprehensive of these studies. Global change imposes a wide range of stresses on the future. That actually looks just about right. Everything we know at this point indicates that those stresses are likely to be of major importance. They are likely to fundamentally alter the range of opportunities that our children and their children encounter. We started the jasper ridge Global Change experiment to project these grasslands into the future. We would hope that, as you walk into the plots, you basically are seeing visions of california for 2075. Narrator in the future, one of the most prominent of Global Change conditions will be increased Greenhouse Gas levels. Over the last 50 years, Carbon Dioxide concentrations have increased every year. If this trend continues, Carbon Dioxide levels may reach twice what they are today by the year 2100. Field we know that plants grow by removing Carbon Dioxide from the atmosphere. They use the energy from sunlight to convert Carbon Dioxide into carbohydrates into plant. And ecosystems on land are taking up a relatively large amount of the carbon thats emitted by human actions, essentially providing a subsidy. And what wed like to know is, as we move intthe future, will that carbon uptake that subsidy increase . Will it decrease . Will it go away d turn froa subsidy into an exburden on the atmosphere . But we dont have very good models that address the full sets of things that occur in real ecosystems. And the jasper ridge experiment allows us the opportunity to get at that in a very precise way that lets us use it as a model system for understanding the controls on carbon balance in other ecosystems. Narrator the primary goal of this elaborate Outdoor Laboratory is to see how these future conditions will affect the ability of ecosystems to store Carbon Dioxide. As these plants grow, they pull caon dioxide out the atmosphere and transform it into plant structure, or biomass. The more these plants grow, the more Carbon Dioxide they store. Earlier experiments, done in controlled environments, show that increased co2 levels led to more abundant plant growth. But the only factor these experiments accounted for was increased Carbon Dioxide. Would plant productivity increase in real ecosystems when other climatechange factors water, heat, and nitrogen are also taken into account . Field by the time we started this experiment in the fall of 1997, there was a lot of controversy about the magnitude of growth responses to elevated atmospheric co2. Most plants increase the instantaneous rate of co2 uptake the instantaneous rate of growth when theyre exposed to elevated atmospheric co2. But there were a range of different results about plant growth. Individual plants in pots or individual plants, separated, in the ground tended to grow much faster under elevated atmospheric co2, and the data from ecosystems were quite mixed. We realized over a period of years that there were lots of artifacts that were introduced by growing plants in isolation or in these controlledgrowth cabinets, and weve moved progressively toward more and more sophisticated designs to get it closer to the way that natural ecosystems work. In order to create a realistic possible future environment for these grasslands, were manipulating four environmental factors. Narrator the jasper ridge experiment is carefully designed so that not just Carbon Dioxide but the other factors predicted in climatechange models can be manipulated. The field consists of 32 circular plots, each 2 meters in diameter. Each plot is cut into quarters, making a total of 128 different treatment areas with each of the possible combinations of the four factors. Each plot combination is duplicated eight times. The factor of extra Carbon Dioxide is delivered with tubing that surrounds half the plots. Co2 levels are controlled by sensors that keep the enrichment to double current atmospheric levels. The system was designed so that, as a function of wind direction, some emitters could be turned off that would be on the downwind side of the plot. So only releasing co2 on the upwind side, and then having the wind carry it across the plot. Narrator the next factor increased temperature is delivered to half of the plots with heat lamps. Dr. Chiariello birds like to perch on these heaters, and bird droppings have a lot of nutrients in them. So one of the concerns that we had was to make sure that we had a control on unintended effects of the heaters. Only half of the plots, of course, have heat. But in designing the experiment, we recognized that it was important to have this infrastructure present in all of the plots. Narrator the final two factors additional nitrogen in a form similar to that expected from increased air pollution and water are added to plots individually. Dr. Chiariello the prediction for california for the next century is that rainfall should increase. The option that we chose was to supplement each major rainfall by about 50 . Narrator over the growing season, the researchers allow the plants to grow to maturity. Then they carefully harvest 10centimeter squares of plant material. Dr. Chriello the first cut at understanding whether or not plants are responding to elevated co2 or to any of these other factors is to see how much plant biomass there is at the end of a growing season. The plant biomass is partlabovground. Its what we see in terms of leaves and flowers and stems. And part of it is below ground in the form of roots and chemicals that have leaked into the soil around the roots. Narrator once the plots are harvested, the samples are dried and then weighed to calculate the amount of carbon the plants removed from the atmosphere each year. This key measure, known as the net primary production, is used in computer models that predict Climate Change effects on other ecosystems. Yeah. After eight years of conducting this experiment, chris and his teams meticulous fieldwork has begun to produce some startling results. Field one of the most unexpecd results from the jasper ridge Global Change experiment is that we found that, under a wide range of conditions, plant growth wasnt increased by elevated atmospheric co2. In fact, under many conditions, elevated atmospheric co2 actually prevents plants from taking full advantage of other resources that are available in the environment. This has quite profound implications for our understanding of ecosystem responses to Global Change and for future Climate Change. If plants, in fact, dont grow more under elevated Carbon Dioxide, it means that atmospheric co2 is liky to grow faster in the future than we have been anticipating. Basically, what it means is that we cant continue to depend on ecosystems to subsidize our emissions of co2 from fossilfuel combustion. Narrator the results from the jasper ridge Global Change experiment indicate that some of the projections for future Carbon Dioxide concentrations may, in fact, be too low. But we couldnt be confident in our answers unless we had collaborators in many other parts of the world who were doing experiments that are similar in some respects. Weave collaborators at the university of minnesota who just found the same resas us that you didnt se a big grth response elevated atmospheric co2 unless you also provided nitrogen. A group working on a pine forest in North Carolina recently published almost the same result. A group in nevada found that, even though elevated co2 increased plant growth, it increased the growth of an Invasive Species that tended to bring wildfire into desert habitats that werent flammable otherwise. I think that, across the community, what were seeing is that the responses to Global Changes tend to be complicated, they tend to be pushing ecosystems in the direction that tends to make them more disturbanceprone, and they tend to not be providing the additional Carbon Storage that we had hoped for when we took the most simpleminded approach to this kind of experiment. Narrator chris field and his many collabotors at the jasper ridge Global Change experiment are expanding the scope of their research to look deeper into the mechanisms that limit plant growth. In years to come, these projects will provide a wealth of information about how ecosystems respond as a whole to humaninduced Climate Change. Field these studies are ongoing. There are a number of details that were still trying to understand. We think of the jasper ridge Global Change experiment as something more like a laboratory than Something Like an experiment. We all Work Together to say, what are the big goals wed like to accomplish . But then we encourage individual initiative in order to figure out how the pieces fit together. For the future, its clear that decisions that we make collectively as the human species determine what the future looks like. Aggressive efforts to limit the emissions of Carbon Dioxide and other heattrapping gases to the atmosphere will lead to a world that is hopefully not too different, one that still provides, essentially, consistent goods and services. With a businessasusual approach, where theres aggressive exploitation of fossilfuel resources and uncontrolled emission of other heattrapping gases, i think were looking at a future thats much bleaker, where were looking at temperatures that are warmer than the planet has seen for the last several million years, where there are critical shortages of water and other essential services that are provided by ecosystems, and where stresses on people and ecosystems and the global habitat are unlike the stresses that weve encountered ever as a species. Funding for this program is provided by. For information about this and other annenberg media programs. Funding for this program was provided by. In honduras, archaeologists piece together fragments of an ancient message. What secrets could these symbols reveal about life among the maya . From ancient sumer, clay tablets reveal astonishing details about daily life 5,000 years ago, and tell the story of the invention of writing. Symbols can be the gateway to the hearts and minds of ancient people