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We are publishing Invisible in the Storm by Ian Roulstone and John Norbury next month. The book explains how mathematics and meteorology come together to predict the weekly weather, prepare us for incredible weather events like Hurricane Sandy, and contribute to our understanding of climate change. They kindly answered a few of my questions for the Princeton University Press Blog:
1. I’ll start with the thing everyone is talking about. It seems like extreme weather more prevalent in recent years. With Hurricane Sandy and the recent unprecedented Nor’Easter behind us (ed. note: I’m writing from NJ), it bears asking whether the future holds more extreme weather? Can mathematics help answer this question?
Mathematicians think about weather and climate in an unusual way. Our ever-changing weather can be visualized as a curve meandering through an abstract mathematical space of logically possible weather. Any one point of the curve corresponds to a particular state of the weather. The surprise is that the curve does not wander around randomly–patterns emerge. One part of the pattern may correspond to ‘warm and dry’ and another part to ‘cold and wet’. Predicting changes in the weather for the week ahead involves working out if the curve will drift from one part of the pattern to another. Understanding climate involves working out how the pattern itself will change.
2. So, is the pattern changing toward more extreme weather or can we not answer this question yet?
If we compare the results from different climate models (from different research institutions and weather bureaus around the world), then they show an increase in global average temperature over the next century. However, this could lead to quite different conditions in different parts of the world. For example, if the Gulf Stream was weakened, Europe could experience colder weather. However, we know our models are not perfect, and mathematics is helping us to understand the errors that are inherent in the compuer-generated simulations. This work is important as it will help us to estimate the likely extremes in weather and climate with greater confidence.
3. To return to the end of your first answer, how can mathematics detect climate change?
Climate depends on many factors: the atmosphere, the oceans, the icecaps, land usage, and life in all its forms. Not only are there many interconnections between these systems, the timescales over which changes occur vary enormously: trees can be felled in a few hours or days–changing the character of the local landscape quickly–but carbon stocks in soil vary much more slowly, perhaps over several millennia. To predict future climate we have to account for the short- and long-timescale effects, and this can pose subtle problems. Mathematics helps us to quantify how the different timescales of the changes in the components of the Earth system impact on predictions of climate change. Using mathematics, we calculate how cloud patterns change over the next five days, and how the Arctic ice-sheet changes over the next five years.
4. How does mathematics help forecasters predict the weather for the week ahead?
One of the main sources of information for a new forecast is yesterday’s forecast. New generations of satellites gather more, and more accurate, readings, ranging from the sea surface temperature to the state of the stratosphere. Data is exchanged freely around the world among weather bureaus; global weather prediction relies upon this protocol. However, we will never have perfect, complete weather data, and this is why we need mathematical techniques to combine the new information with the old.
5. Years ago, it seems like weather was much simpler — will it rain, snow, sleet, or be sunny? These days, mathematics enables weather forecasters to forecast more than rain or shine: the computer simulations are useful for predicting everything from pollen levels and pollution to flood risk and forest fires. Can you explain how mathematics is part of this?
Mathematics is the language we use to describe the world around us in a way that facilitates predictions of the future. Even though hay fever and floods are very different natural phenomena, predictions of their occurrence can be made using mathematical models. Weather forecasters are actively engaged in combining their predictions with models that help us forecast weather-related phenomena.
6. It sounds like a one-way street — mathematics helps us understand meteorology — but you note in the book that the relationship is more reciprocal. Can you elaborate?
To most of us, meteorology and mathematics are a world apart: why should calculus tell us anything about the formation of snowflakes? But mathematics has played an ever-growing and crucial role in the development of meteorology and weather forecasting over the past two centuries. Our story explains how mathematics that was originally developed for very different purposes, such as studying the ether or the dynamics of the solar system, is now helping us to understand the dynamics of the atmosphere and oceans, and the changes in our climate. And it is a two-way process: the diversity of phenomena we seek to quantify means we have to describe them using new mathematical ideas that capture the rapid changes, the slow changes, the randomness, and the order, we observe.
7. Is there a current area of mathematical/meteorological research that you are particularly excited about? Ie – what’s next?
There’s one particular subject that’s attracting a lot of attention right now: it is called data assimilation. This is the part of the forecasting process where new observational information about the state of the atmosphere is combined with the previous forecast, to give us the starting conditions for the next forecast. Improvements to this part of the forecasting process nearly always lead to better forecasts. And the technology applies to modelling the climate too. In this case, we’re not so much interested in whether we have the correct starting conditions, but whether we have used the correct values of the parameters that define the processes and physical phenomena which affect climate–for example, the carbon cycle, from leaves to biomass and carbon dioxide. One of the reasons this is a really exciting area for mathematicians is that we need some new mathematical ideas to analyse these problem. At the moment we rely heavily on math that was developed over 50 years ago–and it works very well–but as we strive to increase the detail we want to represent in our weather and climate models, we have to unravel the Gordian knot that ties together the many different parts of the Earth system we have to represent.
Our video series on the HOW CLIMATE WORKS symposium held at Princeton University this past fall concludes with the Q&A session following the final talk of the day. We hope you have enjoyed your symposium vidoes. For furthur reading, check out our Princeton Primers in Climate series.
Part 8 from the How Climate Works symposium brings us Andrew Ingersoll of the California Institute of Technology on planetary climates. This fall we will be publishing his book of the same toipc PLANETARY CLIMATES.
Part 7 from the How Climate Works symposium features Shawn Marshall of the University of Calgary on the cryosphere. We published his excellent book on the subject in the Fall or 2011 called THE CRYOSPHERE.
Continuing with our series on talks from Princeton’s HOW CLIMATE WORKS symposium, here we see Princeton University geoscience professor Michael Bender discussing Paleoclimate. His new book PALEOCLIMATE will be availble July 2013.
Renowned University of Chicago geophysicist David Archer discussed the Global Carbon Cycle. We published the book of the same name, THE GLOBAL CARBON CYCLE, in the Fall of 2010.
Interview: How to Build a Habitable Planet author Charles H. Langmuir explains How to Build a Comprehensible PublicationDecember 11th, 2012
1) The original edition of “How to Build a Habitable Planet,” written and published by Wally Broecker in 1985, is a legend within the university community for both its unusual breadth and clarity. One of the first books on the Earth system, it did something very new by weaving together many fields that were traditionally kept separate — physics, chemistry, astronomy, all the Earth sciences, and biology — into one, jargon-free narrative. What was the original inspiration behind the writing of this unusual book?
The growing interest in what NASA referred to as habitability.
2) Since publication, this book been used more and more widely within introductory Geology and Earth Science courses, even inspiring courses built around the structure and contents of the book, entitled “How to Build a Habitable Planet.” Did Broecker originally intend for the book to be used within courses? What about this book makes it so ideal for course use?
The book breaks with the tradition of teaching Earth science as a collection of sub-disciplines—minerals, rocks, volcanoes, glaciers, plate tectonics, etc. Instead, we try to have the reader learn where he or she comes from and how human beings are a consequence of an entire history beginning with the Big Bang. So, the book combines the traditional “physical geology” and “historical geology” approaches and includes material from both of them in the context of the overall story of Earth’s evolution, its connection to the rise of Homo sapiens, and our influence and potential role on the planet. Another aspect is the central role that biology plays in Earth’s evolution, and the importance of the interactions between all aspects of Earth, its interior, exterior, life and the cosmos.
3) Charles Langmuir: You teach a course at Harvard – called, “How to Build a Habitable Planet.” How did you originally start using the book in your course? What is the background of the students in your course, and how many students does your course typically attract each year? What do you hope your students will take away from taking your course and reading this book?
I started teaching the course, because I was working on the new version of the book. I used draft chapters in the course and, through teaching it each year, the subject stayed alive. I also saw what material engaged the students, and what material seemed tedious to them. The Harvard course is a general education course — one that is designed for the non-science major. Science majors find the course easy. People who have not taken any science course for years can find it challenging. In my view every college student – actually, every educated human being – should know the essential elements of the story of the Earth and where we come from. How can we engage effectively as modern citizens without such knowledge? We do not necessarily need to know that glaciers make u-shaped valleys and rivers make v-shaped valleys, cool as that is; but, we do need to know where we come from and how we got here, and the implications that has for our planet. I hope that the students will be able to explain to their friends and family how we know the Big Bang is true, why plate tectonics and evolution are facts as well as theory, and the unique place that human beings occupy in human history – possibly marking the beginning of a new eon of geological time, should we survive that long.
The course at Harvard has 60 students in it this year. That, to me, is an ideal size, as it is possible to interact with the students on a personal basis and, at the same time, reach a group of significant size.
4) A few years ago, you (Charles Langmuir and Wally Broecker) began collaborating on a newly revised and expanded edition of “How to Build a Habitable Planet.” How did the idea for this collaboration and revision come about?
Wally pointed out that despite the book’s title, the book had no biology in it, and was weak in terms of its treatment of the solid earth. I had been teaching half of a one semester course in introductory geology at Columbia using parts of the original book, so Wally asked me if I would like to add a couple of chapters to the original book, on plate tectonics and the origin of life. I knew nothing about the origin of life, but loved the original edition and decided to take it on. I then started to learn much more about many aspects of earth evolution, and the book gradually grew to its current size, as I realized that evolution, the rise of oxygen, and the recent work on the discovery of extra-solar planets all needed to be included, as well as the origin of life and more on Earth’s interior.
5) Why did you feel that a new edition was needed? How is the new edition different from the original edition?
The new edition is far more comprehensive, with more than twice the number of chapters of the original edition. Life is now central to the book, and the origin of life, evolution, the transformation of Earth’s exterior by life, and the connections among life, the solid Earth, atmosphere, ocean and cosmos are now a pervasive theme throughout the book. Ocean ridges, convergent margins, mantle convection and the plate tectonic geochemical cycle are also major new additions. All of the chapters, of course, are almost entirely rewritten to reflect the astounding growth in knowledge and understanding that has occurred over the last twenty-five years.
6) One of the later chapters of the book is called “Mankind at the Helm.” How do you feel that the book informs new readers about the state of the art of climate science, and what the fate and role of our species is on our habitable planet, Earth?
We attempt to pose this problem in the context of our overall understanding of our planet. As a species, we are transforming the planet at a rate as fast or faster than many of the great era and eon boundaries of the past, and this is happening within our lifetimes. It is astounding. It is all made possible by our access to “Earth’s treasure chest,” which was gradually built up over billions of years of planetary history. At the same time, a planet with intelligent life and civilization on it is a very different “being” than a planet without such capability. For the first time there is the possibility of monitoring and understanding planetary systems, communicating with other intelligent life, should it exist, and transforming many planetary processes, including evolution and climate.
For climate science, we try to put the current situation in a larger context. It is not just that CO2 is rising, but that the rate of change is far faster then glacial to interglacial transitions, and that human emissions are several hundred times the emissions of volcanoes, which have been a major control on climate modulation over Earth history. And Earth makes new oil at the rate that one gas station pumps gas. We are using up hundreds of millions of years of Earth’s fossil fuel production in a few centuries. These kinds of simple facts put the enormity of human actions in a different context than saying that CO2 is going up in the atmosphere by a few ppm per year and what the consequences are of that.
7) You also write about planetary evolution and the role of extinctions and catastrophes in the history of a planet. What are some of the ways in which catastrophes have affected our planet’s evolution in its history?
Catastrophes driving from Earth’s interior, the cosmos, and possibly life and climate have been a central aspect of Earth’s evolution. Catastrophes interact with evolution in important ways, clearing out the ecospace so that new evolutionary innovations can flourish. Snowball Earth episodes may be related to the rise of oxygen. Most mass extinctions seem to be associated with massive volcanism stemming from the core mantle boundary, and some associated with meteorite impacts. Catastrophes are often at the same time disasters and opportunities. The rise of oxygen can be viewed in the same way. It was a toxic pollutant for anaerobic organisms, and is intrinsically harmful to organic matter, which breaks down in the presence of oxygen. But, it also held the potential for an energy revolution in metabolism that permitted aerobic organisms and ultimately the rise of multi-cellular life. It is important not to be naïve about change. Change is inevitable. It can be both crisis and opportunity.
8) Some say that we are in the midst of a “6th extinction” event, largely caused by humans. Do you think that there is evidence for this view?
Yes. In the book we look at extinctions in terms of the “half-life” of organisms. Looked at in that way, there is an objective assessment of whether the current extinction rate is unusual or not in a planetary context. Life changes rapidly—there is almost complete species turnover in about 43 million years, based on the geological record. Human beings have accelerated extinction rates by ten thousand times relative to the background level that can be quantified for the Phanerozoic. If emergence of new species had been similarly accelerated, some 20% of Earth species would be new in the past two centuries. This shows the magnitude of the human influence. Mass extinctions of the past cannot be constrained to less than a few hundred thousand years. We may be in the midst of one of the most rapid mass extinctions in planetary history; but, of course, it is not yet complete. There is the possibility for us to preserve much of the biodiversity of the planet, but that seems unlikely without a major change in human behavior.
9) Another of your chapters, entitled “Are We Alone?,” speaks to the fact that ~ 700 extrasolar planets have been discovered since the original edition was published. What are some of the ways in which studying other planets and seeking other habitable worlds informs our understanding of our own planet’s climate and evolution?
Of course, this is one of the most exciting developments of modern science. The discoveries to date have been constrained by the methods to exclude truly Earth-like planets (not only in terms of size, but also distance from their star), but that will change in coming years. Perhaps the most exciting development will be if evidence is found for life anywhere else. If it is, then life is pervasive throughout the universe. It is very hard to know whether life is a natural, pervasive planetary process, or whether unique aspects of Earth’s history permitted it—right habitable zone in the galaxy, right habitable zone around a star, just the right volatile budget, a large moon, and so on. But, if we find life any one other place, and we can only look at less than one in a billion places, then life is essentially everywhere.
The other important aspect is all the strange solar systems being discovered, so different from our own, greatly expand our understanding and imagination concerning life elsewhere.
10) Since the original edition was so widely read, you must have heard stories from readers, about the effect that the book had on them. Could you share one such story? What effect do you hope this new edition of this classic book will have on its readers?
The most heartening comments are ones I commonly hear at the end of the course or in the evaluations, such as “I never knew science could be so interesting” or “Everyone should know this stuff!” Just yesterday in office hours, one student said to me that she had been tutoring elementary school children, and they asked where the moon came from. She told them about the giant impact theory, and she said the children’s eyes opened wide, and they became animated, asking all kinds of questions. One of them said, “Oh dear, what happened to all the people?” To me, this reflected our natural human interest in our planet and where we come from, and the innate concern that is there within us, often submerged, for our fellow human beings. In those two aspects of our nature, present in children, latent in all of us, may be a hope for the future.
Charles H. Langmuir & Wally Broecker
Since its first publication more than twenty-five years ago, How to Build a Habitable Planet has established a legendary reputation as an accessible yet scientifically impeccable introduction to the origin and evolution of Earth, from the Big Bang through the rise of human civilization. This classic account of how our habitable planet was assembled from the stuff of stars introduced readers to planetary, Earth, and climate science by way of a fascinating narrative. Now this great book has been made even better. Harvard geochemist Charles Langmuir has worked closely with the original author, Wally Broecker, one of the world’s leading Earth scientists, to revise and expand the book for a new generation of readers for whom active planetary stewardship is becoming imperative.
“To be worth being this unwieldy, a book ought to do something pretty remarkable. And that’s just what How to Build . . . does, as you can tell from its subtitle, The Story of Earth from the Big Bang to Humankind. Now that’s what you call a large canvas.”–Brian Clegg, Popular Science
For those following our HOW CLIMATE WORKS symposium videos, our latest addition is the morning’s Questions & Answers session.
Be among the first to check out our new Earth Science catalog at:
Three new titles in the The Princeton Primers in Climate series are featured in the catalog. Michael L. Bender’s Paleoclimate makes an ideal introduction to the subject. In Climate and Ecosystems, David Schimel looks at how Earth’s living systems profoundly shape the physical world. David Randall’s Atmosphere, Clouds, and Climate offers a short, reader-friendly introduction to atmospheric processes. There are more books in the series and you can find information at: http://press.princeton.edu/catalogs/series/ppic.html . We invite you to browse and download the catalog to find more great books by great authors.
Are you going to the annual American Geophysical Union meeting in San Francisco? We’ll be there at booth 634. Charles H. Langmuir & Wally Broecker will be in our booth on Wednesday, Dec 5th at 3:30 p.m. signing copies of their revised and expanded book, How to Build a Habitable Planet. This classic account of how our habitable planet was assembled from the stuff of stars introduced readers to planetary, Earth, and climate science by way of a fascinating narrative. Now this great book has been made even better. Stop by and chat with the authors. We hope to see you there.
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Harvard Professor of Geochemistry Charles Langmuir celebrates the revised edition of the book that has introduced generations of readers to the science of Earth’s origin and evolutionNovember 20th, 2012
“Life evolves in relationship with the planet, and progressively modifies it to form a single integrated system.”–Charles Langmuir
View the video from its original source at Harvard Museum of Natural History’s website:
Part 2 from the HOW CLIMATE WORKS symposium here at Princeton University features David Schimel, a senior reserach scientist at the Jet Propulsion Lab in Pasadena. He discussed his forthcoming Princeton University Press book CLIMATE AND ECOSYSTEMS, due out in June 2013 in our series Princeton Primers in Climate. In 2007, David was a corecipient of the Nobel peace Prize for his work on the Intergovernmental Panel on Climate Change’s first report on the global cabron cycle.
Check out his talk below.