Science Current Events | Science News | Brightsurf.com
 

Dating an ancient episode of severe global warming

June 16, 2011
Using sophisticated methods of dating rocks, a team including University of Southampton researchers based at the National Oceanography Centre, Southampton, have pinned down the timing of the start of an episode of an ancient global warming known as the Paleocene-Eocene thermal maximum (PETM), with implications for the triggering mechanism.

The early part of the Cenozoic era, which started around 65.5 million years ago witnessed a series of transient global warming events called hyperthermals. The most severe of these was the PETM at the Paleocene-Eocene boundary, around 56 million years ago. Over a period of around 20,000 years, a mere blink of the eye in geological terms, ocean temperatures rose globally by approximately 5°C. There is evidence that the concentration of atmospheric carbon oxide increased, but the phenomena that triggered the event remain controversial.

One possibility is that these hyperthermals were driven by cyclic variations in the eccentricity of the Earth's orbit around the sun. At the cycle peaks, increased temperatures could have caused methane hydrate deposits in the deep sea to release large amounts of methane. Some of this potent greenhouse gas would have entered the atmosphere resulting in further intensification of the climatic warming, which would have continued as the methane was fairly rapidly converted into carbon dioxide in the atmosphere.

Alternatively, it may have been geological processes, unrelated to variation in the Earth's orbit, which could have been the culprit for the warming associated with the PETM. In this scenario, magmatism would have caused the baking of marine organic sediments, leading to the massive release of methane and/or carbon dioxide, possibly through hydrothermal vents, thus initiating the global warming which led to the methane release.

"Determining exactly what triggered the PETM requires very accurate dating of the event itself, to determine whether it occurred during a known maximum in the Earth's orbital eccentricity" explains Adam Charles, a University of Southampton PhD student supervised by Dr Ian Harding, and first author of the newly published report.

To getter a better grip on the numerical age of the Paleocene-Eocene boundary, the researchers measured radio-isotopes of uranium and lead in the mineral zircon, found as crystals in two volcanic ash horizons deposited during the PETM. These rocks were collected from two locations in Spitsbergen, the largest island of the Svalbard Archipelago in the Arctic.

Based on their data, the researchers dated the Paleocene-Eocene boundary at between 55.728 and 55.964 million years ago, which they believe to be the most accurate estimate to date. Their analyses indicated that the onset of the PETM, unlike those of other Eocene hyperthermals, did not occur at the peak of a 400 thousand year cycle in the Earth's orbital eccentricity. Instead, it occurred on the falling limb of a cycle when warming by the sun would not have been at a maximum.

"Compared to other early Eocene hyperthermals, it appears that the PETM was triggered by a different mechanism, and thus may have involved volcanism. However, a thorough test of this hypothesis will require further detailed dating studies," Adam concluded.

###

The researchers are Adam Charles, Ian Harding, Heiko Pälike and John Marshall (Ocean and Earth Science, University of Southampton), Daniel Condon (British Geological Survey), and Ying Cui and Lee Kump (Pennsylvania State University). The research was supported by the Natural Environment Research Council (NERC) and Shell UK, as well as a Philip Leverhulme Prize to Heiko Pälike.

Charles, A. J., Condon, D. J., Harding, I. C., Pälike, H., Marshall, J. E. A., Cui, Y. & Kump, L. Constraints on the numerical age of the Paleocene-Eocene boundary. Geochemistry Geophysics Geosystems 12, Q0AA17, doi:10.1029/2010GC003426



National Oceanography Centre, Southampton (UK)


Related Global Warming Current Events and Global Warming News Articles


New survey on Americans' views on papal encyclical on climate change
A new national survey conducted by The Associated Press-NORC Center for Public Affairs Research and researchers at Yale University found that fewer than 1 in 3 Americans, and 40 percent of Catholics, are aware of Pope Francis's efforts to publicize global warming as a priority issue for the Catholic Church.

More grasslands in Tibet could bring climate improvements
In the Arctic, warming increases like a spiral. Global warming means that the periods of growth are becoming longer and vegetation growth is increasing.

Warming climate is deepening California drought
A new study says that global warming has measurably worsened the ongoing California drought. While scientists largely agree that natural weather variations have caused a lack of rain, an emerging consensus says that rising temperatures may be making things worse by driving moisture from plants and soil into the air.

Harnessing the butterfly effect
The atmosphere is so unstable that a butterfly flapping its wings can, famously, change the course of weather patterns. The celebrated "butterfly effect" also means that the reliability of weather forecasts drops sharply beyond 10 days.

1,800 years of global ocean cooling halted by global warming
Prior to the advent of human-caused global warming in the 19th century, the surface layer of Earth's oceans had undergone 1,800 years of a steady cooling trend, according to a new study

Frequent volcanic eruptions likely cause of long-term ocean cooling
An international team of researchers found an 1800 year-long cooling trend in the surface layer of the Earth's oceans, and that volcanic eruptions were the likely cause of the cooling from 801 to 1800 AD.

On warmer Earth, most of Arctic may remove, not add, methane
In addition to melting icecaps and imperiled wildlife, a significant concern among scientists is that higher Arctic temperatures brought about by climate change could result in the release of massive amounts of carbon locked in the region's frozen soil in the form of carbon dioxide and methane.

On Wikipedia, politically controversial science topics vulnerable to information sabotage
Wikipedia reigns. It's the world's most popular online encyclopedia, the sixth most visited website in America, and a research source most U.S. students rely on. But, according to a paper published today in the journal PLOS ONE, Wikipedia entries on politically controversial scientific topics can be unreliable due to information sabotage.

Big data maps world's ocean floor
Scientists from the University of Sydney's School of Geosciences have led the creation of the world's first digital map of the seafloor's geology.

New digital seafloor map provides answers and more questions
Ocean sediments cover 70% of our planet's surface, forming the substrate for the largest ecosystem on Earth and its largest carbon reservoir -- but the most recent map of seafloor geology was drawn by hand more than 40 years ago.
More Global Warming Current Events and Global Warming News Articles

Climate Change: The Facts

Climate Change: The Facts
by J.Abbot (Author), J.S. Armstrong (Author), A.Bolt (Author), R.Carter (Author), R.Darwall (Author), J.Delingpole (Author), C.Essex (Author), S.Franks (Author), K.Green (Author), D.Laframboise (Author), N.Lawson (Author), B.Lewin (Author), R.Lindzen (Author), J.Marohasy (Author), R.McKitrick (Author), P.Michaels (Author), A.Moran (Author), J.Nova (Author), G.Paltridge (Author), I.Plimer (Author), W.Soon (Author), M.Steyn (Author), A.Watts (Author), Alan Moran (Editor)


Tirelessly promoted by princes, presidents, actors and activists, "climate change" has become a dominant theme of global politics. But what's really going on as the "pause" in global warming prepares to enter its third decade? In this new anthology, leading scientists and commentators from the United States, the United Kingdom, Canada and Australia consider the climate from every angle - the science, the policy and the politics.

Global Warming: The Complete Briefing

Global Warming: The Complete Briefing
by John T. Houghton (Author)


How much of global warming is due to human activities? How far will it be possible to adapt to changes of climate? John T. Houghton's definitive, full colour, guide to climate change answers these questions and more by providing the best and latest information available, including the latest IPCC findings. The simple, logical flow of ideas gives an invaluable grounding in the science, as well as the physical and human impacts of climate change for undergraduate students across a wide range of disciplines. Accessible to both scientists and non-scientists, the text avoids mathematical equations and includes more technical material in boxes, while simple figures help students to understand the conclusions the science leads to without being overwhelmed by vast amounts of data. Questions for...

Global Warming-Alarmists, Skeptics and Deniers: A Geoscientist Looks at the Science of Climate Change

Global Warming-Alarmists, Skeptics and Deniers: A Geoscientist Looks at the Science of Climate Change
by G. Dedrick Robinson (Author), Gene D. Robinson III (Author)


Global Warming-Alarmists, Skeptics & Deniers: A Geoscientist looks at the Science of Climate Change, brings a unique geological perspective to this politically charged issue, a perspective that has been ignored far too long. Written by a father-son team of geoscientist and attorney, it is the concise guide to the global warming controversy that has been long needed. As a university professor and research geologist for thirty years, Dr. Robinson knows that geological science is essential for placing the global warming controversy in proper prospective. One cannot hope to understand how humans might be causing climate change without an understanding of the magnitude and speed natural processed are capable of when it comes to climate change. Earth history is the only yardstick we have to...

The Sixth Extinction: An Unnatural History

The Sixth Extinction: An Unnatural History
by Elizabeth Kolbert (Author)


WINNER OF THE PULITZER PRIZE
ONE OF THE NEW YORK TIMES BOOK REVIEW'S 10 BEST BOOKS OF THE YEAR
A NEW YORK TIMES BESTSELLER
A NATIONAL BOOK CRITICS CIRCLE AWARD FINALISTA major book about the future of the world, blending intellectual and natural history and field reporting into a powerful account of the mass extinction unfolding before our eyes

Over the last half-billion years, there have been Five mass extinctions, when the diversity of life on earth suddenly and dramatically contracted. Scientists around the world are currently monitoring the sixth extinction, predicted to be the most devastating extinction event since the asteroid impact that wiped out the dinosaurs. This time around, the cataclysm is us. In prose that is at once frank, entertaining, and deeply...

This Changes Everything: Capitalism vs. The Climate

This Changes Everything: Capitalism vs. The Climate
by Naomi Klein (Author)


The most important book yet from the author of the international bestseller The Shock Doctrine, a brilliant explanation of why the climate crisis challenges us to abandon the core “free market” ideology of our time, restructure the global economy, and remake our political systems.

In short, either we embrace radical change ourselves or radical changes will be visited upon our physical world. The status quo is no longer an option.

In This Changes Everything Naomi Klein argues that climate change isn’t just another issue to be neatly filed between taxes and health care. It’s an alarm that calls us to fix an economic system that is already failing us in many ways. Klein meticulously builds the case for how massively reducing our greenhouse emissions is our best chance...

Global Warming: Understanding the Forecast

Global Warming: Understanding the Forecast
by David Archer (Author)


Archer's Global Warming: Understanding the Forecast 2nd Edition, is the first real text to present the science and policy surrounding climate change at the right level. Accompanying videos, simulations and instructional support makes it easier to build a syllabus to improve and create new material on climate change. Archer's polished writing style makes the text entertaining while the improved pedagogy helps better understand key concepts, ideas and terms. This edition has been revised and reformulated with a new chapter template of short chapter introductions, study questions at the end, and critical thinking puzzlers throughout. Also a new asset for the BCS was created that will give ideas for assignments and topics for essays and other projects. Furthermore, a number of interactive...

The Global Warming Reader: A Century of Writing About Climate Change

The Global Warming Reader: A Century of Writing About Climate Change
by Bill McKibben (Author)


Our most widely respected environmental writer brings together the essential voices on global warming, from its 19th-century discovery to the present
With the rise of extreme weather events worldwide--witness the devastation wrought by Hurricanes Sandy, Irene, and Katrina, and the sustained drought across the American West--global warming has become increasingly difficult to deny.

What is happening to our planet? And what can we do about it? The Global Warming Reader provides more than thirty-five answers to these burning questions, from more than one hundred years of engagement with the topic. Here is Elizabeth Kolbert's groundbreaking essay "The Darkening Sea," Michael Crichton's skeptical view of climate change, George Monbiot's biting indictment of those who are really using...

Global Warming

Global Warming
by Seymour Simon (Author)


Award-winning science writer Seymour Simon gives you a full-color photographic introduction to the causes and effects of global warming and climate change. Earth's climate has always varied, but it is now changing more rapidly than at any other time in recent centuries. The climate is very complex, and many factors play important roles in determining how it changes. Why is the climate changing? Could Earth be getting warmer by itself? Are people doing things that make the climate warmer?Supports the Common Core State Standards

Global Warming: Alarmists, Skeptics & Deniers; A Geoscientist looks at the Science of Climate Change

Global Warming: Alarmists, Skeptics & Deniers; A Geoscientist looks at the Science of Climate Change
by Moonshine Cove Publishing, LLC


“The author makes it very clear that a changing climate is not unusual. It is in fact the norm -- although change is often so slow that humans cannot detect it directly.  But historical geologists know how to display the evidence to the public. This may be the single most important contribution of this well-written and fact-filled book.”—Dr. S. Fred Singer, Chairman Science & Environmental Policy Project

“Global Warming: Alarmists, Skeptics and Deniers is a refreshing read on a topic of great societal importance; refreshing because, unlike many books published on this subject, the authors of this work evaluate key predictions and controversies of the global warming debate using logic and science.  Most readers will appreciate the book’s arrangement.  Each chapter...

The Age of Global Warming: A History

The Age of Global Warming: A History
by Rupert Darwall (Author)


Rachel Carson's epoch-creating Silent Spring marked the beginnings of the environmental movement in the 1960s, its 'First Wave' peaking at the 1972 Stockholm Conference. The invention of sustainable development by Barbara Ward, along with Rachel Carson the founder of the environmental movement, created an alliance of convenience between First World environmentalism and a Third World set on rapid industrialisation. The First Wave crashed in 1973 with the Yom Kippur War and decade-long energy crisis. Revived by a warming economy of the 1980s, environmentalism found a new, political champion in 1988: Margaret Thatcher. Four years later at the Rio Earth Summit, politics settled the science. One hundred and ninety-two nations agreed that mankind was causing global warming and carbon dioxide...

© 2015 BrightSurf.com