Science Current Events | Science News | Brightsurf.com
 

Thawing permafrost 50 million years ago led to global warming events

April 05, 2012
AMHERST, Mass. - In a new study reported in Nature, climate scientist Rob DeConto of the University of Massachusetts Amherst and colleagues elsewhere propose a simple new mechanism to explain the source of carbon that fed a series of extreme warming events about 55 million years ago, the Paleocene-Eocene Thermal Maximum (PETM), and a sequence of similar, smaller warming events afterward.

"The standard hypothesis has been that the source of carbon was in the ocean, in the form of frozen methane gas in ocean-floor sediments," DeConto says. "We are instead ascribing the carbon source to the continents, in polar latitudes where permafrost can store massive amounts of carbon that can be released as CO2 when the permafrost thaws."

The new view is supported by calculations estimating interactions of variables such as greenhouse gas levels, changes in the Earth's tilt and orbit, ancient distributions of vegetation, and carbon stored in rocks and in frozen soil.

While the amounts of carbon involved in the ancient soil-thaw scenarios was likely much greater than today, implications of the study appear dire for the long-term future as polar permafrost carbon deposits have begun to thaw due to burning fossil-fuels, DeConto adds. "Similar dynamics are at play today. Global warming is degrading permafrost in the north polar regions, thawing frozen organic matter, which will decay to release CO2 and methane into the atmosphere. This will only exacerbate future warming in a positive feedback loop."

He and colleagues at Yale, the University of Colorado, Penn State, the University of Urbino, Italy, and the University of Sheffield, U.K., designed an accurate model―elusive up to now―to satisfactorily account for the source, magnitude and timing of carbon release at the PETM and subsequent very warm periods, which now appear to have been triggered by changes in the Earth's orbit.

Earth's atmospheric temperature is a result of energy input from the sun minus what escapes back to space. Carbon dioxide in the atmosphere absorbs and traps heat that would otherwise return to space. The PETM was accompanied by a massive carbon input to the atmosphere, with ocean acidification, and was characterized by a global temperature rise of about 5 degrees C in a few thousand years, the researchers point out. Until now, it has been difficult to account for the massive amounts of carbon required to cause such dramatic global warming events.

To build the new model, DeConto's team used a new, high-precision geologic record from rocks in central Italy to show that the PETM and other hyperthermals occurred during periods when Earth's orbit around the sun was both highly eccentric (non-circular) and oblique (tilted). Orbit affects the amount, location and seasonality of solar radiation received on Earth, which in turn affects the seasons, particularly in polar latitudes, where permafrost and stored carbon can accumulate.

They then simulated climate-ecosystem-soil interactions, accounting for gradually rising greenhouse gases and polar temperatures plus the combined effects of changes in Earth orbit. Their results show that the magnitude and timing of the PETM and subsequent hyperthermals can be explained by the orbitally triggered decomposition of soil organic carbon in the circum-Arctic and Antarctica.

This massive carbon reservoir at the poles "had the potential to repeatedly release thousands of petagrams of carbon to the atmosphere-ocean system once a long-term warming threshold was reached just prior to the PETM," DeConto and colleagues say. Until now, Antarctica, which today is covered by kilometers of ice, has not been appreciated as an important player in such global carbon dynamics.

In the past, "Antarctica and high elevations of the circum-Arctic were suitable locations for massive carbon storage," they add. "During long-term warming, these environments eventually reached a climatic threshold," with permafrost thaw and the sudden release of stored soil carbon triggered during the Earth's highly eccentric orbits coupled with high tilt.

The model described in the paper also provides a mechanism that helps to explain relatively rapid recovery from hyperthermals associated with orbital extremes occurring about every 1.2 million years, which had until now been difficult.

Overall, they conclude, "an orbital-permafrost soil carbon mechanism provides a unifying model accounting for the salient features of the hyperthermals that other previously proposed mechanisms fail to explain." Further, if the analysis is correct and past extreme warm events can be attributed to permafrost loss, it implies that thawing of permafrost in similar environments observed today "will provide a substantial positive feedback to future warming."

University of Massachusetts at Amherst


Related Global Warming Current Events and Global Warming News Articles


You are here: Home / News / GW Researcher Adapting Breakthrough Technologies to Combat... GW Researcher Adapting Breakthrough Technologies to Combat Parasitic Worm Infections
Recent breakthroughs may pave the way for vaccines and new drugs for those infected by parasitic helminths.

Future-focused women stand up to global warming with taxes, checkbook
Politicians who discredit global warming risk losing a big chunk of the female vote. A new study found women who consider the long-term consequences of their actions are more likely to adopt a liberal political orientation and take consumer and political steps to reduce global warming.

World losing 2,000 hectares of farm soil daily to salt damage: UN University
Every day for more than 20 years, an average of 2,000 hectares of irrigated land in arid and semi-arid areas across 75 countries have been degraded by salt, according to a study by UN University's Canadian-based Institute for Water, Environment and Health, published Oct. 28.

Climate change impacts countered by stricter fisheries management
A new study has found that implementing stricter fisheries management overcame the expected detrimental effects of climate change disturbances in coral reef fisheries badly impacted by the 1997/98 El Niño, according to the Wildlife Conservation Society.

Sea turtles' first days of life: A sprint and a ride towards safety
With new nano-sized acoustic transmitters, scientists from GEOMAR Helmholtz Centre for Ocean Research Kiel, the Turtle Foundation and Queen Mary University of London were able to follow the pathways of loggerhead turtle hatchlings from Cape Verde.

Informative visit to the toilet
Emily loves Justin - Stop global warming - Two more weeks till I graduate!: The exchange of information in public toilets is widespread.

Natural gas boom will not slow climate change
This market effect erases the advantage of lower emissions from the natural gas itself, according to an unprecedented international comparison of computer simulations.

Microfossils reveal warm oceans had less oxygen, Syracuse geologists say
Researchers in Syracuse University's College of Arts and Sciences are pairing chemical analyses with micropaleontology-the study of tiny fossilized organisms-to better understand how global marine life was affected by a rapid warming event more than 55 million years ago.

New catalyst could improve biofuels production
Washington State University researchers have developed a new catalyst that could lead to making biofuels cheaply and more efficiently.

No single explanation for biodiversity in Madagascar
No single "one-size-fits-all" model can explain how biodiversity hotspots come to be, finds a study of more than 700 species of reptiles and amphibians on the African island of Madagascar.
More Global Warming Current Events and Global Warming News Articles

Climate Change: Evidence and Causes (PDF Booklet)

Climate Change: Evidence and Causes (PDF Booklet)
by National Academies Press


Climate Change: Evidence and Causes is a jointly produced publication of The US National Academy of Sciences and The Royal Society. Written by a UK-US team of leading climate scientists and reviewed by climate scientists and others, the publication is intended as a brief, readable reference document for decision makers, policy makers, educators, and other individuals seeking authoritative information on the some of the questions that continue to be asked. Climate Change makes clear what is well-established and where understanding is still developing. It echoes and builds upon the long history of climate-related work from both national academies, as well as on the newest climate-change assessment from the United Nations' Intergovernmental Panel on Climate Change. It touches on current...

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

The Great Global Warming Blunder: How Mother Nature Fooled the World’s Top Climate Scientists

The Great Global Warming Blunder: How Mother Nature Fooled the World’s Top Climate Scientists
by Roy W Spencer (Author)


The Great Global Warming Blunder unveils new evidence from major scientific findings that explode the conventional wisdom on climate change and reshape the global warming debate as we know it. Roy W. Spencer, a former senior NASA climatologist, reveals how climate researchers have mistaken cause and effect when analyzing cloud behavior and have been duped by Mother Nature into believing the Earth’s climate system is far more sensitive to human activities and carbon dioxide than it really is.

In fact, Spencer presents astonishing new evidence that recent warming is not the fault of humans, but the result of chaotic, internal natural cycles that have been causing periods of warming and cooling for millennia. More carbon dioxide in the atmosphere is not necessarily to be feared; The...

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...

Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming

Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming
by Naomi Oreskes (Author), Erik M. Conway (Author)


"Merchants of Doubt should finally put to rest the question of whether the science of climate change is settled. It is, and we ignore this message at our peril."-Elizabeth Kolbert "Brilliantly reported andwritten with brutal clarity."-Huffington Post Merchants of Doubt was one of the most talked-about climate change books of recent years, for reasons easy to understand: It tells the controversialstory of how a loose-knit group of high-level scientists and scientific advisers, with deep connections in politics and industry, ran effective campaigns to mislead the public and deny well-established scientific knowledge over four decades. The same individuals who claim the scienceof global warming is "not settled" have also denied the truth about studies linking smoking to lung cancer, coal...

Unstoppable Global Warming: Every 1,500 Years, Updated and Expanded Edition

Unstoppable Global Warming: Every 1,500 Years, Updated and Expanded Edition
by S. Fred Singer (Author), Dennis T. Avery (Author)


Singer and Avery present—in popular language supported by in-depth scientific evidence—the compelling concept that global temperatures have been rising mostly or entirely because of a natural cycle. Using historic data from two millennia of recorded history combined with the natural physical records found in ice cores, seabed sediment, cave stalagmites, and tree rings, Unstoppable Global Warming argues that the 1,500 year solar-driven cycle that has always controlled the earth's climate remains the driving force in the current warming trend.

Trillions of dollars spent on reducing fossil fuel use would have no effect on today's rising temperatures. The public policy key, Singer and Avery propose, is adaptation, not fruitless attempts at prevention. Further, they offer...

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...

Dire Predictions: Understanding Global Warming - The Illustrated Guide to the Findings of the IPCC

Dire Predictions: Understanding Global Warming - The Illustrated Guide to the Findings of the IPCC
by Michael E. Mann (Author), Lee R. Kump (Author)


The Intergovernmental Panel on Climate Change (IPCC) has been issuing the essential facts and figures on climate change for nearly two decades. But the hundreds of pages of scientific evidence quoted for accuracy by the media and scientists alike, remain inscrutable to the general public who may still question the validity of climate change.

Esteemed climate scientists Michael E. Mann and Lee R. Kump, have partnered with DK Publishing to present Dire Predictions-an important book in this time of global need. Dire Predictions presents the information documented by the IPCC in an illustrated, visually-stunning, and undeniably powerful way to the lay reader. The scientific findings that provide validity to the implications of climate change are presented in clear-cut graphic...

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...

© 2014 BrightSurf.com