Science Current Events | Science News |

University of Pittsburgh Geologists Map Prehistoric Climate Changes in Canada's Yukon Territory

May 09, 2012

PITTSBURGH-Researchers at the University of Pittsburgh have joined an international group of scientists to study past climate changes in the Arctic. Comprising geologists from Pitt's Department of Geology and Planetary Science, the team has analyzed sedimentary and geochemical records of water-level changes in Rantin Lake, located in the boreal forest of Canada's southeastern Yukon Territory. The results were published online in the April issue of Journal of Paleolimnology as one of 18 articles dedicated to reconstructing Arctic lake sediments climate and environmental changes during the Holocene (about 12,000 years before present day).

"During the last 10,000 years, there have been certain times in which rapid climate change events occurred," said David Pompeani, lead author and a Pitt PhD geology student. "By analyzing Rantin Lake, we've contributed a piece of the puzzle toward mapping the timing and magnitude of these prehistoric events throughout the Arctic."

Rantin Lake is part of a watershed containing a series of small lakes hydrologically connected through groundwater flow. The regional climate is subarctic and characterized by warm, wet summers and dry, cold winters. The lake is located at 60 degrees north in the Canadian Arctic, only 30 degrees away from the North Pole, where climate change is expected to be amplified.

In July 2006, the Pitt team-including Mark Abbott, associate professor of geology and planetary science, and Byron Steinman, a former PhD geology student (now a postdoctoral researcher at Penn State University)-collected two sediment cores from the lake for analysis. The sediment cores were split and analyzed for paleoclimate proxy indicators, including geochemical composition, sedimentary structure, and macrofossil content (that which is visible without a microscope). The amount of water in a lake is directly related to its depth. Therefore, a loss in water during droughts is recorded by drop in lake levels, whereas wet periods are characterized by deep waters.

Using these proxy indicators, the researchers were able to make inferences about past variations in the balance between precipitation and evaporation in the southern Yukon. A comparison of the lake-level proxies with a previously developed fossil pollen record from the same lake found that rapid vegetation changes over the Holocene also occurred during shifts in the precipitation/evaporation balance, suggesting hydrologic conditions played an integral role in the evolution of the Yukon's ecosystem. The development of unique shallow-water sediment at the deep-water core site indicated that lake levels dropped significantly during a "megadrought" in the early Holocene.

"About 8,400 years ago, the lake almost dried out," said Pompeani. "We documented the timing of this drought and studied its transition to conditions more typical of what we observed in the late Holocene."

Pitt's study, says Pompeani, contributes to the long-term perspective on natural climate variability that is needed to understand historically unprecedented changes now occurring in the Arctic. Rapid changes in the Arctic climate system that occurred in the relatively recent past can be compared with climate models to improve the understanding of the processes responsible for such nonlinear changes.

Funding for this project was provided by the National Science Foundation.

The Holocene climate project focuses on climate records from the last 8,000 years, including two focus regions: eastern Beringia and the northwest Atlantic. For more information on the Holocene climate project, visit

University of Pittsburgh

Related Climate Change Current Events and Climate Change News Articles

Climate study finds evidence of global shift in the 1980s
Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.

Mountain ranges evolve and respond to Earth's climate, study shows
Ground-breaking new research has shown that erosion caused by glaciation during ice ages can, in the right circumstances, wear down mountains faster than plate tectonics can build them.

No substantive evidence for 'pause' in global warming, study finds
There is no substantive evidence for a 'pause' or 'hiatus' in global warming and the use of those terms is therefore inaccurate, new research from the University of Bristol, UK has found.

Climate change: Warm water is mixing up life in the Arctic
The warming of arctic waters in the wake of climate change is likely to produce radical changes in the marine habitats of the High North.

Low-oxygen 'dead zones' in North Pacific linked to past ocean warming
A new study has found a link between abrupt ocean warming at the end of the last ice age and the sudden onset of low-oxygen, or hypoxic, conditions that led to vast marine dead zones.

Greater potential for transport in climate mitigation
Some argue the transportation sector constitutes a major roadblock on the path to avoiding dangerous climate change.

Crack it! Energy from a fossil fuel without carbon dioxide
The production of energy from natural gas without generating carbon dioxide emissions could fast become a reality, thanks to a novel technology developed by researchers of the Institute for Advanced Sustainability Studies (IASS) in Potsdam and the Karlsruhe Institute of Technology (KIT).

Sequencing algae's genome may aid biofuel production
There's an ancient group of algae that evolved in the world's oceans before our backboned ancestors crawled onto land.

Piping plovers losing breeding habitat to wetland drainage
Piping plovers, a federally threatened species of shorebirds, are likely losing wetland breeding habitat in the Great Plains as a result of wetland drainage, climate change or both, according to a new U.S. Geological Survey study.

UK health professionals unite for stronger measures to tackle climate change
As world leaders prepare to meet in Paris for the 2015 United Nations Climate Change Conference, UK health professionals have formed an alliance of doctors, nurses, and allied health professionals to advocate for stronger measures to tackle climate change.
More Climate Change Current Events and Climate Change 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.

Climate Change: What Everyone Needs to Know®

Climate Change: What Everyone Needs to Know®
by Joseph Romm (Author)

Climate change will have a bigger impact on humanity than the Internet has had. The last decade's spate of superstorms, wildfires, heat waves, and droughts has accelerated the public discourse on this topic and lent credence to climatologist Lonnie Thomson's 2010 statement that climate change "represents a clear and present danger to civilization." In June 2015, the Pope declared that action on climate change is a moral issue.

This book offers the most up-to-date examination of climate change's foundational science, its implications for our future, and the core clean energy solutions. Alongside detailed but highly accessible descriptions of what is causing climate change, this entry in the What Everyone Needs to Know series answers questions about the practical implications of this...

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...

"A Disgrace to the Profession"

"A Disgrace to the Profession"
by Mark Steyn (editor) (Author), Mark Steyn (Editor), Josh (Editor)

The "hockey stick" graph of global temperatures is the single most influential icon in the global-warming debate, promoted by the UN's transnational climate bureaucracy, featured in Al Gore's Oscar-winning movie, used by governments around the world to sell the Kyoto Accord to their citizens, and shown to impressionable schoolchildren from kindergarten to graduation.And yet what it purports to "prove" is disputed and denied by many of the world's most eminent scientists. In this riveting book, Mark Steyn has compiled the thoughts of the world's scientists, in their own words, on hockey-stick creator Michael E Mann, his stick and their damage to science. From Canada to Finland, Scotland to China, Belgium to New Zealand, from venerable Nobel Laureates to energetic young researchers on all...

The Sixth Extinction: An Unnatural History

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

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...

The Thinking Person's Guide to Climate Change

The Thinking Person's Guide to Climate Change
by Robert Henson (Author)

Everybody can be a thinking person when it comes to climate change, and this book is a perfect roadmap.  Start a web search for “climate change” and the first three suggestions are “facts,” “news,” and “hoax.” The Thinking Person's Guide to Climate Change is rooted in the first, up to date on the second, and anything but the last. Produced by one of the most venerable atmospheric science organizations, it is a must-read for anyone looking for the full story on climate change.

Using global research and written with nonscientists in mind, the Guide breaks down the issues into straightforward categories: “Symptoms” covers signs such as melting ice and extreme weather, while “Science” lays out what we know and how we figured it out. “Debates” tackles the...

Climate Change: A Very Short Introduction (Very Short Introductions)

Climate Change: A Very Short Introduction (Very Short Introductions)
by Mark Maslin (Author)

Climate change is still, arguably, the most critical and controversial issue facing the world in the twenty-first century. Previously published as Global Warming: A Very Short Introduction, the new edition has been renamed Climate Change: A Very Short introduction, to reflect the important change in the terminology of the last decade.

In the third edition, Mark Maslin includes crucial updates from the last few years, including the results of the 2013 IPCC Fifth Assessment Report, the effects of ocean acidification, and the impact of changes to global population and health. Exploring key topics in the debate, Maslin makes sense of the complexities of climate change, from political and social issues to environmental and scientific ones. Looking at its predicated impacts, he explores...

Don't Even Think About It: Why Our Brains Are Wired to Ignore Climate Change

Don't Even Think About It: Why Our Brains Are Wired to Ignore Climate Change
by George Marshall (Author)

Most of us recognize that climate change is real yet we do nothing to stop it. What is the psychological mechanism that allows us to know something is true but act as if it is not? George Marshall's search for the answers brings him face to face with Nobel Prize-winning psychologists and Texas Tea Party activists; the world's leading climate scientists and those who denounce them; liberal environmentalists and conservative evangelicals. What he discovers is that our values, assumptions, and prejudices can take on lives of their own, gaining authority as they are shared, dividing people in their wake.With engaging stories and drawing on years of his own research, Marshall argues that the answers do not lie in the things that make us different, but rather in what we share: how our human...

Unstoppable: Harnessing Science to Change the World

Unstoppable: Harnessing Science to Change the World
by Bill Nye (Author), Corey S. Powell (Editor)

Just as World War II called an earlier generation to greatness, so the climate crisis is calling today's rising youth to action: to create a better future.In UNSTOPPABLE, Bill Nye crystallizes and expands the message for which he is best known and beloved. That message is that with a combination of optimism and scientific curiosity, all obstacles become opportunities, and the possibilities of our world become limitless. With a scientist's thirst for knowledge and an engineer's vision of what can be, Bill Nye sees today's environmental issues not as insurmountable, depressing problems but as chances for our society to rise to the challenge and create a cleaner, healthier, smarter world. We need not accept that transportation consumes half our energy, and that two-thirds of the energy you...

Dire Predictions, 2nd Edition: Understanding Climate Change

Dire Predictions, 2nd Edition: Understanding Climate Change
by Michael E. Mann (Author), Lee R. Kump (Author)

Explore global warming with graphics, illustrations, and charts that separate climate change fact from fiction, presenting the truth about global warming in a way that's both accurate and easy to understand. Respected climate scientists Michael E. Mann and Lee R. Kump address important questions about global warming and climate change, diving into the information documented by the IPCC (Intergovernmental Panel on Climate Change) and breaking it down into clear graphics that explain complex climate questions in simple illustrations that present the truth of the global warming problem clearly. These experts take scientific findings about climate change and global warming and use analogies, striking images, and understandable graphics to make the global warming question clear to both...

© 2015