ScienceDaily: Paleoclimatology News

Stone Age technological and cultural innovation accelerated by climate change

Tue, 18 Jun 2013 10:15:15 EDT

Technological innovation during the Stone Age occurred in fits and starts and was climate-driven, according to new research. Abrupt changes in rainfall in South Africa 40,000 to 80,000 years ago triggered the development of technologies for finding refuge and the behavior of modern humans.

'Cold snap' 116 million years ago triggered marine ecosystem crisis

Sun, 16 Jun 2013 15:52:52 EDT

A "cold snap" 116 million years ago triggered a similar marine ecosystem crisis to the ones witnessed in the past as a result of global warming, according to new research. The international study confirms the link between global cooling and a crash in the marine ecosystem during the mid-Cretaceous greenhouse period.

Study of oceans' past raises worries about their future

Fri, 14 Jun 2013 11:16:16 EDT

Scientists have now completed the first global study of changes that occurred in a crucial component of ocean chemistry, the nitrogen cycle, at the end of the last ice age. The results of their study confirm that oceans are good at balancing the nitrogen cycle on a global scale. But the data also shows that it is a slow process that may take many centuries, or even millennia, raising worries about the effects of the scale and speed of current changes in the ocean.

When will the next megathrust hit the west coast of North America?

Wed, 12 Jun 2013 13:31:31 EDT

A new study presents our first glimpse back in geologic time of the recurrence interval of large and megathrust earthquakes impacting the vulnerable BC outer coastline.

New theory proposes solution to long-running debate as to how stable the Earth system is

Mon, 10 Jun 2013 08:42:42 EDT

Researchers have proposed an answer to the long-running debate as to how stable the Earth system is. Earth, with its core-driven magnetic field, oceans of liquid water, dynamic climate and abundant life is arguably the most complex system in the known Universe. Life arose on Earth over three and a half billion years ago and it would appear that despite planetary scale calamities such as the impacts of massive meteorites, runaway climate change and increases in brightness of the Sun, it has continued to grow, reproduce and evolve ever since. Has life on Earth simply been lucky in withstanding these events or are there any self-stabilizing processes operating in the Earth system that would reduce the severity of such perturbations? If such planetary processes exist, to what extent are they the result of the actions of life?

Irish chronicles reveal links between cold weather and volcanic eruptions

Wed, 05 Jun 2013 23:08:08 EDT

Medieval chronicles have given researchers a glimpse into the past to assess how historical volcanic eruptions affected the weather in Ireland up to 1500 years ago. Researchers have successfully linked the climatic aftermath of volcanic eruptions to extreme cold weather events in Ireland over a 1200-year period from 431 to 1649.

Ancient trapped water explains Earth's first ice age

Wed, 05 Jun 2013 13:35:35 EDT

Tiny bubbles of water found in quartz grains in Australia may hold the key to understanding what caused the Earth's first ice age, say scientists.

'Lizard King' fossil shows giant reptiles coexisted with mammals during globally warm past

Wed, 05 Jun 2013 09:04:04 EDT

At nearly six feet long and weighing upwards of 60 pounds, "Morrison's Bearded King" provides new clues on the evolution of plant-eating reptiles and their relationship to global climate and with mammals.

Acceleration of ocean denitrification during deglaciation documented

Mon, 03 Jun 2013 11:39:39 EDT

As ice sheets melted during the deglaciation of the last ice age and global oceans warmed, oceanic oxygen levels decreased and "denitrification" accelerated by 30 to 120 percent, a new international study shows, creating oxygen-poor marine regions and throwing the oceanic nitrogen cycle off balance.

Subfossil forest discovered at building site in Zurich

Wed, 29 May 2013 09:27:27 EDT

The fact that many finds have happened by chance was demonstrated again recently in Zurich. A dendrochronologist was just having a look at a building site when he noticed a few tree stumps on the edge of the loamy building pit that had been discarded by the construction workers as waste timber. Analysis showed the timber he discovered was dated between 12,846 BP** and 13,782 BP. With the support of the building-site management researchers have managed to salvage some 200 ancient pine-tree stumps.

Historic sea-level change along New Jersey coastline mapped

Tue, 28 May 2013 18:10:10 EDT

A new study relied upon fossil records of marshland to reconstruct the changes in sea level along the New Jersey coast going back 10,000 years.

Century-old ocean data provides further confirmation of global warming

Tue, 28 May 2013 10:45:45 EDT

A new NASA and university analysis of ocean data collected more than 135 years ago by the crew of the HMS Challenger oceanographic expedition provides further confirmation that human activities have warmed our planet over the past century.

Antarctic polar icecap is 33.6 million years old, researchers show

Mon, 27 May 2013 10:05:05 EDT

Seasonal primary productivity of plankton communities appeared with the first ice. This phenomenon, still active today, influences global food webs. These findings are based on fossil records in sediment cores at different depths.

Understanding the past and predicting the future by looking across space and time

Sat, 25 May 2013 14:37:37 EDT

Scientists have validated a fundamental assumption at the very heart of a popular way to predict relationships between complex variables.

Origins of human culture linked to rapid climate change

Tue, 21 May 2013 12:14:14 EDT

Rapid climate change during the Middle Stone Age, between 80,000 and 40,000 years ago, sparked surges in cultural innovation in early modern human populations, according to new research.

The mammoth's lament: How cosmic impact sparked devastating climate change

Mon, 20 May 2013 18:55:55 EDT

Researchers have found evidence of a major cosmic event near the end of the Ice Age. The ensuing climate change forced many species to adapt or die.

Reading rock to understand how climate change unfolds

Sat, 18 May 2013 15:32:32 EDT

Geologists reads rock, looking for the natural rules that govern the Earth’s climate in the absence of human activity. New work is challenging many assumptions about the ways drastic climate change unfolds – and what to expect next.

Research helps paint finer picture of massive 1700 earthquake

Tue, 14 May 2013 19:06:06 EDT

In 1700, a massive earthquake struck the west coast of North America, but a lack of local documentation has made studying this historic event challenging. Now, researchers have helped unlock this geological mystery using a fossil-based technique. Their work provides a finer-grained portrait of this earthquake and the changes in coastal land level it produced, enabling modelers to better prepare for future events.

Ice-free Arctic may be in our future, international researchers say

Thu, 09 May 2013 14:20:20 EDT

Analyses of the longest continental sediment core ever collected in the Arctic provide "absolutely new knowledge" of Arctic climate from 2.2 to 3.6 million years ago. The research has major implications for understanding how the Arctic transitioned from a forested landscape without ice sheets to the ice- and snow-covered land we know today.

First biological evidence of a supernova

Wed, 08 May 2013 12:30:30 EDT

In fossil remnants of bacteria, researchers have found a radioactive iron isotope that they trace back to a supernova in our cosmic neighborhood. This is the first proven biological signature of a starburst. An age determination showed that the supernova must have occurred about 2.2 million years ago, roughly around the time when the modern human developed.

Climate change, not human activity, led to megafauna extinction

Mon, 06 May 2013 18:17:17 EDT

Most species of gigantic animals that once roamed Australia had disappeared by the time people arrived, a major review of the available evidence has concluded. The research challenges the claim that humans were primarily responsible for the demise of the megafauna in a proposed "extinction window" between 40,000 and 50,000 years ago, and points the finger instead at climate change.

Elucidating environmental history with 100 million laser beams

Mon, 29 Apr 2013 11:47:47 EDT

By combining high-resolution surface data obtained from laser scanning with subsurface geodata, scientists have succeeded for the first time in providing a full picture of so-called karst depressions on the island of Crete, including a three-dimensional view into the subsurface structure of these funnel-shaped hollows.

Ice tubes in polar seas -- 'brinicles' or 'sea stalactites' -- provide clues to origin of life

Wed, 24 Apr 2013 11:23:23 EDT

Life on Earth may have originated not in warm tropical seas, but with weird tubes of ice -- sometimes called "sea stalactites" -- that grow downward into cold seawater near the Earth's poles, scientists are reporting.

Geochemical method finds links between terrestrial climate and atmospheric carbon dioxide

Mon, 22 Apr 2013 15:49:49 EDT

Scientists used a new chemical technique to measure the change in terrestrial temperature associated with a major shift in global atmospheric CO2 concentrations nearly 34 million years ago. Their results provide further evidence that the concentration of atmospheric carbon dioxide and Earth's surface temperature are inextricably linked.

First 2,000-year-long temperature reconstructions for individual continents

Sun, 21 Apr 2013 15:24:24 EDT

Past climate change varied remarkably between regions. This is demonstrated in a new study coordinated by the international Past Global Changes (PAGES) project, which reconstructed temperature over the past 1,000 to 2,000 years.

Sea-ice ecosystem possibly triggered evolution of baleen whales and penguins

Thu, 18 Apr 2013 14:23:23 EDT

The origin of the unique plankton ecosystem of the circum-Antarctic Southern Ocean can be traced back to the emergence of the Antarctic ice sheets approximately 33.6 million years ago. This discovery shows that the development of the sea-ice ecosystem possibly triggered further adaptation and evolution of larger organisms such as baleen whales and penguins.

Maya Long Count calendar calibrated to modern European calendar using carbon-14 dating

Thu, 11 Apr 2013 19:49:49 EDT

The Maya are famous for their complex, intertwined calendric systems, and now one calendar, the Maya Long Count, is empirically calibrated to the modern European calendar, according to an international team of researchers.

A comet, not an asteroid, may have killed the dinosaurs, experts propose

Thu, 04 Apr 2013 12:24:24 EDT

In a geological moment about 66 million years ago, something killed off almost all the dinosaurs and some 70 percent of all other species living on Earth. Only those dinosaurs related to birds appear to have survived. Most scientists agree that the culprit in this extinction was extraterrestrial, and the prevailing opinion has been that the party crasher was an asteroid. Not so, say two researchers who favor another explanation, asserting that a high-velocity comet led to the demise of the dinosaurs.

Ancient pool of warm water questions current climate models

Wed, 03 Apr 2013 13:13:13 EDT

A huge pool of warm water that stretched out from Indonesia over to Africa and South America four million years ago suggests climate models might be too conservative in forecasting tropical changes. Present in the Pliocene era, this giant mass of water would have dramatically altered rainfall in the tropics, possibly even removing the monsoon. Its decay and the consequential drying of East Africa may have been a factor in Hominid evolution. The missing data for this phenomenon could have significant implications when predicting the future climate.

Ancient climate questions could improve today's climate predictions

Wed, 03 Apr 2013 13:13:13 EDT

Climate models for the early Pliocene might be missing key processes. If researchers can uncover these missing processes, they can apply them to models of modern climate and improve future climate predictions.

Huge and widespread volcanic eruptions triggered the end-Triassic extinction

Fri, 22 Mar 2013 17:43:43 EDT

Some 200 million years ago, an increase in atmospheric CO2 caused acidification of the oceans and global warming that killed off 76 percent of marine and terrestrial species on Earth.

Megavolcanoes tied to pre-dinosaur mass extinction: Apparent sudden climate shift could have analog today

Thu, 21 Mar 2013 14:14:14 EDT

Scientists examining evidence across the world say they have linked the abrupt disappearance of half of earth's species 200 million years ago to a precisely dated set of gigantic volcanic eruptions. The eruptions may have caused climate changes so sudden that many creatures were unable to adapt -- possibly on a pace similar to that of human-influenced climate warming today. The extinction opened the way for dinosaurs to evolve and dominate the planet for the next 135 million years.

Polar bears' family secrets revealed with DNA sequencing

Thu, 14 Mar 2013 18:01:01 EDT

Brown bears on an Alaskan archipelago are the descendants of an ancient polar bear population rather than being the ancestors of modern polar bears, new research shows.

Dinosaur-era climate change study suggests reasons for turtle disappearance

Thu, 14 Mar 2013 14:43:43 EDT

Dramatic climate change was previously proposed to be responsible for the disappearance of turtles 71-million-years ago, because they were considered to be "climate-sensitive" animals. Results of this research, however, show that the disappearance of turtles came before the climate cooled and instead closely corresponds to habitat disturbances, which was the disappearance of wetlands.

Earth warmer today than during 70 to 80 percent of the past 11,300 years

Thu, 07 Mar 2013 14:53:53 EST

Using data from 73 sites around the world, scientists have been able to reconstruct Earth's temperature history back to the end of the last Ice Age, revealing that the planet today is warmer than it has been during 70 to 80 percent of the time over the last 11,300 years.

Researchers find new information about 'Snowball Earth' period

Thu, 28 Feb 2013 15:56:56 EST

Researchers report new clues on the duration of what was a significant change in atmospheric conditions following the Marinoan glaciation.

Evolution and the ice age

Tue, 26 Feb 2013 13:52:52 EST

Scientists are discovering how the evolution of ecosystems has to be taken into account when speculating between different geological eras. Go back to the time of the dinosaurs or to the single-celled organisms at the origins of life, and it is obvious that ecosystems existing more than 65 million years ago and around four billion years ago cannot be simply surmised from those of today.

Tree-ring data show history, pattern to droughts

Sun, 17 Feb 2013 08:30:30 EST

Researchers used more than 1,400 climate-sensitive tree-ring chronologies from multiple tree species across North America to reconstruct the Palmer drought severity index (PDSI), a widely used soil moisture index.

Ice age extinction shaped Australian plant diversity

Wed, 13 Feb 2013 10:50:50 EST

Researchers have shown that part of Australia's rich plant diversity was wiped out by the ice ages, demonstrating that extinction, probably more than evolution, influences biodiversity.

Isotope patterns in ancient volcanic sulfur tell which global cooling episodes were caused by volcanic eruptions

Mon, 11 Feb 2013 16:23:23 EST

Volcanoes are well known for cooling the climate. But just how much and when has been a bone of contention among historians, glaciologists and archeologists. Now a team of atmosphere chemists has come up with a way to say for sure which historic episodes of global cooling were caused by volcanic eruptions.

Studying ice cores from West Antarctica for clues as to why the Earth began to emerge from the Ice Age

Fri, 08 Feb 2013 18:26:26 EST

Scientists made history this year by retrieving additional ice from the main borehole in West Antarctica. Researchers will now work on a section of ice from 17,500 years ago that offers clues as to why the Earth began to emerge from the Ice Age.

New evidence suggests comet or asteroid impact was last straw for dinosaurs

Thu, 07 Feb 2013 14:14:14 EST

While many assume that a comet or asteroid impact killed off the dinosaurs, the actual dates of the impact and extinction are imprecise enough that some have questioned the connection. Scientists have now dated the extinction with unprecedented precision and concluded that the impact and extinction where synchronous. While global climate change probably brought dinosaurs and other creatures to the brink, the impact likely was the final blow.

Volcano location: Greenhouse-icehouse key? Episodic purging of 'carbonate capacitor' drives long-term climate cycle

Thu, 07 Feb 2013 11:50:50 EST

A new study suggests that Earth's repeated flip-flopping between greenhouse and icehouse climates during the past 500 million years may have been caused by an episodic flare-up of volcanoes at key locations where enormous amounts of carbon dioxide were poised for release into the atmosphere.

Tropical rainfall patterns varied through time: Deeper understanding of drought cycles in Central America

Mon, 04 Feb 2013 09:59:59 EST

Historic lake sediment dug up by researchers reveals that oceanic influences on rainfall in Central America have varied over the last 2,000 years, highlighting the fluctuating influence the Atlantic and Pacific Oceans have on precipitation.

Vegetation changes in cradle of humanity: Study raises questions about impact on human evolution

Thu, 31 Jan 2013 12:13:13 EST

What came first: the bipedal human ancestor or the grassland encroaching on the forest? A new analysis of the past 12 million years' of vegetation change in the cradle of humanity is challenging long-held beliefs about the world in which our ancestors took shape -- and, by extension, the impact it had on them.

Prehistoric humans not wiped out by comet, say researchers

Wed, 30 Jan 2013 08:24:24 EST

Comet explosions did not end the prehistoric human culture, known as Clovis, in North America 13,000 years ago, according to new research.

Low extinction rates made California a refuge for diverse plant species

Wed, 09 Jan 2013 10:59:59 EST

The remarkable diversity of California's plant life is largely the result of low extinction rates over the past 45 million years, according to a new study. Although many new species have evolved in California, the rate at which plant lineages gave rise to new species has not been notably higher in California than elsewhere, researchers found.

Jurassic ecosystems were similar to modern: Animals flourish among lush plants

Tue, 08 Jan 2013 13:20:20 EST

In modern ecosystems, animals flourish amid lush vegetation. That was true 150 million years ago too, says a new study by paleontologists. They applied ecological principles to geochemical data from fossil soils and found scientists can infer animal diversity from it: "This illustrates that climate and biota have been ecologically connected for millions of years, indicating human change to global climate will have profound impacts on plants and animals."

Who deforested Central Africa: Humans or climate?

Mon, 07 Jan 2013 11:14:14 EST

It is a much debated question: why did Central African forests become partially fragmented between 2,500 and 2,000 years ago, leaving room for more open forest landscapes and savannah? Recently, researchers attempted to explain that it was the farming Bantu peoples who were responsible for this, through the large-scale clearing that they undertook.

Coral records suggest El Nino activity rises above background

Thu, 03 Jan 2013 14:31:31 EST

By examining a set of fossil corals that are as much as 7,000 years old, scientists have dramatically expanded the amount of information available on the El Nino-Southern Oscillation, a Pacific Ocean climate cycle that affects climate worldwide.

Fluctuating environment may have driven human evolution

Wed, 26 Dec 2012 08:09:09 EST

A series of rapid environmental changes in East Africa roughly 2 million years ago may be responsible for driving human evolution, according to researchers at Penn State and Rutgers University.

Ups and downs of biodiversity after mass extinction

Fri, 21 Dec 2012 08:16:16 EST

The climate after the largest mass extinction so far 252 million years ago was cool, later very warm and then cool again. Thanks to the cooler temperatures, the diversity of marine fauna ballooned, as paleontologists have reconstructed. The warmer climate, coupled with a high carbon dioxide level in the atmosphere, initially gave rise to new, short-lived species. In the longer term, however, this climate change had an adverse effect on biodiversity and caused species to become extinct.

Crisis in Syria has Mesopotamian precedent, experts say

Tue, 18 Dec 2012 11:19:19 EST

New research has revealed intriguing parallels between modern day and Bronze-Age Syria as the Mesopotamian region underwent urban decline, government collapse, and drought.

New approach allows past data to be used to improve future climate projections

Thu, 29 Nov 2012 13:06:06 EST

Climate scientists are still grappling with one of the main questions of modern times: how high will global temperatures rise if the atmospheric concentration of carbon dioxide doubles. Many researchers are turning to the past because it holds clues to how nature reacted to climate change before the anthropogenic impact. The divergent results of this research, however, have made it difficult to make precise predictions about the impact of increased carbon dioxide on future warming.

Skeletons in cave reveal Mediterranean secrets

Wed, 28 Nov 2012 18:29:29 EST

Skeletal remains in an island cave in Favignana, Italy, reveal that modern humans first settled in Sicily around the time of the last ice age and despite living on Mediterranean islands, ate little seafood.

Ancient microbes found living beneath the icy surface of Antarctic lake

Mon, 26 Nov 2012 15:10:10 EST

A pioneering study reveals, for the first time, a viable community of bacteria that survives and ekes out a living in a dark, salty and subfreezing environment beneath nearly 20 meters of ice in one of Antarctica's most isolated lakes.

Using biomarkers from prehistoric human feces to track settlement and agriculture

Mon, 26 Nov 2012 15:10:10 EST

Geoscientists have used a biomarker from human feces in a new way to establish the first human presence, the arrival of grazing animals and human population dynamics in a landscape.

Climate change and the political, human impacts among ancient Maya

Thu, 08 Nov 2012 14:27:27 EST

Archaeologists and earth science researchers has compiled a precisely dated, high-resolution climate record of 2,000 years that shows how Maya political systems developed and disintegrated in response to climate change. The researchers reconstructed rainfall records from stalagmite samples collected from Yok Balum Cave, located nearly three miles from ancient city of Uxbenka, in the tropical Maya Lowlands in southern Belize. They compared their findings to the rich political histories carved on stone monuments at Maya cities throughout the region.

Carbon buried in the soil rises again

Mon, 05 Nov 2012 15:13:13 EST

A team of researchers estimated that roughly half of the carbon buried in soil by erosion will be re-released into the atmosphere within about 500 years, and possibly faster due to climate change.

Climate modeler identifies trigger for Earth's last big freeze

Mon, 05 Nov 2012 15:13:13 EST

For more than 30 years, climate scientists have debated whether flood waters from melting of the enormous Laurentide Ice Sheet, which ushered in the last major cold episode on Earth about 12,900 years ago, flowed northwest into the Arctic first, or east via the Gulf of St. Lawrence, to weaken ocean thermohaline circulation and have a frigid effect on global climate. Now, using new, high-resolution global ocean circulation models, researchers report the first conclusive evidence that this flood must have flowed north into the Arctic first down the Mackenzie River valley.