Taxonomy term

paleoclimate

Bad weather hampered Mongol invasion of Europe

In 1241, the armies of the Mongol Empire, continuing their campaign through Asia and Europe, invaded western Hungary. Before long, however, the Mongols withdrew their forces, beating a sudden retreat that has long baffled historians. Now, drawing on high-resolution climate data from tree rings, researchers may have found a clue as to why: It seems wet weather created adverse conditions for the Mongol army, eventually forcing it to retreat from what was to become historically its westernmost advance.

 
25 Sep 2016

Growth rings in rocks reveal past climate

Paleoclimate studies often depend on mineral or sediment layers deposited seasonally or annually in caves, lakes and ice, but such records leave gaps where caves, lakes or ice sheets aren’t found. Now, scientists using a new technique that analyzes calcite layers ringing pebbles and rocks in arid landscapes are opening a new window onto the climate history of western North America. And because such deposits are found all over the world, the technique might prove to be a useful new tool for studying paleoclimate globally.

02 May 2016

Fossil leaves provide clues to ancient Australian habitat

Researchers have long thought that the scrublands of Australia developed over the last 25 million to 30 million years as part of a global trend toward colder and drier climates in which rainforests yielded ground to more open, fire-prone environments.

20 Apr 2016

Volcanic aerosols not enough to cause mass extinctions?

Mass extinctions — when more than half of Earth’s species disappear in a geologic instant — offer some of the planet’s most perplexing unsolved mysteries. Prolonged periods of volcanic activity have long been prime suspects for these ancient whodunits, the most recent of which finished off the last nonavian dinosaurs at the close of the Cretaceous about 66 million years ago. But scientists debate how drastic the environmental effects of such volcanism might have been, and whether other factors — like asteroid impacts, as in the end-Cretaceous extinction — played a big role as well.

25 Feb 2016

Southbound icebergs off the hook for ice-age cooling

During the Late Pleistocene, changes in North Atlantic Ocean circulation triggered abrupt changes in global climate: In some locations in the Northern Hemisphere, average temperatures dropped by as much as 10 degrees Celsius within a few decades. Scientists have long thought that freshwater from melting icebergs traveling south from the Arctic may have instigated the circulation shifts that contributed to cooling feedback loops. But now, scientists looking at seafloor sediments collected near Iceland have found that pulses of icebergs typically arrived after the onset of cooling episodes, too late to be primary drivers of climate change.
 
11 Aug 2015

Widening the window of human dispersal into Arabia

The vast sea of sand that is much of the Arabian Peninsula presents a formidable barrier to travel, even with today’s modern conveniences. How and when our ancestors crossed this dry expanse after leaving Africa — on their way to populating the rest of the world — has long been a mystery. Now, a new paleoclimate study paints a wetter picture of Arabia during the time of human expansion, and the findings may change scientists’ thinking about the route and timing of early human migrations out of Africa.

31 Jul 2015

Great drying led to great dying down under

If not for the megafaunal extinctions that wiped out many large animals at the end of the Pleistocene, the world might be a very different place today — with humans coexisting alongside still-living saber-toothed tigers, woolly mammoths and 3-meter-tall birds. The agents of these mass extinctions have been debated for decades: Were shifting climates, or our spear-wielding ancestors mainly responsible? A new study of the receding shorelines of Australia’s largest lake has found that a substantial drying of the environment, more so than human pressure, is mostly to blame for the loss of megafauna down under.
 
08 Jul 2015

Did volcanism drive Earth into global glaciation?

Between about 720 million and 635 million years ago, Earth suffered two big chills. During these “Snowball Earth” episodes, geologists think the world’s oceans froze over and glaciers spilled from tropical coastlines. Scientists have previously suggested that intense volcanism, unleashed by the disintegration of the supercontinent Rodinia, plunged Earth into these global glaciations. New research now lends support to this so-called fire-and-ice hypothesis.
05 Jun 2015

Old piles of shells reveal ancient El Niño patterns

Understanding of the El Niño-Southern Oscillation (ENSO) is evolving as scientists unearth new data sources. In a study recently published in Science, scientists turned to the discarded remains of shellfish for a 10,000-year record of eastern Pacific ENSO activity, which offered glimpses into unexpected past ENSO behavior and intensity.

03 Jan 2015

Ancient storms recorded in Yucatán cave

Today, one can find a plethora of records about coastal storms — everything from local news footage of wading meteorologists to the moment-to-moment wind speeds and barometric pressures of entire seasons of Atlantic hurricanes recorded in NOAA databases. Ancient storms are harder to track, unless they left a mark in the geologic record. Now, researchers have a new proxy record, one of the longest to date, to study ancient storms.

23 Dec 2014

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