Sentences with phrase «ancient tree rings»

Using temperature readings from the past 100 years, 1,000 computer simulations and the evidence left in ancient tree rings, Duke University scientists announced yesterday that «the magnitude of future global warming will likely fall well short of current highest predictions.»

The study, led by Michael E. Mann, a climatologist now at Pennsylvania State University, was the first to estimate widespread climate trends by stitching together a grab bag of evidence, including variations in ancient tree rings and temperatures measured in deep holes in the earth.

In Mongolia, U.S. scientists are studying climate clues in ancient tree rings to help answer a crucial question: How will global warming affect Asia's monsoon rains, which supply water for agriculture and drinking to half the world's population?

Ancient tree rings in Baja California and Mexico show there have been 11 such PDO shifts since 1650, averaging 23 years on length.

In some of the e-mail messages, Dr. Mann refers to his assembly of data from a number of different sources, including ancient tree rings and earth core samples, as a «trick.»

If, and only if, ancient tree ring proxies are robust temperature proxies can they be used in the models to moderate or eliminate the mid-evil warming period.

Not exact matches

Hanqin Tian, an ecologist at Auburn University in Alabama who studies modern grasslands, is working on models to correlate ancient grass production with the tree - ring records of weather.

Researchers studying the rings of ancient trees in mountainous central Mongolia think they may have gotten at the mystery of how small bands of nomadic Mongol horsemen united to conquer much of the world within a span of decades, 800 years ago.

Now, some 40 years later, researchers have studied the rings of the ancient trunks and have read from them details about Earth's climate during the Late Pleistocene when the trees were alive.

Scientists see it in tree rings, ancient coral and bubbles trapped in ice cores.

The following article is primarily based on a discussion of radiocarbon dating found in The Biblical Independent tree - ring dating laboratory providing analysis of ancient trees, timber - frame buildings to archaeological timbers.

A study of tree rings in ancient logs and other data meanwhile indicated that since the 1860s, Northern Hemisphere temperatures had soared to a level higher than anything in at least the past thousand years, and at a more rapid rate.

Others worried that it relied too heavily on growth rings from a small number of ancient trees, such as California bristlecone pines that can live thousands of years clinging to mountainsides.

To construct the green line, Jones took tree - ring density data from Annual climate variability in the Holocene: interpreting the message of ancient trees (Briffa 2000).

I think everyone should be aware that tree rings were used for dating ancient sites and for comparisons with other dating methods — varve counting comes to mind.

The tree - ring data match other information about long - term climate change, like the data from ice cores drilled out of ancient glaciers.

Paul Nurse (voice over): Tree rings have been shown to be a good way of measuring ancient temperatures, and they've mostly matched instrumental measurements since the advent of thermometers.

Because we didn't have a systematic global set of thermometer measurements before the 1880s, scientists look at other things they can measure — sediment deposits, or tree ring growth in certain ancient, slow - growing trees — which tend to vary along with temperature.

The reconstruction of long - term fire histories in a given area of a size far greater than the classical lake catchment necessitates time - consuming field research using several complementary methods, including radiocarbon dating of charcoal, tree - ring dating and sometimes allometric scaling of plant traits, to accurately date ancient and recent fire events.

The tree ring data used to create the new atlas comes from pencil - thin cores taken from both living trees and timbers found in ancient construction reaching back more than 2,000 years.

Thus it was easy to dismiss the large climate swings that an Arizona astronomer, Andrew Ellicott Douglass, reported from his studies of tree rings recovered from ancient buildings and Sequoias.

It was already known that around that time a great drought had ravaged the Anasazi culture in the Southwest (the evidence was constricted tree rings in ancient logs from their dwellings).

The IntCal13 calibration curve is not related to climate or solar activity, and is based on the amount of ¹⁴ C found at each tree ring (or speleothem growth) with the goal of being able to date ancient biological materials.

Hints that warming is being caused by emissions from industry and other human activities have been extracted from air bubbles trapped in ancient ice, from variations in tree rings, from the quick retreat of alpine glaciers.

A)- Cloud cover is reduced B)- Winds are reduced C)- Higher temperature water upwells D)- Upwelling is reduced or stopped E) Surface winds are reduced while winds aloft are strong enough to carry away humidity and prevent clouds and precipitation The occurences of el Nino seem to affect the global temperature even more than adjusting data or pretending tree rings are ancient thermometers.

Tree rings and fire scars in ancient pines, giant sequoias and bigcone Douglas - fir trees reveal long - term patterns and causes of changes in fire regimes in those forests, including the roles of people and climate variations.