Sentences with phrase «past global ice»

Not exact matches

Evidence of past glacial advance and retreat is also more easily observed in the Dry Valleys, providing a window into the past behavior of the vast Antarctic ice sheets and their influence on global sea levels.

As global warming melts Earth's ice, unique relics from the past are being revealed — only to be exposed to the elements and rot away

Ice - sheet growth, coupled with favorable changes in Earth's orbit, pushed the planet past a climatic tipping point and led to both the rapid buildup of a permanent ice sheet in the Antarctic and much larger changes in global climate, says HrIce - sheet growth, coupled with favorable changes in Earth's orbit, pushed the planet past a climatic tipping point and led to both the rapid buildup of a permanent ice sheet in the Antarctic and much larger changes in global climate, says Hrice sheet in the Antarctic and much larger changes in global climate, says Hren.

Their field - based data also suggest that during major climate cool - downs in the past several million years, the ice sheet expanded into previously ice - free areas, «showing that the ice sheet in East Greenland responds to and tracks global climate change,» Bierman says.

An unprecedented analysis of North Pacific ocean circulation over the past 1.2 million years has found that sea ice formation in coastal regions is a key driver of deep ocean circulation, influencing climate on regional and global scales.

«Formation of coastal sea ice in North Pacific drives ocean circulation, climate: New understanding of changes in North Pacific ocean circulation over the past 1.2 million years could lead to better global climate models.»

It appears global warming is replicating conditions that, in the past, triggered significant shifts in the stability of the Antarctic ice sheet.

«The past behavior and dynamics of the Antarctic ice sheets are among the most important open questions in the scientific understanding of how the polar regions help to regulate global climate,» said Jennifer Burns, director of the NSF Antarctic Integrated Science System Program.

A new review analyzing three decades of research on the historic effects of melting polar ice sheets found that global sea levels have risen at least six meters, or about 20 feet, above present levels on multiple occasions over the past three million years.

A working group known as PALSEA2 (Paleo constraints on sea level rise) used past records of local change in sea level and converted them to a global mean sea level by predicting how the surface of the Earth deforms due to changes in ice - ocean loading of the crust, along with changes in gravitational attraction on the ocean surface.

Our study underlines that these conditions have led to a large loss of ice and significant rises in global sea level in the past.

As global temperatures continue to increase, the hastening rise of those seas as glaciers and ice sheets melt threatens the very existence of the small island nation, Kiribati, whose corals offered up these vital clues from the warming past — and of an even hotter future, shortly after the next change in the winds.

The Greenland ice sheet is thought to be one of the largest contributors to global sea level rise over the past 20 years, accounting for 0.5 millimeters of the current total of 3.2 millimeters of sea level rise per year.

Disappearing Arctic ice is already helping to amplify global warming beyond what the IPCC had predicted in the past.

However, in the past, researchers have been frustrated in their attempts to achieve global and local control of spin - ice magnetic charges.

If proxy data can confirm that sea ice was indeed the major player in past abrupt climate - change events, it seems less likely that such dramatic abrupt changes will occur due to global warming, when extensive sea - ice cover will not be present.

• Global messages from Antarctica, Dana Bergstrom • Deciphering past climate and ice sheet dynamics from sedimentary records, Carlota Escutia (Antarctic Science Lecture) • Southern Ocean Acidification, Richard Bellerby (Weyprecht Lecture) • Martha T Muse Lecture (Winner for 2014 to be announced)

The global mean temperature rise of less than 1 degree C in the past century does not seem like much, but it is associated with a winter temperature rise of 3 to 4 degrees C over most of the Arctic in the past 20 years, unprecedented loss of ice from all the tropical glaciers, a decrease of 15 to 20 % in late summer sea ice extent, rising sealevel, and a host of other measured signs of anomalous and rapid climate change.

The assessment examines the following content; global warming, the greenhouse effect / gases, natural and human causes of past climate change, evidence of the little ice age, features of tropical storms and the effects and response to tropical storms.

If proxy data can confirm that sea ice was indeed the major player in past abrupt climate - change events, it seems less likely that such dramatic abrupt changes will occur due to global warming, when extensive sea - ice cover will not be present.

On a related note: Does anyone here know where the best source would be for getting a detailed chart of Be-10 concentrations from ice cores plotted against global temps during the past 10,000 years?

When confronted with a contrarian who argues that somehow global warming isn't taking place, I would point to the Arctic sea ice and glaciers — which have even lasted through the warm periods of the past two thousand years — and probably well before.

Mike's work, like that of previous award winners, is diverse, and includes pioneering and highly cited work in time series analysis (an elegant use of Thomson's multitaper spectral analysis approach to detect spatiotemporal oscillations in the climate record and methods for smoothing temporal data), decadal climate variability (the term «Atlantic Multidecadal Oscillation» or «AMO» was coined by Mike in an interview with Science's Richard Kerr about a paper he had published with Tom Delworth of GFDL showing evidence in both climate model simulations and observational data for a 50 - 70 year oscillation in the climate system; significantly Mike also published work with Kerry Emanuel in 2006 showing that the AMO concept has been overstated as regards its role in 20th century tropical Atlantic SST changes, a finding recently reaffirmed by a study published in Nature), in showing how changes in radiative forcing from volcanoes can affect ENSO, in examining the role of solar variations in explaining the pattern of the Medieval Climate Anomaly and Little Ice Age, the relationship between the climate changes of past centuries and phenomena such as Atlantic tropical cyclones and global sea level, and even a bit of work in atmospheric chemistry (an analysis of beryllium - 7 measurements).

Here are some possible choices — in order of increasing sophistication: * All (or most) scientists agree (the principal Gore argument) * The 20th century is the warmest in 1000 years (the «hockeystick» argument) * Glaciers are melting, sea ice is shrinking, polar bears are in danger, etc * Correlation — both CO2 and temperature are increasing * Sea levels are rising * Models using both natural and human forcing accurately reproduce the detailed behavior of 20th century global temperature * Modeled and observed PATTERNS of temperature trends («fingerprints») of the past 30 years agree

In a more recent paper, our own Stefan Rahmstorf used a simple regression model to suggest that sea level rise (SLR) could reach 0.5 to 1.4 meters above 1990 levels by 2100, but this did not consider individual processes like dynamic ice sheet changes, being only based on how global sea level has been linked to global warming over the past 120 years.

The paper also finds that several significant past climate fluctuations — including a warm spell that peaked around 1100 A.D. called the medieval warm period and the so - called little ice age from the 1400s through the 1700s — were global in scope.

There is no «proof» that these are more than natural occurrences (or, admittedly, neither that they are not) and require, for now, really contorted tortuous explanations (snow / ice getting covered with soot, Arctic really getting lots warmer than the few tenths of a degree of the global average just the past 2 - 3 decades, etc.) why AGW is causing them — though they are professed with religious conviction.

The earth has had significant Global Warming for some 20,000 years now... The only real argument is to the degree that mans activity has augmented that... We just came out of one - point - five - million years of continuous glaciation with sheets of two mile thick ice down past the 44th parallel... I will cheerfully deal with warming issues over that, any day...

Here's a link to a graph of global sea ice area over the past 30 years.

Over the past millennium this graph, most of which is obtained from Antarctic ice cores, shows CO2 holding steady at 280 ± 5 ppm up to 1800, when global population was about a billion people and sailing ships and the horse - and - buggy were the most advanced forms of transportation, consuming relatively little energy per capita compared with today.

I suspect that it looked OK in your view or you didn't check; «the paper i cited talks of the hiatus in global temperatures for the past 20 years or so, that the Little Ice Age was global in extent, and that climate models can not account for the observations we already have let alone make adequate predictions about what will happen in the future.

There are many who will not like this recent paper published in Nature Communications on principle as it talks of the hiatus in global temperatures for the past 20 years or so, that the Little Ice Age was global in extent, and that climate models can not account for the observations we already have let alone make adequate predictions about what will happen in the future.

Figures A and B show past variations in the global mean temperature inferred from direct measurements (A) and from the analysis of ice - cores (B).

At the beginning of the Holocene - after the end of the last Ice Age - global temperature increased, and subsequently it decreased again by 0.7 ° C over the past 5000 years.

To answer the question of the Medieval Warm Period, more than 1,000 tree - ring, ice core, coral, sediment and other assorted proxy records spanning both hemispheres were used to construct a global map of temperature change over the past 1,500 years (Mann 2009).

For the past 55 million years the global surface temperature has declined by more than 10 °C from a «hot house» condition into an «ice house» with increasing temperature variability as depicted in Figure 1 (Mya = millions of years ago).

Currently, we are in a period of global cooling and «Arctic sea ice extent... for April 2010 was the largest for that month in the past decade.»

Variations of snow and ice in the past and at present on a global and regional scale.

Qin Dahe, also co-chair of the working group, said: «As the ocean warm, and glaciers and ice sheets reduce, global mean sea level will continue to rise, but at a faster rate than we have experienced over the past 40 years.»

-LSB-...] In fact, the global sea - ice record shows virtually no change throughout the past 30 years, because the quite rapid loss of Arctic sea ice since the satellites were watching has been matched by a near - equally rapid gain of Antarctic sea ice.

This was the conclusion of a scientific paper I co-authored last year, in which our team found more overall global warming (of the oceans, air, land, and ice combined) over the past 15 years than during the prior 15 years.

Consistent with the aforementioned sea level rise acceleration, a number of articles have projected global sea level rise of around 1m or more by 2100, based on past estimates of sea level rise (in response to warming) and based on melting of land ice (with thermal expansion):

The aim of the C - SIDE working group is to reconstruct changes in sea - ice extent in the Southern Ocean for the past 130,000 years, reconstruct how sea - ice cover responded to global cooling as the Earth entered a glacial cycle, and to better understand how sea - ice cover may have influenced nutrient cycling, ocean productivity, air - sea gas exchange, and circulation dynamics.

The paper finds that several significant past climate ups and downs — including the medieval warm period and little ice age — were global in scope, challenging some previous conclusions that these were fairly limited Northern Hemisphere phenomena.

c) Manfred Mudelsee: The phase relations among atmospheric CO2 content, temperature and global ice volume over the past 420 ka, Quaternary Science Reviews, (February 2001) Volume 20, Issue 4, Pages 583 — 589.

Translated by Google from this press release in German at the Alfred Wegener Institute in Germany: Never so much sea ice at Antarctica in the last 30 years In light of global warming, it seems paradoxical that the sea ice cover of the Southern Ocean has covered a larger area in the past month than...

Abrupt and severe temperature shifts have occurred on occasion in the past, typically separated by hundreds of years or more, but shifts of this magnitude that are global in extent have almost always occurred during glacial eras, when the extent of snow and ice allowed for great changes in feedback in response to only modest signals.

Past Speakers Oct 2 - Columbia Professor Todd Gitlin on Fossil Fuel Divestment Oct 3 - Massimo LoBuglio, Environmentalist and Social Entrepreneur Oct 4 - Dr. Radley Horton, Columbia University and co-author of the Obama Administration's Climate Assessment Report Oct 5 - Dr. Jennifer Francis, Rutgers, author of the cutting - edge theory of Arctic Ice Melt and Extreme Weather Oct 9 - Opening Night with climate prophet Dr. James Hansen, NASA scientist, who told Congress in 1988 that global warming had begun Oct 10 — Prof. Andrew Revkin, Pace, plays Climate Music post-show Oct 11 - David Levine - Co-founder and CEO of American Sustainable Business Council Oct 12 - Jaimie Cloud & Griffin Cloud Levine - Teaching Children and Youths Sustainability Oct 16 - Prof. Gerald Markowitz, John Jay College, on industry's relationship to science Oct 17 - Marielle Anzelone, Urban ecologist Oct 18 - Dr. Jannette Barth, Why Not To Frack Oct 19 - Ken Levenson, The Passive House Oct 23 - Prof. Ana Baptista, New School for Social Research, Environmental Justice and Climate Change Oct 24 - Charles Komanoff, Carbon Tax Center, on the need to tax carbon Oct 25 - Prof. Dale Jamieson, NYU, Reason in A Dark Time Oct 26 - Eve Silber and Closing Reception in honor of Father Paul Mayer

Both the observations of mass balance and the estimates based on temperature changes (Table 11.4) indicate a reduction of mass of glaciers and ice caps in the recent past, giving a contribution to global - average sea level of 0.2 to 0.4 mm / yr over the last hundred years.

Global warming began its recovery after the last Snowball Earth, was halted a few times by the ice ages (big and little), and for the past 150 or so years has been slowly been returning to NORMAL.