Sentences with phrase «past ice sheet change»

Not exact matches

The U.S. team is one of three international groups that sought to penetrate Antarctica's subglacial waters in the past month, seeking clues not only to glacial microbiology but also to ice sheet dynamics and the impact of climate change on the continent.

The two studies improve our understand of Greenland's deep past, while raising questions about both the past and future of its giant ice sheet in a changing climate.

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.

While some may see evidence of rapid glacier thinning in the past and again today as evidence that the West Antarctic Ice Sheet is nearing a collapse driven by human - caused climate change, Steig said at this point, scientists just don't know whether that is the case.

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.

A new study by scientists at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, and the University of California, Irvine, shows that while ice sheets and glaciers continue to melt, changes in weather and climate over the past decade have caused Earth's continents to soak up and store an extra 3.2 trillion tons of water in soils, lakes and underground aquifers, temporarily slowing the rate of sea level rise by about 20 percent.

In the study, researchers analyzed a series of transient Coupled General Circulation Model simulations forced by changes in greenhouse gases, orbital forcing, meltwater discharge and the ice - sheet history throughout the past 21,000 years.

For the past eight years, Operation IceBridge, a NASA mission that conducts aerial surveys of polar ice, has produced unprecedented three - dimensional views of Arctic and Antarctic ice sheets, providing scientists with valuable data on how polar ice is changing in a warming world.

This sea level rise estimate is larger than that provided by the last IPCC report, but highlights the need for further research on ice sheet variablity and ice sheet response to climate change, both now and in the past.

I was recently asked to explain why we can use the paleo - climate record this way when it is clear that the greenhouse gas changes (and ice sheets and vegetation) in the past were feedbacks to the orbital forcing rather than imposed forcings.

Past ice - sheet behaviour: retreat scenarios and changing controls in the Ross Sea, Antarctica.

And through detailed studies of the local physics of ice - sheet changes and more refined reconstructions of ice - sheet changes during warm periods of the geological past, scientists may become able to distinguish between the two roads sooner.

That estimate was based in part on the fact that sea level is now rising 3.2 mm / yr (3.2 m / millennium)[57], an order of magnitude faster than the rate during the prior several thousand years, with rapid change of ice sheet mass balance over the past few decades [23] and Greenland and Antarctica now losing mass at accelerating rates [23]--[24].

Currently, the major focus of this thread is on reconstructing past sea - level changes and understanding the implications of these changes for ice - sheet stability and for ocean dynamics.

I was recently asked to explain why we can use the paleo - climate record this way when it is clear that the greenhouse gas changes (and ice sheets and vegetation) in the past were feedbacks to the orbital forcing rather than imposed forcings.

Robert Bindschadler of NASA and Tad Pfeffer at the University of Colorado, both glacier specialists, told me that they saw scant evidence that a yards - per - century rise in seas could be produced from the ice sheets that currently cloak Greenland and West Antarctica, which are very different than what existed in past periods of fast sea - level changes.

But what the GSL now says is that geological evidence from palaeoclimatology (studies of past climate change) suggests that if longer - term factors are taken into account, such as the decay of large ice sheets, the Earth's sensitivity to a doubling of CO2 could itself be double that predicted by most climate models.

For example, the ice age — interglacial cycles that we have been locked in for the past few million years seem to be triggered by subtle changes in the earth's orbit around the sun and in its axis of rotation (the Milankovitch cycles) that then cause ice sheets to slowly build up (or melt away)... which changes the albedo (reflectance) of the earth amplifying this effect.

``... estimates of future rises remain hazy, mostly because there are many uncertainties, from the lack of data on what ice sheets did in the past to predict how they will react to warming, insufficient long - term satellite data to unpick the effects of natural climate change from that caused by man and a spottiness in the degree to which places such as Antarctica have warmed....

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.

If the surface temperature is slow to catch up to that imbalance then the energy imbalance remains large, and we can have sufficient net heating to cause much faster changes in the ice sheets than from the comparatively smaller imbalances caused by the changes in Earth's orbit associated with the glacial periods in the past.

Climate Depot Arctic Fact Sheet — Get the latest peer - reviewed studies and analysis — Arctic Ice Changes in past 3 years due to «shifting winds»

In addition we have coupled the ice model Sicopolis to our Earth System model CLIMBER - 2 to study the stability of the Greenland ice sheet in past and future climate changes.

Scientists extract ice cores from ice sheets and ice caps, studying them to learn about past changes in Earth's climate.

Just ask whether there has been any change in the past few decades in the rate at which icebergs have been breaking off the West Antarctic ice sheet.

Since there is controversy over the subject of climate change, it is important to study the behaviour of ice sheets in the past, in order to predict what may happen in the futureThe study focused on «erratic» rocks, which are rocks that differ totally from the local sedimentary rocks and have been transported there by moving ice.

There is a great book called the Two Mile Time Machine, by Richard Alley, that discusses the Greenland Ice Core Project, and the study of past failures of the ice sheet, and the ensuing almost instant climate chanIce Core Project, and the study of past failures of the ice sheet, and the ensuing almost instant climate chanice sheet, and the ensuing almost instant climate change.

Most of the whiplash climate changes of the past were during icy periods that had ice sheets in Canada and Scandinavia.

The team used changes in dust levels and stable water isotopes in the annual ice layers of the two - mile - long Greenland ice core, which was hauled from the massive ice sheet between 1998 to 2004, to chart past temperature and precipitation swings.

«The observed changes in sea ice on the Arctic Ocean, in the mass of the Greenland ice sheet and Arctic ice caps and glaciers over the past 10 years are dramatic and represent an obvious departure from long - term patterns,» says the report.

That estimate was based in part on the fact that sea level is now rising 3.2 mm / yr (3.2 m / millennium)[57], an order of magnitude faster than the rate during the prior several thousand years, with rapid change of ice sheet mass balance over the past few decades [23] and Greenland and Antarctica now losing mass at accelerating rates [23]--[24].

While sea level has varied greatly in the past, it has generally changed slowly, over many thousands of years — except when ice sheets collapse.

Geological evidence from studies of past climate change now suggests that if longer term factors are taken into account, such as the decay of large ice sheets and the operation of the full carbon cycle, the sensitivity of the Earth to a doubling of CO2 could be double that predicted by most climate models.

Our assumption that global temperature passed the Holocene mean a few decades ago is consistent with the rapid change of ice sheet mass balance in the past few decades [75].

In spite of a century of work, there is a paucity of data on how the ice sheet has changed in the past, limiting our ability to compare current trends, or constrain ice - sheet and climate models.