Sentences with phrase «from ice sheets»

In 2007 IPCC embraced a drastic revision: «New dataâ $ ¦ show [s] that losses from the ice sheets of Greenland and Antarctica have very likely contributed to sea level rise over 1993 to 2003.»

For one thing, he says, it contains a scenario in which the fresh meltwater from ice sheets increases exponentially over time, «which may not be realistic.»

«Humans have adapted to life on earth ranging from ice sheets to mountains to tropics and have survived far warmer and far colder climates than currently being experienced or forecast by the climate doomists,» Prof Plimer said.

We showed that a detailed analysis of the GRACE time series over the time period 2002 — 2009 unambiguously reveals an increase in mass loss from both ice sheets.

Adding together the observed individual components of sea level rise (thermal expansion of the ocean water, loss of continental ice from ice sheets and mountain glaciers, terrestrial water storage) now is in reasonable agreement with the observed total sea - level rise.

Joughin was harsher in his criticism about some of the details, saying that Hansen's projected doubling time of around 10 to 20 years for ice loss from ice sheets is «simply not realistic, as there is not a physical basis for assuming that type of exponential change.»

(2) A steady ongoing ice loss from ice sheets is added in — this has nothing to do with modern warming but is a slow response to earlier climate changes.

Those instruments measure gravity anomalies (and hence mass) and so are will be great at measuring the loss of ice from the ice sheets etc..

FIGURE B The long - term worst - case sea - level rise from ice sheets could be more than 60 m if all of Greenland and Antarctic ice melts.

Much process - based research coupling field work, remote sensing, and modeling is required to advance assessment of the likelihood of a threshold - crossing leading to abrupt sea - level rise from the ice sheets, as well as to improve projections of moregradual sea - level rise that could lead to threshold - crossing events in other systems.

Great progress has been made recently in assessing the current rate of mass loss from the ice sheets (Shepherd et al., 2012), as well as monitoring the changing snowfall, surface melting, and temperature contributing to the changes.

Thus any large and rapid global sea - level rise, if it were to occur, would almost surely be sourced from the ice sheets.

For example, Overpeck et al. (2006), and Hansen (2007) suggest possibilities which could eventually lead to a nonlinear response from ice sheets — accelerating the current observed sea level rise.

Satellite data confirms almost two decades of accelerating ice loss from ice sheets around Antarctica.

At present, most mass loss from ice sheets occurs at their marine margins, through iceberg production and melting by the ocean.

Interactions between the ocean and ice sheets are particularly important in determining ice sheet changes, as a warming ocean can melt the ice shelves, the tongues of ice that extend from the ice sheets into the ocean and buttress the large land - based ice sheets [92], [202]--[203].

Recent observations of unpredicted, local acceleration and consequent loss of mass from both ice sheets (Alley et al., 2005) underscores the inadequacy of existing ice - sheet models, leaving no generally agreed basis for projection, particularly for WAIS (Lemke et al., 2007 Section 4.6.3.3; Meehl et al., 2007 Sections 10.6.4.2 and 10.7.4.4; Vieli and Payne, 2005).

The contributions from ice sheets include the contributions from ice - sheet rapid dynamical change, which are also shown separately.

So then, just when some papers are coming out with projected 4 mm / yr rates, here we have Daniel Bailey at 235, in the course of discussing that there is a larger contribution to SLR from ice sheets rather than thermal expansion he states as follows:

«Over the last couple of decades, the sea - level rise from the ice sheets has been about 0.6 mm / yr, from a reservoir of more than 60 meters, which is about the same as me going on a diet and losing 1/3 of one potato chip over a year.

Second, he demonstrated that prevailing estimates of the 20th century GMSL rise (~ 1.5 to 2.0 mm / year), after correction for the maximum signal from ocean thermal expansion, implied mass flux from ice sheets and glaciers at a level that would grossly misfit the residual GIA - corrected observations of Earth's rotation.

A research scientist at Ohio State's Byrd Polar Research Center, Mosley - Thompson collects ice cores from the ice sheets of Antarctica and Greenland, while colleague Lonnie Thompson, a professor of geological sciences at Ohio State, collects cores from the mountainous ice fields of China and South America.

For instance, projections of sea level rise do not take into account the fact that the flow of ice from the ice sheets in Greenland and Antarctica could be faster in the future than they were in recent years.

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

An expert judgement assessment of future sea level rise from the ice sheets.

What it ignores are the slow feedbacks from the ice sheets and the carbon cycle itself — as it treates both as boundary conditions.

The only way to reconcile the results would be to have had a sharp compensating increase in freshwater from the ice sheets adding to sea level (from 0.7 mm / yr to 2.9 mm / yr).

Uncoupling was most complete along liner troughs that I concluded had been occupied by ice streams, fast currents of ice that drain most of the interior ice from ice sheets past and present.

This was a relatively stable climate (for several thousand years, 20,000 years ago), and a period where we have reasonable estimates of the radiative forcing (albedo changes from ice sheets and vegetation changes, greenhouse gas concentrations (derived from ice cores) and an increase in the atmospheric dust load) and temperature changes.

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.

«the last glacial period is a good example of a large forcing (~ 7 W / m ^ 2 from ice sheets, greenhouse gases, dust and vegetation) giving a large temperature response (~ 5 ºC) and implying a sensitivity of about 3ºC (with substantial error bars).»

From recent instrumental observations alone we are therefore unable to predict whether mass loss from these ice sheets will vary linearly with changes in the rate of sea - level rise, or if a non-linear response is more likely.

However, in periods in the past, say around 8,200 years ago, or during the last ice age, there is lots of evidence that this circulation was greatly reduced, possibly as a function of surface freshwater forcing from large lake collapses or from the ice sheets.

On the other hand, during those periods between widespread glaciation, the water had melted from the ice sheets and polar areas, flowed, back into the oceans and sea level was as high or higher than now.

Interactions between the ocean and ice sheets are particularly important in determining ice sheet changes, as a warming ocean can melt the ice shelves, the tongues of ice that extend from the ice sheets into the ocean and buttress the large land - based ice sheets [92], [202]--[203].

The differences are that the UVic model has a smaller forcing from the ice sheets, possibly because of an insufficiently steep lapse rate (5ºC / km instead of a steeper value that would be more typical of dryer polar regions), and also a smaller change from increased dust.

Scientific knowledge input into process based models has much improved, reducing uncertainty of known science for some components of sea - level rise (e.g. steric changes), but when considering other components (e.g. ice melt from ice sheets, terrestrial water contribution) science is still emerging, and uncertainties remain high.

But an upshot is that the land around Earth's equator, farthest from both ice sheets, is poised to receive the land - ice — sea - level double - punch: Increasing ocean volume and weakening high latitude gravity.

As we have discussed previously, the last glacial period is a good example of a large forcing (~ 7 W / m2 from ice sheets, greenhouse gases, dust and vegetation) giving a large temperature response (~ 5 ºC) and implying a sensitivity of about 3ºC (with substantial error bars).

«the last glacial period is a good example of a large forcing (~ 7 W / m ^ 2 from ice sheets, greenhouse gases, dust and vegetation) giving a large temperature response (~ 5 ºC) and implying a sensitivity of about 3ºC (with substantial error bars).»

Recent projections show that for even the lowest emissions scenarios, thermal expansion of ocean waters21 and the melting of small mountain glaciers22 will result in 11 inches of sea level rise by 2100, even without any contribution from the ice sheets in Greenland and Antarctica.

For one thing, he says, it contains a scenario in which the fresh meltwater from ice sheets increases exponentially over time, «which may not be realistic.»

While satellite measurements and climate models have detailed this recent ice loss, there are far fewer direct measurements of melt collected from the ice sheet itself.

Further, the floating bay ice decreased, allowing easier flow from the ice sheet into the water.

With significant warming in the past decade, there was significant melt from the ice sheet.

A Danish - led study, published today in the journal Environmental Research Letters, examined how microbes from the ice sheet have the potential to resist and degrade globally - emitted contaminants such as mercury, lead, PAH and PCB.

What is causing the mysterious line of volcanoes that emerge from the ice sheet there, and what does it mean for the future of the ice?

It is not clear yet how much of the phosphorus being released from the ice sheet is reaching the open ocean, but if a large amount of phosphorus coming off the glacier makes it to the sea, the nutrient could rev up biological activity of Arctic waters, according to the study's authors.

Hawkings and his collaborators spent three months in 2012 and 2013 gathering water samples and measuring the flow of water from the 600 - square - kilometer (230 - square - mile) Leverett Glacier and the smaller, 36 - square - kilometer (14 - square - mile) Kiattuut Sermiat Glacier in Greenland as part of a Natural Environment Research Council - funded project to understand how much phosphorus, in various forms, was escaping from the ice sheet over time and draining into the sea.

Meltwater from the ice sheet that once covered Canada has left behind clues that could help scientists predict the future of Greenland's vanishing ice