Sentences with phrase «ice sheet changes as»

Since we are talking about the models that are being used today to model the next 50 or so years and that those models don't generally include ice sheet models, it is correct to describe ice sheet changes as forcings in this case.

This seems a bit odd giving an answer that ice sheet changes are caused by ice sheet changes as if some circular reasoning hasn't been resolved.

Not exact matches

Following the maxim of keeping everything as simple as possible, but not simpler, Will Steffen from the Australian National University and I drew up an Anthropocene equation by homing in on the rate of change of Earth's life support system: the atmosphere, oceans, forests and wetlands, waterways and ice sheets and fabulous diversity of life.

Stewart Jamieson from Durham University in England and his colleagues made the discovery by looking for subtle changes in the ice sheet's surface shapes, developed as a result of ice flowing over diverse topography.

The first of these pathways, marine ice sheet instability, has been studied for decades, but the second, marine ice cliff instability, has only recently been considered as an important contributor to future sea level change.

Countless additional forces — melting ice sheets, shifts in precipitation, changes in atmospheric and oceanic circulation, to name a few — will influence the process as well.

This effect is particularly apparent in parts of the West Antarctic Ice Sheet (WAIS), long regarded as the more vulnerable part of the continent to climate change.

The digitized data extend the record of changes at the bottom of the ice sheet, such as the formation of channels as Antarctica's ice flows, by more than two decades.

Today, as warming waters caused by climate change flow underneath the floating ice shelves in Pine Island Bay, the Antarctic Ice Sheet is once again at risk of losing mass from rapidly retreating glacieice shelves in Pine Island Bay, the Antarctic Ice Sheet is once again at risk of losing mass from rapidly retreating glacieIce Sheet is once again at risk of losing mass from rapidly retreating glaciers.

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.

Some climate scientists, including James E. Hansen, former head of the nasa Goddard Institute for Space Studies, say we must also consider slower feedbacks such as changes in the continental ice sheets.

While the ECS factors in such «fast» feedback effects as changes in water vapor — water itself is a greenhouse gas, and saturates warm air better than cold — they argued that slow feedbacks, such as changes in ice sheets and vegetation, should also be considered.

As climate change warms Greenland and more ice melts and makes its way into the sea, the ice sheet is potentially becoming a more important source of nutrients, he said.

What's left to figure out is whether this is happening with other subglacial lakes around the Greenland ice sheet, as well as whether and how to incorporate the findings into models that are aimed at gauging how much Greenland might change with the warming climate and how much water it could add to the rising seas.

«These findings add to mounting evidence suggesting that there are sweet spots or «windows of opportunity» within climate space where so - called boundary conditions, such as the level of atmospheric CO2 or the size of continental ice sheets, make abrupt change more likely to occur.

However, as climate change raises global air temperatures, it is possible that East Antarctic glaciers could start melting, a change that could make the ice sheet shift back into unstable territory.

There was an era called white earth which starts about 700 million years ago with alternating periods of deep ice sheets and then hotter warmer stages which led to formation of various kinds of crystals, and last and luckily we live in the period known as green earth, which started about 400 million years ago when multicellular life arose and wholly changed to biochemical breakdown the makeup of the minerals on the planet again.

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 windAs 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 windas 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 shifting coastline is a sobering reminder that Greenland's ice sheet is changing, as well, in ways that could have dramatic consequences throughout the rest of the world.

BANGLADESH is one of the countries at most risk from climate change, as it is low - lying and could be swamped by rising seas — particularly if they rise by several metres (see «Ice sheets on course for collapse «-RRB-.

Others have used tide gauge data to measure GMSL acceleration, but scientists have struggled to pull out other important details from tide - gauge data, such as changes in the last couple of decades due to more active ice sheet melt.

Even if we could freeze - frame the atmosphere as it is today, sea levels would still rise by 25 metres, says the latest study into the effects of climate change on melting ice sheets.

Indeed, one of the findings in the recent paper by Overpeck et al. (this weeks Science), is that even as the Greenland ice sheet melts faster than originally expected, it still won't provide sufficient meltwater forcing of the North Atlantic circulation (which is the feature of the climate system most commonly implicated in the discussion of «tipping points») to force any sort of threshold change.

«The Greenland ice sheet as a whole is shrinking, melting and reducing in size as the result of globally changing air and ocean temperatures and associated changes in circulation patterns in both the ocean and atmosphere,» Muenchow said.

«The big question is whether the ice sheet will react to these changing ocean conditions as rapidly as it did 14,000 years ago,» said lead author Dr Nick Golledge, a senior research fellow at Victoria's Antarctic Research Centre.

Although experts aren't sure what role climate change played in the ice sheet's demise, they see it as an opportunity to improve our understanding of how glaciers will disintegrate as the planet warms.

This effort is going on, with major projects such as the EU funded Ice2sea project, which has brought together researchers across disciplines, from across Europe, in order to address the challenges faced in predicting the contribution of ice sheets to future sea level change.

Anderson, J.B. and Thomas, M.A., 1991, Marine ice sheet decoupling as a mechanism for rapid, episodic sea - level change: the record of such events and their influence on sedimentation: Sedimentary Geology, v. 70, p. 87 - 104.

It is important to regard the LGM studies as just one set of points in the cloud yielded by other climate sensitivity estimates, but the LGM has been a frequent target because it was a period for which there is a lot of data from varied sources, climate was significantly different from today, and we have considerable information about the important drivers — like CO2, CH4, ice sheet extent, vegetation changes etc..

We call this the Charney climate sensitivity, because it is essentially the case considered by Charney (1979), in which water vapor, clouds and sea ice were allowed to change in response to climate change, but GHG (greenhouse gas) amounts, ice sheet area, sea level and vegetation distributions were taken as specified boundary conditions.

If climate change exceeds the temperature target, scientists warn, there is a greater risk that the world's ice sheets will be destabilized, leading to sharply rising seas, and increasing climate extremes such as droughts, heat waves and floods, which could pose daunting challenges for food and water availability for growing populations.

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].

During periods when ice sheets have been relatively stable, such as the last several millennia (the late Holocene), sub-millennial sea - level variability arose primarily from changes in atmosphere / ocean dynamics.

Slow feedbacks, such as change of ice sheet area and climate - driven changes of greenhouse gases, are not included.

But public awareness of the urgency of the climate challenge remains low even as journalists report more deeply about how global warming will alter our cities and environment and how we'll have to adapt to those changes as wildfires rage, ice sheets melt and seas rise.

National Snow and Ice Data Center This comprehensive National Snow and Ice Data Center Web site, useful for teacher reference or for older students, includes information on snow and ice as indicators of climate change, snow avalanches, blizzards, historical snow data, the climate of the Arctic and Antarctic regions, glaciers, sea ice, ice sheets, ice shelves, and iceberIce Data Center This comprehensive National Snow and Ice Data Center Web site, useful for teacher reference or for older students, includes information on snow and ice as indicators of climate change, snow avalanches, blizzards, historical snow data, the climate of the Arctic and Antarctic regions, glaciers, sea ice, ice sheets, ice shelves, and iceberIce Data Center Web site, useful for teacher reference or for older students, includes information on snow and ice as indicators of climate change, snow avalanches, blizzards, historical snow data, the climate of the Arctic and Antarctic regions, glaciers, sea ice, ice sheets, ice shelves, and iceberice as indicators of climate change, snow avalanches, blizzards, historical snow data, the climate of the Arctic and Antarctic regions, glaciers, sea ice, ice sheets, ice shelves, and iceberice, ice sheets, ice shelves, and iceberice sheets, ice shelves, and iceberice shelves, and icebergs.

Glacial climatic fluctuations caused habitat changes, including the appearance of continental ice sheets as far south as Washington State [37], that may have caused range shifts in locally adapted gray fox populations, with foxes with clade B haplotypes existing as far south as southern California.

Indeed, one of the findings in the recent paper by Overpeck et al. (this weeks Science), is that even as the Greenland ice sheet melts faster than originally expected, it still won't provide sufficient meltwater forcing of the North Atlantic circulation (which is the feature of the climate system most commonly implicated in the discussion of «tipping points») to force any sort of threshold change.

The standard climate sensitivity and climate model do not in - clude effects of «slow» climate feedbacks such as change in ice sheet size.

Among the ice sheet dynamics to fret about I see this change in the temperature of the ice from say -30 C to ice - at - 0C and the subsequent uptake of the heat to go from ice - at - 0C to water - at - 0C as the «dark matter» of the cryosphere.

That is, other feedbacks come into play — vegetation, ice sheets, aerosols, CH4 etc. will all change as a function a warming (or cooling), which are not included in the standard climate sensitivity definition.

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.

In probing the fast - changing ice sheets of Antarctica and Greenland, Gordon Hamilton of the University of Maine exemplified the qualities in the rare breed of scientists, engineers and field staff willing to go to extremes — literally — to help clarify the pace at which seas will rise as warming glacial ice melts.

As temperatures warmed slightly due to insolation changes caused by orbital cycles, ice sheets retreated slightly.

``... 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....

As for irreversible, if an ice sheet starts flowing, or if an albedo change from sea ice gets locked in, I could imagine a climate change being essentially irreversible even if CO2 was brought back down, but it's just speculation, nothing more.

[Response: This is way OT, but it's because as the orbit changes the insolation forcing periodically makes it easier to form ice sheets.

Instead, to constrain the Charney sensitivity from the ice age cycle you need to specifically extract out those long term changes (in ice sheets, vegetation, sea level etc.) and then estimate the total radiative forcing including these changes as forcing, not responses.

In their latest Science paper submittal Jim Hansen, et al. argue that we must reduce atmospheric CO2 to below 350 ppm because so - called «slow feedbacks» such as changes in ice sheet albedo are occurring much faster than expected.

Other forcings, including the growth and decay of massive Northern Hemisphere continental ice sheets, changes in atmospheric dust, and changes in the ocean circulation, are not likely to have the same kind of effect in a future warming scenario as they did at glacial times.