The Greenland Ice Sheet is the second largest ice sheet on Earth and has been losing mass for decades, a trend scientists have linked to a warming climate. However, the mass change experienced by individual coastal glaciers, which flow out from the ice sheet into the ocean, is highly variable. This makes predicting the impact on future sea-level rise difficult.

“We were looking for a way to explain why this variability exists, and we found a way to do it that has never been applied before on this scale,” Felikson said.

Of the 16 glaciers researchers investigated in West Greenland, the study found four that are the most susceptible to thinning: Rink Isbrae, Umiamako Isbrae, Jakobshavn Isbrae and Sermeq Silardleq.

Umiamako Isbrae, Sermeq Silardleq and Jakobshavn Isbrae are already losing mass, with Jakobshavn being responsible for more than 81 percent of West Greenland’s total mass loss over the past 30 years.

The analysis works by calculating how far inland thinning that starts at the terminus of each glacier is likely to extend. Glaciers with thinning that reaches far inland are the most susceptible to ice mass loss.

Just how prone a glacier is to thinning depends on its thickness and surface slope, features that are influenced by the landscape under the glacier. In general, thinning spreads more easily across thick and flat glaciers and is hindered by thin and steep portions of glaciers.

The research revealed that most glaciers are susceptible to thinning between 10 and 30 miles inland. For Jakobshavn, however, the risk of thinning reaches over 150 miles inland—almost one-third of the way across the Greenland Ice Sheet.

“Jakobshavn is particularly vulnerable to thinning because it flows through a very deep trough that extends deep into the ice sheet interior, making the ice thick and the surface flat,” Felikson said.

Among other sources of data, Felikson and his team used a bedrock topography map created with data from NASA’s Ocean Melting Greenland project to determine the thickness of the ice and a digital elevation model from the Greenland Ice Mapping Project, which uses measurements from the Japanese-provided Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA’s Terra satellite, to separate glacier catchments.

Ginny Catania, an associate professor in the University of Texas Jackson School of Geosciences and research associate at UTIG, said the group has plans to apply the shape analysis technique to other glaciers. “Our plan is to extend the analysis so that we can identify glaciers in Antarctica and around the rest of Greenland that are most likely to be susceptible to change in the future,” she said.

We were looking for a way to explain why this variability exists, and we found a way to do it that has never been applied before on this scale,” Felikson said.

Of the 16 glaciers researchers investigated in West Greenland, the study found four that are the most susceptible to thinning: Rink Isbrae, Umiamako Isbrae, Jakobshavn Isbrae and Sermeq Silardleq.

Umiamako Isbrae, Sermeq Silardleq and Jakobshavn Isbrae are already losing mass, with Jakobshavn being responsible for more than 81 percent of West Greenland’s total mass loss over the past 30 years.


Poor Booby thinks Greenland is gaining ice.

Jovial Monk wrote on Apr 20^th, 2017 at 7:11am:


"NASA has released data showing how temperature and rainfall patterns worldwide may change through the year 2100 because of growing concentrations of greenhouse gases in Earth’s atmosphere."


You do know, being a scientist, the difference between data and projections?

BTW- Did you see the difference -

JM - " AGW will affect temperature and precipitation"

NASA -  "temperature and rainfall patterns worldwide may change"

You are several orders of magnitude ahead of NASA. Where do you get your data?

According to Nasa, in 2016 the Earth’s surface temperature shattered the previous record for hottest year by 0.12°C. That record was set in 2015, which broke the previous record by 0.13°C. That record had been set in 2014, beating out 2010, which in turn had broken the previous record set in 2005. . . .

Even including World War II, in the first 100 years of the Nasa data, the high temperature record was broken seven times. It’s been broken seven times in just the past 20 years.

This rapid rate of record-breaking heat (once every three years) is consistent with climate scientists’ expectations. A 2011 paper by Stefan Rahmstorf and Dim Coumou found that as global warming continues, we should expect to set new records about once every four years.

Quote:


Rahmstorf told me that so far, the rate of record-setting temperatures is in line with a consistent human-caused global warming trend:

Quote:

Global temperature wasn’t the only record-setter in 2016. Global warming causes climate change, and North America saw its highest number of storms and floods in over four decades. Globally, we saw over 1.5 times more extreme weather catastrophes in 2016 than the average over the past 30 years. Global sea ice cover plunged to a record low as well. California endured a fifth consecutive year of its worst drought in over a millennium. A drought also savaged the maize harvest in Southern Africa, causing a famine. The list of climate consequences goes on.

testifying before the Senate on the day the record temperatures were announced in a bid to become EPA administrator, Scott Pruitt claimed that we don’t know how much humans are contributing to global warming. . . .

This is simply wrong. We wouldn’t be setting a new temperature record every three years if not for global warming, and there’s no question that the warming is predominantly human-caused. The latest IPCC report stated with 95% confidence that humans are the main cause of global warming since 1950, and most likely responsible for 100% of that temperature rise.

Every study quantifying the various contributions to global warming has found humans are the dominant cause. Our fingerprints are all over climate change – the changes are precisely in line with what we’d expect to see as a result of an increased greenhouse effect from human carbon pollution. . . .

Climate denial is evolving. All of Trump’s nominees rejected his claims that climate change is a hoax, but all cast doubt on the degree to which humans are contributing, and to the threats it poses. It’s a softer, cuddlier form of climate denial that doesn’t reject all scientific research – just the vast majority – and yields the same end result of obstructing climate solutions.

That is to be expected. A longer bushfire season and more and more severe bushfires/wildfires is just one consequence.

Add in rising sea levels (rising more and more rapidly as Antarctica gains less and less net mass) and you can see AGW is causing more and more destruction.

testifying before the Senate on the day the record temperatures were announced in a bid to become EPA administrator, Scott Pruitt claimed that we don’t know how much humans are contributing to global warming. . . .

This is simply wrong. We wouldn’t be setting a new temperature record every three years if not for global warming, and there’s no question that the warming is predominantly human-caused. The latest IPCC report stated with 95% confidence that humans are the main cause of global warming since 1950, and most likely responsible for 100% of that temperature rise.

Every study quantifying the various contributions to global warming has found humans are the dominant cause

Lees take note

That is crap, Ajax.

The Arctic is warming and the sea ice there is shrinking. This NH winter it was even shrinking in winter!

The globe is warming and it is because of the greenhouse gases we emit.

At least you haven’t totally fruitloop unlike Sir Booby de Louse but PLEASE give up on this denialism!

Even that graph shows the ice extent is shrinking!

It is melting. Good, at least you agree.

It has melted further than in the past and shows no sign of slowing.

Temperatures are increasing and they are increasing due to greenhouse gases, principally carbon dioxide and methane.

1°C of heating but the heating has gone on past the 1°C.

Sea level rises, due to the warming of the oceans and the massive ice loss from Greenland will accelerate once Antarctica starts losing ice too: it is gaining mass ATM but at slower and slower rates.

It has melted further than in the past and shows no sign of slowing.

Temperatures are increasing and they are increasing due to greenhouse gases, principally carbon dioxide and methane.

ea level rises, due to the warming of the oceans and the massive ice loss from Greenland

will accelerate once Antarctica starts losing ice too: it is gaining mass ATM but at slower and slower rates.

The warming from the CO2 sees more water vapor in the atmosphere, increasing the GHG effect.

Yes but no but the CO2 is increasing exponentially.

Burning fossil fuels increases the CO2 in the atmosphere.

The warming is melting the tundra and huge frozen deposits of methane are melting and methane is escaping into the atmosphere. Methane is also escaping where greedy idiots are fracking.

Global carbon emissions from fossil fuels have significantly increased since 1900. Since 1970, CO2 emissions have increased by about 90%, with emissions from fossil fuel combustion and industrial processes contributing about 78% of the total greenhouse gas emissions increase from 1970 to 2011. Agriculture, deforestation, and other land-use changes have been the second-largest contributors.[1]

Emissions of non-CO2 greenhouse gases have also increased significantly since 1900. To learn more about past and projected global emissions of non-CO2 gases, please see the EPA report, Global Anthropogenic Non-CO2 Greenhouse Gas Emissions: 1990-2020.

Hm of the extra CO2 is dissolved in the oceans?

Climate Change 2007: Working Group I: The Physical Science Basis
Contents99.7
9.7 Combining Evidence of Anthropogenic Climate Change <>
The widespread change detected in temperature observations of the surface (Sections 9.4.1, 9.4.2, 9.4.3), free atmosphere (Section 9.4.4) and ocean (Section 9.5.1), together with consistent evidence of change in other parts of the climate system (Section 9.5), strengthens the conclusion that greenhouse gas forcing is the dominant cause of warming during the past several decades. This combined evidence, which is summarised in Table 9.4, is substantially stronger than the evidence that is available from observed changes in global surface temperature alone (Figure 3.6).

The evidence from surface temperature observations is strong: The observed warming is highly significant relative to estimates of internal climate variability which, while obtained from models, are consistent with estimates obtained from both instrumental data and palaeoclimate reconstructions. It is extremely unlikely (<5%) that recent global warming is due to internal variability alone such as might arise from El Niño (Section 9.4.1). The widespread nature of the warming (Figures 3.9 and 9.6) reduces the possibility that the warming could have resulted from internal variability. No known mode of internal variability leads to such widespread, near universal warming as has been observed in the past few decades. Although modes of internal variability such as El Niño can lead to global average warming for limited periods of time, such warming is regionally variable, with some areas of cooling (Figures 3.27 and 3.28). In addition, palaeoclimatic evidence indicates that El Niño variability during the 20th century is not unusual relative to earlier periods (Section 9.3.3.2; Chapter 6). Palaeoclimatic evidence suggests that such a widespread warming has not been observed in the NH in at least the past 1.3 kyr (Osborn and Briffa, 2006), further strengthening the evidence that the recent warming is not due to natural internal variability. Moreover, the response to anthropogenic forcing is detectable on all continents individually except Antarctica, and in some sub-continental regions. Climate models only reproduce the observed 20th-century global mean surface warming when both anthropogenic and natural forcings are included (Figure 9.5). No model that has used natural forcing only has reproduced the observed global mean warming trend or the continental mean warming trends in all individual continents (except Antarctica) over the second half of the 20th century. Detection and attribution of external influences on 20th-century and palaeoclimatic reconstructions, from both natural and anthropogenic sources (Figure 9.4 and Table 9.4), further strengthens the conclusion that the observed changes are very unusual relative to internal climate variability.

The energy content change associated with the observed widespread warming of the atmosphere is small relative to the energy content change of the ocean, and also smaller than that associated with other components such as the cryosphere. In addition, the solid Earth also shows evidence for warming in boreholes (Huang et al., 2000; Beltrami et al., 2002; Pollack and Smerdon, 2004). It is theoretically feasible that the warming of the near surface could have occurred due to a reduction in the heat content of another component of the system. However, all parts of the cryosphere (glaciers, small ice caps, ice sheets and sea ice) have decreased in extent over the past half century, consistent with anthropogenic forcing (Section 9.5.5, Table 9.4), implying that the cryosphere consumed heat and thus indicating that it could not have provided heat for atmospheric warming. More importantly, the heat content of the ocean (the largest reservoir of heat in the climate system) also increased, much more substantially than that of the other components of the climate system (Figure 5.4; Hansen et al., 2005; Levitus et al., 2005). The warming of the upper ocean during the latter half of the 20th century was likely due to anthropogenic forcing (Barnett et al., 2005; Section 9.5.1.1; Table 9.4). While the statistical evidence in this research is very strong that the warming cannot be explained by ocean internal variability as estimated by two different climate models, uncertainty arises since there are discrepancies between estimates of ocean heat content variability from models and observations, although poor sampling of parts of the World Ocean may explain this discrepancy. However, the spatial pattern of ocean warming with depth is very consistent with heating of the ocean resulting from net positive radiative forcing, since the warming proceeds downwards from the upper layers of the ocean and there is deeper penetration of heat at middle to high latitudes and shallower penetration at low latitudes (Barnett et al., 2005; Hansen et al., 2005). This observed ocean warming pattern is inconsistent with a redistribution of heat between the surface and the deep ocean.

The observed warming is highly significant relative to estimates of internal climate variability which, while obtained from models, are consistent with estimates obtained from both instrumental data and palaeoclimate reconstructions.

What hiatus?

Instead, observations show the pattern expected from greenhouse gas effects: Earth’s surface and troposphere have warmed, but the stratosphere has cooled.

A medley of forces influences the glacial-interglacial cycle, including the amount of solar radiation reaching the Earth, which is controlled mainly by Earth’s orbital shape and axial tilt, the composition of gasses and aerosols and extent of cloud cover in the atmosphere, and the reflectivity of Earth’s surface (for example, the extent of ice and vegetation cover at high latitudes). A reduction in incoming summer solar radiation would be the primary trigger for glaciation, but atmospheric CO2 concentrations—the primary driver of climate change—must be relatively low, too.

How low is “relatively low”? Tzedakis and colleagues compared ice and marine records from previous interglacials and found that, given the current small decrease in summer solar radiation, CO2 concentrations would have to fall to around 240 ppm for the next glacial period to take place.

A medley of forces influences the glacial-interglacial cycle, including the amount of solar radiation reaching the Earth, which is controlled mainly by Earth’s orbital shape and axial tilt, the composition of gasses and aerosols and extent of cloud cover in the atmosphere, and the reflectivity of Earth’s surface (for example, the extent of ice and vegetation cover at high latitudes). A reduction in incoming summer solar radiation would be the primary trigger for glaciation, but atmospheric CO2 concentrations—the primary driver of climate change—must be relatively low, too.

How low is “relatively low”? Tzedakis and colleagues compared ice and marine records from previous interglacials and found that, given the current small decrease in summer solar radiation, CO2 concentrations would have to fall to around 240 ppm for the next glacial period to take place.

Since the Industrial Revolution, however, atmospheric CO2 levels have been trending higher and higher. They reached an estimated 395.09 ppm globally in January 2013. So, if business proceeds as usual, with carbon release being driven primarily by fossil-fuel burning, we likely have a long thaw ahead of us. Modeling work by geophysical scientist David Archer has shown, for instance, that burning all potential fossil carbon on Earth—5,000 gigatons—would be enough to delay the next glaciation by 500,000 years.

The real question, then, might have more to do with the next “age,” generally, that we face, rather than the next ice age. Some scientists consider the current era to be defined by human influence, what Dutch chemist Paul J. Crutzen dubbed the Anthropocene Epoch, which has its origins in the Industrial Age.

"Of course there is a climate change connection, because the oceans and sea surface temperatures are higher now because of climate change, and in general that adds 5 to 10 percent to the precipitation," Kevin Trenberth, a climate scientist with the National Center for Atmospheric Research, said. "There have been many so-called 500-year floods along the Mississippi about every five to 10 years since 1993."   

Sea level rise threatening historic sites, even telephone poles in Tasmania:

https://www.nytimes.com/2017/04/26/climate/tasmania-global-warming-shoreline-ero...

Jovial Monk wrote on May 8^th, 2017 at 7:36pm:

They found that although humans were still invading and clearing primary forest, they were disturbing an even greater area of secondary forest, plantation and woodland.

Altogether, this clearing of regenerated forest and plantation accounted for 53% of gross tree cover loss, the researchers say, and up to 35% of the above-ground carbon released to the atmosphere.

Fire cleared about 9% of the primary forest, with the damage peaking during the droughts of 2005, 2007 and 2010. – Climate News Network


http://climatenewsnetwork.net/amazon-rainforest-double-jeopardy/

Wildfires becoming more frequent and more unmanageable with AGW and the wildfires in turn add to the CO2 in the air and so increase AGW.

The brown dog tick is one nonnative species that appears to be well-established in the state, Beckmen said.

Soaring temperatures in the Arctic have triggered a huge seasonal surge in carbon dioxide emissions from thawing permafrost and may be tipping the region toward becoming a net source of heat-trapping greenhouse gases, a new study shows.

Even into early winter, when the ground would have been frozen 40 years ago, microbes in the permafrost are continuing to release heat-trapping greenhouse gases. Carbon dioxide emissions are now outpacing the uptake of CO2 during the spring and summer growing season, the study suggests.

The study's authors, researchers from Harvard, the National Oceanic and Atmospheric Administration and other institutions, measured atmospheric CO2 in Alaska and found that emissions from October through December have increased by 73 percent since 1975 and that the increase correlates with rising summer temperatures.

The findings suggest that global climate models are underestimating how much greenhouse gas pollution will be unleashed as the Arctic continues to warm at twice the global average rate, said lead author Roisin Commane of the Harvard School of Engineering and Applied Sciences.

The Arctic climate feedback loop is stronger than scientists estimated, Commane said. Global warming thaws permafrost, releasing more greenhouse gases, which causes yet more warming.

"It's consistent with the effects of a warming Arctic," she said. "We're seeing very large emissions in the early winter. When I looked at the models used by the IPCC [Intergovernmental Panel on Climate Change], none of them looked at the fall respiration. They didn't realize how important that is."

Year-round measurements of CO2 emissions from permafrost have been sparse up to now, and some widely cited studies suggested that rising emissions from thawing permafrost were offset by increased uptake from Arctic forests. But according to the new research, those calculations need to be revised.

Plants inhale massive amounts of CO2 in the spring and summer growing season. Then, in the fall and winter, the plants die and decompose, releasing CO2 and methane. That cycle gives the global CO2 level its signature zigzag pattern. In the Arctic, emissions during the decomposition phase are outpacing CO2 uptake during the growing season, according to the study.

A recent report from the Arctic Council found that near-surface permafrost has warmed by more than 0.5 degrees Celsius in the last 10 years, and that summer thawing has deepened at most monitoring locations.

Permafrost currently covers about 5.8 million square miles. A study published in April that looked at the impact rising temperatures would have on the permafrost and found that as much as 2.5 million square miles of it could thaw if global temperatures reached 2 degree Celsius above pre-industrial temperatures. Another study, published in February, found that 52,000 square miles of Canadian permafrost was already in rapid decline.

The new Alaska study is another step toward understanding how sensitive the Arctic is to increasing temperatures. The Arctic permafrost seals in a massive store of carbon, roughly double the amount of CO2 currently in Earth's atmosphere. If the trends being seen in Alaska are similar in Siberia and Canada, it would have a big effect on the global carbon budget, said co-author Pieter Tans, with NOAA's Earth Systems Research laboratory.

"The important thing in this paper is, it shows where the models fail. They don't capture these cold-season emissions very well," said Donatella Zona of San Diego State University in California, who was not involved in the new research.

"We need to make the case that this is important and get the resources to expand the studies in other areas, especially Siberia," she said.

at the end of the world’s hottest ever recorded year l

Lees: blah blah blah oh Mummy, don’t let global temperatures increase, I am frightened.

methane is like 35 times more powerful than CO2 but not as long lasting.

from the astonishing highs of 2016,

On land? Quite a few I suppose.