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Jai and Hans, This video is pertinent to your discussion on the rebound effect... Duncan Clark- The Burning Question
Toggle Commented yesterday on Miscellanea at Arctic Sea Ice
September Arctic sea-ice minimum predicted by spring melt-pond fraction The area of Arctic September sea ice has diminished from about 7 million km2 in the 1990s to less than 5 million km2 in five of the past seven years, with a record minimum of 3.6 million km2 in 2012). The strength of this decrease is greater than expected by the scientific community, the reasons for this are not fully understood, and its simulation is an on-going challenge for existing climate models. With growing Arctic marine activity there is an urgent demand for forecasting Arctic summer sea ice4. Previous attempts at seasonal forecasts of ice extent were of limited skill. However, here we show that the Arctic sea-ice minimum can be accurately forecasted from melt-pond area in spring. We find a strong correlation between the spring pond fraction and September sea-ice extent. This is explained by a positive feedback mechanism: more ponds reduce the albedo; a lower albedo causes more melting; more melting increases pond fraction. Our results help explain the acceleration of Arctic sea-ice decrease during the past decade. The inclusion of our new melt-pond model promises to improve the skill of future forecast and climate models in Arctic regions and beyond. [I can't log on again, so I'm adding this directly: Thanks a lot for this, Boa05att! It confirms what I've been suspecting for a while. Neven]
Toggle Commented yesterday on Miscellanea at Arctic Sea Ice
High predictability of the winter Euro–Atlantic climate from cryospheric variability Seasonal prediction skill for surface winter climate in the Euro–Atlantic sector has been limited so far1, 2, 3. In particular, the predictability of the winter North Atlantic Oscillation, the mode that largely dominates regional atmospheric and climate variability, remains a hurdle for present dynamical prediction systems4, 5. Statistical forecasts have also been largely elusive6, 7, 8, but October Eurasian snow cover has been shown to be a robust source of regional predictability9, 10. Here we use maximum covariance analysis to show that Arctic sea-ice variability represents another good predictor of the winter Euro–Atlantic climate at lead times of as much as three months. Cross-validated hindcasts of the winter North Atlantic Oscillation index using September sea-ice anomalies yield a correlation skill of 0.59 for the period 1979/1980–2012/2013, suggesting that 35% of its variance could be predicted three months in advance. This skill can be further enhanced, at the expense of a shorter lead time, by using October Eurasian snow cover as an additional predictor. Skilful predictions of winter European surface air temperature and precipitation are also obtained with September sea ice as the only predictor. We conclude that it is important to incorporate Arctic sea-ice variability in seasonal prediction systems.
Toggle Commented Mar 23, 2014 on PIOMAS March 2014 at Arctic Sea Ice
Study coauthor Shfaqat A. Khan of the Technical University of Denmark told Mashable he was surprised to find such significant ice loss in northeast Greenland, considering how cold and dry that region is. Previous studies of sea level rise had not included the prospect of melting there, he said. “Nature is changing faster than expected and seems to respond much stronger than expected to small fluctuations,” he said. “This also means that predictions of future sea level rise need to be revised.” More worrisome, Khan and his coauthors said, is that these glaciers help hold back a nearly 370-mile long ice stream that extends deep into Greenland’s interior. This ice stream accounts for about 16% of the total ice sheet, and if it destabilizes, it could have severe consequences for low-lying coastal cities worldwide. While the northwest and southeast section of Greenland have dramatically lost ice, researchers believed the northeast section was holding its ground. From 1978-2003, that was true, but ice loss has accelerated rapidly since mid-2003... By 2012, the snout of the Zachariae glacier had receded more than 12.4 miles from its 2003 position. In comparison, the Jakobshavn glacier, located in southeast Greenland and long considered one of the fastest-changing glaciers on the island, has retreated 21.7 miles over the past 150 years.
Toggle Commented Mar 16, 2014 on PIOMAS March 2014 at Arctic Sea Ice
Changes in Arctic melt season and implications for sea ice loss Abstract The Arctic-wide melt season has lengthened at a rate of 5 days decade−1 from 1979 to 2013, dominated by later autumn freezeup within the Kara, Laptev, East Siberian, Chukchi, and Beaufort seas between 6 and 11 days decade−1. While melt onset trends are generally smaller, the timing of melt onset has a large influence on the total amount of solar energy absorbed during summer. The additional heat stored in the upper ocean of approximately 752 MJ m−2 during the last decade increases sea surface temperatures by 0.5 to 1.5 °C and largely explains the observed delays in autumn freezeup within the Arctic Ocean's adjacent seas. Cumulative anomalies in total absorbed solar radiation from May through September for the most recent pentad locally exceed 300–400 MJ m−2 in the Beaufort, Chukchi, and East Siberian seas. This extra solar energy is equivalent to melting 0.97 to 1.3 m of ice during the summer.
Toggle Commented Mar 11, 2014 on PIOMAS March 2014 at Arctic Sea Ice
Warm rivers play role in Arctic sea ice melt The heat from warm river waters draining into the Arctic Ocean is contributing to the melting of Arctic sea ice each summer, a new NASA study finds.
Toggle Commented Mar 6, 2014 on Another ice extreme at Arctic Sea Ice
Warming from Arctic Sea Ice Melting More Dramatic than Thought Scientists based at the University of California, San Diego have analyzed Arctic satellite data from 1979 to 2011, and have found that average Arctic albedo levels have decreased from 52 percent to 48 percent since 1979 — twice as much as previous studies based on models have suggested, the team reports today (Feb. 17) in the journal Proceedings of the National Academy of Sciences. The amount of heat generated by this decrease in albedo is equivalent to roughly 25 percent of the average global warming currently occurring due to increased carbon dioxide levels, the team reports. "Although more work is needed, a possible implication of this is that the amplifying feedback of Arctic sea ice retreat on global warming is larger than has been previously expected," study co-author Ian Eisenman told Live Science.
Climate model projections show an Arctic-wide end-of-century temperature increase of +13° Celsius [23°F!] in late fall and +5° Celsius [9°F] in late spring if the status quo continues and current emissions increase without a mitigation scenario.
Arctic Warmth in Early February Sees 200,000 Square Kilometers of Sea Ice Lost, Greenland Melt as New Study Finds Massive Glacier Triples its Seaward Velocity
Toggle Commented Feb 5, 2014 on 2014 Nares Strait ice bridges at Arctic Sea Ice
Decline of Arctic sea ice: Evaluation and weighting of CMIP5 projections Trends of Arctic September sea ice area (SSIA) are investigated through analysis of Coupled Model Intercomparison Project phase 5 (CMIP5) data. The large range across models is reduced by weighting them according to how they match nine observed parameters. Calibration of this refined SSIA projection to observations of different 5 year averages suggests that nearly ice-free conditions, where ice area is less than 1 × 106 km2, will likely occur between 2039 and 2045, not accounting for internal variability. When adding internal variability, we demonstrate that ice-free conditions could occur as early as 2032. The 2013 rebound in ice extent has little effect on these projections. We also identify that our refined projection displays a change in the variability of SSIA, indicating a possible change in regime.
Arctic amplification dominated by temperature feedbacks in contemporary climate models Climate change is amplified in the Arctic region. Arctic amplification has been found in past warm1 and glacial2 periods, as well as in historical observations3, 4 and climate model experiments5, 6. Feedback effects associated with temperature, water vapour and clouds have been suggested to contribute to amplified warming in the Arctic, but the surface albedo feedback—the increase in surface absorption of solar radiation when snow and ice retreat—is often cited as the main contributor7, 8, 9, 10. However, Arctic amplification is also found in models without changes in snow and ice cover11, 12. Here we analyse climate model simulations from the Coupled Model Intercomparison Project Phase 5 archive to quantify the contributions of the various feedbacks. We find that in the simulations, the largest contribution to Arctic amplification comes from a temperature feedbacks: as the surface warms, more energy is radiated back to space in low latitudes, compared with the Arctic. This effect can be attributed to both the different vertical structure of the warming in high and low latitudes, and a smaller increase in emitted blackbody radiation per unit warming at colder temperatures. We find that the surface albedo feedback is the second main contributor to Arctic amplification and that other contributions are substantially smaller or even opposeArctic amplification.
Colorado Bob, Looks like we might not have too long to wait: El Nino conditions look set to develop over the next year.
Toggle Commented Jan 11, 2014 on Looking for winter weirdness 2014 at Arctic Sea Ice
Scotland just had it's wettest month ever in December...
"Data from Europe's Cryosat spacecraft suggests there were almost 9,000 cu km of ice at the end of this year's melt season. This is close to 50% more than in the corresponding period in 2012..... "This is why we're really quite surprised by what we've seen in 2013. "We didn't expect the greater ice extent left at the end of the summer melt to be reflected in the volume. "But it has been. And the reason is related to the amount of multi-year ice in the Arctic." Dr Don Perovich is a sea-ice expert at Dartmouth College, US. He said Cryosat's data tallied with observations made by other spacecraft. "In previous summers, some of the [multi-year ice] migrated over to the Alaska and Siberia areas where it melted. But this past summer, it stayed in place because of a change in wind patterns. And so there'll likely be more multi-year ice next year than there was this year," "
Toggle Commented Dec 16, 2013 on Arctic Report Card 2013 at Arctic Sea Ice
Hi all, Carbonbrief have an interesting blog today about when the arctic is expected to be ice free:
Toggle Commented Dec 12, 2013 on PIOMAS December 2013 at Arctic Sea Ice
Sorry John but global energy use is growing exponentially: As are CO2 emissions:
Toggle Commented Nov 29, 2013 on In memoriam: Albert A. Bartlett at Arctic Sea Ice
Scientists have revealed plans to examine temperature changes in the Arctic Ocean after a long-term study found the Greenland Sea is warming 10 times faster than the global ocean
Thawing Permafrost: The Speed of Coastal Erosion in Eastern Siberia Has Nearly Doubled
Prof. Jenifer Francis "I think the case has strengthened. I’ve done a bit more research into the linkage with the very warm Arctic following the record 2012 ice loss, and it appears that the heat released from the Arctic Ocean in the fall created a substantial positive anomaly in the upper-level atmospheric heights in the North Atlantic. This likely contributed to the strong ridge and blocking high that existed when Sandy came along, and that ultimately not only steered Sandy westward but also set up the strong pressure gradient between Sandy and the blocking high that caused the enormous expanse of tropical-storm-force winds from Delaware to Nova Scotia."
Influence of Arctic sea ice on European summer precipitation. The results suggest a causal link between observed sea ice anomalies, large-scale atmospheric circulation and increased summer rainfall over northern Europe. Thus, diminished Arctic sea ice may have been a contributing driver of recent wet summers.
Eurasian Arctic climate over the past millennium as recorded in the Akademii Nauk ice core (Severnaya Zemlya)
"The heat is on, at least in the Arctic. Average summer temperatures in the Eastern Canadian Arctic during the last 100 years are higher now than during any century in the past 44,000 years and perhaps as long ago as 120,000 years, says a new University of Colorado Boulder study."
@Coulouir It's from this video called 'The New Arctic'||
CLIMATE REPORT: “Is the Unthinkable Now Possible?” With Chris Hope and Peter Wadhams Tom Bowman talks with economist Chris Hope and oceanographer Peter Wadhams about how rapid changes in the Arctic could have devastating impacts on the rest of the world.
Toggle Commented Aug 6, 2013 on Arctic time bombs at Arctic Sea Ice
Methane hydrates: a volatile time bomb in the Arctic Byu Prof. Carlos Durante and Dr. Antonio Delgado Huertas
Toggle Commented Jul 29, 2013 on Arctic time bombs at Arctic Sea Ice