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"Recasting the Climate Debate: Feedbacks That Set the Time Scale for Irreversible Change Dissected with New Laser and Optical Technology" by James Anderson
Special issue in 'Philosophical Transactions of the Royal Society A' on "Arctic sea ice reduction: the evidence, models and impacts"
Recent studies e.g. The geographical distribution of fossil fuels unused when limiting global warming to 2 °C make clear that: "We show that development of resources in the Arctic and any increase in unconventional oil production are incommensurate with efforts to limit average global warming to 2 °C." Obama knows this, and he's said himself that: "We’re not going to be able to burn it all. Over the course of the next several decades, we’re going to have to build a ramp from how we currently use energy to where we need to use energy. And we’re not going to suddenly turn off a switch and suddenly we’re no longer using fossil fuels, but we have to use this time wisely, so that you have a tapering off of fossil fuels replaced by clean energy sources that are not releasing carbon … But I very much believe in keeping that 2 [degree] Celsius target as a goal." But by allowing Shell to go and drilling the Arctic he's undermining he own professed goals of reaching the 2°C target and showing how hollow his words are. This ability to do one thing and say another with regards to climate change is something that psychologists have begun to call "stealth denial"
Toggle Commented May 14, 2015 on Bill McKibben nails it at Arctic Sea Ice
The surprising reason why Arctic warming could be worse than previously thought
Toggle Commented Apr 21, 2015 on CryoSat-2 sea ice thickness maps at Arctic Sea Ice
Hi Neven, Sorry I missed you. I'm glad you had a good time. It is a bit overwhelming isn't it! Is this the BBC scoop you were mentioning? :-) '3D Cryosat' tracks Arctic winter sea ice
Hey Neven, I'm going to be there too! I'm intending to sit in on the Polar Climate Predictability and Prediction session as well. Who knows maybe we'll bump into each other. If you can make it you would probably like this session on Wednesday afternoon: CL2.6 Arctic climate change: governing mechanisms and global implications
Arctic Warming and Increased Weather Extremes: The National Research Council Speaks "A new report from the National Research Council (NRC) details the findings of recent Arctic research: Arctic sea ice in all seasons is declining and the rate of loss is increasing. Multiple lines of study show this is impacting weather outside of the Arctic. Increased energy (heat) in the Arctic is slowing the progress of the jet stream around globe, allowing weather systems to linger, increasing the risk of severe weather happening more often in any one place. Increased warmth also means increased moisture in the Arctic - which increases the amount of snow, which in turn causes the jet stream to concentrate winter weather in North America and Eurasia."
Toggle Commented Jul 17, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
Tracking the breakup of Arctic summer sea ice As sea ice begins to melt back toward its late September minimum, it is being watched as never before. Scientists have put sensors on and under ice in the Beaufort Sea for an unprecedented campaign to monitor the summer melt. The international effort hopes to figure out the physics of the ice edge in order to better understand and predict open water in Arctic seas.
Toggle Commented Jul 16, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
Hey CB, have you got a link to a ref for this? "The fires in Canada. are burning 6 feet into the the ground. We have seen this before." I'd really like to see it, thanks. :-)
Toggle Commented Jul 16, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
Arctic summer sea ice is disappearing fast, but can we rescue it? Diminishing Arctic sea ice is perhaps the most iconic consequence of climate change. And there's a good chance we'll lose it in summer before too long if emissions stay high, according to a new paper. But its demise is not a foregone conclusion - with a swift peak and decline in greenhouse gases we could still reverse that trend, the scientists say.,-but-can-we-rescue-it?utm_content=buffer76a44&utm_medium=social&
Toggle Commented Jul 14, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
I find it unlikely that the Canadians would be planting trees as part of a carbon sequestration scheme. Most coupled vegetation climate models I've seen show that the the northward migration of the tree line will decrease the planets albedo and that this will offset any gain from carbon sequestration and actually act as an additional warming feedback.
Toggle Commented Jun 11, 2014 on The day the ice cap died at Arctic Sea Ice
Future increases in Arctic precipitation linked to local evaporation and sea-ice retreat Precipitation changes projected for the end of the twenty-first century show an increase of more than 50 per cent in the Arctic regions. This marked increase, which is among the highest globally, has previously been attributed primarily to enhanced poleward moisture transport from lower latitudes. Here we use state-of-the-art global climate models to show that the projected increases in Arctic precipitation over the twenty-first century, which peak in late autumn and winter, are instead due mainly to strongly intensified local surface evaporation (maximum in winter), and only to a lesser degree due to enhanced moisture inflow from lower latitudes (maximum in late summer and autumn). Moreover, we show that the enhanced surface evaporation results mainly from retreating winter sea ice, signalling an amplified Arctic hydrological cycle. This demonstrates that increases in Arctic precipitation are firmly linked to Arctic warming and sea-ice decline. As a result, the Arctic mean precipitation sensitivity (4.5 per cent increase per degree of temperature warming) is much larger than the global value (1.6 to 1.9 per cent per kelvin). The associated seasonally varying increase in Arctic precipitation is likely to increase river discharge and snowfall over ice sheets (thereby affecting global sea level), and could even affect global climate through freshening of the Arctic Ocean and subsequent modulations of the Atlantic meridional overturning circulation
Toggle Commented May 26, 2014 on Greenland 2013 in review at Arctic Sea Ice
Sentinel satellite spies ice cap speed-up
Toggle Commented May 8, 2014 on PIOMAS May 2014 at Arctic Sea Ice
Nature Paper: Half Of Arctic Warming Due To Pacific
Toggle Commented May 8, 2014 on PIOMAS May 2014 at Arctic Sea Ice
Swell and sea in the emerging Arctic Ocean Ocean surface waves (sea and swell) are generated by winds blowing over a distance (fetch) for a duration of time. In the Arctic Ocean, fetch varies seasonally from essentially zero in winter to hundreds of kilometers in recent summers. Using in situ observations of waves in the central Beaufort Sea, combined with a numerical wave model and satellite sea ice observations, we show that wave energy scales with fetch throughout the seasonal ice cycle. Furthermore, we show that the increased open water of 2012 allowed waves to develop beyond pure wind seas and evolve into swells. The swells remain tied to the available fetch, however, because fetch is a proxy for the basin size in which the wave evolution occurs. Thus, both sea and swell depend on the open water fetch in the Arctic, because the swell is regionally driven. This suggests that further reductions in seasonal ice cover in the future will result in larger waves, which in turn provide a mechanism to break up sea ice and accelerate ice retreat.
Toggle Commented Apr 28, 2014 on Miscellanea at Arctic Sea Ice
Jai and Hans, This video is pertinent to your discussion on the rebound effect... Duncan Clark- The Burning Question
Toggle Commented Apr 23, 2014 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 Apr 23, 2014 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.