Tampilkan postingan dengan label decline. Tampilkan semua postingan
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Selasa, 03 Juni 2014

Arctic sea ice in steep decline

Arctic sea ice area is in steep decline. The yellow line on the image below shows the sea ice area for 2014 up to June 1st, showing an almost vertical fall over the past few days.

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The Naval Research Laboratory image below compares the May 14, 2014, sea ice concentration (left) with the sea ice concentration forecast for June 10, 2014 (run on June 2, 2014, on the right).

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The NOAA image below shows sea surface temperature anomalies on June 3rd, 2014.


The NOAA image shows the huge sea surface temperature anomalies all over the Northern Hemisphere on June 3rd, 2014. Large areas with sea surface temperature anomalies up to 8 degrees Celsius and higher show up in and around the Arctic Ocean

[ click on image to enlarge ]
The image below shows sea surface temperature anomalies up to 1.5 degrees Celsius over the May-June 2014 period, with global average anomalies that hover just above 1 degree Celsius.



Above sea surface anomalies are very high, much higher than historic annual temperature anomalies over land and oceans, as shown on the image below for comparison.


In conclusion, the situation spells bad news for the sea ice, also given the prospect of an El NiƱo event projected to occur later this year. As discussed in earlier posts, the sea ice is already very thin, and as this image shows, ocean heat is melting the sea ice from beneath, while the sun is warming up the ice from above. At this time of year, insolation in the Arctic is at its highest, as Earth reaches its maximum axial tilt toward the sun of 23° 26'. In fact, insolation during the months June and July is higher in the Arctic than anywhere else on Earth, as discussed at this earlier post.

Feedbacks further accelerate warming in the Arctic, as described in the earlier post Feedbacks in the Arctic. Temperature rises of the water close to the seafloor of the Arctic Ocean is very dangerous, as heat penetrating sediments there could cause hydrate destabilization, resulting in huge amounts of methane entering the atmosphere over the Arctic Ocean.





Kamis, 26 Desember 2013

Sea Ice in decline between Svalbard and Greenland

[ click on image to enlarge ]
Above image shows that Earth's highest atmospheric methane concentrations are recorded over the Arctic Ocean. The insets show lower methane concentrations over various continents, North and South America (top left), Europe (mid right), Australia bottom left) and Antarctica (bottom right).

The top right inset shows sea ice thickness, illustrating that methane is escaping from the sea floor of the Arctic Ocean and is transported by currents to the thinner edges of the sea ice, where it is entering the atmosphere.

As discussed in a recent post, methane can be bubbling up in the Arctic Ocean with a force strong enough to prevent sea ice from forming in the area. This feedback is depicted in the Diagram of Doom further below as feedback #13.


Around this time of year, Arctic sea ice is typically growing rapidly, both in extent and thickness.

However, the above image shows that in the area marked by the white circle, between Svalbard and Greenland, the sea ice is actually in decline.

[ click on image to enlarge ]
This decline is caused by methane that is entering the atmosphere in the area as warmer water continues to be transported by the Gulf Stream into the Arctic Ocean, as discussed in previous posts such as this one, and as also illustrated by the image on the right.

Warmer than average waters have been entering the Arctic Ocean along the Gulf Stream since July 2013, when changes to the Jet Stream contributed to waters off the North American coast reaching record warmest temperatures, as depicted in the Diagram of Doom below as feedback #11.

In summary, the above images show that methane makes it hard for ice to form, while the warm water of the West Spitzbergen Current is pushing the ice away, breaking up even the thickest ice to the north of Greenland.

Surface temperatures in the area have been extremely high recently. This part of the Arctic Ocean was hit by an 18+°C anomaly during the week from December 16 to December 22, 2013, as illustrated by the image below.


On some days that week, anomalies of 20+°C were recorded over an even larger part of the Arctic Ocean, as described in a previous post. These anomalies show how a number of feedbacks can interact and contribute to huge warming peaks in the Arctic Ocean, such as methane releases (feedbacks #2 and #13 in the diagram below) and changes to the Jet Stream (feedbacks #10 and #11 in the diagram below).

This spells bad news for the sea ice. Some people may have hoped that the thicker sea ice north of Greenland would take decades to disappear. However, as depicted in the Diagram of Doom below, feedbacks can hugely accelerate sea ice decline. As sea ice declines further, more open water make it more likely that stronger storms and cyclones will appear that can rip the sea ice apart and move the pieces into the Atlantic Ocean in a matter of days.

The image below, by Jim Pettit, illustrates the ongoing decline of the sea ice.


Thirteen feedbacks that can accelerate warming in the Arctic are depicted in the diagram below.


Specific feedbacks are described in the following posts:
- Diagram of Doom
- Further feedbacks of sea ice decline in the Arctic
- Causes of high methane levels over Arctic Ocean
- Methane Release caused by Earthquakes
- How Do We Act in the Face of Climate Chaos?
- The astounding global warming impact on our oceans . . .
- Methane emerges from warmer areas
Feedbacks are pictured in a more general way in the image below.


Above image shows how the accumulation of the many feedbacks and their interaction leads to ever stronger albedo changes, while the resulting accelerated warming in the Arctic causes increasing quantities of methane to be released from the seafloor of the Arctic Ocean, in turn leading to runaway global warming, as also pictured in the image below.

[ click on image to enlarge ]
As above image shows, a polynomial trendline already points at global temperature anomalies of 5°C by 2060. Even worse, a polynomial trendline for the Arctic shows temperature anomalies of 4°C by 2020, 7°C by 2030 and 11°C by 2040, threatening to cause major feedbacks to kick in, including albedo changes and methane releases that will trigger runaway global warming that looks set to eventually catch up with accelerated warming in the Arctic and result in global temperature anomalies of 20°C+ by 2050.

To reduce these risks, comprehensive and effective action is needed, such as described at the Climate Plan blog.

Selasa, 13 Agustus 2013

Arctic Death Spiral - Evolution to July 2013

Image by Andy Lee Robinson, from http://haveland.com/share/arctic-death-spiral.png
The video below is a visualization of the Arctic Death Spiral showing the evolution of the volume of sea-ice over time from 1979 to July 2013.

The rate of ice loss in the Arctic is staggering. Since 1979, the volume of Summer Arctic sea ice has declined by more than 80% and is accelerating faster than scientists believed it would, or even could melt.


Pitch of the notes are proportional to the average sea-ice volume for each month. Spectral filters are derived from the average sea-ice volume for each year. Produced using Perl and PovRay, Midi perl and Reason and Virtualdub on a cluster of Linux servers.


Above image is another way to visualize the data. It is a screenshot from the video below, by Andy Lee Robinson, illustrating the dramatic decline since 1979 until July 2013.

Andy Lee Robinson
The soundtrack "Arctic Requiem" also by Andy Lee Robinson, is available for free download: http://haveland.com/share/Arctic-Requiem.mp3

Sea Ice Volume is calculated using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS, Zhang and Rothrock, 2003) developed at APL/PSC.

Source data is available from:
http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/


Senin, 28 Januari 2013

Further feedbacks of sea ice decline in the Arctic

Arctic sea ice currently acts as a shield, preventing methane from entering the atmosphere, concludes a study by researchers from two Chinese scientific institutes

The researchers observed more methane in the water under the sea ice than the methane in the air above the sea ice. They conclude that the sea ice collects and holds the methane in places close enough to the surface for the methane to be consumed through photochemical and biochemical oxidation. In other words, sufficient light can reach the spots where methane assembles underneath the ice for the methane to get consumed by biological processes.

Change of CH4 mixing ratio over time in the chamber on under-ice water. In CBS1–CBS3, CH4mixing ratios fluctuated in the first 1–2 h and then increased, suggesting significant emission of CH4. No increasing trend in CBS4 might due to the relatively short sampling time (only 2 h) during which CH4mixing ratio had not started increasing.
A study by the Alfred Wegener Institute led by Marcel Nicolaus has found that where melt water collects on the ice, far more sunlight and therefore energy is able to penetrate the ice than is the case for white ice without ponds. The consequence is that the ice is absorbing more solar heat, is melting faster, and more light is available for the ecosystems in and below the ice.

As the sea ice has decreased in volume over the years, there now is mainly thin, first-year ice, extensively covered with melt ponds in the summer months, where once metre-thick, multi-year ice used to be. Additionally, the melt ponds have a different color, causing further albedo change. “Their colour depends entirely on how thick the remaining ice below the melt pond is and the extent to which the dark ocean beneath can be seen through this ice. Melt ponds on thicker ice tend to be turquoise and those on thin ice dark blue to black”, explains Dr. Marcel Nicolaus, sea ice physicist and melt pond expert at the Alfred Wegener Institute.

Graphic depiction of the amount of sunlight above and underneath the Arctic sea ice. The growing coverage of the ice by darker meltponds increases the share of sunlight, which passes the sea ice. That means, the space underneath the ice becomes brighter and warmer. Furthermore less sunlight is refleced back into the atmosphere. Graphic: Marcel Nicolaus/Yves Nowak, Alfred Wegener Institute
Marcel Nicolaus explains: “The young thin ice with the many melt ponds does not just permit three times as much light to pass through than older ice. It also absorbs 50 per cent more solar radiation. This conversely means that this thin ice covered by melt ponds reflects considerably fewer sun rays than the thick ice. Its reflection rate is just 37 per cent. The young ice also absorbs more solar energy, which causes more melt. The ice melts from inside out to a certain extent,” says Marcel Nicolaus.

Marcel Nicolaus adds: “The greater the share of one-year ice in the sea ice cover, the more melt ponds will form and the larger they will be. This will also lead to a decreasing surface albedo (reflectivity) and transmission into the ice and ocean will increase. The sea ice will become more porous, more sunlight will penetrate the ice floes, and more heat will be absorbed by the ice. This is a development which will further accelerate the melting of the entire sea ice area.”

These studies contain an important warning. As the sea ice gets thinner, more sunlight and therefore energy is penetrating the ice and getting absorbed. Initially, this will increase the growth of bacteria that break down methane collecting underneath the sea ice. Eventually however, as sea ice retreats further, there will be less opportunities for methane to be held underneath the sea ice and broken down by bacteria. Instead, more methane will then enter the atmosphere unaffected.

These are further feedbacks of sea ice retreat, in addition to the many feedbacks described in the Diagram of Doom. Sea ice is declining at exponential pace. The big danger is that a huge rise of temperatures in the Arctic will destabilize huge amounts of methane currently held in the seabed. Comprehensive and effective action is needed now to avoid catastrophe.

References

- Sea ice in the Arctic Ocean: Role of shielding and consumption of methane - Xin He et al.
http://dx.doi.org/10.1016/j.atmosenv.2012.10.029

Melt ponds cause the Artic sea ice to melt more rapidly - Alfred Wegener Institute news release

- Changes in Arctic sea ice result in increasing light transmittance and absorption - Marcel Nicolaus et al. DOI: 10.1029/2012GL053738

Jumat, 25 Januari 2013

Arctic sea ice volume decline animation

Screenshot showing the exponential decline of minimum Arctic sea ice volume at the bottom end of the annual graphs
To see a 3-D animation of the decline of Arctic sea ice volume over the years, click on the play button below.


This excellent animation was produced by Andy Lee Robinson using PIOMAS data.

The image below was part of last year's post Polar jet stream appears hugely deformed. The image highlights that Arctic sea ice minimum volume in 2012 was only 19.3% what it was in 1979. The background image, prepared by Wipneus, shows an exponential trend projecting a 2013 minimum of only 2000 cubic km of sea ice, with a margin of error that allows Arctic sea ice to disappear altogether this year, i.e. in less than six  months time. 


Related

- Polar jet stream appears hugely deformed

Jumat, 26 Oktober 2012

Hurricane Sandy moving inland

Hurricane Sandy is moving inland and its impact is forecast to be felt as far away as in Toronto and Ottawa.

Coastal Watches/Warnings and 5-Day Track Forecast Cone
Hurricane SANDY Advisory #019       11:00 PM EDT Fri October 26, 2012
from:  National Hurricane Center (check link for updates!)



Paul Beckwith,
B.Eng, M.Sc. (Physics),
Ph.D. student (Climatology)
and Part-time Professor,
University of Ottawa
 
This prompted Paul Beckwith to make the following comments:

All storms veer to the right in the northern hemisphere due to the spinning of the earth (1 revolution per day). Except when there is a tilted high pressure region northward and it has to go left and there is a massive low pressure region left that sucks it there as well. 

Why the high pressure ridge and massive low pressure? Because the jet stream is wavier and slower, a situation that is happening more and more often, because of massive sea ice decline this summer. Which is due to Arctic amplification feedbacks. Which in turn is due to rising greenhouse gases. Which is due to humans.

The situation is further illustrated by the image below, from ClimateCentral.

An atmospheric "blocking pattern" will push Sandy north, then northwestward, into the Mid-Atlantic or Northeast. Click to enlarge the image.     Credit: Remik Ziemlinski, Climate Central.
In an earlier post, Paul Beckwith described that a very rare cyclone churned up the entire Arctic region for over a week in early August 2012, destroying 20% of the ice area by breaking it into tiny chunks, melting it, or spitting it into the Atlantic. Cold fresh surface water from melted sea ice mixed with warm salty water from a 500 metre depth! Totally unexpected. A few more cyclones with similar intensity could have eliminated the entire remaining ice cover. Thankfully that didn't happen. What did happen was Hurricane Leslie tracked northward and passed over Iceland as a large storm. It barely missed the Arctic this time. Had the storm tracked 500 to 600 kilometres westward, Leslie would have churned up the west coast of Greenland and penetrated directly into the Arctic Ocean basin.

We dodged a bullet, at least this year. This luck will surely run out. What can we do about this? How about getting our politicians to listen to climatologists, for starters.

Below, rainfall forecast from the Hydrometereological Prediction Center of the National Weather Service - check the link for updates! 




Related

- Vanishing Arctic sea ice is rapidly changing global climatearctic-news.blogspot.com/2012/09/vanishing-arctic-sea-ice-is-rapidly-changing-global-climate.html

- Storm enters Arctic region

- Huge cyclone batters Arctic sea ice
arctic-news.blogspot.com/2012/08/huge-cyclone-batters-arctic-sea-ice.html

Open Letter to Canadian MPs

Paul Beckwith
Food is the new oil. Land is the new gold.

The world food situation is deteriorating. Grain stocks have dropped to a dangerously low level. The World Food Price Index has doubled in a decade. The ranks of the hungry are expanding. Political unrest is spreading.

On the demand side of the food equation, there will be 219,000 people at the dinner table tonight who were not there last night. And some 3 billion increasingly affluent people are moving up the food chain, consuming grain-intensive livestock and poultry products.

At the same time, water shortages and heat waves are making it more difficult for farmers to keep pace with demand. As grain-exporting countries ban exports to keep their food prices down, importing countries are panicking. In response, they are buying large tracts of land in other countries to grow food for themselves. The land rush is on.

Could food become the weak link for us as it was for so many earlier civilizations? This slideshow presentation, based on Lester Brown's latest book, Full Planet, Empty Plates: The New Geopolitics of Food Scarcity, explains why world food supplies are tightening and tells what we need to do about it.
http://www.earth-policy.org/books/fpep/fpep_presentation

My video clip filmed about 3 weeks ago on Parliament Hill explains the clear connections between crop failures/droughts/floods/extreme weather/sea ice/greenhouse gases/climate change...
http://www.youtube.com/watch?feature=player_embedded&v=zw1GEp8UBj4

This is my presentation on Parliament Hill (Center blog) a few months ago at the All-Party Climate Change Caucus meeting.
https://docs.google.com/file/d/0ByLujhsHsxP7NG42RjVQLXBrV1k/edit

This is a longer version of the linkages between food shortages and declining sea ice.
https://docs.google.com/file/d/0ByLujhsHsxP7NThkM05iN1BXZ2s/edit


Please let me know what your plan is to deal with this coming turmoil.
I look forward to your response.


Sincerely,

Paul Beckwith (B.Eng. Engineering Physics, M.Sc. Physics, presently working on Ph.D. in climatology)

Big changes in Arctic within years

Above interactive graphic illustrates the decline of the annual sea ice minimum volume in the Arctic over the years.

What trend can best be fitted to these data? Below, I've added a trendline that I believe best fits the data, but I encourage others to come up with better trends.


The trend points at 2014 as the year when Arctic sea ice will first reach zero volume for some time during that year. As discussed in the earlier post Getting the Picture, the Arctic Ocean looks set to be ice-free for a period of at least three months in 2015 (August, September and October), and for a period of at least 6 months from the year 2020 (June through to November).

Natural variability and strong feedbacks may speed things up further. Decline of sea ice in 2012 was such that we can expect a very low volume in December 2012, which could lead to inclusion of December in the period projected to be ice-free from 2020. That would make the ice-free period seven month long, i.e. well over half a year.

The image below shows the three areas where albedo change will be felt most in the Arctic, i.e. sea ice loss, decline of albedo in Greenland and more early and extensive retreat of snow and ice cover in other areas in the Arctic.


Related

- Getting the Picture
arctic-news.blogspot.com/2012/08/getting-the-picture.html

- Albedo change in the Arctic
arctic-news.blogspot.com/2012/07/albedo-change-in-arctic.html

- Greenland is melting at incredible rate
arctic-news.blogspot.com/2012/07/greenland-is-melting-at-incredible-rate.html

- Albedo change in the Arctic threatens to cause runaway global warming

Amplification of climate change in the Arctic

In contrast to multi-year old ice, first-year old ice—ice that formed only since the last melt season—is thinner, saltier, and much more prone to melt.


Over the years, the loss of sea ice has become especially manifest in the older ice, as illustrated by the image below.


Salt content and hardness play a part in multi-year ice’s resistance to melt, explains a recent NOAA article, but the main characteristic that allows the ice to survive the melt season is thickness.

Screenshots from: PIOMAS Arctic Sea Ice Thickness Simulation 1978-2011
The decline in thickness over the years goes a long way to explain the self-reinforcing character of sea ice decline in the Arctic.

As another recent NOAA article describes, there is “something extra” behind the record ice retreats of the past 6 years: each June, the prevailing winds shifted from their normal west-to-east direction and instead blew strongly from the south across the Bering and Chuchki Seas (left on the image below), over the North Pole, and out toward Fram Strait. (The length of the lines is qualitative: longer lines mean stronger winds.)

Average June wind vectors in 2007-2012 (orange) compared to 1981-2010 average (white) based on NCEP reanalysis data provided by Physical Sciences Division at NOAA ESRL. Map by Dan Pisut, NOAA Environmental Visualization Lab.

The image below shows the unusual air pressure patterns that gave rise to the wind shift. Air pressure across the Arctic in Junes from 2007-2012 was completely lopsided, with two pockets of higher-than-average pressure sprawled across the North American Arctic and Greenland. These areas of high pressure act like boulders in a river. They slow and disrupt the normal westerly flow of the wind, forcing it to make, large, meandering detours to the north or south.

Average geopotential height anomaly at 700 millibar pressure level in Junes from 2007-2012 compared to the long-term average (1981-2010) based on NCEP reanalysis data provided by PSD at NOAA ESRL. Orange colors are higher-than-average pressure; blue is lower-than-average pressure.     Map by Dan Pisut, NOAA Environmental Visualization Lab.
Arctic oceanographer and his NOAA colleagues think these “blocking highs” on the North American side of the Arctic created the unusually strong southerly flow that brought warm air into the central Arctic and over Greenland. The persistent southerly winds would help explain both the record low sea ice extent in summer 2012, as well as the island-wide melting of the surface of the Greenland Ice Sheet, which satellites detected in July 2012.

“This story started with us trying to figure out why the sea ice extents of the past 6 years or so have been so much lower than we would expect based on the long-term warming trend alone,” says Overland, “and we think this unusual circulation of the Arctic atmosphere is major part of it.”

Why, asks Overland, have these high pressure patterns have been forming so consistently each June for the past six years? The repeated appearance of these atmospheric features each June is so unusual that it’s the equivalent of a 1-in-a-1000 event. Can this be attributed to natural variability?

Instead, Overland’s hunch is that the cause is a change in the atmosphere that is itself connected to climate change in some way, possibly linked to record and near-record low June snow cover in the Canadian Arctic in recent years. “We don’t know that part of the story yet,” he says, “but this would certainly be the type of amplification of climate change [warming triggers changes that lead to more warming] we have been expecting to see in the Arctic.”

References

- Arctic Sea Ice Getting Thinner, Younger
http://www.climatewatch.noaa.gov/article/2012/arctic-sea-ice-getting-thinner-younger

- June wind shift a little something extra behind recent Arctic ice losses
http://www.climatewatch.noaa.gov/article/2012/june-wind-shift-a-little-something-extra-behind-recent-arctic-ice-losses

- Poles apart: A record-breaking summer and winter
http://nsidc.org/arcticseaicenews/2012/10/poles-apart-a-record-breaking-summer-and-winter/

- PIOMAS Arctic Sea Ice Thickness Simulation 1978-2011, published Sep 14, 2012 by ArctischePinguin
https://www.youtube.com/watch?v=G1TLzgSlGtQ

Related

- Arctic summer wind shift
http://arctic-news.blogspot.com/2012/10/arctic-summer-wind-shift.html

- The recent shift in early summer Arctic atmospheric circulation
http://www.agu.org/pubs/crossref/2012/2012GL053268.shtml

- Presentation by Dr. Jennifer Francis, Rutgers University
https://www.youtube.com/watch?v=RtRvcXUIyZg
http://marine.rutgers.edu/~francis/pres/Francis_Vavrus_2012GL051000_pub.pdf