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Senin, 09 Juni 2014

Arctic Sea Ice Steep Decline Continues

Steep decline of the Arctic sea ice continues. The yellow line on the image below follows 2014 sea ice area up to June 5 and shows that sea ice area now is close to a record low for the time of the year.

[ click on image to enlarge ]

The Naval Research Laboratory image below compares sea ice concentration on May 14, 2014 (left) with the sea ice concentration forecast for June 15, 2014 (run on June 7, 2014, on the right).

Above image shows falling sea ice concentration, with low sea ice concentration extending to the center of the Arctic Ocean.

Low sea ice concentration at the center of the Arctic Ocean is an ominous sign; at last year's minimum, very little sea ice was left close to the North Pole, as discussed in an earlier post.

On the right is an image of the University of Bremen showing sea ice concentration on June 8, 2014 (click on the images to enlarge them).

Arctic sea ice already is very thin, as discussed in recent posts. The image below shows that the sea ice volume trend down to zero was confirmed for the months April and May 2014.

[ image by Andy Lee Robinson based on PIOMAS data, click on image to enlarge ]

The lowest sea ice volume for 2014 is expected to be reached in September, and - given the shape the ice is in now - will likely be one of the lowest minima on record. In fact, there is a chance that there will be no ice left whatsoever later this year. As illustrated by the image by Wipneus below, an exponential curve based on annual minima from 1979 points at zero ice volume end 2016, with the lower limit of the 95% confidence interval pointing at zero ice end of 2014.

As the sea ice disappears, a lot more heat will be absorbed by the Arctic Ocean. Sea ice reflects 50% to 70% of the incoming energy, describes NSIDC.org, but thick sea ice covered with snow reflects as much as 90% of the incoming solar radiation. Melting of snow creates melt ponds on the ice and because shallow melt ponds have an albedo of approximately 0.2 to 0.4, the surface albedo drops to about 0.75. As melt ponds grow and deepen, the surface albedo can drop to 0.15. The ocean reflects only 6% of the incoming solar radiation and absorbs the rest. Snow and ice decline comes with a further feedback in that all the energy that during the melt went into transforming ice into water will - in the absence of ice - now be absorbed by the ocean as well.

Accelerated Warming in the Arctic

[ from the post Near-Term Human Extinction ]

Such feedbacks are causing warming to accelerate in the Arctic Ocean, as depicted in above image and described in the earlier post Feedbacks in the Arctic. Much of the Arctic Ocean is very shallow and the seafloor is thus vulnerable to warming. The Gulf Stream can be expected to keep carrying warmer water into the Arctic Ocean, so the situation is dire, while extreme weather events such as heatwaves and cyclones can make the situation even worse.

The NOAA image below shows huge sea surface temperature anomalies all over the Northern Hemisphere on June 8, 2014.

[ click on image to enlarge ]

Large areas with sea surface temperature anomalies up to 8°C and higher show up in and around the Arctic Ocean, as further illustrated by the image below.

[ click on image to enlarge ]

The image below shows high sea surface temperature anomalies from February 21, 2014, up to June 9, 2014, on the Northern Hemisphere (red bars), next to global average anomalies (orange/shaded bars).

The global sea surface temperature anomaly is worrying (a 1.25°C anomaly was reached on May 22, 2014). See the NOAA website to compare this with earlier months. Note that on specific spots the anomaly is much higher, as illustrated by the images further above.

Warm surface waters in the Arctic sea ice spell bad news, given that the sea ice is already at or close to record lows, in terms of area and volume.

And as ocean heat threatens to melt the sea ice from beneath, the sun is now strongly warming up the ice from above. Insolation in the Arctic is at its highest at this time of year, 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.

The diminishing temperature difference between the equator and the North Pole reduces the speed at which the Jet Stream circumnavigates Earth and it makes the Jet Stream become wavier, increasing opportunities for cold air to escape from the Arctic and for warm air to move in. More extreme weather increases the chance of intense and prolonged heatwaves and fierce cyclones, storms and winds to hit the Arctic Ocean.

Making things even worsen, there is the prospect of an El Niño event, projected to occur later this year. According to NOAA (June 5, 2014), the chance of El Niño is 70% during the Northern Hemisphere summer and reaches 80% during the fall and winter. El Niño odds are even higher than this, according to this post at the Wunderground blog.

Methane

Temperature rises of the water close to the seafloor of the Arctic Ocean are very dangerous, as heat can penetrate sediments and cause hydrate destabilization. Huge amounts of methane are held in sediments at the seafloor, in the form of free gas and hydrates. In shallow waters, methane released from the seafloor can more easily enter the atmosphere without getting broken down by microbes in the water.

Methane levels are already very high. On June 6, 2014, mean global methane reached levels as high as 1809 ppb, with peaks as high as 2516 ppb.

Methane release from the seafloor of the Arctic Ocean will warm up the Arctic even further, triggering even more methane releases, heatwaves, wildfires and further feedbacks, in a spiral of runaway warming, threatening to cause starvation, destruction and extintion at massive scale across the globe.

Earthquakes

Earthquakes are a further worry. A huge amount of melting takes place in Greenland, as described in the post Ten Cubic Kilometers of Ice Lost From Jakobshavn Glacier in Less than One Month. As the ice disappears, a large weight is lefted from Greenland, causing the Earth's crust there to be lifted in a phenomenon referred to as isostatic rebound. This can cause earthquakes to occur on the seafloor of the waters around Greenland, as illustrated by the image below.

[ click on image to enlarge ]

As the image below shows, the faultline alongside Greenland crosses the Arctic Ocean and extends into the Laptev Sea and Siberia, an area recently hit by two large earthquakes.

[ click on image to enlarge ]

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.

[ click on image to enlarge ]

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).

[ click on image to enlarge ]

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 Niño 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.

Post by Sam Carana.

Selasa, 22 April 2014

Arctic Sea Ice in Steep Descent

Arctic sea ice area is in steep descent, as illustrated by the image below. Sea ice area was only smaller at this time of the year in 2007, for all years for which satellite data are available.

[ click on image to enlarge ]

Earlier this year, on March 9, 2014, Arctic sea ice area was at a record low for the time of the year. Since then, area did show some growth for a while, to the north of Scandinavia. This growth could be attributed largely to strong winds that made the sea ice spread with little or no growth in volume. The 30-day Naval Research Laboratory animation below shows recent sea ice speed and drift.

Indeed, sea ice volume in March 2014 was the 2nd lowest on record. Only March 2011 had a lower volume as discussed in a recent post. The 30-day Naval Research Laboratory animation below shows recent sea ice thickness.

Low sea ice volume and area jointly suggest there could be a total collapse of the sea ice later this year, in line with observation-based non-linear trends. For years, this blog has warned that observation-based projections point at Arctic sea ice disappearance within years, with dire consequences for the Arctic and for the world at large.

As said, winds are responsible for much of sea ice variability, and winds could either slow down or speed up such a collapse. On this point, it's good to remember what Prof. Peter Wadhams said in 2012:

". . apart from melting, strong winds can also influence sea ice extent, as happened in 2007 when much ice was driven across the Arctic Ocean by southerly winds. The fact that this occurred can only lead us to conclude that this could happen again. Natural variability offers no reason to rule out such a collapse, since natural variability works both ways, it could bring about such a collapse either earlier or later than models indicate.

In fact, the thinner the sea ice gets, the more likely an early collapse is to occur. It is accepted science that global warming will increase the intensity of extreme weather events, so more heavy winds and more intense storms can be expected to increasingly break up the remaining ice, both mechanically and by enhancing ocean heat transfer to the under-ice surface."

The image on the right, produced with NOAA data, shows mean coastal sea surface temperatures of over 10°C (50°F) in some areas in the Arctic on August 22, 2007.

In shallow waters, heat can more easily reach the bottom of the sea. In 2007, strong polynya activity caused more summertime open water in the Laptev Sea, in turn causing more vertical mixing of the water column during storms in late 2007, found a 2011 study, and bottom water temperatures on the mid-shelf increased by more than 3°C (5.4°F) compared to the long-term mean.

Another study found that drastic sea ice shrinkage causes increase in storm activities and deepening of the wind-wave-mixing layer down to depth ~50 m (164 ft) that enhance methane release from the water column to the atmosphere. Indeed, the danger is that heat will warm up sediments under the sea, containing methane in hydrates and as free gas, causing large amounts of this methane to escape rather abruptly into the atmosphere.

Such warming would come on top of ever-warmer water that is carried by the Gulf Stream into the Arctic Ocean and that has already been blamed for large methane releases from the seafloor of the Arctic Ocean last year.

The prospect of an El Niño event, as discussed in an earlier post, makes the situation even more dire.

The consequences of sea ice collapse will be devastating, as all the heat that previously went into transforming ice into water will be asbsorbed by even darker water, from where less sunlight will be reflected back into space. The danger is that further warming of the Arctic Ocean will trigger massive methane releases that could lead to extinction at massive sclae, including extinction of humans.

Hopefully, more people will realize the urgency of the situation and support calls for comprehensive and effective action as discussed at the Climate Plan blog.

Links

- March 2014 Arctic Sea Ice Volume 2nd Lowest On Record
http://arctic-news.blogspot.com/2014/04/march-2014-arctic-sea-ice-volume-2nd-lowest-on-record.html

- Supplementary Evidence by Professor Peter Wadhams
http://arctic-news.blogspot.com/2012/04/supplementary-evidence-by-prof-peter.html

- Has the Descent begun?
http://arctic-news.blogspot.com/2014/03/has-the-descent-begun.html

- Nea-term Human Extinction
http://arctic-news.blogspot.com/2014/04/near-term-human-extinction.html

- Climate Plan blog
http://climateplan.blogspot.com

Post by Sam Carana.

Rabu, 12 Maret 2014

Has the descent begun?

On March 9, 2014, Arctic sea ice area was at a record low for the time of the year, at only 12.88731 square kilometers.

Sea ice extent shows a similar descent, as illustrated by the NSIDC image below.

NSIDC update: The image below shows that Arctic sea ice extent was 14.583 square kilometers on March 11, 2014 (light green line), a record low for this time of the year and smaller than it was in 2006 (magenta line) and 2011 (orange line) at this time of the year.

The situation is dire, given that methane concentrations have risen strongly following an earthquake that hit the Gakkel Ridge on March 6, 2014, as illustrated by the image below.

[ click on image to enlarge ]

Huge amounts of methane have been released from the seafloor of the Arctic Ocean over the past half year, and the resulting high methane concentrations over the Arctic will contribute to local temperature rises.

The image below shows that sea surface temperatures are anomalously high in the Arctic Ocean and off the east coast of North America, from where warm water is carried by the Gulf Stream into the Arctic Ocean.

The prospect of an El Niño event makes the situation even more dire. NOAA recently issued an El Niño Watch. This follows a conclusion by an international research team that found a 75% likelyhood of an El Niño event in late 2014.

The consequences of sea ice collapse would be devastating, as all the heat that previously went into transforming ice into water will be asbsorbed by even darker water, from where less sunlight will be reflected back into space. The danger is that further warming of the Arctic Ocean will trigger massive methane releases is unacceptable and calls for comprehensive and effective action as discussed at the Climate Plan blog.

Related

- M4.5 Earthquake hits Gakkel Ridge
http://arctic-news.blogspot.com/2014/03/m45-earthquake-hits-gakkel-ridge.html

- Climate Plan blog
http://climateplan.blogspot.com

Post by Sam Carana.

Senin, 10 Maret 2014

M4.5 Earthquake hits Gakkel Ridge

The above image shows recent large methane release over the Gakkel Ridge, the faultline that crosses the Arctic Ocean between the northern tip of Greenland and the Laptev Sea (red line on map). Methane readings were as high as 2395 ppb at 586 mb, an altitude that often shows high methane readings originating from the Arctic Ocean.

An earthquake with a magnitude of 4.5 hit the Gakkel Ridge at a depth of 2 km on March 6, 2014, at 11:17.17.0 UTC. The location is shown on the map below.

[ click on image to enlarge ]

The image below shows more recent methane readings, around March 8, 2014.

The image below is a Naval Research Laboratory forecast of sea ice thickness for March 8, 2014, run on March 3, 2014.

Meanwhile, the sea ice is close to record lows (for the time of the year), as illustrated by the images below. The image directly below shows sea ice area.

The image below shows sea ice extent.

The image below, by Wipneus, shows sea ice volume.

The image below, by Andy Lee Robinson, offers a different way of looking at sea ice volume, the Arctic Death Spiral.

Post by Sam Carana.

Senin, 12 Agustus 2013

Cyclone raging on Thin Ice

Another cyclone is raging over the Arctic Ocean. The Naval Research Laboratory image below shows the speed and drift of the sea ice.

[ click on image to enlarge ]

Last time a cyclone hit the Arctic, this resulted in a temporary increase in area covered by sea ice, as shown on the Cryosphere Today image below. The cyclone pushed down on the sea ice, flattening it and pushing it sideways.

Note that area as measured by the Cryosphere Today includes all spots that have a 15% or higher concentration of ice. This way of measuring area ignores the fact that the cyclone reduced the sea ice concentration in many spots, from a high sea ice concentration (around 90%) to a lower concentration (less than 80%), as shown on the Naval Research Laboratory image below.

Furthermore, sea ice has since dropped in thickness, as illustrated by the Naval Research Laboratory image below.

Much of the ice is now less than one meter thick, while some areas close to the North Pole have ice that is only between zero and half a meter thick.

The cyclone is raging most fiercely in those areas and much of the ice is drifting out into the Atlantic Ocean.

Neven mentioned at the Arctic Sea Ice Blog that average thickness (crudely calculated by dividing PIOMAS (PI) volume numbers with Cryosphere Today (CT) sea ice area numbers, see image below) had a very steep drop in July, similar to the drop in 2010. This year's trend line is now lowest, probably signifying that the ice pack is spread out and thin at the edges (read: melting potential).

[ click on image to enlarge ]

The image below, from the University of Bremen, Germany, shows sea ice concentration on August 11, 2013.

Minggu, 16 Juni 2013

Arctic Sea Ice September 2013 Projections

What will the Arctic Sea Ice look like in September 2013?

Several projections for Arctic sea ice extent are being discussed at places such as ARCUS (Arctic Research Consortium of the United States) and the Arctic Sea Ice Blog. The image below, from ARCUS, shows various projections of September 2013 arctic sea extent (defined as the monthly average for September) with a median value of 4.1 million square kilometers, with quartiles of 3.8 and 4.4 million square kilometers.

Note that sea ice extent in the above projections is defined as area of ocean with at least 15% ice, in line with the way the NSIDC calculates extent. By contrast, the Danish Meteorological Institute includes areas with ice concentration higher than 30% to calculate ice extent.

Rather than looking at the projected average for September, one could also project the minimum value for September 2013. And rather than looking at sea ice extent, one could also look at sea ice area, which differs from sea ice extent as the NSIDC FAQ page describes:

A simplified way to think of extent versus area is to imagine a slice of Swiss cheese. Extent would be a measure of the edges of the slice of cheese and all of the space inside it. Area would be the measure of where there is cheese only, not including the holes. That is why if you compare extent and area in the same time period, extent is always bigger.

Above image shows Sam Carana's projected minimum area of 2 million square km for 2013, based on data by Cryosphere Today and on numerous factors, such as continued warming of the water underneath the ice, stronger cyclones, etc.

Roughly in line with above image, by Wipneus, Sam Carana's projection for Arctic sea ice minimum volume is 2,000 cubic km in September 2013.

Readers are invited to submit comments below with further projections.

Jumat, 14 September 2012

Arctic sea ice decline continues

The image below, from The Cryosphere Today, shows that Arctic sea ice has shrunk in area by 11.446871 million square km from March 28, 2012, to September 11, 2012, a fall of over 83.66 percent in 167 days.

The image below illustrates the dramatic drop in sea ice extent (total area of at least 15% ice concentration) for the last 7 years, compared to the average 1972-2011, as calculated by the Polar View team at the University of Bremen, Germany.

Sabtu, 08 September 2012

Two important images

As Arctic sea ice continues to decline, breaking one record after the other, one wonders what more can be said to capture the significance of what is happening. Two images spring to mind.

The image below, from The Cryosphere Today, shows that Arctic sea ice has shrunk in area by 11.41475 million square km from March 28, 2012, to September 6, 2012, a fall of about 83¼ percent in 162 days.

The image below illustrates the dramatic drop in sea ice volume over the years. The image is based on data calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) developed at the Applied Physics Laboratory/Polar Science Center at the University of Washington.

The PIOMAS data for the annual minimum values are the black dots. The trend (in red) is added by Wipneus and points at the start of the year 2015 as the moment when ice volume will first reach zero. The red point indicates the most recent value for 2012 volume, noting of course that this value may still come down further as the year progresses.

This image is further discussed in the post Getting the picture.

Sabtu, 01 September 2012

Sea ice area falls below 2.5 million square km

Arctic sea ice area has fallen below 2.5 million square km.

Sea ice area was 2.48831 million square km on the 242nd day of 2012, as shown on the image below by The Cryosphere Today.

Sea ice area was 13.70851 million square km on the 88th day of 2012. That's a loss of 11.2202 million square km, or about 82%. And there's still quite a few days to go in the melting season.

Rabu, 29 Agustus 2012

Arctic sea ice area already shrank by over 81 percent this year

Arctic sea ice area already shrank by over 81% this year.

Arctic sea ice area was 13.70851 million square km on the 88th day of 2012, as illustrated on the image below by The Cryosphere Today. The image further below shows that only 2.59449 million square km was left of Arctic sea ice area on the 238th day of 2012. In other words, less than 19% is left of the sea ice area there was earlier this year.

And there's still quite a few days to go in the melting season.