Weatherdem's Weblog

Bridging climate science, citizens, and policy


Leave a comment

State of Polar Sea Ice – April 2013: Arctic Sea Ice Decline and Antarctic Sea Ice Gain

Global polar sea ice area in April 2013 tracked back to climatological normal conditions (1979-2009) from the temporary surplus the previous two months.  This follows January and February’s improvement from September 2012′s significant negative deviation from normal conditions (from -2.5 million sq. km. to +750,000 sq. km.).  While Antarctic sea ice gain was slightly more than the climatological normal rate following the austral summer, Arctic sea ice loss was slightly more than normal during the same period.

Arctic Sea Ice

According to the NSIDC, sea ice creation during April measured 1.5 million sq. km.  This melt rate was approximately normal for the month, so April′s extent remained below average again.  Instead of measuring near 15 million sq. km., April 2013′s average extent was only 14.37 million sq. km., a 630,000 sq. km. difference.  In terms of annual maximum values, 2013′s 15.13 million sq. km. was 733,000 lower than normal.

Barents Sea (Atlantic side) ice once again fell from its climatological normal value during the month after remaining low during most of the winter.  Kara Sea (Atlantic side) ice temporarily recovered from its wintertime low extent and reached normal conditions, which is also different from spring 2012′s conditions, before 2013 melt caused the extent to fall below normal conditions again.  The Bering Sea (Pacific side), which saw ice extent growth due to anomalous northerly winds in 2011-2012, saw similar conditions in December 2012 through February 2013.  This caused anomalously high ice extent in the Bering Sea again this winter.  As it did previously this winter, an extended negative phase of the Arctic Oscillation allowed cold Arctic air to move far southward and brought warmer than normal air to move north over parts of the Arctic.  The AO’s tendency toward its negative phase in recent winters is related to the lack of sea ice over the Arctic Ocean in September each fall.  Warmer air slows the growth of ice, especially ice thickness.  This slow growth allows more melt than normal during the subsequent summer, which helps establish and maintain negative AO phases.  This is a destructive annual cycle for Arctic sea ice.

In terms of climatological trends, Arctic sea ice extent in April has decreased by 2.3% per decade, the lowest of any calendar month.  This rate is closest to zero in the late winter/early spring months and furthest from zero in late summer/early fall months.  Note that this rate also uses 1979-2000 as the climatological normal.  There is no reason to expect this rate to change significantly (much more or less negative) any time soon, but increasingly negative rates are likely in the foreseeable future.  Additional low ice seasons will continue.  Some years will see less decline than other years (e.g., 2011) – but the multi-decadal trend is clear: negative.  The specific value for any given month during any given year is, of course, influenced by local and temporary weather conditions.  But it has become clearer every year that humans have established a new climatological normal in the Arctic with respect to sea ice.  This new normal will continue to have far-reaching implications on the weather in the mid-latitudes, where most people live.

Continue Reading →


4 Comments

State of Polar Sea Ice – March 2013: Annual Arctic Maximum and Antarctic Minimum Reached

For the second time in only six years, and the third time in ten years, global polar sea ice area in February and March 2013 mimicked climatological normal conditions (1979-2009).  This follows January’s improvement from September 2012′s significant negative deviation from normal conditions.  While Antarctic sea ice loss occurred slower than the climatological normal rate, Arctic sea ice gain was more rapid than normal during February.  Polar sea ice recovered from an extensive deficit of 2.5 million sq. km. area late last year to a 0.5 million sq. km. surplus within the last week.

Arctic Sea Ice

According to the NSIDC, weather conditions once again caused less freezing to occur on the Atlantic side of the Arctic Ocean and more freezing on the Pacific side than normal this winter.  Similar conditions occurred during the past six boreal winters.  Sea ice creation during February measured 766,000 sq. km.  Despite this rather rapid growth (38% higher than normal), February′s extent remained well below average for the month.  Instead of measuring near 15.64 million sq. km., February 2013′s average extent was only 14.66 million sq. km., a 980,000 sq. km. difference!  The Arctic likely reached its maximum annual extent about 10 days ago.  In terms of annual maximum values, 2013′s 15.13 million sq. km. was 733,000 lower than normal.February’s relatively high rate of ice formation for February related to the lack of existing sea ice at the beginning of the month.  Without ice already in the Ocean, new ice formed as winter continued.

Barents Sea (Atlantic side) ice finally edged toward its climatological normal value during the month after remaining low this winter, as it did in the past 10 winters.  Kara Sea (Atlantic side) ice recovered from low extent the past couple of months, which is different from February 2012′s conditions.  The Bering Sea (Pacific side), which saw ice extent growth due to anomalous northerly winds in 2011-2012, saw similar conditions in December 2012 through February 2013.  This caused anomalously high ice extent in the Bering Sea again this winter.  As it did previously this winter, a negative phase of the Arctic Oscillation allowed cold Arctic air to move far southward and brought warmer than normal air to move north over parts of the Arctic.  The AO’s tendency toward its negative phase in recent winters is related to the lack of sea ice over the Arctic Ocean in September each fall.

In terms of climatological trends, Arctic sea ice extent in February has decreased by 2.9% per decade, the lowest of any calendar month.  This rate is closest to zero in the late winter/early spring months and furthest from zero in late summer/early fall months.  Note that this rate also uses 1979-2000 as the climatological normal.  There is no reason to expect this rate to change significantly (much more or less negative) any time soon, but increasingly negative rates are likely in the foreseeable future.  Additional low ice seasons will continue.  Some years will see less decline than other years (e.g., 2011) – but the multi-decadal trend is clear: negative.  The specific value for any given month during any given year is, of course, influenced by local and temporary weather conditions.  But it has become clearer every year that humans have established a new climatological normal in the Arctic with respect to sea ice.  This new normal will continue to have far-reaching implications on the weather in the mid-latitudes, where most people live.

Arctic Pictures and Graphs

The following graphic is a satellite representation of Arctic ice as of February 11, 2013:

 photo Arctic_sea_ice_20130211_zps0a8dd08b.png

Figure 1UIUC Polar Research Group‘s Northern Hemispheric ice concentration from 20130211.

Here is the similar image from March 24, 2013:

 photo Arctic_sea_ice_20130325_zpsc64e9758.png

Figure 2UIUC Polar Research Group‘s Northern Hemispheric ice concentration from 20130324.

As is normal for this time of year, there is not a large difference between these two graphics.  Any differences are primarily due to storm systems’ presence that push ice around, or the lack thereof.  The lack of sea ice in the Barents Sea (north of Europe) is problematic because wind and ocean currents typically pile sea ice up on the Atlantic side of the Arctic.  Sea ice presence in the Bering Sea (between Alaska and Russia) does not alleviate this problem because currents take ice from that area and transport it into the Arctic and then out into the Atlantic.  The sea ice on the Atlantic side would be among the first that currents transport and then melt during the spring.  With sea ice missing on the Atlantic side, currents will more easily transport Arctic sea ice to southern latitudes where it melts.

Many people questioned the overall health of the Arctic ice pack earlier this month when images (like the one below) and video documented extensive cracks in the ice in the Chukchi and Beaufort Seas.  A fellow blogger (and new author!) emailed me about this phenomenon and I wrote that I would blog my thoughts on the topic.  As Andrew Freedman wrote, “According to the National Snow and Ice Data Center (NSIDC) in Boulder, Colo., this fracturing event appears to be related to a storm that passed over the North Pole on Feb. 8, 2013, creating strong off-shore ice motion. The event is unusual but not unheard of, as similar patterns were seen in early 2011 and 2008. However, the NSIDC said the fracturing this time is more extensive.”  The worry is the extent and size of the cracks and leads as well as the early calendar date at which they are all appearing – up to weeks before normal.

I found this article on the topic and agree with Greg Laden, the author.  The cracks and leads  might be a big deal or they might not.  We will have to wait until the minimum sea ice extent occurs in September before we issue judgment.  The scientifically sound course of action would be to wait until early cracks appeared in multiple seasons and then see what the range of response later in the year is.  For all we know, the cracks could allow for even more ice to form in March than normal and delay the onset of melting.  It strikes me as scientifically unsound and even irresponsible to conjecture about the existence and effect of processes, which we do not understand well.  If scientists crow about upcoming devastating Arctic sea ice loss this year and reality doesn’t conform to their wishes, how much credibility with the public do they engender?  I think observers should stay patient and discuss the phenomena and effects we do understand – there is plenty of material with which to work!

 photo Arctic-sea-ice-sat-pic-20130312_zpsd8fe90e9.jpg

Figure 3 – NOAA AVHRR infrared picture of Arctic sea ice on 20130312.

The following graph of Arctic ice volume from the end of February demonstrates:

 photo SeaIceVolumeAnomaly_20130228_zps1777b889.png

Figure 4PIOMAS Arctic sea ice volume time series through February 2013.

As the graph shows, volume (length*width*height) hit another record minimum in June 2012.  Moreover, the volume remains far from normal since it just returned to the -2 standard deviation envelope (light gray).  I understand that most readers don’t have an excellent handle on statistics, but conditions between -1 and -2 standard deviations are rare and conditions outside the -2 standard deviation threshold (see the line below the shaded area on the graph above) are incredibly rare: the chances of 3 of them occurring in 3 subsequent years under normal conditions are extraordinarily low (you have a better chance of winning the Powerball than this).  Hence my assessment that “normal” conditions in the Arctic are shifting from what they were in the past few centuries; a new normal is developing.  Note further that the ice volume anomaly returned to near the -1 standard deviation envelope in early 2011, early 2012, and now early 2013.  In each of the previous two years, volume fell rapidly outside of the -2 standard deviation area with the return of summer.  That means that natural conditions are not the likely cause; rather, another cause is much more likely to be responsible for this behavior: human influence.

Arctic Sea Ice Extent

Take a look at February’s areal extent time series data:

 photo N_stddev_timeseries_20130325_zps9c8c87bc.png

Figure 5NSIDC Arctic sea ice extent time series through late March 2013 compared with last five years’ data and climatological norm (dark gray line) and standard deviation envelope (light gray).

As you can see, this year’s extent (light blue cuve) grew more rapidly in December than February.  This graph also shows that this year’s extent remained at historically low levels through the winter, well below average values (thick gray curve), just as it did in the previous five winters, which are also shown on this graph.  In this month’s version, NSIDC also plotted the previous four years’ data (2008 through 2012).  You can also see what happened to conditions during late March and early April last spring (dark green curve).  A late season freeze surge occurred, which delayed the date of maximum extent by a number of weeks.  Last year’s surge has no bearing on what might happen over the next couple of weeks this year.  Weather conditions and some low-frequency climate oscillations (AO) are different this year and have more bearing on ice conditions than last year’s date of maximum extent.

Antarctic Pictures and Graphs

Here is a satellite representation of Antarctic sea ice conditions from February 11, 2013:

 photo Antarctic_sea_ice_20130211_zps2eff7662.png

Figure 6UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20130211.

And here is the corresponding graphic from March 24, 2013:

 photo Antarctic_sea_ice_20130325_zpsbb795acd.png

Figure 7UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20130324.

Ice growth is easily visible around the continent.  There is more Antarctic sea ice today than there normally is on this date in the year.  The reason for this is the extra ice in the Weddell Sea (east of the Antarctic Peninsula that juts up toward South America).  This ice exists this austral summer due to an anomalous atmospheric circulation pattern: persistent high pressure west of the Weddell sea pushed sea ice north.  The same winds that pushed the sea ice north also moved cold Antarctic air over the Sea, which has kept ice melt rate well below normal.  A similar mechanism helped sea ice form in the Bering Sea so far this winter.  Where did the anomalous winds come from?  We can again point to a climatic relationship.

The difference between the noticeable and significant long-term Arctic ice loss and relative lack of Antarctic ice loss is largely and somewhat confusingly due to the ozone depletion that took place over the southern continent in the 20th century.  This depletion has caused a colder southern polar stratosphere than it otherwise would be, reinforcing the polar vortex over the Antarctic Circle.  This is almost exactly the opposite dynamical condition than exists over the Arctic with the negative phase of the Arctic Oscillation.  The southern polar vortex has helped keep cold, stormy weather in place over Antarctica that might not otherwise would have occurred to the same extent and intensity. The vortex and associated anomalous high pressure centers kept ice and cold air over places such as the Weddell Sea this year.

As the “ozone hole” continues to recover during this century, the effects of global warming will become more clear in this region, especially if ocean warming continues to melt sea-based Antarctic ice from below (subs. req’d).  The strong Antarctic polar vortex will likely weaken back to a more normal state and anomalous high pressure centers that keep ice flowing into the ocean will not form as often.  For now, we should perhaps consider the lack of global warming signal due to lack of ozone as relatively fortunate.  In the next few decades, we will have more than enough to contend with from Greenland ice sheet melt.  Were we to face a melting West Antarctic Ice Sheet at the same time, we would have to allocate many more resources.  Of course, in a few decades, we’re likely to face just such a situation.

Finally, here is the Antarctic sea ice extent time series through mid-March:

 photo S_stddev_timeseries_20130325_zpsf34ff5a5.png

Figure 8NSIDC Antarctic sea ice extent time series through late March 2013.

Policy

Given the lack of climate policy development to date, Arctic conditions will likely continue to deteriorate for the foreseeable future.  The Arctic Ocean will soak up additional energy (heat) from the Sun due to lack of reflective sea ice.  Additional energy in the climate system creates cascading and nonlinear effects throughout the system.  For instance, excess energy pushes the Arctic Oscillation to a more negative phase, which allows anomalously cold air to pour south over Northern Hemisphere land masses while warm air moves over the Arctic during the winter.  This in turn impacts weather patterns throughout the year across the mid-latitudes.

More worrisome for long-term concerns is the heat that impacts land-based ice.  As glaciers and ice sheets melt, sea-level rise occurs.  Beyond the increasing rate of sea-level rise due to thermal expansion (excess energy, see above), storms have more water to push onshore as they move along coastlines.  We can continue to react to these developments as we’ve mostly done so far and allocate billions of dollars in relief funds because of all the human infrastructure lining our coasts.  Or we can be proactive, minimize future global effects, and reduce societal costs.  The choice remains ours.

Errata

Here are my State of Polar Sea Ice posts from February and January 2013. For further comparison, here is my State of Polar Sea Ice post from March 2012.

Update

I meant to include the following two graphs in this post because of the historical nature they represent.

 photo Arctice_sea_ice_area_20120918_2_zps7e4bc6a2.png

Figure 9 – Time series of Arctic sea ice area from UIUC from 1979 to Sep. 18, 2012.

 photo Arctic_sea_ice_area_20130326_zps5d70869e.png

Figure 10 – Time series of Arctic sea ice area from UIUC from 1979 to Mar. 25, 2013.

The difference between these two graphics is obvious since they were taken near the time of minimum area (2012) and maximum area (2013).  In terms of magnitude, the freeze season of 2012-2013 produced the highest amount of frozen ice area in the modern record (11.168 million sq. km.).  The value of ice area last September was the lowest on record and the value of ice area earlier this month was the highest in four years.  March’s area value occurred because of the factors I discussed above that boil down to this: the relative lack of thick ice in recent winters permitted rapid ice growth, albeit thin ice that melts quickly the following year.  In addition to new record low area values in the future, significant oscillations from minimum to maximum and back again are likely to occur in the future as well.  This does not contradict climate change; it is a manifestation of climate change.  I hope write more about this topic soon, but countries are reconstructing international policy (military and economic) as a result of the changes seen in the Arctic.  Those policy shifts will have societal repercussions, which I venture say few people realize today.


2 Comments

State of Polar Sea Ice – February 2013: Arctic Below and Antarctic Above Normal

Global polar sea ice area in early February 2013 mimics climatological normal conditions (1979-2009), after improvement in the past month.  Antarctic sea ice loss is occurring slower than the climatological normal rate.  Arctic sea ice gain is more rapid than normal.  Polar sea ice recovered from an extensive deficit of -2.5 million sq. km. area late last year to near-zero anomaly within the last week.

Arctic Ice

According to the NSIDC, weather conditions once again caused less freezing to occur on the Atlantic side of the Arctic Ocean and more freezing on the Pacific side than normal.  Similar conditions occurred during the past six boreal winters.  Sea ice creation during January measured 1.36 million sq. km.  Despite this rather rapid growth, January′s extent remained well below average for the month.  Instead of measuring near 14.84 million sq. km., January 2013′s extent was only 13.78 million sq. km., a 1.06 million sq. km. difference!  The Barents Sea recorded lower than average sea ice, which is an unusual condition for January.  Kara Sea ice recovered from low extent the past couple of months.  The Bering Sea, which saw ice extent growth due to anomalous northerly winds in 2011-2012, saw similar conditions in December 2012 and January 2013.  This has caused anomalously high ice extent in the Bering Sea.  Previously this winter, a negative phase of the Arctic Oscillation allowed cold Arctic air to move far southward and brought warmer than normal air to move north over parts of the Arctic.  The AO has returned to a more neutral phase in the past month, which has kept Arctic air closer to where it normally is this time of year.

In terms of longer, climatological trends, Arctic sea ice extent in January has decreased by 3.2% per decade.  This rate is closest to zero in the spring months and furthest from zero in late summer/early fall months.  Note that this rate also uses 1979-2000 as the climatological normal.  There is no reason to expect this rate to change significantly (more or less negative) any time soon, but increasingly negative rates are likely in the foreseeable future.  Additional low ice seasons will continue.  Some years will see less decline than other years (e.g., 2011) – but the multi-decadal trend is clear: negative.  The specific value for any given month during any given year is, of course, influenced by local and temporary weather conditions.  But it has become clearer every year that humans have established a new climatological normal in the Arctic with respect to sea ice.  This new normal will continue to have far-reaching implications on the weather in the mid-latitudes, where most people live.

Arctic Pictures and Graphs

The following graphic is a satellite representation of Arctic ice as of January 9, 2013:

Photobucket

Figure 1UIUC Polar Research Group‘s Northern Hemispheric ice concentration from 20130109.

Here is the similar image from February 11th 2013:

 photo Arctic_sea_ice_20130211_zps0a8dd08b.png

Figure 2UIUC Polar Research Group‘s Northern Hemispheric ice concentration from 20130211.

The lack of sea ice in the Barents Sea (north of Europe) is problematic because wind and ocean currents typically pile sea ice up on the Atlantic side of the Arctic.  Sea ice presence in the Bering Sea (between Alaska and Russia) does not alleviate this problem because currents take ice from that area and transport it into the Arctic.  That sea ice will be among the first to melt completely come spring.  With sea ice missing on the Atlantic side, currents will more easily transport Arctic sea ice to southern latitudes where it melts.

Overall, the health of the ice pack is not healthy, as the following graph of Arctic ice volume from the end of January demonstrates:

 photo SeaIceVolumeAnomaly_20130131_zps54d600f7.png

Figure 3PIOMAS Arctic sea ice volume time series through January 2013.

As the graph shows, volume (length*width*height) hit another record minimum in June 2012.  Moreover, the volume remains far from normal since it just returned to the -2 standard deviation envelope (light gray).  I understand that most readers don’t have an excellent handle on statistics, but conditions between -1 and -2 standard deviations are rare and conditions outside the -2 standard deviation threshold (see the line below the shaded area on the graph above) are incredibly rare: the chances of 3 of them occurring in 3 subsequent years under normal conditions are extraordinarily low (you have a better chance of winning the Powerball than this).  Hence my assessment that “normal” conditions in the Arctic are shifting from what they were in the past few centuries; a new normal is developing.  Note further that the ice volume anomaly returned to near the -1 standard deviation envelope in early 2011, early 2012, and now early 2013.  In each of the previous two years, volume fell rapidly outside of the -2 standard deviation area with the return of summer.  That means that natural conditions are not the likely cause; rather, another cause is much more likely to be responsible for this behavior: human influence.

Arctic Sea Ice Extent

Take a look at January’s areal extent time series data:

 photo N_stddev_timeseries_20130211_zpsfdf23a52.png

Figure 4NSIDC Arctic sea ice extent time series through early February 2013.

As you can see, the extent (light blue line) grew rapidly in November but still remained at historically low levels through the winter.  The extent remained well below average values (thick gray line) throughout the fall and early winter.  The time series of sea ice extent for previous low years is also shown on this graph.  In this month’s version, NSIDC also plotted the previous four years’ data.  You can see the effect of the wintertime conditions that I described above: the difference between a year’s extent and the average value in January or February is smaller than the difference in October.  This leads us to examine the differences between the historical mean, the negative two standard deviation (light gray) below that mean, and the 2012-2013 time series.

Antarctic Pictures and Graphs

Here is a satellite representation of Antarctic sea ice conditions from January 9, 2013:

Photobucket

Figure 5UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20130109.

And here is the corresponding graphic from February 11th:

 photo Antarctic_sea_ice_20130211_zps2eff7662.png

Figure 6UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20130211.

Ice loss is easily visible around the continent.  There is slightly more Antarctic sea ice today than there normally is on this date in the year.  The reason for this is the extra ice in the Weddell Sea (east of the Antarctic Peninsula that juts up toward South America).  This ice exists this winter due to an anomalous atmospheric circulation pattern: persistent high pressure west of the Weddell sea pushed sea ice north.  The same winds that pushed the sea ice north also moved cold Antarctic air over the Sea, which has kept ice melt rate well below normal.  A similar mechanism helped sea ice form in the Bering Sea so far this winter.

As a reminder, the difference between long-term Arctic ice loss and relative lack of Antarctic ice loss is largely and somewhat confusingly due to the ozone depletion that took place over the southern continent in the 20th century.  This depletion has caused a colder southern polar stratosphere than it otherwise would be, reinforcing the polar vortex over the Antarctic Circle.  This is almost exactly the opposite dynamical condition than exists over the Arctic with the negative phase of the Arctic Oscillation.  The southern polar vortex has helped keep cold, stormy weather in place over Antarctica that might not otherwise would have occurred to the same extent and intensity.  As the “ozone hole” continues to recover during this century, the effects of global warming will become more clear in this region, especially if ocean warming continues to melt sea-based Antarctic ice from below (subs. req’d).  For now, we should perhaps consider the lack of global warming signal due to lack of ozone as relatively fortunate.  In the next few decades, we will have more than enough to contend with from melting on Greenland.  Were we to face melting West Antarctic Ice Sheet at the same time, we would have to allocate many more resources.  Of course, in a few decades, we’re likely to face just such a situation.

Finally, here is the Antarctic sea ice extent time series from February 11th:

 photo S_stddev_timeseries_20130211_zpsad16917a.png

Figure 7NSIDC Antarctic sea ice extent time series through early February 2013.

Policy

Given the lack of climate policy development to date, Arctic conditions will likely continue to deteriorate for the foreseeable future.  The Arctic Ocean will soak up additional energy from the Sun due to lack of reflective sea ice.  Additional energy in the climate system creates cascading effects through the system.  The energy pushes the Arctic Oscillation to a negative phase, which allows anomalously cold air to pour south over Northern Hemisphere land masses while warm air moves over the Arctic.  This impacts weather patterns throughout the year.

More worrisome for long-term concerns is the heat that impacts land-based ice.  As glaciers and ice sheets melt, sea-level rise occurs.  Beyond the increasing rate of sea-level rise, storms have more water to push onshore as they move along coastlines.  We can continue to react to these developments as we’ve mostly done so far.  Or we can be proactive, minimize future global effects, and reduce societal costs.  The choice remains ours.

Errata

Here are my State of the Poles posts from January and September.


4 Comments

State of Polar Sea Ice – January 2013: Arctic Below and Antarctic Above Normal

Global polar sea ice area in early January 2013 remains below climatological normal conditions (1979-2009), but has improved in the past month.  Antarctic sea ice loss is occurring at a climatological normal rate.  Arctic sea ice gain is slightly more rapid than normal, but we should expect this given the record low extent that occurred in September 2012.  Polar sea ice recovered from an extensive deficit of -2.5 million sq. km. area late last year to a -500,000 sq. km. anomaly within the last week.

In March-April 2012, global sea ice area was above normal, but sea ice area anomaly quickly turned negative and then spent an unprecedented length of time near the -2 million sq. km. deficit in the modern era in 2012.  Generally poor environmental conditions (warm surface temperatures and certain wind patterns) established and maintained this condition, predominantly across the Arctic last year.  For the third time in modern history, the minimum global sea ice area fell below 17.5 million sq. km. and for the fourth time in modern history, the anomalous global sea ice area fell below -2 million sq. km.  This is a significant development given that Antarctic sea ice area has been slightly above average during the past few years.  This means that the global anomaly is almost entirely due to worsening Arctic ice conditions.

The rapid ice melt and record-setting area and extent values that occurred in 2012 are the top weather/climate story for 2012, in my opinion.  I think we have clearly seen a switch to new conditions in the Arctic.  Whether these events will occur in similar magnitude or are merely transitory as the Arctic continues to move to a new stable state that the climate will not achieve for years or decades remains to be seen.  The problem is we don’t know all of the ramifications of moving toward or achieving that new state.  Additionally, I don’t think we want to know.

Arctic Ice

According to the NSIDC, weather conditions once again caused less freezing to occur on the Atlantic side of the Arctic Ocean and more freezing on the Pacific side.  Similar conditions occurred during the past six years.  Sea ice creation during December measured 2.33 million sq. km.  Despite this rather rapid growth, December′s extent remained far below average for the month.  Instead of measuring near 13.36 million sq. km., December 2012′s extent was only 12.2 million sq. km., a 1.16 million sq. km. difference!  The Barents and Kara Seas remained ice-free, which is a very unusual condition for them in December.  Recent ice growth in the Seas has slightly alleviated this state, but this is happening very late in the season.  The Bering Sea, which saw ice extent growth due to anomalous northerly winds in 2011-2012, saw similar conditions in December 2012.  This has caused anomalously high ice extent in the Bering Sea.  Temperatures over the Barents and Kara Seas were 5-9°F above average while temperatures over Alaska were 4-13°F below average.  The reason for this is another negative phase of the Arctic Oscillation, which allows cold Arctic air to move southward.  This allows warm sub-arctic air to move north.

In terms of longer, climatological trends, Arctic sea ice extent in December has decreased by 3.5% per decade.  This rate is closest to zero in the spring months and furthest from zero in late summer/early fall months.  Note that this rate also uses 1979-2000 as the climatological normal.  There is no reason to expect this rate to change significantly (more or less negative) any time soon, but increasingly negative rates are likely in the foreseeable future.  Additional low ice seasons will continue.  Some years will see less decline than other years (like this past year) – but the multi-decadal trend is clear: negative.  The specific value for any given month during any given year is, of course, influenced by local and temporary weather conditions.  But it has become clearer every year that humans have established a new climatological normal in the Arctic with respect to sea ice.  This new normal will continue to have far-reaching implications on the weather in the mid-latitudes, where most people live.

Arctic Pictures and Graphs

The following graphic is a satellite representation of Arctic ice as of September 17, 2012 (yes, it’s been that long since I’ve written a Polar post):

Photobucket

Figure 1UIUC Polar Research Group‘s Northern Hemispheric ice concentration from 20120917.

Here is the similar image from January 9, 2013:

Photobucket

Figure 2UIUC Polar Research Group‘s Northern Hemispheric ice concentration from 20130109.

September’s picture shows the minimum extent that occurred in 2012.  You can easily see the substantial growth of sea ice since then.  This comparison provides a good opportunity to point out something important: even in an epoch of anthropogenic global warming, the Arctic will continue to see wintertime sea ice.  There is no solar radiation warming the surface directly and temperatures fall well below freezing for a long time.  The loss of sea ice will continue to occur and will worsen significantly in the summer.  That loss of ice when the sun is overhead is what climate scientists expect to drive numerous changes around the globe.  Incoming solar radiation, instead of being largely reflected back out into space, will instead be mostly absorbed by a darker ocean.  That radiation will stay in the Earth’s climate system as heat, which will cause many cascading effects to occur – effects we largely do not know about because we’ve never lived on a planet with missing summer sea ice at a pole.

The lack of sea ice in the Barents and Kara Seas (north of Europe and far western Russia) is problematic because wind and ocean currents typically pile sea ice up on the Atlantic side of the Arctic.  Sea ice presence in the Bering Sea (between Alaska and Russia) does not alleviate this problem because currents take ice from that area and transport it into the Arctic.  That sea ice will be among the first to melt completely come spring.  With sea ice missing on the Atlantic side, currents will transport Arctic sea ice to southern latitudes where it melts.  The possibility that January’s picture will look similar to September’s picture is therefore higher in 2013 than it was in say 1983.

Overall, the health of the remaining ice pack is not healthy, as the following graph of Arctic ice volume from the end of December demonstrates:

Photobucket

Figure 3PIOMAS Arctic sea ice volume time series through December 2012.

As the graph shows, volume (length*width*height) hit another record minimum in June 2012.  Moreover, the volume is far, far outside the 2 standard deviation envelope (lighter gray contour surrounding the darker gray contour and blue median value).  I understand that most readers don’t have an excellent handle on statistics, but conditions between -1 and -2 standard deviations are rare and conditions outside the -2 standard deviation threshold (see the line below the shaded area on the graph above) are incredibly rare: the chances of 3 of them occurring in 3 subsequent years under normal conditions are extraordinarily low (you have a better chance of winning your state lottery than this).  Hence my assessment that “normal” conditions in the Arctic are shifting from what they were in the past few centuries; a new normal is developing.  Note further that the ice volume anomaly returned to near the -1 standard deviation envelope in early 2011, early 2012, and now early 2013.  In each of the previous two years, volume fell rapidly outside of the -2 standard deviation area with the return of summer.  That means that natural conditions are not the likely cause; rather, another cause is much more likely to be responsible for this behavior: human influence.

Arctic Sea Ice Extent

Take a look at December’s areal extent time series data:

Photobucket

Figure 4NSIDC Arctic sea ice extent time series through early January 2013.

As you can see, the extent (light blue line) grew rapidly in October, then remained at historically low levels through November and December.  The extent remained well below average values (thick gray line) throughout the fall and early winter.  The time series of sea ice extent for previous low years is also shown on this graph, which is what I term NSIDC’s supplemental graph.  In this month’s version, they also plotted the previous five years’ data.  You can see the effect of the winter-time conditions that I described above: the difference between a year’s extent and the average value in Jan/Feb is smaller than the difference in October.  This leads us to examine the differences between the historical mean, the negative two standard deviation (light gray) below that mean, and the 2012-2013 time series.  I can come up with a number of adjectives to describe that difference, but I’ll settle with “stunning”.

Antarctic Pictures and Graphs

Here is a satellite representation of Antarctic sea ice conditions from September 17th:

Photobucket

Figure 5UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20120917.

And here is the corresponding graphic from January 9th:

Photobucket

Figure 6UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20130109.

Ice loss is easily visible around the continent, the more so since there is a 3+ month time difference between Figures 5 and 6.  There is slightly more Antarctic sea ice today than there normally is on this date in the year.  As a reminder, the difference between long-term Arctic ice loss and relative lack of Antarctic ice loss is largely and somewhat confusingly due to the ozone depletion that took place over the southern continent in the 20th century.  This depletion has caused a colder southern polar stratosphere than it otherwise would be, reinforcing the polar vortex over the Antarctic Circle.  This is almost exactly the opposite dynamical condition than exists over the Arctic with the negative phase of the Arctic Oscillation.  The southern polar vortex has helped keep cold, stormy weather in place over Antarctica that might not otherwise would have occurred to the same extent and intensity.  As the “ozone hole” continues to recover during this century, the effects of global warming will become more clear in this region, especially if ocean warming continues to melt sea-based Antarctic ice from below (subs. req’d).  For now, we should perhaps consider the lack of global warming signal due to lack of ozone as relatively fortunate.  In the next few decades, we will have more than enough to contend with from melting on Greenland.  Were we to face melting West Antarctic Ice Sheet at the same time, we would have to allocate many more resources.  Of course, in a few decades, we’re likely to face just such a situation.

Finally, here is the Antarctic sea ice extent time series from January 9th:

Photobucket

Figure 8NSIDC Antarctic sea ice extent time series through early January 2013.

Antarctic sea ice extent remained at or above average to some extent through the austral spring and early summer, which is good news.

Policy

I just read an opinion piece in Scientific American regarding the sorry state of Arctic sea ice. The author, a scientist, advocated that we do not have time to negotiate mitigation treaties. In order to save the ice, we have to research and deploy geoengineering technologies. Let me state by position on this clearly and strongly: we do not know the effects from geoengineering (solar radiation management or carbon dioxide removal) and more than the know the range and magnitude of effects from greenhouse gas emissions. Moreover, basic governance structures for geoengineering research do not currently exist, to say nothing of deployment. If you think international climate policy is complex and hasn’t moved forward quickly, you should think long and hard before advocating for geoengineering research and deployment. Single-actors are probably the biggest worry when you consider the lack of accountability if somebody conducts an experiment. The few small-scale experiments that have come close to real-world execution by national government scientists around the world caused quick and severe public outcries. The main reason for this is something that affects most scientific endeavors: the lack of effective communication with the public prior to carrying out research.  Engaging the public could be viewed as surrendering power and autonomy.  But I view it as a critical component to continued public funding of science and technology research.

Errata

Here are my State of the Poles posts from September and July.

You can find NSIDC’s January report here.


11 Comments

State of the Poles – Mid-September 2012: Record Low Arctic Ice Extent; Antarctic Ice Above Climatological Normal

Judging by recent search terms used to get to this blog and the relative recent peak in traffic, readers have been searching for this post.  I wanted to wait a little longer into the month so that I could capture the expected Arctic minimum, which officially occurred on the 16th of September.  The NSIDC announced this date, after which I started gathering the plots that are found below.  This post will be longer than it usually is because this year’s minimum shattered the record minimum set in 2007, which shattered the previous record set in 2005.  Most of the post is made up of figures, so I encourage readers to at least view them to get a good picture of today’s conditions.  I’m purposefully framing things this way to relay the truly stunning situation the Arctic is in today.  2012 is additional proof the Arctic cryosphere is searching for a new stable point, but hasn’t found it yet.  That does not bode well for the rest of the globe.  With that, let’s begin.

The state of global polar sea ice area in mid-September 2012 remains significantly below climatological normal conditions (1979-2009).  Arctic sea ice loss is solely responsible for this condition.  In fact, if Antarctic sea ice were closer to its normal value, the global area would be much lower than it is today.  Arctic sea ice melted quickly in August and the first half of September because it was thinner than usual and winds helped push ice out of the Arctic where it could melt at lower latitudes; Antarctic sea ice has refrozen at a faster than normal rate during the austral winter.  Polar sea ice recovered from an extensive deficit of -2 million sq. km. area late last year to a +750,000 sq. km. anomaly in March 2012 before falling back to a -2.2 million sq. km. deficit earlier this month.

After starting the year at a deficit from normal conditions, sea ice area spent an unprecedented length of time near the -2 million sq. km. deficit in the modern era in 2011 (i.e., almost the entire calendary year).  Generally poor environmental conditions (warm surface temperatures and certain wind patterns) established and maintained this condition, predominantly across the Arctic last year.  The last time global sea ice area remained near 19 million sq. km. during May was in 2007, when the Arctic extent hit its modern day record minimum.  The maximum in the boreal spring the past two years was ~19.5 million sq. km.

Conditions were prime for another modern-day record sea ice extent minimum to occur in September.  Specific weather conditions helped to determine how 2012′s extent minimum ranks compared to the last 33 years, but it was the overall poor condition of Arctic sea ice that contributed to this year’s record low values.

Continue Reading →


3 Comments

Why Design of Carbon Markets Is So Important

Various interested parties have written about the efficacy (or lack thereof) with regard to carbon-related market schemes of all sizes and types.  Probably one of the more visible programs is the global emissions offset scheme enacted in the wake of the Kyoto Protocol.  This is the case for good reason: Kyoto represented the largest effort to date to deal with carbon emissions and related activities at the international level.  The short story can be summarized by two competing viewpoints.  On the one hand are people who think the Kyoto-scheme was real progress because it did something for the first time.  On the other hand, critics claim that the scheme is a failure for any number of reasons, most not actually dealing with real-world facts.

Who’s right?  Well, as usual, there are valid points made on both sides.  It is true that a global market was created where none before it existed.  In and of itself, that is probably a good thing.  It allows us to monitor how such a program works and make modifications with time if something needs to be tweaked or overhauled.  To that point, the critics make a good argument.  The scheme very likely isn’t working.  But critics will leave it at that without examining it in further detail.

I’m going to look at one part of the scheme in a little more detail and explain why the scheme isn’t working as efficiently as it should.

Quickly: there are too many credits in the market.  In economic terms, there is a drastic oversupply of offset credits.  By definition, the market will operate inefficiently.  How inefficient is the market?  After all, if we are talking about just a little oversupply, we are also talking about small inefficiency.  How does 1,000X oversupply grab you?  Yes, that number is correct and it is wildly inefficient.  This scheme is laughable (or would be if part of a comedy routine).  Unfortunately, it is what passes for real-world policy today.

Continue Reading →

Follow

Get every new post delivered to your Inbox.

Join 164 other followers