Global polar sea ice area in March 2014 remained at or near climatological normal conditions (1979-2008). This represents early 2013 conditions continuing to present when sea ice area was at or above the average daily value. Global sea ice area values consist of two components: Arctic and Antarctic sea ice. Conditions are quite different between these two regions: Antarctic sea ice continues to exist abundantly while Arctic sea ice remained well below normal again during the past five months.
The NSIDC made a very important change to its dataset in June. With more than 30 years’ worth of satellite-era data, they recalculated climatological normals to agree with World Meteorological Organization standards. The new climatological era runs from 1981-2010 (see Figure 6 below). What impacts did this have on their data? The means and standard deviations now encompass the time period of fastest Arctic melt. As a consequence, the 1981-2010 values are much lower than the 1979-2000 values. This is often one of the most challenging conditions to explain to the public. “Normal”, scientifically defined, is often different from “normal” as most people refer to it. U.S. temperature anomalies reported in the past couple of years refer to a similar 1981-2010 “normal period”. Those anomalies are smaller in value than if we compared them to the previous 1971-2000 “normal period”. Thus, temperature anomalies don’t seem to increase as much as they would if scientists referred to the same reference period.
Arctic Sea Ice
According to the NSIDC, March 2014′s average extent was 14.80 million sq. km., a 730,000 sq. km. difference from normal conditions. This value is the maximum for 2014 as more sunlight and warmer spring temperatures now allow for melting ice. March 2014 sea ice extent continued a nearly two-year long trend of below normal values. The deficit from normal was different each month during that time due to weather conditions overlaying longer term climate signals. Arctic sea ice extent could increase during the next month or so depending on specific wind conditions, but as I wrote above, we likely witnessed 2014’s maximum Arctic sea ice extent 10 or so days ago.
Sea ice anomalies at the edge of the pack are of interest. There is slightly more ice than normal in the St. Lawrence and Newfounland Seas on the Atlantic side of the pack. Barents sea ice area, meanwhile, is slightly below normal. Bering Sea ice recently returned to normal from below normal, while Sea of Okhotsk sea ice remains below normal. The ice in these seas will melt first since they are on the edge of the ice pack and are the thinnest since they just formed in the last month.
March average sea ice extent for 2014 was the fifth lowest in the satellite record. The March linear rate of decline is 2.6% per decade relative to the 1981 to 2012 average, as Figure 1 shows (compared to 13.7% per decade decline for September: summer ice is more affected from climate change than winter ice). Figure 1 also shows that March 2014′s mean extent ranked fifth lowest on record.
Figure 1 – Mean Sea Ice Extent for March: 1979-2014 [NSIDC].
Arctic Pictures and Graphs
The following graphic is a satellite representation of Arctic ice as of October 1st, 2013:
Figure 2 – UIUC Polar Research Group‘s Northern Hemispheric ice concentration from 20131001.
The following graphic is a satellite representation of Arctic ice as of January 15th, 2014:
Figure 3 – UIUC Polar Research Group‘s Northern Hemispheric ice concentration from 20140115.
The following graphic is a satellite representation of Arctic ice as of April 1st, 2014:
Figure 4 – UIUC Polar Research Group‘s Northern Hemispheric ice concentration from 20140401.
I captured Figure 2 right after 2013’s date of minimum ice extent occurrence. I wasn’t able to put together a post in January on polar sea ice, but captured Figure 3 for future reference. You can see the rapid growth of ice area and extent in three month’s time. Since January, additional sea ice formed, but not nearly as much as during the previous three months. Figure 4 shows conditions just after the annual maximum sea ice area occurred. From this point through late September, the overall trend will be melting ice – from the edge inward.
The following graph of Arctic ice volume from the end of January (PIOMAS updates are not available from the end of February or March) demonstrates the relative decline in ice health with time:
Figure 5 – PIOMAS Arctic sea ice volume time series through January 2014.
The blue line is the linear trend, identified as -3,000 km^3 (+/- 1,000 km^3) per decade. In 1980, there was a +5,000 km^3 anomaly compared to 2013’s -6,000 km^3 anomaly – a difference of 11,000 km^3. How much ice is that? That volume of ice is equivalent to the volume in Lake Superior!
Arctic Sea Ice Extent
Take a look at March’s areal extent time series data:
Figure 6 – NSIDC Arctic sea ice extent time series through early April 2014 (light blue line) compared with four recent years’ data, climatological norm (dark gray line) and +/-2 standard deviation envelope (light gray).
This figure puts winter 2013-14 into context against other recent winters. As you can see, Arctic sea ice extent was at or below the bottom of the negative 2nd standard deviation from the 1981-2012 mean. The 2nd standard deviation envelope covers 95% of all observations. That means the past five winters were extremely low compared to climatology. With the maximum ice extent in mid-March, 2014’s extent now hovers near record lows for the date. Previous winters saw a late-season ice formation surge caused by specific weather patterns. Those patterns are not likely to increase sea ice extent this boreal spring. This doesn’t mean much at all for projections of minimum sea ice extent values, as the NSIDC discusses in this month’s report.
Antarctic Pictures and Graphs
Here is a satellite representation of Antarctic sea ice conditions from October 1, 2013:
Figure 7 – UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20131001.
And here is the corresponding graphic from January 15th, 2014:
Figure 8 – UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20140115.
The following graphic is a satellite representation of Antarctic ice as of April 2nd, 2014:
Figure 9 – UIUC Polar Research Group‘s Southern Hemispheric ice concentration from 20140402.
Antarctic sea ice clearly hit its minimum between mid-January and early April. In fact, that date was likely six weeks ago. Antarctic sea ice is forming again as austral fall is underway. As in recent austral summers, the lack of sea ice around some locations in Figure 8 is related to melting land-based ice. Likewise, sea ice presence around other locations is a good indication that there is less land-based ice melt. Figure 8 looks different from other January’s prior to 2012 and 2013. Additionally, Antarctic weather in recent summers differed from previous years in that winds blew land-based ice onto the sea, especially east of the Antarctic Peninsula (jutting up towards South America), which replenished the sea ice that did melt. The net effect of the these and other processes kept Antarctic sea ice at or above the 1979-2008 climatology’s positive 2nd standard deviation, as Figure 10 below shows.
Finally, here is the Antarctic sea ice extent time series through early April:
Figure 10 – NSIDC Antarctic sea ice extent time series through early April 2014.
The fact that Arctic ice extent continues well below average while Antarctic ice extent continues well above average for the past couple of years works against climate activists who claim climate change is nothing but disaster and catastrophe. A reasonable person without polar expertise likely looks at Figures 6 and 10 and says, “I don’t see evidence of catastrophe here. I see something bad in one place and something good in another place.” For people without the time or inclination to invest in the layered nuances of climate, most activists come off sounding out of touch. If climate change really were as clearly devastating as activists screamed it was, wouldn’t it be obvious in all these pictures and plots? Or, as I’ve commented at other places recently, do you really think people who are insecure about their jobs and savings even have the time for this kind of information? I don’t have one family member or friend that regularly questions me about the state of the climate, despite knowing that’s what I research and keep tabs on. Well actually, I do have one family member, but he is also a researcher and works in supercomputing. Neither he nor I are what most people would consider “average Joes” on this topic.
Given the lack of climate policy development at a national or international level to date, Arctic conditions will likely continue to deteriorate for the foreseeable future. This is especially true when you consider that climate effects today are largely due to greenhouse gas concentrations from 30 years ago. It takes a long time for the additional radiative forcing to make its way through the entire climate system. The Arctic Ocean will soak up additional energy (heat) from the Sun due to lack of reflective sea ice each summer. 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 (witness winter 2013-14 weather stories) across the mid-latitudes and prevents rapid ice growth where we want it.
More worrisome for the long-term 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.