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.