3/31/2016 8:10:11 PM
Arctic Ice Stalls and Dives
It's always a challenge to know what sea ice will do from week to week or month to month. It's a lot easier to know what will happen over longer periods of years or decades. Sea ice scientists at the National Snow and Ice Data Center in Boulder, Colorado made this point abundantly clear at a seminar I attended a while back.
This winter, however, those scientists may have found it a bit easier to predict the record low sea ice across the Arctic. It's been blistering hot up there for the past couple of months-at least by Arctic metrics,. While it's possible that Arctic ice might still edge up a bit, it appears that March 24 set the record low winter time maximum extent: how's that for a brain twister? Just how much lower was it? Winter sea ice is now about two times the size of Texas lower than it was in 1979.
If anyone needs more insights on the problem, ponder that the 13 lowest maximum ice extents have occurred over the last 13 years. Some of the area lost was likely marginal polar bear habitat, but, just like habitat loss experienced by wildlife across the world, the process usually starts at the edges and erodes towards the core of a species' range.
What will this new low maximum mean for polar bears? It's almost impossible to know because the important time of the year is just ahead for the bears. It's feeding and breeding season in the Arctic: both love and the smell of dead seals are in the air. If the ice melts quickly, we can make some pretty accurate predictions that polar bear body condition will be low, which will effect both reproduction and survival rates. The biggest factor is the sea ice break-up date and, even then, the importance of this metric varies throughout the 19 polar bear populations: at least for now.
Polar bear scientists are sea ice fanatics. We watch satellite images, examine the ice charts, scrutinize the tracks of bears we're following, and examine our data for patterns. We can hope the bears have a good spring but that might be wishful thinking. We might be better off pondering how we'll reduce our carbon footprints so that future generations will have polar bear footprints to ponder.