Arctic and Antarctic

What determines how much coverage a climate study gets?

It probably goes without saying that it isn’t strongly related to the quality of the actual science, nor to the clarity of the writing. Appearing in one of the top journals does help (Nature, Science, PNAS and occasionally GRL), though that in itself is no guarantee. Instead, it most often depends on the ‘news’ value of the bottom line. Journalists and editors like stories that surprise, that give something ‘new’ to the subject and are therefore likely to be interesting enough to readers to make them read past the headline. It particularly helps if a new study runs counter to some generally perceived notion (whether that is rooted in fact or not). In such cases, the ‘news peg’ is clear.

And so it was for the Steig et al “Antarctic warming” study that appeared last week. Mainstream media coverage was widespread and generally did a good job of covering the essentials. The most prevalent peg was the fact that the study appeared to reverse the “Antarctic cooling” meme that has been a staple of disinformation efforts for a while now.

[Read more…] about Warm reception to Antarctic warming story

Guest commentary from Mauri Pelto

Changes occurring in marine terminating outlet glaciers of the Greenland Ice Sheet and ice shelves fringing the Antarctic Peninsula have altered our sense of the possible rate of response of large ice sheet-ice shelf systems. There is a shared mechanism at work that has emerged from the detailed observations of a number of researchers, that is the key to the onset and progression of the ice retreat. This mechanism is shared despite the vastly different nature of the environments of Jakobshavns Isbrae, Wilkins Ice Shelf and the Petermann Glacier.
[Read more…] about What links the retreat of Jakobshavn Isbrae, Wilkins Ice Shelf and the Petermann Glacier?

This is a continuation of the previous (and now unwieldy) post on the current Arctic situation. We’ll have a proper round up in a few weeks.

Guest contribution from Mauri S. Pelto

Ice shelves are floating platforms of ice fed by mountain glaciers and ice sheets flowing from the land onto the ocean. The ice flows from the grounding line where it becomes floating to the seaward front, where icebergs calve. For a typical glacier when the climate warms the glacier merely retreats, reducing its low elevation, high melting area by increasing its mean elevation. An ice shelf is nearly flat and cannot retreat in this fashion. Ice shelves cannot persist unless the entire ice shelf is an accumulation zone, where snowpack does not completely melt even in the summer.

[Read more…] about Ice Shelf Instability

Guest Commentary by Mauri Pelto

The net loss in volume and hence sea level contribution of the Greenland Ice Sheet (GIS) has doubled in recent years from 90 to 220 cubic kilometers/year has been noted recently (Rignot and Kanagaratnam, 2007). The main cause of this increase is the acceleration of several large outlet glaciers. There has also been an alarming increase in the number of photographs of meltwater draining into a moulin somewhere on the GIS, often near Swiss Camp (35 km inland from the calving front). The story goes—warmer temperatures, more surface melting, more meltwater draining through moulins to glacier base, lubricating glacier bed, reducing friction, increasing velocity, and finally raising sea level. Examining this issue two years RealClimate suggested this was likely the correct story. A number of recent results suggest that we need to take another look at this story.

[Read more…] about Moulins, Calving Fronts and Greenland Outlet Glacier Acceleration

Guest commentary from Spencer Weart, science historian

Despite the recent announcement that the discharge from some Antarctic glaciers is accelerating, we often hear people remarking that parts of Antarctica are getting colder, and indeed the ice pack in the Southern Ocean around Antarctica has actually been getting bigger. Doesn’t this contradict the calculations that greenhouse gases are warming the globe? Not at all, because a cold Antarctica is just what calculations predict… and have predicted for the past quarter century.

It’s not just that Antarctica is covered with a gazillion tons of ice, although that certainly helps keep it cold. The ocean also plays a role, which is doubly important because of the way it has delayed the world’s recognition of global warming.

[Read more…] about Antarctica is Cold? Yeah, We Knew That