Half of our planet is seasonally warming now. The wobble that slants the sun’s rays in the northern hemisphere, where most of the habitable landmass exists, brings summer to the southern hemisphere. The equinox that brought night to the arctic, and halted the annual melting season for sea ice in the arctic sea, brought daylight to Antarctica, and began the season of melting to the band of water surrounding that continent. Shortly after the long Antarctic dawn a significant anomaly in southern sea ice levels was first observed; the sea ice levels dropped to historic lows, and have continued at record low levels as the Antarctic melting season approaches its halfway point. The anomaly is really striking. Sea ice coverage is now around two million square kilometers less than has been observed at the same point in the melt cycle in recent years. That is a lot of missing ice.
Until last year the recent Antarctic sea ice coverage data has been trending at record high levels. Temperatures were increasing dramatically in Antarctica so, since higher temperatures should melt ice faster, increased sea ice was counter-intuitive. I like anomalies so I wrote a blog post about it in July of 2014. I postulated that the increased sea ice was actually driven by the higher temperatures and increased melting as lower-density meltwater would freeze faster at higher atmospheric temperatures than the bulk higher-salt seawater it floated on. There have now been several papers postulating the same thing. However, I am much cooler for coming up with the idea simply by doing an inventory of my belly-button lint and waving my hands around; I avoided any reliance on authoritative observational data(aka reality) or pesky modeling. Though I should note that the fact that the melt-water enhanced sea ice coverage hypothesis can be easily derived from introspection just shows how it is also an intuitively natural explanation, and that lends it some elegance.
Any discussion of a major data set in climate science runs afoul of poor reporting and deliberate obfuscation. Just last month Tom Edinburgh and Jonathan Day teased Antarctic sea-ice extent data out of the century-old logbooks from the Scott and Shackleton expeditions. Who would not find this information interesting; the scientists who collected this data literally died while in the field collecting it! Most data sets are not so melodramatic; I have rarely encountered an Excell spreadsheet that has brought a flush of pride in being human to my eyes, and so it is exciting to see papers like the Day and Edinburgh “The Cryosphere” paper. Now picture the record high maximum sea ice extent coupled with a human-interest driven estimate of little sea ice difference in 100 years, and, well, you have the fuel climate denial runs on. Day himself wrote clarification articles trying to point out that his presentation of the Scott- Shackleton data did nothing to disprove global climate change, and I wonder if he was surprised that his words of clarification were not important to the denier crowd.
“Previous studies have concluded, the Antactic and Greenland ice sheets are probably thickening rather than melting” -- Myron Ebell
Climate change deniers come in several flavors. The most common these days is the “it is warming but people are not causing it”flavor. The POTUS has put Myron Ebell of the Competitive Enterprise Institute in as transition lead, and therefore most likely post-transition head of, the EPA. Myron is a “little or no warming” denier. Michael Shnayerson called CEI “one of the brightest stars in its constellation of climate skeptics” in a 2007 Vanity Fair article about Myron. It appears as if Trump has enlisted Myron as another general, like Betsy DeVos who I wrote about in an earlier post, in his war on science; Myron will apparently handle the global climate change front.
Temperatures in the arctic can swing in a matter of hours by an order of magnitude more than the values given for warming as a result of global climate change. Bizarre föhn winds can even raise temperatures to well above freezing in the Antarctic winter; on July 14th 2010 one such wind was observed to spike temperatures at a monitoring station from around minus twenty-seven (Fahrenheit) to plus fifty degrees (a total shift of 77oF or almost 43oC) in a few hours. Despite the fact that “the place that’s warmed the most was the Antarctic Peninsula”, (John Turner, a researcher with the British Antarctic Survey) even that large increase (5.4 degrees Fahrenheit, or just about 3 degrees Celsius) is swamped by the Antarctic’s wild short-term weather phenomena.
So how can a source of confusing information as large as the continent of Antarctica provide something useful to talk about? I, like many of you who read this blog, like ambiguity, but hate obfuscation; mysteries are interesting, but murkiness is not. I believe Antarctica presents us with a game of honest mysteries played for truly terrifying stakes. Likely levels of melt of just the West Antarctic ice sheet could raise the level of the sea by 3.2 meters (like 10 feet). Does this melting take a hundred years, or much less? There are other scary contributors to potential sea level rise, like the Greenland ice sheet, but Antarctica is the major player, so it is very worth looking at. The stakes of such a huge rise in sea level include, of course: displacing hundreds of millions of people, destabilizing all of human civilization, diseases and famines, decline of humanity, and yada...yada...yada; you get the picture I’m sure.
So what does this interesting potential shift in melting patterns for Antarctica bode for the future of humanity? I’m not sure of course, but it is probably not good. One of the ways in which the water goes from on the land, where it does not make the seas rise, into the sea, where it does, is by the fracturing of glaciers flowing into the sea. In Antarctica many of those glaciers are held in place by large floating ice shelves. Some of these ice shelves, like Larsen A and B, have been collapsing in recent years, and more are expected to follow. The glaciers the collapsing ice shelves release could rapidly (not weeks, but maybe decades) cause the sea levels to measurably rise.
I –for one- am kinda interested in the rate of progression of phenomena that could cause the collapse of civilization. There are all sorts of great questions. Unfortunately, as part of the war on science, parts of NASA that examine earth-based phenomena, like global climate change, may not be adequately funded by the incoming administration. This could prevent us from adequately understanding what is going on on our planet.
I do think I can authoritatively state, at least as far as rising sea levels are concerned, that one can put off stockpiling popcorn and ammunition until it goes on sale over the northern hemisphere summer.