Newly Discovered Meltwater Streams Flow Beneath the Antarctic Ice Sheet

The Telegraph reports that previously undetected streams of meltwater have been observed beneath the Antarctic ice sheet. "The streams of water, some of which are 250m in height and stretch for hundreds of kilometres, could be destabilising parts of the Antarctic ice shelf immediately around them and speeding up melting, researchers said. However, they added that it remains unclear how the localised effects of the channels will impact on the future of the floating ice sheet as a whole. The British researchers used satellite images and radar data to measure variations in the height of the Filchner-Ronne Ice Shelf in West Antarctica, which reveal how thick the ice is." The paper itself is paywalled, but the abstract is available online.

Comments

The (actual) Surf

[MrKaos]

I know, the correlation/causation comment will come up, but you would never know the water temperature unless you got in the water and feel it for yourself over 2-3 decades of actually being in the water and knowing when to get in. I wouldn't call 250metres a stream, but other noticable thing is the way the weather has changed from a smooth transition to summer where it gradually got hotter to bursts of weather change where you will suddenly get days of really warm weather in winter and then back to cold and visa versa in summer.

I regularly goes for a swim or a surf on the east coast of Australia and for the last decade years the water has been really cold during seasons where I used to notice it was pretty warm. It has altered my whole habit of surfing. I used to go into the water around September and now it's late October. I love the waves but the goolie shock is just to severe. My mates would say the same thing and often the comment 'at least we know where the ice caps are melting to' would come up.

Re:The (actual) Surf

[MrKaos]

I also wanted to mention that it would be cool to get some little robots into these streams and map them under the ice to find out where they start and finish.

Re:The (actual) Surf

[MrKaos]

However, a very likely alternative cause for you guys feeling colder would be that you're getting older; as people get older, they feel colder quicker.

Oh no doubt about that, I have to leave my walking stick at the beach so I can find my towel!!!

I cannot find any data on the Pacific ocean near Australia, but in many places oceans are getting slightly cooler. This has nothing to do with melt water, though; there's much too little of that to have a measurable influence, especially at your latitude. Instead, it is most probably due to changing currents.

I'm generally lean but have a bit of fat after winter so the icey water just strips it from you (apart from having a wettie on - which slows me down) so it seems to balance out and I want to catch as many waves as I can.

The thing is I have to swim really hard to get the waves so I'm working a lot to get them. The waves I'm after are about the same as the ones for a board as I am a pretty big guy and I get moving pretty fast. Catching them close to shore is dangerous as the waves tend to dump you on sand and I have been badly concussed from that before. Because of that I generally swim a good 100-300 meters from shore where the waves are bigger from sand banks - which you can see underwater.

When I'm out there I can feel the difference between the first metre and, when diving down, the next four or five (I'm a shark chicken - I don't want to be lunch so I keep an eye out). The water temperature is generally more stable the deeper you go but what gets me is that it is more often consistently cold all the way to the surface than not. You can feel the difference in certain patches of water as the temperature changes when you swim through them. This is the biggest change that I note (apart from seeing less penguins, seals and turtles).

Current change seems like a good point however I would then expect it to cycle between behaviours. So it could be because I'm an old bastard however there is a distinct change in the patterns of water temperature that entails the frequency and duration of warm patches of water. Whatever is happening, something is going on.

Re:Ummmm

[JWSmythe]

Well, if it's increasing in surface area, but decreasing in mass, that would be a problem.

I think the concern they're trying to address is the same as one of the arctic ice concerns.

http://en.wikipedia.org/wiki/Outburst_flood

About 8,300 to 7,700 years ago, the melting ice dam over Hudson Bay's southernmost extension narrowed to the point where pressure and its buoyancy lifted it free, and the ice-dam failed catastrophically. Lake Ojibway's beach terraces show that it was 250 metres (820 ft) above sea level. The volume of Lake Ojibway is commonly estimated to have been about 163,000 cubic kilometres, more than enough water to cover a flattened-out Antarctica with a sheet of water 10 metres (33 ft) deep. That volume was added to the world's oceans in a matter of months.

I'm not saying that it's possible, or even probable. It's just an example of what destabilized polar ice can do. There's a whole lot of mass there.

Remember, the 2004 Indian Ocean Tsunami was caused by a 1,000 mile long rift shifting by 50 feet over a few minutes. If a sufficiently sized chunk (or chunks) of ice moved enough, there could be catastrophic effects for boating and coastal areas.

The long-term sea-level rise will be slow, and civilization will change around it. The short term effects of such events can be fast and catastrophic.

Re:Is the end nigh again?

[CadentOrange]

I found the GP perfectly reasonable. We've discovered a new phenomenon, we need a baseline measurement before jumping to any conclusions. Claiming it is proof of warming is premature and smacks of alarmist bullshit. The sort of bullshit that is really ideologically driven.