Eric Worrall writes:
Based on the current rate of Antarctic ice growth, how long until an ice bridge forms between South America and Antarctica?
Lets start with a simplification – if you squint hard Antarctica is a circle. Antarctica, according to Wikipedia, is 14 million square miles. Sea ice this year covered 20 million square miles. So what is the radius of a 34 million square mile circle?
area = PI x radius ^ 2
so
(34,000,000 / PI) ^ 0.5 = 3289 miles
So the radius of our “circular” Antarctica is approximately 3289 miles.
According to Wikipedia, the distance between Antarctica and South America is 500 miles. http://en.wikipedia.org/wiki/Drake_Passage So we need to calculate, what is the perfectly circular volume of sea ice required to increase the radius by another 500 miles?
Using our area calculation,
Area = PI x radius ^ 2
Area = PI * (3289 + 500) ^ 2 = 45 million square miles.
Since 34 million square miles (the land area of Antarctica + sea ice) is already taken, to increase the radius of Antarctica enough to close the gap, ice growth needs to fill in another 11 million square miles.
At say 300,000 square miles growth per year (lets not forget, this year busted records by 600,000 square miles), and via my drastically simplified calculation, we could expect Antarctic ice to close the Drake passage in 36 years – by 2050.
Interestingly 2055 – 2060 is the peak of the coming Little Ice Age event predicted by Dr. Khabibullo Abdusamatov, head of the space research sector of the Russian Academy of Sciences’ astronomical observatory, in his press release in 2006.
http://en.ria.ru/russia/20060825/53143686.html
This is a very rough calculation, so please don’t take it as a firm prediction – I am most definitely not a polar ice or ocean expert. There are many other factors, such as the brutal winds and currents which blast through the Drake Passage, which would likely impede the formation of sea ice. On the other hand, the growth of ice would increase the albedo of an enormous area of ocean, causing more sunlight to be reflected back into space – though as we are talking about polar ocean, it doesn’t receive much sunlight to start with.
Story Title:
One line summary of story: The growth of Antarctic ice
Ice growings and cold go hand in hand.
Therefore ice growing from the southern point of south America, mostly the eastern side, might reduce the time before south America and Antarctica “meets”.
In fact, considering also potential ice growth from south america makes the “bridge” a little less unrealistic?
Kind regards, Frank
But the curents in that spot make the area hard to “conquer” for the ice..
The albedo effect of additional ice in the polar daylight reflects energy – a positive feedback. The insulating effect of additional ice in the polar night prevents heat loss from the ocean surface – a negative feedback. Since the incominging sunlight is at a low angle, but the outgoing long wave radiation can go straight up, I suspect the negative feedback has dominance, and the rate of Antarctic ice growth would slow down.
Note that Antarctica led the warming leading up to the inception of the Holocene, beginning as early as 20,000 years ago, well in advance of the Bolling-Allerod.
http://onlinelibrary.wiley.com/doi/10.1029/97GL02658/pdf
Why could Antarctica not lead the Holocene termination also?
This has been one of my thoughts as well. The start of an ice age might take the combination of the right Milankovitch cycle and an increase in the Antarctic sea ice. This is somewhat supported by the observations of more sea ice during the LIA. Just a little more sea ice might have pushed the planet into a glaciation mode.
If this is correct it means it wouldn’t be all that difficult to stop another ice age. Just add a couple of satellites that reflected more solar energy on the sea ice. Wouldn’t have much of an impact on anything else and could keep the sea ice from reaching a critical point.
“This is a very rough calculation, so please don’t take it as a firm prediction – I am most definitely not a polar ice or ocean expert.”
Why would we let your lack of expertise get in the way of a perfectly good prediction. We must act now!
@ROM 3:08am.
But we know we jest.
The difference is no one here is demanding that taxpayers world wide surrender their wealth, liberty and future hope to mitigate the imaginary Doom.
Having read the comments I see most of us fail Climatology 101,lacking the prolific use of May.Might. Could and such weasel words, I guess we need the same help that Dr Fruitfly got from the PR firms.
The message must be emotional, appear to contain information and all predictions are to be forecast far enough into the future to avoid exposure.
However after all these years of listening to self professed “serious persons” babbling about the doom from CO2, extrapolated from the lefthand upper quadrant of a cyclic pattern,it is a lot of fun to use real world trends(however temporary) to mock the righteous fools.
The difference I trust, is most of us know we know very little of climate, that we are hardwired to see patterns where none may exist and that we are fully capable of being completely wrong about everything we think we know.
This being the reason I respect the constraints of the scientific method, while having no obligation to respect individual scientists, institutions or authorities.
Show me your work being the key to communication.
Since the Drake Passage was open during the Little Ice Age, it appears nothing short of a full blown Ice Age would close it. But if you truly don’t mind another ice age, it would be funny.
Oh XXXX I will be able to by car to Brisbane from here in Sao Paulo. Great won’t have to pay those ridiculously high airplane fares LOL (will use wind powered car)
Seriously, this could be start of some sort of SH cooling but only in very Southern Latitudes. So far its had absolutely no effect on tropical, sub-tropical or temperate zone (ie Santiago) temperatures over the past 4 years. What is noticeable in my humble view is that it seems the cold air masses around Antarctica are larger but are not extending north (as they did when Antarctica extent was “normal”. It could be a compensating mechanism perhaps….
Eric Worral :Yes temperatures on the East Coast of Australia do seem to be well below average (not much) but constantly during the past 3 years or so.. Brisbane (24C today), in particular is subject to westerly surface winds (850mb) from huge offshore highs fed by Antarctic air. This in fact may be a real cooler effect from a larger Antarctic, This is of course total suposition on my part. LOL
Here in the SW of Australia, the main effect I’d look for is stronger Southern Ocean cold fronts, resulting in more heavy rainfall events. Although not necessarily more rain, due to several complicating factors.
My anecdotal observation is heavy rainfall events do seem to becoming more frequent. But maybe I didn’t take notice in the past.
How can you even ask this question?
I mean, what with all the manmade CO2 going to boil the oceans in the next 50-100 years.
We shouldn’t fall into the trap that the warmists are stuck in and have been since the 1980s, that of taking a short term trend and extrapolating it indefinitely into the future. But, this is an interesting question. What would the possible climate implications be if this did occur…
How long before we can take a snowmobile from South America to New Zealand? That’s what I want to know.
Just an engineer that has done heat transfer, the real kind, all of my career, I doubt it will happen due to the massive water energy transfers around the cape. However if it does, it truly is bad news. Real global cooling and cooling is soooooooooooo much worse than warming. If AlGore says it can never happen buy coal futures.
As a taxpayer, I would gladly contribute a small portion of my income tax to building a 5 star resort on the southern tip of South America for climate alarmists to have a place to enjoy their hard earned vacation time. Me, … I’ll settle with Caribbean.
Those arguing that Antarctica is isolated from the rest of the world by the circumpolar current overlook the deep ocean THC circulation. But we’re talking about century-millennial timescales. Colder Antarctica will – at first – increase southern deep water formation and influence global climate in the long term.
There are two stable states of global climate. One in which polar deep water formation energizes deep circulation resulting in more transport of equatorial water to the poles, resulting in smaller ice caps and warmer climate. The other state is when this deep circulation slows down – for instance the gulf stream stops. This state has much larger ice caps and colder (glacial) climate.
The real danger of expanding Antarctic sea ice is that it could interfere with deep circulation and deep water formation, pushing the system towards a switch from one state to the other.
Should it freeze over all the way to S. America it could be a disruptive event. The removal of surface winds could change upwelling and have an impact on global circulation patters. I see that “phlogiston” has just addressed this. I concur.
The assumption that the ice should expand to fill the Drake Passage is a linear projection that may or may not be valid. However, with a narrowed Drake Passage and volcanic or earthquake activity around the West Antarctic Ice Sheet a break away of a substantial portion of the WAIS perhaps in several large pieces, is possible indeed it is not such an unlikely event. If these large pieces of ice sheet were to be carried into the Drake Passage by ocean currents they could result in a partial blockage of the channel. Occurring at midwinter this could lead to a sea ice bridge. Whether the currents through that narrow passage would allow the blockage to form would be an interesting question. But as Phlogiston says “phlogiston September 24, 2014 at 6:09 pm” A blockage of the Drake Passage leading to disruption of the thermohaline circulation could have an immediate and indeterminate effect on world climate.
I think the biggest danger would be in dodging high speed icebergs in 40 ft. seas.
The only reason that is has not grown to alarmism, is perhaps that it was not on the radar, because of “more ice” and not less. Anyway it seems to be a much more realistic near future than the constant predictions of ice sheets collapsing in a far far away future.
It is in fact worse than the north west passage, that has never really been open.
Has there been any investigation on what has happened to the sum-total of ice? That is Arctic and Antarctic put together? Has the total remained constant, reduced, or increased? I am a lay person, so please answer in simple language.
BTW, Cryosphere Today seems to be mostly down. Whats Up (or down) With That?
arctic.atmos.uiuc.edu/cryosphere/
Some basic questions are begging for an answer:
1. How far from S Pole to S America islands, and mainland
2. How far does the ice extend already, in the winter
3. What is the remaining distance to be closed by ice expansion
Wow, lots of errors in the original post – and they don’t seem to have been consistently corrected in the replies above.
1. As others have noted, the measurements in the article are reported as miles (or square miles) but are actually km (or km^2)
2. The assumption of a flat circle is significantly off from the spherical calculation.
3. Finally, I don’t think the measures of sea ice extent are actually all that good. You can get as good or better an estimate by eyeballing the map and visually estimating the “average” latitude of the sea ice extent.
With that in mind, I get:
radius of earth (km): 6371
average latitude of ice extent (deg): 60
current area under ice = 2*pi*r^2*(1-cos(90-lat)) = 34.2 million km^2
To match RACookPE1978’s estimate of total = 38.5 million km^2, the current sea ice extent would have to be wobbling around the 58th parallel. That does not match any recent image I can find.
Continuing…
approx latitude of the southern tip of SA: 56
target area under ice = 43.6 million km^2
needed ice growth: 9.4 million km^2
at 300k/yr: 31 years
Alternative:
If instead of eyeballing the average latitude of current sea ice extent, you use the real latitude of the ice now closest to Cape Horn, you might get a better approximation of the real needed growth since whatever currents or other factors are distorting the current ice extent from a perfect circle are likely to continue. That would change:
lat current: 61.5
current equivalent area: 31 million km^2
time: 42 years
This alternative is a really weak assumption, however, and is directly contradicted by observations. Antarctic ice extent is well above normal all around Antarctica EXCEPT right at the western peninsula where it is actually below normal. That observation also invalidates the ‘circular growth’ assumption in the main scenario. It was a fun little exercise, though.