I’ve often written that the Antarctic isn’t melting any time soon. I doubt that non-climatologists realize just how much the Antarctic has to warm to even think about melting. For this demonstration, I’ve downloaded the Reader temperature data from the BAS. Most of the below code was written by Ryan O.
#Antarctic Ground station names, lat/lon, nearest grid cells, distances, geographic group
temp.idx = matrix(nrow = 109, ncol = 10)
temp.idx[1, ] = c("Adelaide", -67.8, 292.1, 48, 41, 40, 55, 54, 41.68639807, 1)
temp.idx[2, ] = c( "Amundsen_Scott", -90, 0, 1970, 1971, 2040, 1900, 1969, 29.9732532, 4)
temp.idx[3, ] = c( "Arturo_Prat", -62.5, 300.3, 3, 2, 4, 8, 9, 134.1041535, 1)
temp.idx[4, ] = c( "Asuka", -71.5, 24.1, 3243, 3162, 3244, 3163, 3161, 44.99882239, 4)
temp.idx[5, ] = c( "Belgrano_I", -78, 321.2, 926, 925, 879, 977, 976, 70.63341805, 4)
temp.idx[6, ] = c( "Belgrano_II", -77.9, 325.4, 974, 1029, 973, 1028, 975, 27.52472898, 4)
temp.idx[7, ] = c( "Bellingshausen", -62.2, 301.1, 2, 1, 3, 7, 8, 142.4397892, 1)
temp.idx[8, ] = c( "Byrd", -80, 240, 817, 818, 864, 863, 816, 13.24221794, 2)
temp.idx[9, ] = c( "Campbell", -52, 169, 4935, 4934, 4865, 4793, 4864, 1639.851284, 1)
temp.idx[10, ] = c( "Casey", -66.3, 110.5, 5423, 5422, 5393, 5394, 5450, 68.60901916, 4)
temp.idx[11, ] = c( "Davis", -68.6, 78, 5334, 5299, 5260, 5300, 5261, 32.453277, 4)
temp.idx[12, ] = c( "Deception", -63, 299.3, 4, 3, 10, 9, 11, 108.4405257, 1)
temp.idx[13, ] = c( "Dumont_Durville", -66.7, 140, 4576, 4500, 4501, 4499, 4575, 55.12623375, 4)
temp.idx[14, ] = c( "Esperanza", -63.4, 303, 6, 1, 15, 7, 2, 31.74784973, 1)
temp.idx[15, ] = c( "Faraday", -65.4, 295.6, 21, 22, 13, 29, 28, 56.14826582, 1)
temp.idx[16, ] = c( "Ferraz", -62.1, 301.6, 1, 2, 6, 7, 3, 135.1830542, 1)
temp.idx[17, ] = c( "Gough", -40.4, 350.1, 1855, 1450, 1583, 1856, 1451, 3385.574039, 1)
temp.idx[18, ] = c( "Great_Wall", -62.2, 301, 2, 1, 3, 7, 8, 144.3266525, 1)
temp.idx[19, ] = c( "Grytviken", -54.3, 323.5, 6, 1, 15, 7, 2, 1795.237216, 1)
temp.idx[20, ] = c( "Halley", -75.5, 333.6, 1021, 1022, 1080, 1079, 1081, 28.00646963, 4)
temp.idx[21, ] = c( "Jubany", -62.2, 301.4, 1, 2, 3, 7, 6, 135.3601642, 1)
temp.idx[22, ] = c( "King_Sejong", -62.2, 301.3, 2, 1, 3, 7, 6, 140.335687, 1)
temp.idx[23, ] = c( "Leningradskaja", -69.5, 159.4, 3240, 3157, 3156, 3239, 3155, 53.99238049, 4)
temp.idx[24, ] = c( "Macquarie", -54.5, 158.9, 4273, 4196, 3647, 3566, 3967, 1632.703337, 1)
temp.idx[25, ] = c( "Marambio", -64.2, 303.3, 15, 8, 7, 9, 6, 19.63652572, 1)
temp.idx[26, ] = c( "Marion", -46.8, 37.8, 4502, 4426, 4350, 4650, 4577, 2455.134345, 1)
temp.idx[27, ] = c( "Mario_Zucchelli", -74.7, 164.1, 2646, 2647, 2645, 2648, 2732, 30.02328627, 3)
temp.idx[28, ] = c( "Marsh", -62.4, 301.1, 2, 1, 3, 7, 8, 120.8924296, 1)
temp.idx[29, ] = c( "Mawson", -67.6, 62.9, 5196, 5139, 5197, 5140, 5250, 11.74122039, 4)
temp.idx[30, ] = c( "McMurdo", -77.92, 166.67, 2418, 2419, 2416, 2417, 2345, 7.885579706, 3)
temp.idx[31, ] = c( "Mirny", -66.5, 93, 5483, 5462, 5484, 5463, 5436, 33.4106842, 4)
temp.idx[32, ] = c( "Molodeznaja", -67.7, 45.9, 4650, 4651, 4577, 4723, 4795, 14.61550264, 4)
temp.idx[33, ] = c( "Neumayer", -70.7, 351.6, 1451, 1517, 1858, 1787, 1584, 6.016633582, 4)
temp.idx[34, ] = c( "Novolazarevskaya", -70.8, 11.8, 2496, 2573, 2574, 2422, 2658, 18.54203705, 4)
temp.idx[35, ] = c( "O_Higgins", -63.3, 302.1, 1, 7, 6, 2, 15, 15.54485958, 1)
temp.idx[36, ] = c( "Orcadas", -60.7, 315.3, 6, 1, 15, 7, 2, 814.7070993, 1)
temp.idx[37, ] = c( "Rothera", -67.5, 291.9, 41, 40, 47, 48, 51, 8.923597155, 1)
temp.idx[38, ] = c( "Russkaya", -74.8, 223.1, 699, 700, 741, 657, 698, 47.7955837, 2)
temp.idx[39, ] = c( "San_Martin", -68.1, 292.9, 55, 54, 48, 62, 61, 15.22295047, 1)
temp.idx[40, ] = c( "Scott_Base", -77.85, 166.77, 2418, 2419, 2417, 2416, 2345, 7.885579706, 3)
temp.idx[41, ] = c( "Signy", -60.7, 314.4, 6, 1, 15, 7, 2, 766.003401, 1)
temp.idx[42, ] = c( "Syowa", -69, 39.6, 4197, 4198, 4274, 4121, 4122, 40.10138004, 4)
temp.idx[43, ] = c( "Vostok", -78.5, 106.9, 3855, 3934, 3694, 3776, 3775, 51.25190992, 4)
temp.idx[44, ] = c( "Zhongshan", -69.4, 76.4, 5259, 5209, 5154, 5210, 5155, 20.31622125, 4)
temp.idx[45, ] = c( "Bonaparte_Point", -64.8, 295.9, 13, 5, 12, 20, 21, 44.3733877, 1)
temp.idx[46, ] = c( "Butler_Island", -72.2, 299.8, 223, 250, 195, 278, 166, 17.33735847, 1)
temp.idx[47, ] = c( "Byrd", -80, 240.6, 817, 818, 816, 864, 863, 5.856875557, 2)
temp.idx[48, ] = c( "Cape_Denison", -67, 142.7, 4349, 4425, 4348, 4272, 4501, 44.79745815, 4)
temp.idx[49, ] = c( "Cape_King", -73.6, 166.6, 2566, 2649, 2567, 2650, 2490, 19.99906213, 3)
temp.idx[50, ] = c( "Cape_Philips", -73.1, 169.6, 2491, 2492, 2490, 2493, 2569, 37.08498924, 3)
temp.idx[51, ] = c( "Cape_Ross", -76.7, 163, 2642, 2643, 2564, 2641, 2726, 33.29787583, 3)
temp.idx[52, ] = c( "Casey_Airstrip", -66.3, 110.8, 5423, 5422, 5450, 5393, 5394, 42.86898755, 4)
temp.idx[53, ] = c( "Casey_New_Airstrip", -66.3, 110.8, 5423, 5422, 5450, 5393, 5394, 42.86898755, 4)
temp.idx[54, ] = c( "Clean_Air", -89.99, 179.99, 1970, 1971, 2040, 1900, 1969, 29.9732532, 4)
temp.idx[55, ] = c( "D_10", -66.7, 139.8, 4576, 4500, 4499, 4501, 4575, 40.52006846, 4)
temp.idx[56, ] = c( "D_47", -67.4, 138.7, 4575, 4499, 4574, 4648, 4500, 18.62263574, 4)
temp.idx[57, ] = c( "D_57", -68.1, 137.5, 4497, 4573, 4496, 4574, 4572, 29.68688679, 4)
temp.idx[58, ] = c( "D_80", -70, 134.9, 4416, 4417, 4493, 4340, 4339, 29.29911398, 4)
temp.idx[59, ] = c( "Dome_C_II", -75.1, 123.4, 4098, 4174, 4023, 4099, 3943, 50.26200551, 4)
temp.idx[60, ] = c( "Dome_F", -77.3, 39.7, 3341, 3260, 3259, 3342, 3340, 23.22316898, 4)
temp.idx[61, ] = c( "Doug", -82.3, 246.8, 1002, 952, 907, 1112, 860, 27.93340239, 2)
temp.idx[62, ] = c( "Drescher", -72.87, 340.97, 1132, 1133, 1134, 1197, 1196, 32.60891964, 4)
temp.idx[63, ] = c( "Elaine", -83.1, 174.2, 2055, 2125, 2126, 2056, 2054, 38.61377024, 3)
temp.idx[64, ] = c( "Elizabeth", -82.6, 222.9, 1242, 1180, 1305, 1243, 1181, 56.51167125, 2)
temp.idx[65, ] = c( "Enigma_Lake", -74.7, 164, 2646, 2647, 2645, 2732, 2731, 30.13542191, 3)
temp.idx[66, ] = c( "Erin", -84.9, 231.2, 1431, 1366, 1498, 1239, 1303, 50.91496271, 2)
temp.idx[67, ] = c( "Ferrell", -77.9, 170.8, 2276, 2277, 2275, 2274, 2348, 36.26682375, 3)
temp.idx[68, ] = c( "GC41", -71.6, 111.3, 4842, 4912, 4913, 4770, 4984, 24.97980932, 4)
temp.idx[69, ] = c( "GEO3", -68.7, 61.1, 5079, 5014, 5141, 5142, 5015, 15.50248633, 4)
temp.idx[70, ] = c( "GF08", -68.5, 102.1, 5353, 5318, 5386, 5354, 5385, 39.98831567, 4)
temp.idx[71, ] = c( "Gill", -80, 181.4, 1922, 1992, 1923, 1993, 1851, 18.55797104, 3)
temp.idx[72, ] = c( "Harry", -83, 238.6, 1114, 1115, 1175, 1058, 1057, 40.55293055, 2)
temp.idx[73, ] = c( "Henry", -89, 359, 1892, 1893, 1891, 1894, 1890, 466.9032731, 4)
temp.idx[74, ] = c( "Hi_Priestley_Gl", -73.6, 160.7, 2901, 2817, 2902, 2818, 2984, 13.87841726, 3)
temp.idx[75, ] = c( "LGB10", -71.3, 59.2, 4664, 4663, 4734, 4591, 4735, 32.34699498, 4)
temp.idx[76, ] = c( "LGB20", -73.8, 55.7, 4291, 4134, 4212, 4213, 4058, 9.036639558, 4)
temp.idx[77, ] = c( "LGB35", -76, 65, 4068, 4142, 4219, 4143, 3993, 40.11379661, 4)
temp.idx[78, ] = c( "LGB59", -73.5, 76.78, 4676, 4677, 4747, 4603, 4604, 15.53572843, 4)
temp.idx[79, ] = c( "Larsen_Ice_Shelf", -66.9, 299.1, 49, 43, 42, 50, 57, 17.55978504, 1)
temp.idx[80, ] = c( "Law_Dome_Summit", -66.7, 112.7, 5395, 5424, 5425, 5363, 5396, 19.65541292, 4)
temp.idx[81, ] = c( "Lettau", -82.5, 185.6, 1847, 1846, 1848, 1845, 1916, 99.19493816, 3)
temp.idx[82, ] = c( "Limbert", -75.4, 300.1, 458, 497, 420, 538, 498, 43.56113626, 1)
temp.idx[83, ] = c( "Linda", -78.5, 168.4, 2346, 2345, 2347, 2348, 2344, 7.312975998, 3)
temp.idx[84, ] = c( "Lynn", -74.2, 160.4, 2900, 2816, 2815, 2901, 2899, 29.01424379, 3)
temp.idx[85, ] = c( "Manuela", -74.9, 163.7, 2646, 2645, 2647, 2731, 2732, 35.49586369, 3)
temp.idx[86, ] = c( "Marble_Point", -77.4, 163.7, 2564, 2563, 2489, 2488, 2642, 27.32305531, 3)
temp.idx[87, ] = c( "Marilyn", -80, 165.1, 2413, 2343, 2414, 2342, 2484, 25.48352667, 3)
temp.idx[88, ] = c( "Minna_Bluff", -78.6, 166.7, 2417, 2418, 2416, 2344, 2419, 56.36846685, 3)
temp.idx[89, ] = c( "Mount_Siple", -73.2, 232.9, 456, 419, 494, 495, 382, 115.8677037, 2)
temp.idx[90, ] = c( "Nansen_Ice_Sheet", -74.8, 163.3, 2731, 2645, 2646, 2730, 2732, 58.82892652, 3)
temp.idx[91, ] = c( "Nico", -89, 89.7, 2392, 2463, 2321, 2393, 2464, 324.8575404, 4)
temp.idx[92, ] = c( "Pegasus_North", -77.9, 166.5, 2418, 2417, 2419, 2416, 2489, 23.96057281, 3)
temp.idx[93, ] = c( "Pegasus_South", -78, 166.6, 2418, 2417, 2419, 2416, 2345, 16.24984004, 3)
temp.idx[94, ] = c( "Penguin_Point", -67.6, 146.2, 4196, 4272, 4348, 4349, 4424, 7.449501047, 4)
temp.idx[95, ] = c( "Port_Martin", -66.8, 141.4, 4501, 4425, 4424, 4500, 4348, 31.55325773, 4)
temp.idx[96, ] = c( "Possession_Island", -71.9, 171.2, 2494, 2493, 2492, 2491, 2571, 134.1092842, 3)
temp.idx[97, ] = c( "Priestley_Gl", -74.3, 163.2, 2731, 2732, 2647, 2730, 2646, 19.00585189, 3)
temp.idx[98, ] = c( "Racer_Rock", -64.1, 298.4, 4, 10, 9, 5, 11, 49.47196117, 1)
temp.idx[99, ] = c( "Relay_Station", -74, 43.1, 3822, 3743, 3823, 3742, 3821, 7.636661371, 4)
temp.idx[100, ] = c( "Santa_Claus_Island", -65, 294.3, 14, 22, 21, 13, 29, 84.15697374, 1)
temp.idx[101, ] = c( "Schwerdtfeger", -79.9, 170, 2272, 2273, 2202, 2271, 2203, 13.05798907, 3)
temp.idx[102, ] = c( "Scott_Island", -67.4, 180, 3157, 3240, 3322, 3404, 3485, 422.0673688, 4)
temp.idx[103, ] = c( "Siple", -75.9, 276, 324, 358, 293, 395, 359, 50.35567713, 2)
temp.idx[104, ] = c( "Sutton", -67.1, 141.4, 4425, 4501, 4424, 4500, 4349, 22.90986224, 4)
temp.idx[105, ] = c( "Terra_Nova_Bay", -74.7, 164.1, 2646, 2647, 2645, 2648, 2732, 30.02328627, 3)
temp.idx[106, ] = c( "Theresa", -84.6, 244.2, 1236, 1363, 1173, 1113, 1299, 88.8988494, 2)
temp.idx[107, ] = c( "Tourmaline_Plateau", -74.1, 163.4, 2732, 2731, 2648, 2817, 2647, 15.38304621, 3)
temp.idx[108, ] = c( "Uranus_Glacier", -71.4, 291.1, 124, 146, 110, 109, 123, 15.74802782, 1)
temp.idx[109, ] = c( "Whitlock", -76.2, 168.4, 2419, 2348, 2347, 2418, 2346, 173.4223562, 3)
all.idx=matrix(nrow = 109, ncol = 10)
all.idx[, 1] = as.vector(as.character(temp.idx[, 1]))
all.idx = data.frame(all.idx)
all.idx[, 2:10] = as.vector(as.numeric(temp.idx[, 2:10]))
rm(temp.idx)
### Get manned station data from MET READER
reader.names = all.idx[1:44, 1]
all.manned = getReader(x=reader.names, type = "surface")
all.manned = window(all.manned, start = 1957, end = c(2009, 12))
save(all.manned, file = "manned.RData")
### Get AWS data from MET READER
reader.names = all.idx[45:109, 1]
all.aws = getReader(x=reader.names, type = "aws")
all.aws = window(all.aws, start=1957, end = c(2009, 12))
save(all.aws, file = "aws.RData")
allsta=cbind(all.manned, all.aws)
dimnames(allsta)[[2]]=all.idx[,1]
download.file("http://faculty.washington.edu/steig/nature09data/data/Tir_lons.txt", "Tir_lons.txt", mode = "wb")
download.file("http://faculty.washington.edu/steig/nature09data/data/Tir_lats.txt", "Tir_lats.txt", mode = "wb")
lon = read.table("tir_lons.txt")
lat = read.table("tir_lats.txt")
sat.coord = cbind(lon,lat)
Once the temperature data was downloaded, I plotted histograms of the manned and automatic temperature stations separately.
The X axis is the temperature, the Y axis is the number of times that particular temperature was measured in the Antarctic.
Note that the Automatic Stations don’t have as many above zero temperatures as the manned ones. This is caused by the fact that some of the manned stations are not on the Antarctic mainland, but rather are on nearby islands.
Neither one of these tells us the true story though. Many of the manned stations are clumped together on the Antarctic peninsula which is the warmest area of the mainland. So in order to figure this out, we need to distribute the station information according to area. Below is a plot of Antarctic temperatures in June 2009. The temperatures are distributed on a grid according to closest station.
This is early winter in the Antarctic. You can see by the blockiness that there is considerable spacing between some stations. I created one plot per year distributed on this grid of 5509 station coordinates and then plotted a histogram of the result.
You can see from this that there are very very few measurements ever taken on the Antarctic continent that exceed zero degrees Celcius. These are month long averages of course but from the area weighted plot only 1.8 percent of all of the temperature measurements have ever exceeded zero C for a monthly average. Also from this data, the average temperature for the Antarctic (summer, spring, fall and winter) is a bone chilling minus 26.29 degrees C. Twenty six degrees below freezing — average.
Only 0.1 % have ever exceeded 2C for a month.
If we were to have 2 degrees of uniform warming a full 6 percent of the temperature measurements would cross the monthly freezing line — but the key is, which stations cross into positive territory?
Hmm, the peninsula is above zero like 20 percent of the time. The graph below shows what percentage of stations would cross zero if we had a uniform 3 degrees of warming. I did this by calculating which stations have ever crossed minus 3.
The whole eastern edge of the image shows about 10 percent of the time above minus 3 C. So if we had 3 C of warming this century, this area of the Antarctic would see a very small fraction of the year – very slightly above freezing.
It’s incredible that anyone would claim that the Antarctic could substantially melt in even a century scale timeframe due to human influences. However, that makes it one of many unique things I’ve learned about climate science.
Other key sections of code:
</p>
<p style="text-align: left;">### Parse for ground stations (NOT RUN)
Yo = window(allsta, start=1957)
surf.coord = all.idx[,2:3]
statnumber = length(surf.coord[, 1])
colnames(Yo) = dimnames(allsta)
### Find nearest stations (NOT RUN)
stationindex = array(0, dim=c(5509, 636))
### Cycle through each time
for (j in 1:636)
{
### Find stations with data
grndmask = !is.na(Yo[j, ])
### Cycle through each grid point
for (i in 1:5509)
{
### Get distances
dist = gCirc(surf.coord[, 1], surf.coord[, 2], sat.coord[i, 2], sat.coord[i, 1], 6371)
print(min(dist))
### Store nearest station
stationindex[i, j] = which(min(dist[grndmask]) == dist)[1]
}
print(j)
}
tempdat=array(NA, dim=c(5509, 636))
for (j in 1:636)
{
tempdat[,j]=allsta[j,stationindex[,j]]
}
hist(all.aws,main="Raw Histogram \nAutomatic Weather Station Temperature Measurements\n Since 1956",breaks=40,xlim=c(-90,20),xlab="Degrees C")
savePlot("c:/agw/plots/antarctic histogram AWS.jpg",type="jpg")
hist(all.manned,main="Raw Histogram \nManned Weather Station Temperature Measurements\n Since 1956",breaks=40,xlim=c(-90,20),xlab="Degrees C")
savePlot("c:/agw/plots/antarctic histogram manned.jpg",type="jpg")
hist(tempdat,main="Area Weighted Histogram \nAll Antarctic Temperature Measurements\n Since 1956",breaks=40,xlim=c(-90,20),xlab="Degrees C")
savePlot("c:/agw/plots/antarctic histogram.jpg",type="jpg")
the Air Vent 
Your graphs and presentations are very clever. They certainly impress me, but then I remember the stir caused in the medics’ dining room by the first calculator we had ever seen! (about 1966).
Please can at least some (one) of our politicians discover your site.
Great post – please can I check that I’ve understood? Is the first of the two percentage normalised plots the current situation or the minus 2degC situation? The text initially implies you are exploring the effect of 2degC warming and then you appear to present two graphics the second of which explores the effect of 3degC warming. Also I’m sorry but I don’t understand but what is the “grid of 5509 station coordinates”? – sorry if this is a dumb question.
And FWIW I think the shape of the area weighted histogram is interesting. The relative lack of frequencies in the minus50degC seems curious? Looking at the gridded temperature plot for June2009 it seems there is a big jump across the boundary from Concordia to Casey and Vostok to Mimy. I used to have a plot or link to the READER station locations but can’t find it at the moment. I’m guessing the step is explained by a lack of intermediate stations between the coast and the deep interior of Vostok? I think a plot of actual station locations would help the post. Thanks
A minor quibble on your input data. Some of the stations listed are not within the Antarctic circle. Some (eg Macquarie Island) are not even in Antarctica. As for where “Marion” is, at 46.8 degrees South, I’ve no idea. Getting rid of the spurious stations would probably lose most of the higher temp readings.
#3 Alex, The closest station algorithm sorts out stations which are not in the area. I mentioned them in the post. They are not used in the main histogram or the final plots.
OK, I missed your ref to “nearby islands”. Not sure that I agree about “nearby”! Gough Island, 40.4 degrees south? And I didn’t pick up that they were excluded later on. Your overall point is well made, an excellent post.
REPLY: Where else except climate blogland can someone put up an obscure reference to temperature stations and receive qualified criticism of which ones you used. Nice job.
The whole eastern edge of the image shows about 10 percent of the time above minus 3 C. So if we had 3 C of warming this century, this area of the Antarctic would see a very small fraction of the year – very slightly above freezing.
It’s incredible that anyone would claim that the Antarctic could substantially melt in even a century scale timeframe due to human influences. However, that makes it one of many unique things I’ve learned about climate science.
you are repeating an error that Steven Goddard kept making while talking about arctic sea ice.
temperature is measured in the shadow and averaged over time (a month here!) and a region.
melt happens in direct sunlight, during the hottest part of the period and in the hottest place of the region.
your analysis is lacking a basis…
Jeff,
I am interested in learning from your analysis. I downloaded the first section of R code; but it is missing “getReader()”.
I have looked in a number of places on the net with out finding it. Would you mind supplying a link to this R library code?
Thank you for the article and your effort. I believe there is quite a bit I could learn.
GMcKee
getReader = function(x = reader.names, type = "surface") { ### Set up dummy time series reader.data = ts(matrix(NA, ncol = 1, nrow = 800), start = 1957, freq = 12) for (i in 1:length(x)) { ### Download READER data data.url = paste("http://www.antarctica.ac.uk/met/READER/", type, "/", x[i], ".All.temperature.txt", sep = "") temp = read.table(data.url, sep = "", skip=1, na.strings = "-", stringsAsFactors = FALSE) ### Make a logical array to throw away pre-1957 datemap = (temp[, 1] > 1956) temp = temp[datemap, ] ### Get earliest date startdate = temp[1,1] ### Stack to a single column and make a time series temp = ts(matrix(t(temp[,-1]), ncol = 1), start = startdate, freq = 12) ### Place data into reader.data reader.data = ts.union(reader.data, temp) } ### Remove dummy column and return reader.data = reader.data[, -1] colnames(reader.data) = x reader.data }That’s courtesy Ryan O again. Sorry I left it out.
I’ve also left off quite a bit of the graphing functions. Let me know if you need that too.
here’s another chunk you’ll need. Sorry, these were located in multiple files on my workspace. Sometimes people don’t run the code but just read it, I’m glad to see others with interest.
gCirc = function(lat.1, lon.1, lat.2, lon.2, r) { ### Convert to radians lat.1 = lat.1 * pi / 180 lat.2 = lat.2 * pi / 180 lon.1 = lon.1 * pi / 180 lon.2 = lon.2 * pi / 180 ### Get delta longitude D.lon = lon.2 - lon.1 ### First numerator value D.rho.num.1 = (cos(lat.2) * sin(D.lon)) ^ 2 ### Second numerator value D.rho.num.2 = (cos(lat.1) * sin(lat.2) - sin(lat.1) * cos(lat.2) * cos(D.lon)) ^ 2 ### Calculate numerator D.rho.num = sqrt(D.rho.num.1 + D.rho.num.2) ### Calculate denominator D.rho.den = sin(lat.1) * sin(lat.2) + cos(lat.1) * cos(lat.2) * cos(D.lon) ### Calculate angular distance D.rho = atan2(D.rho.num, D.rho.den) ### Calculate linear distance d = r * D.rho d }The mass balance of Antarctica is a balance between the snow accumulated on top and the ice lost (ice calving, sublimation and surface melt). For ice sheets the loss occurs in an extreme narrow coastal region and yet it balances the gain in central regions. A change in climate will influence both the loss and gain terms.
To think that you have proved that there can be no net mass loss simply because temperatures are generally below freezing on the continent is ludicrous. Sorry.
#11 Precip
To think that I’ve claimed that there is no possibility for mass loss is also silly. It’s just not as great a problem as climate science would have us believe. Climate science is better at predicting temp than local long-term precipitation caused by CO2. Saying global warming will melt the Antarctic is just silly crystal ball hand waiving. If the water falls from the sky, sit frozen on the Antarctic ground it will!
I don’t agree with sod’s opinion as usual (whether you get a net growth depends on two factors, net loss of ice during summer, versus total snow accumulation during winter, but he’s right it is more complicated than you have suggested).
The other (real) issue is warming ocean currents and the issue of the stability of the West Antarctica Ice Sheet (WAIS), which due to subsidence sits on the ocean floor. Nobody who should be taken seriously is suggesting the much larger East Antarctica Ice Sheet is going to melt… in fact the predictions are it will grow in size because of increased precipitation from warming climate.
If the WAIS melts, we could expect as much at 5-m rise in sea level from it, though 3-m net loss over a 1000 year melt period is more likely (that works out to an additional 3-mm/year average).
Carrick,
I just don’t see how any substantial portion of the Antarctic is capable of melting with the temperatures predicted by the IPCC. Certainly extreme things happened on ten thousand year timescales in the past but it’s not reasonable to think that a couple degrees C will melt any portion of the Antarctic.
http://www.skepticalscience.com/antarctica-gaining-ice.htm
Jeff, check out the wiki link.. The issue is ice loss via the interaction of the WAIS with ocean currents not ice loss from melting.
Jeff ID, while your data and graphs dramatically show how cold it is Antarctica, I am quite sure that one could show that under certain climate conditions that a net ice loss could be experienced under average cooling temperatures in Antarctica and a net gain in ice realized with a general warming in the same region.
What about sublimation of ice at temperatures below the freezing point?
I still feel that behind the Eric Steig et al. paper on the Antarctica was the authors’ intentions to imply that the warming in the Peninsula could and was spreading not only to West Antarctica but to East Antarctica also. And that did happen in their admittedly less than realistic method of apportioning the Antarctica temperatures (trends). Showing an eastward warming trend would also increase the possibility of reinforcing the worry about a faster meltdown on the Antarctica.
I also think it is better to look at the thesis for a rapid destabilization of the West Antarctica Ice Sheet and determine how substantial the evidence and theory backing it are than to throw out our own personal anti-thesis. I noticed that Carrick’s link to the WAIS talks about destablization and references the Steig et al. paper.
I don’t think Jeff’s post works as a formal, logical refutation of the possibility of significant ice loss in the Antarctic given the temperatures discussed. What it is, though, is a very helpful, pragmatic smell test — something that is so often missing in this field.
There are so many things that are pushed by CAGW that just don’t pass the smell test. Could they occur as a matter of logic under certain circumstances? Perhaps. But do we have any reasonable basis for thinking they will occur? Probably not. Jeff’s post is helpful in precisely that vein.
Those making grand claims about this or that event occurring in the future bear the burden of proof to show detailed scientific support for their claims. The idea that such claims can simply be stated and then the burden shifts to others to refute the claims is nonsense.
Eric,
That is exactly the point. Of course ice in the Antarctic can melt and sublimate but you have to get your head around the magnitude in order to take alarmist points in context.
Carrick,
While you are correct about some of the discussions on melting, Wiki is a particularly bad source of information on the Antarctic. They tend to retain conclusions from the warmest papers and ignore the better quality ones. It’s not a total 100% bias but I’ve read enough now on the Antarctic to detect the problem. For instance, Ryan calculated a trend of 0.06C/Decade for west Antarctica using one method and 0.10 for another. Both use infilling methods which by their nature, tend to bleed peninsula warming into larger areas. The meaning of two trends with so much difference is that we don’t have the fidelity of measurement required to narrow it down. Wiki still writes about the West Antarctic warming of 0.10C/Decade as though it were known fact.
I guess what I’m saying is that the WAIS is in absolutely no danger of going anywhere from a bit of warming. It might change, we might see some sublimation and reduction but it will still be there for the next several thousand years even if we see 5C of warming – which I very much doubt also. In several thousand years, if the sheet does melt, we can simply move. The buildings, farms and whatever else will be in need of updating by then anyway.
Jeff, I have to disagree with you on this one. Wiki is completely in line with other references I’ve seen with respect to the mechanisms for WAIS collapse. Certainly their explanation for the collapse is much better referenced that your dismissal of it.
Your theorized mechanism has nothing to do with the reasons that scientists have given for ice loss, which again are related to the marine nature of the WAIS.
I’m not sure why this is so hard for you to admit.
#21 I am only pointing out that it will be incredibly difficult for the Antarctic to melt. Laypeople don’t understand how cold it is because they haven’t seen the data.
On another topic if you chose the Antarctic wiki version because they found links to papers that’s fine. I would mention that there are papers on that wiki list which exaggerate the problem. Is that enough of an admission?
By the way, what collapse?
Jeff, I think that if you are saying that we should be weary of references that are used to speculate on a rapid change in sea level and ice losses from the WAIS, I would agree and say we could have an interesting thread just delving into those references a bit.
Remember that Jim Hansen has been in the forefront of a rapid loss of ice from the WAIS by it reaching one of his alarming tipping points that he so frequently uses as a talking point to influence public opinion on climate change. To me those kinds of statements are red flags for looking more closely at the evidence behind these conjectures. Based on their biases, I am sure that the IPCC would have not hesitated to use the Hansen tipping point if it had any number of references that could have backed that conjecture. We could start by looking at the Wiki references.
The foregoing from the WAIS Wiki article, while citing several references, certainly, in my view, is worded very much as conjecture at this point.
#21 I am only pointing out that it will be incredibly difficult for the Antarctic to melt. Laypeople don’t understand how cold it is because they haven’t seen the data.
“laypeople” will be seriously confused by your article. you do not even mention the mechanic that makes the Antarctic lose ice mass.
instead you make false claims about temperatures below the zero making melt impossible.
Carrick is 100% right.
I don’t mention it because I don’t believe it has any chance of melting the WAIS. I find the whole argument about the WAIS completely unconvincing.
Sure there will be short term stuff, there always is. Long term melt the whole thing….. hmmm. …nope it’s way too cold.
I think that you will find that the references from the Wiki article are mainly editorializing. The best reference I could access is excerpted below and gives the state of the “art” on the WAIS. Much uncertainty.
http://www.jsg.utexas.edu/walse/statement.html
I think I would believe Jeff rather than wiki on anything related to AGW.
Just look at the text quoted by Kenneth. At first glanced it looks well referenced. But [4] is not a reference at all, it’s just a footnote. [5] and [6] turn out to be the same paper. [7] and [8] are just quotes from BAS, more or less duplicate. [9] is scaremongering newspaper article quoting Hansen. So there is one paper.
The section on warming is based on Steig et al which we know is a load of ****.
A masterpiece of disinformation by Connolley and his team.
Kenneth F
I gave up on Wiki as a credible source for anything “climate”, having seen instant and biased editing, which is well documented on CA and elsewhere. It surprises me not that wiki would quote Hansen. Tainted as badly as the worst of CRU and Gore.
Chip Knappenberger explains in the link below how the supposed IPPC “review” becomes (my words) a biased assessment of the literature on Antarctica sea ice trends. He also points to referencing which is implied to but does not support the IPCC assessments. All similar to what Wiki does with its references on such climate topics.
It is all well and good to conjecture, but it is very important to then call a conjecture a conjecture.
http://www.masterresource.org/2010/03/yet-another-incorrect-ipcc-assessment-antarctic-sea-ice-increase/
Jeff ID:
It’s easy to understand how ocean currents lead to calving of ice and how that could accelerate ice loss. At the least you have to admit the studies are based on physical models of the interaction of ocean currents with ice sheets. Whether or not in a warming globe this is accelerated is one question, but it’s quite clear the Antarctica surface temperature plays no role in the conjectured accelerated ice loss.
Mark and the others…what you are doing by dissing wiki is just another form of the “attack the messenger” logical fallacy. I counted 11 studies cited in that section. That’s 11 more than Jeff and the rest of you have cited in rebuttal.
I still find it remarkable that people think that hand-waving is a subtable substitute for rigorous study. In this case, I haven’t even seen an argument beyond “I can’t believe they cited Hansen”. Or anything that approaches a credible explanation from Jeff for why he finds the various computer-based models “unconvincing.
Carrick,
You’re a smart guy, do you believe the WAIS will calve away or from the papers you’ve read do you find the discussion convincing? It’s as several have pointed out, a lot of conjecture with no real knowledge.
All that aside, the title of the post is why the antarctic isn’t going to melt anytime soon. I make no argument about sublimation or additional calving. The point of it was to show people just how far below zero the Antarctic is so they can judge for themselves whether the WAIS will be there in a hundred years. I would bet big money that it will definitely still be there and won’t look much different from today.
I don’t feel the need to cite any papers on temperature, but I certainly could. We’ve submitted on the topic and that required reading a LOT of antarctic papers. I’m very much familiar with the arguments you present, and as I said earlier, there is plenty of exaggeration IMHO.
Carrick, it is stretch to say that 11 references to “studies” were presented in the Wiki article. Much of the referencing is circular and really reference only a small amount of original work. In fact there is common phrase used in many: slumbering giant is awakening or something parenthetical to that. I count six papers referenced.
We can, of course, all read the references from Wiki and decide what they mean because hard evidence to support the conjectures does not evidently exist.
Finally, I think that we all can recognize that Jeff Id’s antithesis is conjecture, but I sometimes think that that nuance is lost with Wiki when one can say “see here this link to Wiki” and without further comment or support.
I had only a single reservation on the Knappenberger comment and replies and that was that no one talked about the amount of auto correlation of the series and the need to adjust the CIs if the correlations were significant/sufficient. I do not believe that was an issue with the IPCC either. When Knappenberger was discussing monthly versus annual data was an ideal time to broach the subject.
Carrick,
I am not looking at Wiki. Please list links to those papers you claim support the idea of increased calving or whatever MIGHT cause a reduction of the Antarctic ice sheet so we can evaluate them.
If they are like much of what is in the IPCC AR4 you lose.
Jeff when you make the above statement you need to be more precise. A melting Antarctica means what? Obviously the Antarctica melts/sublimates (partially) all the time and then refreezes so that meaning would be meaningless. On the other hand, the Antarctica melting all the way and all the time would be nearly as meaningless unless the temperatures there reached those of southern FL.
That is why I find problematic the statement that the Artic ice will melt completely without noting that it will refreeze to some extent in the winter and melting “all the way” means at its minimum area/extent.
I think the important considerations/consequences with melting of the Artic is what it will do to the earth’s albedo and setting up any significant feedback effects.
With the Antarctica the important consequence would be a net change in ice accumulation over long periods of time and its affect on sea levels. By the way, should we be concerned with a lowering of the sea levels? I once visited a college acquaintance with a home on Lake Michigan in Gary, IN and then proceeded to walk several blocks to get the shore of a then temporarily depleted lake.
Jeff ID:
Let’s put it this way Jeff. If I were to test whether the WAIS was melting or not, I would start with the theories that say way it’s melting, not invent my own theory that is at odds with why they say it is melting, test the theory and “prove it’s not”.
You start with the theory and its premises if you want to disprove it. You don’t invent your own.
I suppose that would be the case if I were to attempt to disprove the calving. I believe it very much exists and it has existed for a very long time.
Proving or disproving that is an entirely different post.
Jeff, the title of your post is “Why the Antarctic Is Not Melting Anytime Soon.” If the standard theory is related to the instability of the WAIS to ocean currents, and what you’ve addressed a completely different theory, not supported by any researcher in the field…
…don’t you see there’s a problem here?
Carrick,
While I see your point, I don’t consider it a problem, sorry. When you ask less educated people about sea level rise, global warming and the Antarctic, what is the standard type of answer? They think it will warm, the ice will melt and the sea will rise. Actually, it’s not so easy or fast a process. One of the things I’ve done here since the beginning is display data so that non-experts can grasp the magnitude of the claims. When I see large sections of the Antarctic which have never measured above zero average temp, it has meaning to me.
People really think the Antarctic will get warm enough to melt. So I made a post saying why it won’t happen any time soon.
On a separate topic, you may consider me more skeptical of the WAIS stuff than I should be but the quality of our knowledge of the WAIS followed with conclusion really doesn’t help my attitude about the science in general.
It is interesting to note that from this plot the peninsula could in fact show quite a bit of melting. The mainland is pretty safe though in my opinion.
Carrick and Jeff why argue about your hypotheses when you can both state what a reasonable one would be for what you are conjecturing/theorizing. For Carrick it would be his interpretation of the calving and instability hypothesis and not that he accepts it.
I would think that one would need a clear cut and detailed explanation of what is meant by a “melting” Antarctica and how you get from an increasing trend in calving over relatively short time periods over replenishment locally/regionally to a tipping point for large net losses from the AWIS over long time periods.
Here are the issues I have with claims that there could be significant melting from the Antarctic and resulting sea level rise any time soon:
When you get past the headlines, the posited cause is warmer ocean water causing the melt. My first problem with this is that the steady increase in extent of Antarctic sea ice over the satellite period makes it very hard to believe that the Southern ocean has increased ability to melt fresh water ice when it has decreased ability to melt sea ice (whose melting point is several degrees lower).
But suppose the waters around the Antarctic really are warming. The argument there is that the warm water under the ice shelves has increased ability to break off large pieces that will then float away to warmer waters and melt much more quickly. Even if true, due to the fact that the ice shelves are already floating, there will be no discernable effect on sea level.
If the sea water is in contact with “grounded” ice sheets (i.e. no ice shelves), then it is only in contact with the edge surface, and a degree or two of difference in sea water temperature will make very little difference in the rate of melting of the ice.
The cited Wiki article says that “Large parts of the WAIS sit on a bed which is below sea level and slopes downward inland.[4] This slope, and the low isostatic head, mean that the ice sheet is theoretically unstable: a small retreat could in theory destabilize the entire WAIS leading to rapid disintegration.” This leaves me scratching my head. Anyway I think about it, this “sloping downward inland” should be a powerful stabilizing effect (and my graduate work and professional life has always been in feedback systems). Can anyone point me to a source that shows why it might be the opposite?
Kenneth Fritsch:
Yes I agree with this. What I would say though is it should be an agreed to interpretation of what the scientists are claiming. While it’s worthwhile debunking common place notions (to the degree that anybody who actually holds those views is visiting this site), IMO one should spend your time examining the theoretical framework for ice loss, and I claim that is tied to the instability of the WAIS.
I also think some people are conflating criticism of a method with belief in a particular outcome. That’s not here in my case, I hold no strong opinion about the stability of the WAIS either way…
Curt:
I admit I don’t full understand that one myself… It might be worth digging up the IPCC report and see if they summarize the physics of this a bit better.
Carrick, I would really like to see a post from you at sometime. Honestly, you are very educated on AGW (and other things), you have a view which is different than my own many times. People don’t always need to read my thoughts, and it would be interesting. I’m sure you have figured out what blogland expects.
My guess is that it wouldn’t take you much effort for you to write an opinion piece. It may be fun to write a math one also.
Interesting discussion. There was a very interesting guest article posted at RC by Mauri Pelto last year: http://www.realclimate.org/index.php/archives/2009/11/is-pine-island-glacier-the-weak-underbelly-of-the-west-antarctic-ice-sheet/
When drilling deep into rock over the decades, geologists learned that there were surprises. Seismic reflection interpretation methods improved steadily as more ground truth came in, but some of the most fundamental surprises came from the Russian Kola Superdeep drill hole that reached over 12,000 meters (40,200 ft). Because this was such an expensive program, the Russians took the time to do many secondary experiments that are not normally done in deep commercial holes because they are not vital.
One of the findings was that the concept of pressure variation with depth had to be rethought. As an example, some minerals start with water of dehydration which can be expelled at depth to give an overpressure in metamorphism. This overpressure – or another mechanism of several hypothesised – can cause microfracturing of the rocks at depth and it can open up the rocks for the passage of water. Indeed, at Kola, not just water but water with bacteria was found at depths of over 6 km. (The possibility of contamination should not be excluded).
Rock minerals are more complicated than ice. The rate of new learning about deep holes in rocks has parallels to deep holes in ice. That is, it would be unwise to assume that we know most of what needs to be known about ice recovered from deep cores.
Have a think about pressure variation with depth in deep ice holes. Ask yourself if pressure closes them immediately after the drill apparatus is removed. Keep an open mind about the possibility that there is microfracturing, water migration, bacterial life ….
Consider (in the context of this thread) that even if ice melts at the surface, it might move in part or in whole under the surface, to re-freeze. Have you ever seen a temperature profile down a deep ice hole like Vostok? Or a log of porosity or permeability?
The book of learning should not be closed lightly.
Jeff, I would love to take you up on that offer. My boss would probably kill me if I took the time necessary to do that right now. Maybe when things wind down a bit. That’ll give me plenty of time to consider a suitable topic.
47,
Might I suggest ocean heat accumulation measurements (where there are currently published estimates of post-2003 that are divergent), or any of the multitude of climate related “tipping points”. A critical and reasoned reviewed on any of these would be informative.
Not that I have a voice, but I second the Carrick nomination. An independent and informed mind.
===========================
Thank you Kim for the kind words.
SteveF, Knox and Douglas might be a good place to start.
Re: Carrick (Sep 20 20:27),
If the surface under the glacier slopes upward, then as the edge of the glacier retreats, the bottom of the ice will eventually be above sea level. If it slopes downward then retreat will expose more ice to the ocean.
DeWitt:
Yep this makes perfect sense. Thanks.
#24:
Basic question: What does this mean, “and slopes downward inland”? To me, that says the slope is AWAY from the open ocean.
Even if it means the opposite of what I read, I have two points.
1. Does anyone know anything at all about the underlying topography? If it is anything like the Antarctica I’ve seen many times in films and videos, it is extremely rocky and uneven. Such a configuration has a “mechanical grip” on whatever lies on it – meaning that it is not just friction holding the ice, but the jaggedness of the bedrock. This could completely hold the ice sheet, regardless of melting – until the weight above relieves the ice sheet to the point of floating.
2. ALL ice sheets are inherently unstable. Those that float certainly. Those anchored to the bedrock ARE anchored to the bedrock. And how that configuration changes over time KNOW ONE KNOWS.
The Wiki article starts out with “a small retreat could in theory destabilize the entire WAIS. [emphasis added]” This is patently speculation. A small retreat could destabilize PARTS of the WAIS. Small parts. There is no way the entire anchored ice sheet is going to be destabilized by a small retreat.
Wiki, in “publishing” an uncertainty has an obligation to spell out the OTHER side of ant uncertainty, not to just give the uncertainty and then stop right there. When the bulk of the evidence is that the ice sheet has been there for many tens of thousands of years, the empirical evidence is that this likelihood is extremely doubtful. Only claims that now is an unusually exceptional time are the only way they can make such a speculation and expect to be taken seriously. But when they do so, they also should expect someone to challenge their extraordinary claims.
#6 – Sod, what do you think happens to ice that melts on the surface of mile thick ice? It runs downhill – into the mass of the frozen ice. And what happens there? It will get refrozen, in almost every case. It is not like there are huge rivulets running down to the base everywhere. At the edges, yes, it melts there and runs down, just as it calves ice. In fact that is a part of the process of calving – the ice is weakened by warming enough that the leading edge cannot keep cantilevering more and more out in the water; the buoyancy is not enough to provide enough “reaction force” to counter the weight. But to look at what happens on the edge and extrapolate that to what is going on OVER solid ground does not make sense.
That melting happens “in the hottest place of the region”. Jeff doesn’t deny that happens. And you say melt happens – but ONLY when the hottest is above 0C. It will even happen when NOT the hottest is above 0C. Go figure! But that is exactly what his graphs are intended to point out.
But his other point – his MAIN point – was that it WON’T melt, even “during the hottest part of the period” – UNLESS that hottest part ALSO is above 0C.
Or did you miss those points? But you are also wrong in saying, “melt happens in direct sunlight,” as if that is the only time ice melts. Ice in shadow will also melt, of course, if the temp rises above 0C. I assume you meant primarily in direct sunlight.
All in all, that sentence LOOKED like it said something solid, but it had holes in it from start to finish. We assume you meant to say all that in a way less vulnerable to criticism, but what you did say wasn’t very true, all in all.
Of all the references in Wiki article linked by Carrick the one linked below is the best in explaining the mechanism that are thought to or might be operating in producing glacier calving in the WAIS. I do not see any hard evidence that these mechanism are well understood and appear to be a work in progress.
Note though how these articles tend to play out. Reference to a conjecture (even though it might be well thought out one) for a mechanism, then you add in some re-estimates of what that mechanism might produce in a worst case scenario with regards to sea level change given a catastrophic loss of WAIS ice and finally make references to a sleeping giant and some iffy references to it probably being caused by global warming.
The source of calving increase is apparently warm ocean currents that are influenced primarily by wind and changes in wind. The big “if” in connecting the increased calving of WAIS to global warming then becomes connecting changing wind currents to global warming and assuming that these currents have not operated in relatively recent times when the earth was cooler.
http://books.google.com/?id=f9YqF73oe4IC
#27 –
I just have to take that and jump all over it.
They put human influence first in that short list of possible causes.
Fact: The Intertropical Convergence Zone blocks all but a very small percentage of NH winds from getting to the SH, and vice versa. It is a REAL barrier. The climate of the two hemispheres are two independent systems. The only appreciable interaction between them is that the ICZ moves north or south a bit from time to time.
The NH Hadley Cell and the SH Hadley Cell have practically no mixing between the two – and in order for NH influences to get to the Southern Ocean, that mixing must first occur.
With the great majority of human CO2 and OTHER possible climate-changing effects occurring in the NH, this makes no sense, to think that NH activity causes problems in the Antarctic. Is there enough climate-threatening human activity in the SH? Well, it is FAR less than the NH had, say, 50 years ago, in the mid-20th-century cool down period. Was the ARCTIC melting 50 years ago? No.
So attributing any current Antarctic calving/melting to the relatively meager SH human activity OR much greater NH human activity fails on both counts. In one case, it defies historical reality, and in the other it defies meteorological reality. Warming effects in the SH aren’t enough by themselves, and warming effects in the NH can’t GET there.
#50 Carrick,
I had already read the paper you pointed out. Here is the problem (from that paper):
This study Average = 0 – 700 – 0.063 +/– 0. 15
Loehle [8] 0 – 700 – 0.22 ± 0.3 – 0.31 ± 0.3
Pielke [7] 0 – 700 – 0.076 ± 0.214 – 0.163 ± 0.214
Douglass and Knox [9] 0 – 700 – 0.157 ± 0.99 – 0.244 ± 0.99
Von Schuckmann et al.[10] 0 – 2000 + 0.77 ± 0.11 + 0.68 ± 0.11
And let me add Cazenave et al (2008) 0 – 700 – very low (implied from thermal expansion attribution)
A perfect example of “they can’t all be right” if I ever saw one. The contribution below 700 meters is expected to be very small over any short period, yet Von Schuckmann et al come to a drastically different conclusion than all other studies. Please note that Von Schuckmann is being used (routinely and consistently) to suggest that the GCM’s are right, the climate is extremely sensitive to radiative forcing, and (of course)… we are all doomed without cap and trade.
Is this incredible discrepancy due to a HUGE contribution of heat below 700 meters? Or is it just that the Von Schuckmann methodology (clearly not the same) is simply nutty? I noted in reading each of the individual papers that every one except Von Schuckmann shows a very clear annual heat signal (not surprising) while Von Schuckmann shows none. Makes me rub my chin and say… ‘Wait a minute…’
I think a smart guy like you could shed some light.
Certainly it’s unknowanty but there is much of that these days.
Re: feet2thefire (Sep 21 17:00),
The ITCZ doesn’t block ocean currents. So far, however, I haven’t found any evidence that there is a net flow of energy in the ocean from one hemisphere to the other.
#58
Google “cross-equatorial winds”. There is a net exchange of heat energy flux from hemisphere to hemisphere, even within atmospheric circulation alone.
One reference that pops up:
Mantis and Clement, GRL 36, 2009. (Behind a pay wall unfortunately.)
There’s also a thesis on line by Heaviside, 2010. See chapter 3.
It would be interesting to look at measurements of mean cross-equatorial winds. The claim is that currently there is a net transport north-to-south (there has to be of course, if the north is heating up faster than the south).
Carrick,
The north-south differential could be one of the strongest indicators of warming. It’s too bad the ocean isn’t more balanced. — no that isn’t facetious. Were the hemispheric ocean area more balanced we would have much better quality answers.
Cross-equitorial winds? Winds around antarctica? Surely we’re not suggesting that these are the same thing and that, therefore, there is a transport from the NH to the Antarctic region? Maybe the NH and Antarctica are teleconnected?
Re: Eric Anderson (Sep 23 02:56),
There does seem to be some evidence that the polar regions of the NH and SH move in opposite directions or at least the rate of change does. That suggests that at any given time there is net heat transport from one hemisphere to another and that it can change direction. This transport, if it exists, may be related to the AMO and the PDO. We have 150 years or so of AMO and (IIRC) PDO data but we only have fairly good ice coverage data for the last 30 years.
The closure of the Isthmus of Panama and the separation of South America from Antarctica are thought by some to be related to the current state of affairs like the Antarctic ice cap and the ice age cycles of the last 2 million years.
Perhaps someone should ask Bob Tisdale to chime in.
My impression from his charting of official sea surface temperature data is that, if anything, the Southern Ocean has been through a slow multidecadal cooling trend.
That says nothing about ocean currents or what could be happening a few hundred metres below the surface. But really, where is the evidence that changing currents are causing increased calving.
I have little faith that the “models” can really predict with reliability future changes in circum-antartic currents and marine heat transport.
Something else that should be examined- what does the Argo bouy network say about deep water temperature and measured heat content in the Southern Ocean (as opposed to the global ocean)? Is the heat content of the Southern Ocean actually increasing or is it stable to declining as in the global ocean since about 2003?
Is there a chance that local oceanic cooling could increase the stability of the WAIS? After all the supposed global atmospheric warming hardly seems to have diminished the winter sea ice extent around Antarctica over the last 30 years.
Carrick #59
A 2009 thesis presenting the Ferrell 1856 tri-cellular model of atmospheric circulation… LOL
Tom, I guess you were talking about Figure 1.2? It appears in the background section via an Encyclopedia Britannica illustration. Obviously it’s pretty simplistic, but he didn’t seem to rely on it. Figure 1.6 gives a more complete picture.
1) http://www.skepticalscience.com/Antarctica-absolute-temperatures-too-cold-ice-loss.htm
2) Paleoclimate studies suggest that sea levels were significantly higher in the last interglacial, with only slightly higher global temperatures. Now, temperature estimates going back 100,000 years are hard, but if the interglacial _was_ a lot warmer than is currently estimated, that would suggest much higher climate sensitivity. There is some differences in orbital state in terms of season length and warming distribution, but analysis suggests that those differences shouldn’t have led to major differences between Antarctic state in the interglacial compared to today.
A good reference for the paleoclimate stuff is http://www.nature.com/nature/journal/v462/n7275/full/nature08686.html
Key paragraph from Clark and Huybers (discussing the results that Kopp et al. showed):
“Evidence that sea level during the last interglacial was 4–6 metres higher than at present has long been proposed as a possible analogue for the equilibrium sea-level response to future anthropogenic warming5,6. But the sea-level records may include a local response to geophysical adjustments from the preceding glaciation, and thus may not accurately record the global sea level7. Furthermore, the implications of 4 or 6 m of rise are quite different: if sea level increases by only 4 m, much of it can be reconciled as being due to thermosteric rise and partial loss of the Greenland ice sheet; anything more requires a contribution from Antarctica.”
So, at least according to Kopp et al., there is decent paleoclimate evidence that a significant chunk of WAIS did melt, when global temp was only 1-2 degrees warmer than today, and there is some evidence that the rate of SLR at current SLR was two to three times the present rate…
Our theoretical understanding of ice sheet loss mechanisms is, admittedly, not great yet, but combined with the paleoclimate results is fairly suggestive, and I don’t think the level of confidence you present about Antarctic melt based on your analysis is at all justified given the existing evidence. (I’m not saying it is 100% certain that the WAIS is doomed to melt if global temperatures rise 2 degrees C – but it seems likely that a decent chunk of it will be vulnerable at that temperature. I have more uncertainty about the rate of that melt… eg, will it contribute a few mm this century, a few cm, or tens of cm? Any of those seem plausible)
-M
Jeff # 8, 9, 10
Thank you very much for the missing R functions. I included them into the R script from your original post, and it now runs and generates output files.
Am I missing a link on the network to Ryan O’s R code? I don’t mean to take your time while I am getting up to speed, but the graphic routines do sound like they would be useful.
FWIW, I don’t have much to contribute on WAIS or sea level changes. I am more inclined to explore the spatial-temporal temperature characteristics. If I understand some of the information on your blog correctly, the Antarctic temperature data could be a good starting point for some EDA on my part.
I apologize my delay in getting back to you and this topic. I thank you for your help in obtaining the necessary R source code to have a set of temperature time series to explore. I am still very much at the nuts and bolts stage and feel that I still have quite a bit to learn.
GMcKee
Whether or not global warming exists is irrelevant. Everybody agrees that fossil fuels are an unrenewable resource, right? We need alternative energy resources to prevent a future energy crisis that could take place when we eventually run out of our precious fossil fuels. So for those who believe global warming is a hoax, we still need to make decisions that would decrease global warming if it is actually true. The methods that are used to prevent global warming also preveent a future energy crisis. So for those who believe in global warming, there are two disasters averted, and for those who doon’t believe in global warming, there is one crisis averted.
Thinker,
There is no renewable energy ‘replacement’ for fossil fuels. They will be replaced in time as they run out 100% without disastrous legislative fiat. I believe they will be replaced faster if we do nothing except use the lowest cost source. Legislation of non-working technologies like biofuel and wind are simply corporate payoffs and have nothing to do with ‘greener’ or better energy. If you are one of the die hards who beleives that we ‘must do something’, your only engineering choice which has any possibility of making a significant dent, is nuclear.
That is your only working option.
Of course, like most who can write ‘renewable energy’ sentence, I doubt you realize that engineering-wise, there are no other options.