1 00:00:05,990 --> 00:00:50,020 yes 2 00:00:50,020 --> 00:00:50,030 3 00:00:50,030 --> 00:00:52,490 Alaska's Glacier Bay has fascinated 4 00:00:52,490 --> 00:00:52,500 Alaska's Glacier Bay has fascinated 5 00:00:52,500 --> 00:00:54,380 Alaska's Glacier Bay has fascinated naturalists and glaciologists for 6 00:00:54,380 --> 00:00:54,390 naturalists and glaciologists for 7 00:00:54,390 --> 00:00:58,009 naturalists and glaciologists for centuries named the National Monument in 8 00:00:58,009 --> 00:00:58,019 centuries named the National Monument in 9 00:00:58,019 --> 00:01:02,689 centuries named the National Monument in 1925 and a national park in 1980 Glacier 10 00:01:02,689 --> 00:01:02,699 1925 and a national park in 1980 Glacier 11 00:01:02,699 --> 00:01:05,570 1925 and a national park in 1980 Glacier Bay today attracts more than 250,000 12 00:01:05,570 --> 00:01:05,580 Bay today attracts more than 250,000 13 00:01:05,580 --> 00:01:09,710 Bay today attracts more than 250,000 visitors a year just 200 years ago the 14 00:01:09,710 --> 00:01:09,720 visitors a year just 200 years ago the 15 00:01:09,720 --> 00:01:12,700 visitors a year just 200 years ago the entire Bay was covered by glacier ice 16 00:01:12,700 --> 00:01:12,710 entire Bay was covered by glacier ice 17 00:01:12,710 --> 00:01:15,200 entire Bay was covered by glacier ice with the help of ground and satellite 18 00:01:15,200 --> 00:01:15,210 with the help of ground and satellite 19 00:01:15,210 --> 00:01:17,540 with the help of ground and satellite measurements study of the recession of 20 00:01:17,540 --> 00:01:17,550 measurements study of the recession of 21 00:01:17,550 --> 00:01:19,850 measurements study of the recession of the glaciers of Glacier Bay as well as 22 00:01:19,850 --> 00:01:19,860 the glaciers of Glacier Bay as well as 23 00:01:19,860 --> 00:01:21,859 the glaciers of Glacier Bay as well as in other areas is providing us with 24 00:01:21,859 --> 00:01:21,869 in other areas is providing us with 25 00:01:21,869 --> 00:01:24,320 in other areas is providing us with important clues about changes in global 26 00:01:24,320 --> 00:01:24,330 important clues about changes in global 27 00:01:24,330 --> 00:01:30,790 important clues about changes in global climate 28 00:01:30,790 --> 00:01:30,800 29 00:01:30,800 --> 00:01:33,790 a glacier is a dynamic system consisting 30 00:01:33,790 --> 00:01:33,800 a glacier is a dynamic system consisting 31 00:01:33,800 --> 00:01:37,750 a glacier is a dynamic system consisting of snow ice and often rock debris that 32 00:01:37,750 --> 00:01:37,760 of snow ice and often rock debris that 33 00:01:37,760 --> 00:01:39,460 of snow ice and often rock debris that transports material from higher 34 00:01:39,460 --> 00:01:39,470 transports material from higher 35 00:01:39,470 --> 00:01:42,190 transports material from higher elevations where snow accumulates to 36 00:01:42,190 --> 00:01:42,200 elevations where snow accumulates to 37 00:01:42,200 --> 00:01:45,480 elevations where snow accumulates to lower elevations where snow and ice melt 38 00:01:45,480 --> 00:01:45,490 lower elevations where snow and ice melt 39 00:01:45,490 --> 00:01:49,390 lower elevations where snow and ice melt snow becomes glacier ice over time when 40 00:01:49,390 --> 00:01:49,400 snow becomes glacier ice over time when 41 00:01:49,400 --> 00:01:51,040 snow becomes glacier ice over time when the pressure of increasing layers are 42 00:01:51,040 --> 00:01:51,050 the pressure of increasing layers are 43 00:01:51,050 --> 00:01:53,700 the pressure of increasing layers are snow accumulating year after year 44 00:01:53,700 --> 00:01:53,710 snow accumulating year after year 45 00:01:53,710 --> 00:01:56,530 snow accumulating year after year transforms the snow first into fern 46 00:01:56,530 --> 00:01:56,540 transforms the snow first into fern 47 00:01:56,540 --> 00:01:59,590 transforms the snow first into fern which is very dense snow and eventually 48 00:01:59,590 --> 00:01:59,600 which is very dense snow and eventually 49 00:01:59,600 --> 00:02:08,290 which is very dense snow and eventually into ice today there are over 200 50 00:02:08,290 --> 00:02:08,300 into ice today there are over 200 51 00:02:08,300 --> 00:02:10,720 into ice today there are over 200 separate smaller glaciers in Glacier Bay 52 00:02:10,720 --> 00:02:10,730 separate smaller glaciers in Glacier Bay 53 00:02:10,730 --> 00:02:13,270 separate smaller glaciers in Glacier Bay National Park to the delight of park 54 00:02:13,270 --> 00:02:13,280 National Park to the delight of park 55 00:02:13,280 --> 00:02:15,960 National Park to the delight of park visitors who view them from cruise ships 56 00:02:15,960 --> 00:02:15,970 visitors who view them from cruise ships 57 00:02:15,970 --> 00:02:21,190 visitors who view them from cruise ships private boats and kayaks glaciers at the 58 00:02:21,190 --> 00:02:21,200 private boats and kayaks glaciers at the 59 00:02:21,200 --> 00:02:22,870 private boats and kayaks glaciers at the head of tar inlet of the most 60 00:02:22,870 --> 00:02:22,880 head of tar inlet of the most 61 00:02:22,880 --> 00:02:25,840 head of tar inlet of the most spectacular these include the Grand 62 00:02:25,840 --> 00:02:25,850 spectacular these include the Grand 63 00:02:25,850 --> 00:02:29,740 spectacular these include the Grand Pacific and the margaery together they 64 00:02:29,740 --> 00:02:29,750 Pacific and the margaery together they 65 00:02:29,750 --> 00:02:31,960 Pacific and the margaery together they comprise three kilometers of ice front 66 00:02:31,960 --> 00:02:31,970 comprise three kilometers of ice front 67 00:02:31,970 --> 00:02:35,680 comprise three kilometers of ice front which is cowling into the sea the Johns 68 00:02:35,680 --> 00:02:35,690 which is cowling into the sea the Johns 69 00:02:35,690 --> 00:02:37,930 which is cowling into the sea the Johns Hopkins and Marjorie glaciers are each 70 00:02:37,930 --> 00:02:37,940 Hopkins and Marjorie glaciers are each 71 00:02:37,940 --> 00:02:40,120 Hopkins and Marjorie glaciers are each about one-and-a-half kilometres wide and 72 00:02:40,120 --> 00:02:40,130 about one-and-a-half kilometres wide and 73 00:02:40,130 --> 00:02:44,530 about one-and-a-half kilometres wide and 22 kilometers long they are both dwarfed 74 00:02:44,530 --> 00:02:44,540 22 kilometers long they are both dwarfed 75 00:02:44,540 --> 00:02:47,110 22 kilometers long they are both dwarfed by the Grand Pacific glacier a tall 76 00:02:47,110 --> 00:02:47,120 by the Grand Pacific glacier a tall 77 00:02:47,120 --> 00:02:49,510 by the Grand Pacific glacier a tall towers 60 to 90 meters above the water 78 00:02:49,510 --> 00:02:49,520 towers 60 to 90 meters above the water 79 00:02:49,520 --> 00:02:52,750 towers 60 to 90 meters above the water at their term and I with another 120 80 00:02:52,750 --> 00:02:52,760 at their term and I with another 120 81 00:02:52,760 --> 00:02:55,660 at their term and I with another 120 meters below the water surface these 82 00:02:55,660 --> 00:02:55,670 meters below the water surface these 83 00:02:55,670 --> 00:02:57,729 meters below the water surface these glaciers calve icebergs into the ocean 84 00:02:57,729 --> 00:02:57,739 glaciers calve icebergs into the ocean 85 00:02:57,739 --> 00:03:00,550 glaciers calve icebergs into the ocean on a regular basis grilling visitors 86 00:03:00,550 --> 00:03:00,560 on a regular basis grilling visitors 87 00:03:00,560 --> 00:03:06,110 on a regular basis grilling visitors with the splash and thunder 88 00:03:06,110 --> 00:03:06,120 89 00:03:06,120 --> 00:03:08,270 written records of the glaciers in 90 00:03:08,270 --> 00:03:08,280 written records of the glaciers in 91 00:03:08,280 --> 00:03:09,800 written records of the glaciers in Glacier Bay began with George 92 00:03:09,800 --> 00:03:09,810 Glacier Bay began with George 93 00:03:09,810 --> 00:03:14,240 Glacier Bay began with George Vancouver's visit in 1794 ground 94 00:03:14,240 --> 00:03:14,250 Vancouver's visit in 1794 ground 95 00:03:14,250 --> 00:03:16,610 Vancouver's visit in 1794 ground observations beginning in the late 1800s 96 00:03:16,610 --> 00:03:16,620 observations beginning in the late 1800s 97 00:03:16,620 --> 00:03:18,500 observations beginning in the late 1800s and ground-based and satellite 98 00:03:18,500 --> 00:03:18,510 and ground-based and satellite 99 00:03:18,510 --> 00:03:20,600 and ground-based and satellite measurements in recent years have shown 100 00:03:20,600 --> 00:03:20,610 measurements in recent years have shown 101 00:03:20,610 --> 00:03:23,809 measurements in recent years have shown that many glaciers in and near Glacier 102 00:03:23,809 --> 00:03:23,819 that many glaciers in and near Glacier 103 00:03:23,819 --> 00:03:32,500 that many glaciers in and near Glacier Bay have been receding some rapidly 104 00:03:32,500 --> 00:03:32,510 105 00:03:32,510 --> 00:03:35,259 when a glacier recedes water from the 106 00:03:35,259 --> 00:03:35,269 when a glacier recedes water from the 107 00:03:35,269 --> 00:03:37,270 when a glacier recedes water from the melting ice is released into the ocean 108 00:03:37,270 --> 00:03:37,280 melting ice is released into the ocean 109 00:03:37,280 --> 00:03:40,990 melting ice is released into the ocean and sea level rises though the greatest 110 00:03:40,990 --> 00:03:41,000 and sea level rises though the greatest 111 00:03:41,000 --> 00:03:42,880 and sea level rises though the greatest potential for sea level rise is from 112 00:03:42,880 --> 00:03:42,890 potential for sea level rise is from 113 00:03:42,890 --> 00:03:44,289 potential for sea level rise is from melting of the Antarctic and Greenland 114 00:03:44,289 --> 00:03:44,299 melting of the Antarctic and Greenland 115 00:03:44,299 --> 00:03:47,380 melting of the Antarctic and Greenland ice sheets the small glaciers of the 116 00:03:47,380 --> 00:03:47,390 ice sheets the small glaciers of the 117 00:03:47,390 --> 00:03:49,990 ice sheets the small glaciers of the world such as those in Glacier Bay would 118 00:03:49,990 --> 00:03:50,000 world such as those in Glacier Bay would 119 00:03:50,000 --> 00:03:52,569 world such as those in Glacier Bay would contribute to a sea-level rise of about 120 00:03:52,569 --> 00:03:52,579 contribute to a sea-level rise of about 121 00:03:52,579 --> 00:03:54,640 contribute to a sea-level rise of about six-tenths of a meter if they were to 122 00:03:54,640 --> 00:03:54,650 six-tenths of a meter if they were to 123 00:03:54,650 --> 00:04:02,649 six-tenths of a meter if they were to melt completely precise measurements of 124 00:04:02,649 --> 00:04:02,659 melt completely precise measurements of 125 00:04:02,659 --> 00:04:04,330 melt completely precise measurements of glacier changes may be made by 126 00:04:04,330 --> 00:04:04,340 glacier changes may be made by 127 00:04:04,340 --> 00:04:07,449 glacier changes may be made by ground-based surveying the light 128 00:04:07,449 --> 00:04:07,459 ground-based surveying the light 129 00:04:07,459 --> 00:04:10,210 ground-based surveying the light glaciologist William O field began 130 00:04:10,210 --> 00:04:10,220 glaciologist William O field began 131 00:04:10,220 --> 00:04:12,250 glaciologist William O field began photographing and measuring glaciers in 132 00:04:12,250 --> 00:04:12,260 photographing and measuring glaciers in 133 00:04:12,260 --> 00:04:17,050 photographing and measuring glaciers in Glacier Bay in 1926 many of the glacier 134 00:04:17,050 --> 00:04:17,060 Glacier Bay in 1926 many of the glacier 135 00:04:17,060 --> 00:04:19,270 Glacier Bay in 1926 many of the glacier terminus positions map by field and his 136 00:04:19,270 --> 00:04:19,280 terminus positions map by field and his 137 00:04:19,280 --> 00:04:21,219 terminus positions map by field and his colleagues are shown on the map of 138 00:04:21,219 --> 00:04:21,229 colleagues are shown on the map of 139 00:04:21,229 --> 00:04:23,409 colleagues are shown on the map of Glacier Bay prepared by the National 140 00:04:23,409 --> 00:04:23,419 Glacier Bay prepared by the National 141 00:04:23,419 --> 00:04:27,700 Glacier Bay prepared by the National Park Service glacier work in the early 142 00:04:27,700 --> 00:04:27,710 Park Service glacier work in the early 143 00:04:27,710 --> 00:04:29,320 Park Service glacier work in the early part of this century was even more 144 00:04:29,320 --> 00:04:29,330 part of this century was even more 145 00:04:29,330 --> 00:04:32,700 part of this century was even more difficult and hazardous than it is today 146 00:04:32,700 --> 00:04:32,710 difficult and hazardous than it is today 147 00:04:32,710 --> 00:04:35,110 difficult and hazardous than it is today scientists had to roll through iceberg 148 00:04:35,110 --> 00:04:35,120 scientists had to roll through iceberg 149 00:04:35,120 --> 00:04:37,480 scientists had to roll through iceberg laden water to reach many of the glacier 150 00:04:37,480 --> 00:04:37,490 laden water to reach many of the glacier 151 00:04:37,490 --> 00:04:40,570 laden water to reach many of the glacier fronts detailed measurements in Glacier 152 00:04:40,570 --> 00:04:40,580 fronts detailed measurements in Glacier 153 00:04:40,580 --> 00:04:43,270 fronts detailed measurements in Glacier Bay made by field and others have 154 00:04:43,270 --> 00:04:43,280 Bay made by field and others have 155 00:04:43,280 --> 00:04:45,250 Bay made by field and others have provided an excellent description of the 156 00:04:45,250 --> 00:04:45,260 provided an excellent description of the 157 00:04:45,260 --> 00:04:47,770 provided an excellent description of the dates and magnitude of changes in the 158 00:04:47,770 --> 00:04:47,780 dates and magnitude of changes in the 159 00:04:47,780 --> 00:04:53,860 dates and magnitude of changes in the glaciers there 160 00:04:53,860 --> 00:04:53,870 161 00:04:53,870 --> 00:04:57,620 the once enormous Muir glacier located 162 00:04:57,620 --> 00:04:57,630 the once enormous Muir glacier located 163 00:04:57,630 --> 00:04:59,900 the once enormous Muir glacier located in what is now mere Inlet in the East 164 00:04:59,900 --> 00:04:59,910 in what is now mere Inlet in the East 165 00:04:59,910 --> 00:05:02,300 in what is now mere Inlet in the East arm of Glacier Bay was named for John 166 00:05:02,300 --> 00:05:02,310 arm of Glacier Bay was named for John 167 00:05:02,310 --> 00:05:05,390 arm of Glacier Bay was named for John Muir the famous naturalist and explorer 168 00:05:05,390 --> 00:05:05,400 Muir the famous naturalist and explorer 169 00:05:05,400 --> 00:05:07,939 Muir the famous naturalist and explorer who visited Glacier Bay in the late 19th 170 00:05:07,939 --> 00:05:07,949 who visited Glacier Bay in the late 19th 171 00:05:07,949 --> 00:05:12,560 who visited Glacier Bay in the late 19th century in 1905 just 26 years after 172 00:05:12,560 --> 00:05:12,570 century in 1905 just 26 years after 173 00:05:12,570 --> 00:05:15,670 century in 1905 just 26 years after mirrors first visit Fremont Morris wrote 174 00:05:15,670 --> 00:05:15,680 mirrors first visit Fremont Morris wrote 175 00:05:15,680 --> 00:05:17,719 mirrors first visit Fremont Morris wrote formally the mirror presented a 176 00:05:17,719 --> 00:05:17,729 formally the mirror presented a 177 00:05:17,729 --> 00:05:20,330 formally the mirror presented a perpendicular front at least 200 feet in 178 00:05:20,330 --> 00:05:20,340 perpendicular front at least 200 feet in 179 00:05:20,340 --> 00:05:22,640 perpendicular front at least 200 feet in height from which huge Berg's were 180 00:05:22,640 --> 00:05:22,650 height from which huge Berg's were 181 00:05:22,650 --> 00:05:25,280 height from which huge Berg's were detached at frequent intervals the sight 182 00:05:25,280 --> 00:05:25,290 detached at frequent intervals the sight 183 00:05:25,290 --> 00:05:27,350 detached at frequent intervals the sight and sound of one of these vast masses 184 00:05:27,350 --> 00:05:27,360 and sound of one of these vast masses 185 00:05:27,360 --> 00:05:29,540 and sound of one of these vast masses falling from the cliff or suddenly 186 00:05:29,540 --> 00:05:29,550 falling from the cliff or suddenly 187 00:05:29,550 --> 00:05:32,060 falling from the cliff or suddenly appearing from the submarine I slit was 188 00:05:32,060 --> 00:05:32,070 appearing from the submarine I slit was 189 00:05:32,070 --> 00:05:34,550 appearing from the submarine I slit was something which once witness was not to 190 00:05:34,550 --> 00:05:34,560 something which once witness was not to 191 00:05:34,560 --> 00:05:37,670 something which once witness was not to be forgotten it was grand and impressive 192 00:05:37,670 --> 00:05:37,680 be forgotten it was grand and impressive 193 00:05:37,680 --> 00:05:40,430 be forgotten it was grand and impressive beyond description fortunately the 194 00:05:40,430 --> 00:05:40,440 beyond description fortunately the 195 00:05:40,440 --> 00:05:42,620 beyond description fortunately the recent changes in the mirror have not 196 00:05:42,620 --> 00:05:42,630 recent changes in the mirror have not 197 00:05:42,630 --> 00:05:44,570 recent changes in the mirror have not increased its impressiveness from a 198 00:05:44,570 --> 00:05:44,580 increased its impressiveness from a 199 00:05:44,580 --> 00:05:46,820 increased its impressiveness from a scenic standpoint instead of the 200 00:05:46,820 --> 00:05:46,830 scenic standpoint instead of the 201 00:05:46,830 --> 00:05:49,250 scenic standpoint instead of the imposing cliff of ice the front is 202 00:05:49,250 --> 00:05:49,260 imposing cliff of ice the front is 203 00:05:49,260 --> 00:05:51,920 imposing cliff of ice the front is sloping and seems to be far less active 204 00:05:51,920 --> 00:05:51,930 sloping and seems to be far less active 205 00:05:51,930 --> 00:05:56,390 sloping and seems to be far less active than formerly the Muir glacier is now 206 00:05:56,390 --> 00:05:56,400 than formerly the Muir glacier is now 207 00:05:56,400 --> 00:05:58,400 than formerly the Muir glacier is now but a small remnant of its former glory 208 00:05:58,400 --> 00:05:58,410 but a small remnant of its former glory 209 00:05:58,410 --> 00:06:00,680 but a small remnant of its former glory and has nearly retreated up out of the 210 00:06:00,680 --> 00:06:00,690 and has nearly retreated up out of the 211 00:06:00,690 --> 00:06:03,800 and has nearly retreated up out of the ocean in fact many of the large 212 00:06:03,800 --> 00:06:03,810 ocean in fact many of the large 213 00:06:03,810 --> 00:06:05,900 ocean in fact many of the large Tidewater glaciers that John Muir first 214 00:06:05,900 --> 00:06:05,910 Tidewater glaciers that John Muir first 215 00:06:05,910 --> 00:06:08,870 Tidewater glaciers that John Muir first observed in 1879 have been reduced to 216 00:06:08,870 --> 00:06:08,880 observed in 1879 have been reduced to 217 00:06:08,880 --> 00:06:11,920 observed in 1879 have been reduced to small glaciers that terminate on land 218 00:06:11,920 --> 00:06:11,930 small glaciers that terminate on land 219 00:06:11,930 --> 00:06:14,570 small glaciers that terminate on land land that is uncovered as glaciers 220 00:06:14,570 --> 00:06:14,580 land that is uncovered as glaciers 221 00:06:14,580 --> 00:06:17,480 land that is uncovered as glaciers recede from its plant and animal life to 222 00:06:17,480 --> 00:06:17,490 recede from its plant and animal life to 223 00:06:17,490 --> 00:06:25,279 recede from its plant and animal life to appear and flourish beginning with the 224 00:06:25,279 --> 00:06:25,289 appear and flourish beginning with the 225 00:06:25,289 --> 00:06:27,490 appear and flourish beginning with the launch of the first Landsat satellite in 226 00:06:27,490 --> 00:06:27,500 launch of the first Landsat satellite in 227 00:06:27,500 --> 00:06:31,100 launch of the first Landsat satellite in 1972 we have with a spatial resolution 228 00:06:31,100 --> 00:06:31,110 1972 we have with a spatial resolution 229 00:06:31,110 --> 00:06:33,469 1972 we have with a spatial resolution of up to 30 meters been able to acquire 230 00:06:33,469 --> 00:06:33,479 of up to 30 meters been able to acquire 231 00:06:33,479 --> 00:06:35,210 of up to 30 meters been able to acquire detailed satellite images of the 232 00:06:35,210 --> 00:06:35,220 detailed satellite images of the 233 00:06:35,220 --> 00:06:37,520 detailed satellite images of the glaciers of Glacier Bay and measure 234 00:06:37,520 --> 00:06:37,530 glaciers of Glacier Bay and measure 235 00:06:37,530 --> 00:06:41,089 glaciers of Glacier Bay and measure changes in those glaciers to satellite 236 00:06:41,089 --> 00:06:41,099 changes in those glaciers to satellite 237 00:06:41,099 --> 00:06:43,610 changes in those glaciers to satellite sensors the multispectral scanner and 238 00:06:43,610 --> 00:06:43,620 sensors the multispectral scanner and 239 00:06:43,620 --> 00:06:46,100 sensors the multispectral scanner and the more advanced thematic mapper allow 240 00:06:46,100 --> 00:06:46,110 the more advanced thematic mapper allow 241 00:06:46,110 --> 00:06:48,469 the more advanced thematic mapper allow us to measure glaciers without having to 242 00:06:48,469 --> 00:06:48,479 us to measure glaciers without having to 243 00:06:48,479 --> 00:06:55,159 us to measure glaciers without having to visit the area 244 00:06:55,159 --> 00:06:55,169 245 00:06:55,169 --> 00:06:57,589 maps drawn by earlier explorers of 246 00:06:57,589 --> 00:06:57,599 maps drawn by earlier explorers of 247 00:06:57,599 --> 00:06:59,360 maps drawn by earlier explorers of Glacier Bay can be registered to or 248 00:06:59,360 --> 00:06:59,370 Glacier Bay can be registered to or 249 00:06:59,370 --> 00:07:01,879 Glacier Bay can be registered to or overlaying on satellite images using 250 00:07:01,879 --> 00:07:01,889 overlaying on satellite images using 251 00:07:01,889 --> 00:07:05,839 overlaying on satellite images using computer techniques common stable points 252 00:07:05,839 --> 00:07:05,849 computer techniques common stable points 253 00:07:05,849 --> 00:07:07,939 computer techniques common stable points between the map and the images are 254 00:07:07,939 --> 00:07:07,949 between the map and the images are 255 00:07:07,949 --> 00:07:10,070 between the map and the images are located and digitally overlaying using 256 00:07:10,070 --> 00:07:10,080 located and digitally overlaying using 257 00:07:10,080 --> 00:07:13,580 located and digitally overlaying using image processing techniques one image is 258 00:07:13,580 --> 00:07:13,590 image processing techniques one image is 259 00:07:13,590 --> 00:07:15,519 image processing techniques one image is stretched in relationship to the other 260 00:07:15,519 --> 00:07:15,529 stretched in relationship to the other 261 00:07:15,529 --> 00:07:18,619 stretched in relationship to the other once the images are registered we can 262 00:07:18,619 --> 00:07:18,629 once the images are registered we can 263 00:07:18,629 --> 00:07:20,330 once the images are registered we can measure changes in glacier terminus 264 00:07:20,330 --> 00:07:20,340 measure changes in glacier terminus 265 00:07:20,340 --> 00:07:22,550 measure changes in glacier terminus positions from the time of the earliest 266 00:07:22,550 --> 00:07:22,560 positions from the time of the earliest 267 00:07:22,560 --> 00:07:29,260 positions from the time of the earliest maps to the present 268 00:07:29,260 --> 00:07:29,270 269 00:07:29,270 --> 00:07:31,820 using computer techniques we can 270 00:07:31,820 --> 00:07:31,830 using computer techniques we can 271 00:07:31,830 --> 00:07:34,040 using computer techniques we can register elevation data to satellite 272 00:07:34,040 --> 00:07:34,050 register elevation data to satellite 273 00:07:34,050 --> 00:07:37,400 register elevation data to satellite images this allows us to obtain a 274 00:07:37,400 --> 00:07:37,410 images this allows us to obtain a 275 00:07:37,410 --> 00:07:39,170 images this allows us to obtain a three-dimensional perspective and 276 00:07:39,170 --> 00:07:39,180 three-dimensional perspective and 277 00:07:39,180 --> 00:07:42,260 three-dimensional perspective and actually appear to fly by an area 278 00:07:42,260 --> 00:07:42,270 actually appear to fly by an area 279 00:07:42,270 --> 00:07:54,760 actually appear to fly by an area enabling more realistic visualization 280 00:07:54,760 --> 00:07:54,770 281 00:07:54,770 --> 00:07:56,830 measurements of the Muir glacier have 282 00:07:56,830 --> 00:07:56,840 measurements of the Muir glacier have 283 00:07:56,840 --> 00:07:58,900 measurements of the Muir glacier have shown that the terminus retreated up the 284 00:07:58,900 --> 00:07:58,910 shown that the terminus retreated up the 285 00:07:58,910 --> 00:08:00,850 shown that the terminus retreated up the mirror inlet at a rate of about four 286 00:08:00,850 --> 00:08:00,860 mirror inlet at a rate of about four 287 00:08:00,860 --> 00:08:03,210 mirror inlet at a rate of about four tenths of a kilometer per year between 288 00:08:03,210 --> 00:08:03,220 tenths of a kilometer per year between 289 00:08:03,220 --> 00:08:07,330 tenths of a kilometer per year between 1794 and 1892 for a total retreat to 290 00:08:07,330 --> 00:08:07,340 1794 and 1892 for a total retreat to 291 00:08:07,340 --> 00:08:10,809 1794 and 1892 for a total retreat to more than 40 kilometers satellite 292 00:08:10,809 --> 00:08:10,819 more than 40 kilometers satellite 293 00:08:10,819 --> 00:08:12,640 more than 40 kilometers satellite measurements derived from images 294 00:08:12,640 --> 00:08:12,650 measurements derived from images 295 00:08:12,650 --> 00:08:19,659 measurements derived from images acquired in 1973 1980 1983 and 1986 show 296 00:08:19,659 --> 00:08:19,669 acquired in 1973 1980 1983 and 1986 show 297 00:08:19,669 --> 00:08:21,610 acquired in 1973 1980 1983 and 1986 show that the Muir glacier terminus went back 298 00:08:21,610 --> 00:08:21,620 that the Muir glacier terminus went back 299 00:08:21,620 --> 00:08:24,820 that the Muir glacier terminus went back more than seven kilometres between 1973 300 00:08:24,820 --> 00:08:24,830 more than seven kilometres between 1973 301 00:08:24,830 --> 00:08:27,730 more than seven kilometres between 1973 and 1986 with most of that retreat 302 00:08:27,730 --> 00:08:27,740 and 1986 with most of that retreat 303 00:08:27,740 --> 00:08:36,920 and 1986 with most of that retreat occurring between 1973 and 1983 304 00:08:36,920 --> 00:08:36,930 305 00:08:36,930 --> 00:08:39,600 mcBride glaciers the most active glacier 306 00:08:39,600 --> 00:08:39,610 mcBride glaciers the most active glacier 307 00:08:39,610 --> 00:08:42,990 mcBride glaciers the most active glacier and mirror inlet it is still receding 308 00:08:42,990 --> 00:08:43,000 and mirror inlet it is still receding 309 00:08:43,000 --> 00:08:45,210 and mirror inlet it is still receding and over the last two decades has formed 310 00:08:45,210 --> 00:08:45,220 and over the last two decades has formed 311 00:08:45,220 --> 00:08:48,330 and over the last two decades has formed an impressive Inlet as recorded by 312 00:08:48,330 --> 00:08:48,340 an impressive Inlet as recorded by 313 00:08:48,340 --> 00:08:50,550 an impressive Inlet as recorded by satellite datum the terminus of the 314 00:08:50,550 --> 00:08:50,560 satellite datum the terminus of the 315 00:08:50,560 --> 00:08:52,530 satellite datum the terminus of the McBride glacier retreated almost three 316 00:08:52,530 --> 00:08:52,540 McBride glacier retreated almost three 317 00:08:52,540 --> 00:08:57,570 McBride glacier retreated almost three kilometres between 1973 in 1986 and the 318 00:08:57,570 --> 00:08:57,580 kilometres between 1973 in 1986 and the 319 00:08:57,580 --> 00:08:59,430 kilometres between 1973 in 1986 and the nearby Burroughs glacier shrank 320 00:08:59,430 --> 00:08:59,440 nearby Burroughs glacier shrank 321 00:08:59,440 --> 00:09:01,800 nearby Burroughs glacier shrank considerably filling lakes with its 322 00:09:01,800 --> 00:09:01,810 considerably filling lakes with its 323 00:09:01,810 --> 00:09:04,920 considerably filling lakes with its meltwater note the increase in the 324 00:09:04,920 --> 00:09:04,930 meltwater note the increase in the 325 00:09:04,930 --> 00:09:06,750 meltwater note the increase in the amount of vegetation the vicinity of 326 00:09:06,750 --> 00:09:06,760 amount of vegetation the vicinity of 327 00:09:06,760 --> 00:09:11,250 amount of vegetation the vicinity of burrows glacier in 1986 the burrows is 328 00:09:11,250 --> 00:09:11,260 burrows glacier in 1986 the burrows is 329 00:09:11,260 --> 00:09:13,830 burrows glacier in 1986 the burrows is now a dying ice field having been cut 330 00:09:13,830 --> 00:09:13,840 now a dying ice field having been cut 331 00:09:13,840 --> 00:09:21,370 now a dying ice field having been cut off from a source of nourishment 332 00:09:21,370 --> 00:09:21,380 333 00:09:21,380 --> 00:09:23,750 still other glaciers have been in 334 00:09:23,750 --> 00:09:23,760 still other glaciers have been in 335 00:09:23,760 --> 00:09:27,800 still other glaciers have been in equilibrium or advancing some like the 336 00:09:27,800 --> 00:09:27,810 equilibrium or advancing some like the 337 00:09:27,810 --> 00:09:29,960 equilibrium or advancing some like the Johns Hopkins have stopped their retreat 338 00:09:29,960 --> 00:09:29,970 Johns Hopkins have stopped their retreat 339 00:09:29,970 --> 00:09:31,850 Johns Hopkins have stopped their retreat and have advanced during the period 340 00:09:31,850 --> 00:09:31,860 and have advanced during the period 341 00:09:31,860 --> 00:09:35,960 and have advanced during the period covered by the satellite record also the 342 00:09:35,960 --> 00:09:35,970 covered by the satellite record also the 343 00:09:35,970 --> 00:09:39,350 covered by the satellite record also the lamp Lou Reed Marjorie and Grand Pacific 344 00:09:39,350 --> 00:09:39,360 lamp Lou Reed Marjorie and Grand Pacific 345 00:09:39,360 --> 00:09:43,030 lamp Lou Reed Marjorie and Grand Pacific glaciers are all advancing at this time 346 00:09:43,030 --> 00:09:43,040 glaciers are all advancing at this time 347 00:09:43,040 --> 00:09:45,800 glaciers are all advancing at this time the nearby Brady glacier has been 348 00:09:45,800 --> 00:09:45,810 the nearby Brady glacier has been 349 00:09:45,810 --> 00:09:49,880 the nearby Brady glacier has been advancing since 1794 however the major 350 00:09:49,880 --> 00:09:49,890 advancing since 1794 however the major 351 00:09:49,890 --> 00:09:51,830 advancing since 1794 however the major feature of Glacier Bay is the 352 00:09:51,830 --> 00:09:51,840 feature of Glacier Bay is the 353 00:09:51,840 --> 00:09:53,780 feature of Glacier Bay is the large-scale retreat of its Tidewater 354 00:09:53,780 --> 00:09:53,790 large-scale retreat of its Tidewater 355 00:09:53,790 --> 00:09:57,580 large-scale retreat of its Tidewater glaciers and both mirror and tar inlets 356 00:09:57,580 --> 00:09:57,590 glaciers and both mirror and tar inlets 357 00:09:57,590 --> 00:10:00,260 glaciers and both mirror and tar inlets Tidewater glaciers like the mirror and 358 00:10:00,260 --> 00:10:00,270 Tidewater glaciers like the mirror and 359 00:10:00,270 --> 00:10:03,430 Tidewater glaciers like the mirror and the Marjorie terminate in the sea 360 00:10:03,430 --> 00:10:03,440 the Marjorie terminate in the sea 361 00:10:03,440 --> 00:10:05,450 the Marjorie terminate in the sea Tidewater glaciers follow their own 362 00:10:05,450 --> 00:10:05,460 Tidewater glaciers follow their own 363 00:10:05,460 --> 00:10:07,520 Tidewater glaciers follow their own cycles that are independent of 364 00:10:07,520 --> 00:10:07,530 cycles that are independent of 365 00:10:07,530 --> 00:10:15,290 cycles that are independent of short-term climate changes there are 366 00:10:15,290 --> 00:10:15,300 short-term climate changes there are 367 00:10:15,300 --> 00:10:17,720 short-term climate changes there are also non Tidewater glaciers near Glacier 368 00:10:17,720 --> 00:10:17,730 also non Tidewater glaciers near Glacier 369 00:10:17,730 --> 00:10:21,950 also non Tidewater glaciers near Glacier Bay many of which are receding recession 370 00:10:21,950 --> 00:10:21,960 Bay many of which are receding recession 371 00:10:21,960 --> 00:10:23,960 Bay many of which are receding recession of non Tidewater glaciers in the area is 372 00:10:23,960 --> 00:10:23,970 of non Tidewater glaciers in the area is 373 00:10:23,970 --> 00:10:26,390 of non Tidewater glaciers in the area is probably due to amelioration of the 374 00:10:26,390 --> 00:10:26,400 probably due to amelioration of the 375 00:10:26,400 --> 00:10:29,660 probably due to amelioration of the regional climate meteorological data 376 00:10:29,660 --> 00:10:29,670 regional climate meteorological data 377 00:10:29,670 --> 00:10:32,330 regional climate meteorological data from the nearby stations at juneau Sitka 378 00:10:32,330 --> 00:10:32,340 from the nearby stations at juneau Sitka 379 00:10:32,340 --> 00:10:35,240 from the nearby stations at juneau Sitka and Yakutat show a tendency toward an 380 00:10:35,240 --> 00:10:35,250 and Yakutat show a tendency toward an 381 00:10:35,250 --> 00:10:36,680 and Yakutat show a tendency toward an increase in average summer air 382 00:10:36,680 --> 00:10:36,690 increase in average summer air 383 00:10:36,690 --> 00:10:38,870 increase in average summer air temperature since about nineteen forty 384 00:10:38,870 --> 00:10:38,880 temperature since about nineteen forty 385 00:10:38,880 --> 00:10:44,689 temperature since about nineteen forty when the meteorological record began 386 00:10:44,689 --> 00:10:44,699 387 00:10:44,699 --> 00:10:46,859 combining the extensive records of 388 00:10:46,859 --> 00:10:46,869 combining the extensive records of 389 00:10:46,869 --> 00:10:48,479 combining the extensive records of explorers beginning the late 18th 390 00:10:48,479 --> 00:10:48,489 explorers beginning the late 18th 391 00:10:48,489 --> 00:10:50,699 explorers beginning the late 18th century with more recent efforts of 392 00:10:50,699 --> 00:10:50,709 century with more recent efforts of 393 00:10:50,709 --> 00:10:53,099 century with more recent efforts of glaciologists and computer scientists a 394 00:10:53,099 --> 00:10:53,109 glaciologists and computer scientists a 395 00:10:53,109 --> 00:10:55,139 glaciologists and computer scientists a wealth of information has been obtained 396 00:10:55,139 --> 00:10:55,149 wealth of information has been obtained 397 00:10:55,149 --> 00:10:57,329 wealth of information has been obtained about the d glaciation of Glacier Bay 398 00:10:57,329 --> 00:10:57,339 about the d glaciation of Glacier Bay 399 00:10:57,339 --> 00:11:00,839 about the d glaciation of Glacier Bay Alaska as these glaciers and others 400 00:11:00,839 --> 00:11:00,849 Alaska as these glaciers and others 401 00:11:00,849 --> 00:11:02,879 Alaska as these glaciers and others continue to change or if they remain 402 00:11:02,879 --> 00:11:02,889 continue to change or if they remain 403 00:11:02,889 --> 00:11:05,609 continue to change or if they remain stable over time the satellite record 404 00:11:05,609 --> 00:11:05,619 stable over time the satellite record 405 00:11:05,619 --> 00:11:07,289 stable over time the satellite record will permit assessment of the impact of 406 00:11:07,289 --> 00:11:07,299 will permit assessment of the impact of 407 00:11:07,299 --> 00:11:09,359 will permit assessment of the impact of changing climate on the glaciers and 408 00:11:09,359 --> 00:11:09,369 changing climate on the glaciers and 409 00:11:09,369 --> 00:11:11,939 changing climate on the glaciers and many of the non Tidewater glaciers are 410 00:11:11,939 --> 00:11:11,949 many of the non Tidewater glaciers are 411 00:11:11,949 --> 00:11:14,549 many of the non Tidewater glaciers are excellent indicators of regional climate 412 00:11:14,549 --> 00:11:14,559 excellent indicators of regional climate 413 00:11:14,559 --> 00:12:42,440 excellent indicators of regional climate and climate change 414 00:12:42,440 --> 00:12:42,450 415 00:12:42,450 --> 00:13:08,090 you 416 00:13:08,090 --> 00:13:08,100 417 00:13:08,100 --> 00:13:18,070 you 418 00:13:18,070 --> 00:13:18,080 419 00:13:18,080 --> 00:13:20,140 you