WEBVTT 00:01.134 --> 00:03.470 align:left position:20% line:83% size:70% - [Alex] Could this little trailer help save 00:03.470 --> 00:05.271 align:left position:10% line:89% size:80% the drought-stricken West 00:05.271 --> 00:07.874 align:left position:20% line:83% size:70% by bringing more rain and snow to the region? 00:09.442 --> 00:11.611 align:left position:20% line:83% size:70% That's what these engineers think. 00:11.611 --> 00:13.346 align:left position:20% line:83% size:70% They've parked the trailer up here 00:13.346 --> 00:15.448 align:left position:10% line:89% size:80% in the mountains of Colorado, 00:15.448 --> 00:18.218 align:left position:20% line:83% size:70% in hopes of changing the weather. 00:18.218 --> 00:20.420 align:left position:20% line:83% size:70% And there's dozens of them just like this 00:20.420 --> 00:22.455 align:left position:20% line:89% size:70% in use right now. 00:23.590 --> 00:25.692 align:left position:20% line:83% size:70% It might all sound like science fiction, 00:25.692 --> 00:27.827 align:left position:20% line:83% size:70% but it's a weather modification technique 00:27.827 --> 00:29.729 align:left position:20% line:89% size:70% called cloud seeding, 00:29.729 --> 00:31.131 align:left position:20% line:83% size:70% and it was first done successfully 00:31.131 --> 00:33.066 align:left position:20% line:89% size:70% as early as the 1940s. 00:34.334 --> 00:36.970 align:left position:20% line:83% size:70% In Colorado, some ski towns were cloud seeding 00:36.970 --> 00:39.305 align:left position:20% line:89% size:70% as far back as the '70s. 00:39.305 --> 00:42.375 align:left position:20% line:83% size:70% And it's also been used around the globe. 00:42.375 --> 00:45.078 align:left position:10% line:83% size:80% China's cloud seeding program reportedly had a plan 00:45.078 --> 00:47.680 align:left position:20% line:83% size:70% to make clouds rain before they had a chance 00:47.680 --> 00:50.583 align:left position:20% line:83% size:70% to float over the Beijing Olympic stadium. 00:50.583 --> 00:54.587 align:left position:10% line:83% size:80% You can find cloud seeding from California to North Dakota. 00:54.587 --> 00:57.757 align:left position:10% line:89% size:80% But how does cloud seeding work? 00:57.757 --> 00:59.826 align:left position:20% line:83% size:70% To learn more, I've come to Colorado 00:59.826 --> 01:03.396 align:left position:20% line:83% size:70% to see how seeding works up close and personal. 01:03.396 --> 01:04.864 align:left position:10% line:89% size:80% The night before I arrived, 01:04.864 --> 01:07.400 align:left position:10% line:89% size:80% the clouds above me were seeded. 01:07.400 --> 01:09.569 align:left position:20% line:83% size:70% - We are approaching the location 01:09.569 --> 01:11.671 align:left position:10% line:89% size:80% of our cloud seeding generator. 01:11.671 --> 01:14.140 align:left position:10% line:83% size:80% - [Alex] Scott Griebling is a water resources engineer 01:14.140 --> 01:16.509 align:left position:20% line:83% size:70% for the local water conservancy district. 01:16.509 --> 01:18.778 align:left position:20% line:83% size:70% The locations chosen for these sites 01:18.778 --> 01:22.482 align:left position:10% line:83% size:80% had the right elevation and can reach the perfect clouds. 01:22.482 --> 01:25.919 align:left position:10% line:83% size:80% - Our district has come to the conclusion that cloud seeding 01:25.919 --> 01:27.987 align:left position:20% line:83% size:70% and weather modification is a very safe 01:27.987 --> 01:29.322 align:left position:10% line:89% size:80% and very cost effective way 01:29.322 --> 01:31.758 align:left position:20% line:83% size:70% of increasing local water supplies. 01:31.758 --> 01:35.061 align:left position:20% line:83% size:70% - [Alex] So how do you seed a cloud? 01:35.061 --> 01:36.863 align:left position:20% line:83% size:70% - Hey, welcome to our remote generator. 01:36.863 --> 01:38.498 align:left position:20% line:83% size:70% - [Alex] Garrett Cammans is president 01:38.498 --> 01:39.732 align:left position:10% line:89% size:80% of a cloud seeding company 01:39.732 --> 01:43.002 align:left position:20% line:83% size:70% that operates hundreds of cloud seeding sites. 01:43.002 --> 01:44.604 align:left position:20% line:83% size:70% - And it sounds like you're terraforming 01:44.604 --> 01:46.406 align:left position:20% line:83% size:70% or completely changing the climate of an area, 01:46.406 --> 01:48.374 align:left position:10% line:89% size:80% but that's not how it works. 01:48.374 --> 01:50.777 align:left position:10% line:83% size:80% - [Alex] Since clouds are basically water vapor, 01:50.777 --> 01:53.913 align:left position:10% line:83% size:80% the idea is to release particles into the clouds 01:53.913 --> 01:55.381 align:left position:20% line:89% size:70% that will attract water, 01:55.381 --> 01:58.952 align:left position:10% line:83% size:80% making it easier for water droplets or snowflakes to form. 01:58.952 --> 02:00.453 align:left position:20% line:89% size:70% They get heavier, 02:00.453 --> 02:03.957 align:left position:10% line:83% size:80% and eventually fall to earth instead of staying in the sky. 02:03.957 --> 02:06.226 align:left position:20% line:83% size:70% This Colorado team uses a solution 02:06.226 --> 02:08.862 align:left position:20% line:83% size:70% with a chemical called silver iodide, 02:08.862 --> 02:10.096 align:left position:20% line:89% size:70% which, when burned, 02:10.096 --> 02:13.800 align:left position:20% line:83% size:70% splits into billions of particles per gram. 02:13.800 --> 02:15.869 align:left position:10% line:89% size:80% - Ice is the perfect seeder. 02:15.869 --> 02:18.538 align:left position:20% line:83% size:70% Clouds seed themselves with ice crystals. 02:18.538 --> 02:20.640 align:left position:20% line:83% size:70% Silver iodide is really the closest 02:20.640 --> 02:22.709 align:left position:10% line:89% size:80% and similar structure as ice, 02:22.709 --> 02:25.111 align:left position:20% line:83% size:70% so that's why we are using silver iodide. 02:25.111 --> 02:27.614 align:left position:20% line:83% size:70% - [Alex] Here, Cammans activates the flame. 02:27.614 --> 02:31.317 align:left position:10% line:83% size:80% It contains a silver iodide solution mixed with propane. 02:31.317 --> 02:34.220 align:left position:10% line:83% size:80% A series of tanks and regulators manage the pressure 02:34.220 --> 02:37.590 align:left position:10% line:83% size:80% and exact flow rate of the silver iodide solution. 02:37.590 --> 02:39.359 align:left position:20% line:83% size:70% - A typical storm system will only drop 02:39.359 --> 02:41.027 align:left position:10% line:89% size:80% about 10% of its moisture. 02:41.027 --> 02:42.295 align:left position:20% line:83% size:70% We're hoping that the storm system 02:42.295 --> 02:46.266 align:left position:20% line:83% size:70% will drop 10 1/2 to 11 1/2% of its moisture. 02:46.266 --> 02:50.170 align:left position:10% line:83% size:80% - [Alex] Okay, but does cloud seeding actually work? 02:50.170 --> 02:52.272 align:left position:20% line:83% size:70% - We would come out with research aircraft 02:52.272 --> 02:53.940 align:left position:10% line:89% size:80% and with ground-based radars, 02:53.940 --> 02:56.309 align:left position:20% line:83% size:70% and we would basically measure the atmosphere 02:56.309 --> 02:59.512 align:left position:10% line:83% size:80% prior to cloud seeding and during cloud seeding. 02:59.512 --> 03:01.381 align:left position:20% line:83% size:70% - [Alex] The landmark Snowie project set out 03:01.381 --> 03:03.116 align:left position:20% line:89% size:70% to discover just that. 03:03.116 --> 03:05.018 align:left position:30% line:83% size:60% It took a pretty clever approach. 03:05.018 --> 03:07.687 align:left position:20% line:83% size:70% A plane flying back and forth dropped chemicals 03:07.687 --> 03:09.322 align:left position:30% line:89% size:60% into the clouds. 03:09.322 --> 03:11.958 align:left position:10% line:83% size:80% When the team studied the resulting precipitation, 03:11.958 --> 03:15.261 align:left position:20% line:83% size:70% they found it had snowed in a zigzag pattern, 03:15.261 --> 03:18.331 align:left position:20% line:83% size:70% matching the path of the seeding agent's flow. 03:18.331 --> 03:20.233 align:left position:20% line:83% size:70% Could it have all just been a fluke? 03:20.233 --> 03:22.869 align:left position:20% line:83% size:70% - We were in shock or in disbelief. 03:22.869 --> 03:23.803 align:left position:20% line:83% size:70% And then, of course, we were saying, 03:23.803 --> 03:25.538 align:left position:10% line:89% size:80% "Okay, we saw it one day. 03:25.538 --> 03:27.440 align:left position:20% line:89% size:70% Can we repeat it?" 03:27.440 --> 03:28.741 align:left position:20% line:83% size:70% - [Alex] They did the same experiment 03:28.741 --> 03:30.210 align:left position:20% line:89% size:70% several more times. 03:30.210 --> 03:32.045 align:left position:20% line:83% size:70% As the wind blew the seeding agent, 03:32.045 --> 03:35.114 align:left position:20% line:83% size:70% the same zigzag line of precipitation appeared, 03:35.114 --> 03:38.184 align:left position:10% line:83% size:80% which you would never see in a natural snowfall. 03:38.184 --> 03:39.586 align:left position:20% line:89% size:70% - This is revolutionary 03:39.586 --> 03:42.789 align:left position:20% line:83% size:70% because we have a hard time quantifying 03:42.789 --> 03:45.091 align:left position:20% line:83% size:70% what really comes out from cloud seeding. 03:45.091 --> 03:47.627 align:left position:20% line:83% size:70% - [Alex] So, at least in some situations, 03:47.627 --> 03:50.697 align:left position:20% line:83% size:70% cloud seeding can increase precipitation, 03:50.697 --> 03:53.166 align:left position:20% line:83% size:70% but is up against challenging odds. 03:53.166 --> 03:55.401 align:left position:20% line:83% size:70% - Concern about reservoir levels. 03:55.401 --> 03:57.070 align:left position:20% line:89% size:70% Over the last 43 years, 03:57.070 --> 04:00.873 align:left position:10% line:83% size:80% snowpack has only been this low or lower seven times. 04:03.009 --> 04:04.244 align:left position:20% line:89% size:70% - I'm in a creek. 04:04.244 --> 04:06.913 align:left position:10% line:89% size:80% Snow is crucial to the Rockies. 04:06.913 --> 04:10.850 align:left position:10% line:83% size:80% Because as it gradually melts, water runs downstream, 04:10.850 --> 04:14.320 align:left position:20% line:83% size:70% replenishing bodies of water for nearby towns. 04:14.320 --> 04:17.690 align:left position:10% line:83% size:80% That's why Colorado's Water Conservation Board partnered 04:17.690 --> 04:20.360 align:left position:10% line:83% size:80% with a water conservancy district to share the cost 04:20.360 --> 04:24.530 align:left position:10% line:83% size:80% of hiring a cloud seeding company to seed in the area. 04:24.530 --> 04:27.300 align:left position:10% line:89% size:80% But is cloud seeding safe? 04:27.300 --> 04:30.436 align:left position:10% line:83% size:80% Silver iodide has been used since the 19th century 04:30.436 --> 04:31.604 align:left position:20% line:89% size:70% in photo development, 04:31.604 --> 04:34.173 align:left position:20% line:83% size:70% and also as an antiseptic in medicine. 04:34.173 --> 04:37.110 align:left position:10% line:83% size:80% Exposure to a large amount of it could even lead 04:37.110 --> 04:39.212 align:left position:10% line:89% size:80% to skin and eye irritation. 04:39.212 --> 04:42.649 align:left position:10% line:83% size:80% High levels of silver iodide in one area could be toxic 04:42.649 --> 04:45.285 align:left position:20% line:83% size:70% to organisms in our water and soil. 04:45.285 --> 04:46.552 align:left position:10% line:89% size:80% For these reasons and others, 04:46.552 --> 04:48.921 align:left position:20% line:83% size:70% state cloud seeding efforts are reported 04:48.921 --> 04:50.823 align:left position:20% line:89% size:70% to federal agencies. 04:50.823 --> 04:52.058 align:left position:10% line:89% size:80% - And we wanna be conscious. 04:52.058 --> 04:53.259 align:left position:20% line:83% size:70% We don't really wanna put a lot of silver 04:53.259 --> 04:54.861 align:left position:20% line:89% size:70% into the atmosphere. 04:54.861 --> 04:56.329 align:left position:20% line:89% size:70% - [Alex] Over the years, 04:56.329 --> 04:58.531 align:left position:10% line:83% size:80% another big concern about cloud seeding has been 04:58.531 --> 05:01.801 align:left position:20% line:83% size:70% that it could cause too much precipitation, 05:03.269 --> 05:06.739 align:left position:10% line:83% size:80% such as this massive flood in a small town in the UK, 05:06.739 --> 05:10.176 align:left position:10% line:83% size:80% which destroyed homes and killed more than 30 people. 05:10.176 --> 05:11.644 align:left position:20% line:89% size:70% While circumstantial, 05:11.644 --> 05:15.515 align:left position:10% line:83% size:80% some linked it to a nearby cloud seeding program. 05:15.515 --> 05:19.886 align:left position:20% line:77% size:70% - Cloud seeding programs actually have to play by the rules. 05:19.886 --> 05:22.288 align:left position:20% line:83% size:70% As soon as they have a certain snow depth, 05:22.288 --> 05:26.392 align:left position:20% line:83% size:70% they stop seeding in order to prevent floods. 05:26.392 --> 05:28.661 align:left position:20% line:83% size:70% - [Alex] Today, Cammans' company has hundreds 05:28.661 --> 05:29.996 align:left position:20% line:89% size:70% of seeding sites, 05:29.996 --> 05:31.497 align:left position:20% line:89% size:70% and across the globe, 05:31.497 --> 05:33.933 align:left position:10% line:83% size:80% several other nations are testing the technology. 05:35.535 --> 05:38.304 align:left position:20% line:77% size:70% In fact, nearly every meteorologist I spoke with told me 05:38.304 --> 05:41.474 align:left position:20% line:83% size:70% to get ready, as they expect cloud seeding, 05:41.474 --> 05:45.912 align:left position:10% line:83% size:80% once a big question mark, to increase in frequency. 05:45.912 --> 05:48.147 align:left position:20% line:83% size:70% As for the potential to impact drought, 05:48.147 --> 05:49.415 align:left position:20% line:89% size:70% it may be a long time 05:49.415 --> 05:51.517 align:left position:10% line:89% size:80% before scientists know for sure. 05:51.517 --> 05:54.454 align:left position:20% line:83% size:70% Even if widely used, it's still difficult 05:54.454 --> 05:59.425 align:left position:10% line:83% size:80% to quantify exactly how much additional precipitation comes 05:59.425 --> 06:01.427 align:left position:20% line:89% size:70% from seeding a cloud. 06:01.427 --> 06:03.129 align:left position:20% line:83% size:70% We all know about the greenhouse effect, 06:03.129 --> 06:06.199 align:left position:10% line:83% size:80% but how many of us understand why it happens? 06:06.199 --> 06:07.967 align:left position:10% line:89% size:80% Our friends at Reactions uncover 06:07.967 --> 06:10.737 align:left position:20% line:83% size:70% what's so unique about carbon dioxide 06:10.737 --> 06:14.140 align:left position:10% line:83% size:80% that has allowed it to transform our entire planet. 06:14.140 --> 06:15.708 align:left position:20% line:83% size:70% Check out the link in the description, 06:15.708 --> 06:17.543 align:left position:10% line:89% size:80% and let them know Nova sent you.