[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.93,0:00:04.87,Default,,0000,0000,0000,,[It's time to start talking\Nabout engineering our climate]
Dialogue: 0,0:00:04.90,0:00:08.37,Default,,0000,0000,0000,,What if there was a way\Nto build a thermostat
Dialogue: 0,0:00:08.39,0:00:11.13,Default,,0000,0000,0000,,that allowed you to turn down\Nthe temperature of the earth
Dialogue: 0,0:00:11.16,0:00:12.42,Default,,0000,0000,0000,,anytime you wanted?
Dialogue: 0,0:00:13.70,0:00:18.08,Default,,0000,0000,0000,,Now, you would think if somebody\Nhad a plausible idea about how to do that,
Dialogue: 0,0:00:18.11,0:00:20.36,Default,,0000,0000,0000,,everybody would be very excited about it,
Dialogue: 0,0:00:20.39,0:00:22.98,Default,,0000,0000,0000,,and there would be lots\Nof research on how to do it.
Dialogue: 0,0:00:23.45,0:00:27.96,Default,,0000,0000,0000,,But in fact, a lot of people\Ndo understand how to do that.
Dialogue: 0,0:00:28.71,0:00:32.86,Default,,0000,0000,0000,,But there's not much support\Nfor research in this area.
Dialogue: 0,0:00:33.44,0:00:35.63,Default,,0000,0000,0000,,And I think part of it
Dialogue: 0,0:00:35.66,0:00:38.66,Default,,0000,0000,0000,,is because there are some real\Nmisunderstandings about it.
Dialogue: 0,0:00:39.02,0:00:42.90,Default,,0000,0000,0000,,So I'm not going to try to convince you\Ntoday that this is a good idea.
Dialogue: 0,0:00:43.86,0:00:48.55,Default,,0000,0000,0000,,But I am going to try to get\Nyour curiosity going about it
Dialogue: 0,0:00:48.57,0:00:51.74,Default,,0000,0000,0000,,and clear up some\Nof the misunderstandings.
Dialogue: 0,0:00:52.27,0:00:56.39,Default,,0000,0000,0000,,So, the basic idea of solar geoengineering
Dialogue: 0,0:00:56.41,0:00:59.04,Default,,0000,0000,0000,,is that we can cool things down
Dialogue: 0,0:00:59.06,0:01:01.80,Default,,0000,0000,0000,,just by reflecting\Na little bit more sunlight
Dialogue: 0,0:01:01.82,0:01:02.98,Default,,0000,0000,0000,,back into space.
Dialogue: 0,0:01:03.73,0:01:09.03,Default,,0000,0000,0000,,And ideas about how to do this\Nhave been around literally for decades.
Dialogue: 0,0:01:10.02,0:01:14.48,Default,,0000,0000,0000,,Clouds are a great way to do that,\Nthese low-lying clouds.
Dialogue: 0,0:01:14.51,0:01:17.03,Default,,0000,0000,0000,,Everybody knows it's cooler under a cloud.
Dialogue: 0,0:01:17.48,0:01:21.78,Default,,0000,0000,0000,,I like this cloud because it has exactly\Nthe same water content
Dialogue: 0,0:01:21.80,0:01:23.68,Default,,0000,0000,0000,,as the transparent air around it.
Dialogue: 0,0:01:24.09,0:01:28.34,Default,,0000,0000,0000,,And it just shows that even a little bit\Nof a change in the flow of the air
Dialogue: 0,0:01:28.36,0:01:29.78,Default,,0000,0000,0000,,can cause a cloud to form.
Dialogue: 0,0:01:30.48,0:01:33.08,Default,,0000,0000,0000,,We make artificial clouds all the time.
Dialogue: 0,0:01:33.82,0:01:37.18,Default,,0000,0000,0000,,These are contrails,\Nwhich are artificial water clouds
Dialogue: 0,0:01:37.20,0:01:39.70,Default,,0000,0000,0000,,that are made by the passing\Nof a jet engine.
Dialogue: 0,0:01:40.25,0:01:45.59,Default,,0000,0000,0000,,And so, we're already changing\Nthe clouds on earth.
Dialogue: 0,0:01:45.62,0:01:46.93,Default,,0000,0000,0000,,By accident.
Dialogue: 0,0:01:46.96,0:01:51.54,Default,,0000,0000,0000,,Or, if you like to believe it,\Nby supersecret government conspiracy.
Dialogue: 0,0:01:51.56,0:01:53.63,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:01:53.66,0:01:56.78,Default,,0000,0000,0000,,But we are already doing this quite a lot.
Dialogue: 0,0:01:56.81,0:02:00.38,Default,,0000,0000,0000,,This is a NASA picture of shipping lanes.
Dialogue: 0,0:02:00.40,0:02:03.83,Default,,0000,0000,0000,,Passing ships actually cause\Nclouds to form,
Dialogue: 0,0:02:03.86,0:02:05.97,Default,,0000,0000,0000,,and this is a big enough effect
Dialogue: 0,0:02:05.99,0:02:10.99,Default,,0000,0000,0000,,that it actually helps reduce\Nglobal warming already by about a degree.
Dialogue: 0,0:02:11.51,0:02:14.45,Default,,0000,0000,0000,,So we already are doing solar engineering.
Dialogue: 0,0:02:15.35,0:02:17.39,Default,,0000,0000,0000,,There's lots of ideas\Nabout how to do this.
Dialogue: 0,0:02:17.42,0:02:19.40,Default,,0000,0000,0000,,People have looked at everything,
Dialogue: 0,0:02:19.42,0:02:22.85,Default,,0000,0000,0000,,from building giant parasols\Nout into space
Dialogue: 0,0:02:22.87,0:02:25.79,Default,,0000,0000,0000,,to fizzing bubble waters in the ocean.
Dialogue: 0,0:02:26.31,0:02:29.52,Default,,0000,0000,0000,,And some of these are actually\Nvery plausible ideas.
Dialogue: 0,0:02:30.66,0:02:35.01,Default,,0000,0000,0000,,One that was published recently\Nby David Keith at Harvard
Dialogue: 0,0:02:35.04,0:02:38.73,Default,,0000,0000,0000,,is to take chalk and put dust\Nup into the stratosphere,
Dialogue: 0,0:02:38.75,0:02:41.01,Default,,0000,0000,0000,,where it reflects off sunlight.
Dialogue: 0,0:02:41.04,0:02:42.49,Default,,0000,0000,0000,,And that's a really neat idea,
Dialogue: 0,0:02:42.51,0:02:45.93,Default,,0000,0000,0000,,because chalk is one of the most\Ncommon minerals on earth,
Dialogue: 0,0:02:45.96,0:02:49.66,Default,,0000,0000,0000,,and it's very safe -- it's so safe,\Nwe put it into baby food.
Dialogue: 0,0:02:50.66,0:02:54.86,Default,,0000,0000,0000,,And basically, if you throw chalk\Nup into the stratosphere,
Dialogue: 0,0:02:54.89,0:02:59.70,Default,,0000,0000,0000,,it comes down in a couple of years\Nall by itself, dissolved in rainwater.
Dialogue: 0,0:03:00.59,0:03:04.71,Default,,0000,0000,0000,,Now, before you start worrying\Nabout all this chalk in your rainwater,
Dialogue: 0,0:03:04.74,0:03:08.95,Default,,0000,0000,0000,,let me explain to you\Nhow little of it it actually takes.
Dialogue: 0,0:03:09.45,0:03:12.22,Default,,0000,0000,0000,,And that turns out to be\Nvery easy to calculate.
Dialogue: 0,0:03:13.12,0:03:15.86,Default,,0000,0000,0000,,This is a back-of-the-envelope\Ncalculation I made.
Dialogue: 0,0:03:15.88,0:03:17.24,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:03:17.27,0:03:19.46,Default,,0000,0000,0000,,(Applause)
Dialogue: 0,0:03:19.48,0:03:23.95,Default,,0000,0000,0000,,I assure you, people have done\Nmuch more careful calculations,
Dialogue: 0,0:03:23.98,0:03:25.83,Default,,0000,0000,0000,,and it comes out with the same answer,
Dialogue: 0,0:03:25.85,0:03:31.61,Default,,0000,0000,0000,,which is that you have to put chalk up\Nat the rate of about 10 teragrams a year
Dialogue: 0,0:03:31.64,0:03:35.44,Default,,0000,0000,0000,,to undo the effects of the CO2\Nthat we've already done --
Dialogue: 0,0:03:35.47,0:03:38.91,Default,,0000,0000,0000,,just in terms of temperature,\Nnot all the effects, but the temperature.
Dialogue: 0,0:03:39.34,0:03:41.54,Default,,0000,0000,0000,,So what does that look like?
Dialogue: 0,0:03:41.56,0:03:44.54,Default,,0000,0000,0000,,I can't visualize 10 teragrams per year.
Dialogue: 0,0:03:45.59,0:03:51.80,Default,,0000,0000,0000,,So I asked the Cambridge\NFire Department and Taylor Milsal
Dialogue: 0,0:03:51.82,0:03:53.32,Default,,0000,0000,0000,,to lend me a hand.
Dialogue: 0,0:03:54.96,0:03:59.53,Default,,0000,0000,0000,,This is a hose pumping water\Nat 10 teragrams a year.
Dialogue: 0,0:04:00.51,0:04:03.26,Default,,0000,0000,0000,,And that is how much
Dialogue: 0,0:04:03.28,0:04:06.86,Default,,0000,0000,0000,,you would have to pump\Ninto the stratosphere
Dialogue: 0,0:04:06.89,0:04:10.73,Default,,0000,0000,0000,,to cool the earth back down\Nto pre-industrial levels.
Dialogue: 0,0:04:11.82,0:04:16.71,Default,,0000,0000,0000,,And it's amazingly little;\Nit's like one hose for the entire earth.
Dialogue: 0,0:04:17.24,0:04:19.49,Default,,0000,0000,0000,,Now of course, you wouldn't\Nreally use a hose,
Dialogue: 0,0:04:19.51,0:04:22.02,Default,,0000,0000,0000,,you'd fly it up in airplanes\Nor something like that.
Dialogue: 0,0:04:22.44,0:04:27.54,Default,,0000,0000,0000,,But it's so little, it would be like\Nputting a handful of chalk
Dialogue: 0,0:04:27.56,0:04:30.40,Default,,0000,0000,0000,,into every Olympic\Nswimming pool full of rain.
Dialogue: 0,0:04:30.89,0:04:32.22,Default,,0000,0000,0000,,It's almost nothing.
Dialogue: 0,0:04:33.19,0:04:37.54,Default,,0000,0000,0000,,So why don't people like this idea?
Dialogue: 0,0:04:37.57,0:04:39.29,Default,,0000,0000,0000,,Why isn't it taken more seriously?
Dialogue: 0,0:04:39.32,0:04:42.11,Default,,0000,0000,0000,,And there are some\Nvery good reasons for that.
Dialogue: 0,0:04:43.32,0:04:48.37,Default,,0000,0000,0000,,A lot of people really don't think\Nwe should be talking about this at all.
Dialogue: 0,0:04:48.40,0:04:52.84,Default,,0000,0000,0000,,And, in fact, I have some\Nvery good friends in the audience
Dialogue: 0,0:04:52.86,0:04:54.26,Default,,0000,0000,0000,,who I respect a lot,
Dialogue: 0,0:04:55.13,0:04:58.46,Default,,0000,0000,0000,,who really don't think\NI should be talking about this.
Dialogue: 0,0:04:59.06,0:05:01.90,Default,,0000,0000,0000,,And the reason is that they're concerned
Dialogue: 0,0:05:01.92,0:05:05.37,Default,,0000,0000,0000,,that if people imagine\Nthere's some easy way out,
Dialogue: 0,0:05:05.40,0:05:08.98,Default,,0000,0000,0000,,that we won't give up\Nour addiction to fossil fuels.
Dialogue: 0,0:05:09.55,0:05:11.29,Default,,0000,0000,0000,,And I do worry about that.
Dialogue: 0,0:05:11.87,0:05:14.10,Default,,0000,0000,0000,,I think it's actually a serious problem.
Dialogue: 0,0:05:14.93,0:05:19.91,Default,,0000,0000,0000,,But there's also, I think,\Na deeper problem,
Dialogue: 0,0:05:20.66,0:05:26.03,Default,,0000,0000,0000,,which is: nobody likes the idea\Nof messing with the entire earth --
Dialogue: 0,0:05:26.06,0:05:27.26,Default,,0000,0000,0000,,I certainly don't.
Dialogue: 0,0:05:27.78,0:05:30.15,Default,,0000,0000,0000,,I love this planet, I really do.
Dialogue: 0,0:05:30.18,0:05:32.21,Default,,0000,0000,0000,,And I don't want to mess with it.
Dialogue: 0,0:05:32.63,0:05:36.47,Default,,0000,0000,0000,,But we're already changing our atmosphere,
Dialogue: 0,0:05:36.49,0:05:38.05,Default,,0000,0000,0000,,we're already messing with it.
Dialogue: 0,0:05:39.00,0:05:45.26,Default,,0000,0000,0000,,And so I think it makes sense\Nfor us to look for ways
Dialogue: 0,0:05:45.28,0:05:47.13,Default,,0000,0000,0000,,to mitigate that impact.
Dialogue: 0,0:05:47.52,0:05:49.43,Default,,0000,0000,0000,,And we need to do research to do that.
Dialogue: 0,0:05:49.46,0:05:51.98,Default,,0000,0000,0000,,We need to understand\Nthe science behind that.
Dialogue: 0,0:05:52.88,0:05:58.19,Default,,0000,0000,0000,,I've noticed that there's a theme\Nthat's kind of developed at TED,
Dialogue: 0,0:05:58.21,0:06:02.55,Default,,0000,0000,0000,,which is kind of, "fear versus hope,"
Dialogue: 0,0:06:02.58,0:06:05.97,Default,,0000,0000,0000,,or "creativity versus caution."
Dialogue: 0,0:06:07.03,0:06:09.04,Default,,0000,0000,0000,,And of course, we need both of those.
Dialogue: 0,0:06:09.75,0:06:12.23,Default,,0000,0000,0000,,So there aren't any silver bullets.
Dialogue: 0,0:06:12.26,0:06:14.53,Default,,0000,0000,0000,,This is certainly not a silver bullet.
Dialogue: 0,0:06:16.33,0:06:20.14,Default,,0000,0000,0000,,But we need science to tell us\Nwhat our options are;
Dialogue: 0,0:06:20.16,0:06:24.47,Default,,0000,0000,0000,,that informs both\Nour creativity and our caution.
Dialogue: 0,0:06:25.29,0:06:29.81,Default,,0000,0000,0000,,So I am an optimist\Nabout our future selves,
Dialogue: 0,0:06:30.43,0:06:34.43,Default,,0000,0000,0000,,but I'm not an optimist\Nbecause I think our problems are small.
Dialogue: 0,0:06:35.20,0:06:41.20,Default,,0000,0000,0000,,I'm an optimist because I think\Nour capacity to deal with our problems
Dialogue: 0,0:06:41.22,0:06:43.35,Default,,0000,0000,0000,,is much greater than we imagine.
Dialogue: 0,0:06:43.86,0:06:45.16,Default,,0000,0000,0000,,Thank you very much.
Dialogue: 0,0:06:45.18,0:06:46.20,Default,,0000,0000,0000,,(Applause)
Dialogue: 0,0:06:46.22,0:06:48.37,Default,,0000,0000,0000,,This talk sparked\Na lot of controversy at TED2017,
Dialogue: 0,0:06:48.40,0:06:50.45,Default,,0000,0000,0000,,and we encourage you\Nto look at discussions online
Dialogue: 0,0:06:50.48,0:06:51.78,Default,,0000,0000,0000,,to see other points of view.
Dialogue: 0,0:00:00.26,0:00:01.90,Default,,0000,0000,0000,,[A provocation from Danny Hillis:]